help pfilt and low values dgp

Somehow cant use the command pfilt or change the pcomb, does this has to do
with the program Radiance? I have installed the version of windows from the
site, with evalglare v1.11windows . The problem is that I have composed a
.hdr (out of 7 jpg on a mac) and after using the command c:/HDRI>evalglare
-vth -vh 140 -vv 80 image.hdr all the dgp results are really low, less than
5%. The problem can be in the .hdr (calibrated as well) or is in the way
evalglare is not working as it shoot on my computer.

*.hdr file* (post-it is calibration point 167,98)


*images* original

*command printscreen*

Need the help!

Greetings Jacobus

*Jasper Overduin*
MSc Building Technology graduate student at Delft University of Technology

*S* Groenhoevelaan 3
*P* 2343 BP Oegstgeest
*T* +31 6 15 64 48 56 (NL)
*T* +56 9 51 11 76 48 (CL)
*E *[email protected]
*Skype *jasper.overduin

Hi Jasper,

why are you using -vth -vh 140 -vv 80 when in your header of the HDR image the view is specified as -vtv -vh 98.797409 -vv 75.402067 ?
Manipulating the lense type is really dangerous - in that case you change from a perspective view to a hemispherical fish eye view, without changing the image!!

If I apply evalglare for your image I get 0.17 as DGP (which is still very low, but you have only 2000cd/m2 as maximum value, so this can be expected). Be aware, that DGP accounts only for glare from a high amount of daylight and/or spots of extreme luminances (>50000cd/m2), but not for contrasted glare between task (e.g. Monitor) and immediate surroundings for lower adaptation levels. This is subject of current research (also here at EPFL) and there might be an extension of the DGP in future, depending on the outcome of new experiments.

Back to the lens-type:
It is extremely important, that the right view type is given to evalglare, otherwise ALL calculated values (it doesn't matter if this is evalglare or findglare) are wrong. These errors could be huge, more than 100% for calculating the illuminance out of a 180 degree image.

If you manipulate an image by pcomb, in general the view is marked as "invalid" in the header, because with that tool you could manipulate the image in a way, that the original view is not valid any more. This is why from evalglare version 1.0 on a check on the header was included, because many people were creating wrong headers without knowing it and then evalglare was calculating wrong values, when the header was invalid.

In addition for calculating the DGP it is important to have the illuminance at camera level. evalglare calculates this value out of the image. But if the image does not cover 180 degree, then the calculated value for the illuminance is too low. For that reason, the -i option was included, so you can provide the illuminance to evalglare (when you measure it with an illuminance sensor).

So in your case, you should measure the illuminance just besides the lens.
Then (in case this is the right lens description) you should use
evalglare -i LUXVALUE -vtv -vh 98.797409 -vv 75.402067 IMAGE_NAME
or better, if your task is always at the same place:
evalglare -i LUXVALUE -vtv -vh 98.797409 -vv 75.402067 -T 395 230 .6 -c CHECK_FILE_PICTURE IMAGE_NAME

good luck!

Jan

···

Am 4/30/15 um 6:04 PM schrieb Jasper Overduin:

Somehow cant use the command pfilt or change the pcomb, does this has to do with the program Radiance? I have installed the version of windows from the site, with evalglare v1.11windows . The problem is that I have composed a .hdr (out of 7 jpg on a mac) and after using the command c:/HDRI>evalglare -vth -vh 140 -vv 80 image.hdr all the dgp results are really low, less than 5%. The problem can be in the .hdr (calibrated as well) or is in the way evalglare is not working as it shoot on my computer.

*.hdr file* (post-it is calibration point 167,98) https://www.dropbox.com/s/4z69y358yt8ii4z/1_sv_am.hdr?dl=0
*images* original https://www.dropbox.com/sh/adyyxjkv6eykyek/AAC96QUTpLh_Ef2U8Mppki8ta?dl=0
*command printscreen* https://www.dropbox.com/s/0pbn105p0z0iinu/Imp%20pan.jpg?dl=0

Need the help!

Greetings Jacobus

*
*Jasper Overduin*
MSc Building Technology graduate student at Delft University of Technology*
*

*S* Groenhoevelaan 3
*P*2343 BP Oegstgeest
*T* +31 6 15 64 48 56 (NL)
*T* +56 9 51 11 76 48 (CL)
*E *[email protected] <mailto:[email protected]>
*Skype *jasper.overduin

_______________________________________________
Radiance-general mailing list
[email protected]
http://www.radiance-online.org/mailman/listinfo/radiance-general

--
Dr.-Ing. Jan Wienold
Ecole Polytechnique F�d�rale de Lausanne (EPFL)
EPFL ENAC IA LIPID

http://people.epfl.ch/jan.wienold
LE 1 111 (Office)
Phone +41 21 69 30849

Thank you for the fast reply. We are still having some problems with the
outcome of Evalglare. With an external luxometre we have done some tests
now. The DGP is still very low or zero. It seems that in almost all the
case the DGP is low. In literature we read that values above 20% are
normal. What do you think? is the data much better if we use a full 180
degree lens?

.hdr file https://www.dropbox.com/s/l10x7tri49btr8r/ff.hdr?dl=0

print screen cmd

test.pic https://www.dropbox.com/s/nspdu01477mchsz/test.pic?dl=0

···

Greetings Jasper

*Jasper Overduin*
MSc Building Technology graduate student at Delft University of Technology

*S* Groenhoevelaan 3
*P* 2343 BP Oegstgeest
*T* +31 6 15 64 48 56 (NL)
*T* +56 9 51 11 76 48 (CL)
*E *[email protected]
*Skype *jasper.overduin

On 30 April 2015 at 13:55, Jan Wienold <[email protected]> wrote:

Hi Jasper,

why are you using -vth -vh 140 -vv 80 when in your header of the HDR
image the view is specified as -vtv -vh 98.797409 -vv 75.402067 ?
Manipulating the lense type is really dangerous - in that case you change
from a perspective view to a hemispherical fish eye view, without changing
the image!!

If I apply evalglare for your image I get 0.17 as DGP (which is still
very low, but you have only 2000cd/m2 as maximum value, so this can be
expected). Be aware, that DGP accounts only for glare from a high amount of
daylight and/or spots of extreme luminances (>50000cd/m2), but not for
contrasted glare between task (e.g. Monitor) and immediate surroundings for
lower adaptation levels. This is subject of current research (also here at
EPFL) and there might be an extension of the DGP in future, depending on
the outcome of new experiments.

Back to the lens-type:
It is extremely important, that the right view type is given to
evalglare, otherwise ALL calculated values (it doesn't matter if this is
evalglare or findglare) are wrong. These errors could be huge, more than
100% for calculating the illuminance out of a 180 degree image.

If you manipulate an image by pcomb, in general the view is marked as
"invalid" in the header, because with that tool you could manipulate the
image in a way, that the original view is not valid any more. This is why
from evalglare version 1.0 on a check on the header was included, because
many people were creating wrong headers without knowing it and then
evalglare was calculating wrong values, when the header was invalid.

In addition for calculating the DGP it is important to have the
illuminance at camera level. evalglare calculates this value out of the
image. But if the image does not cover 180 degree, then the calculated
value for the illuminance is too low. For that reason, the -i option was
included, so you can provide the illuminance to evalglare (when you measure
it with an illuminance sensor).

So in your case, you should measure the illuminance just besides the
lens.
Then (in case this is the right lens description) you should use
evalglare -i LUXVALUE -vtv -vh 98.797409 -vv 75.402067 IMAGE_NAME
or better, if your task is always at the same place:
evalglare -i LUXVALUE -vtv -vh 98.797409 -vv 75.402067 -T 395 230 .6 -c
CHECK_FILE_PICTURE IMAGE_NAME

good luck!

Jan

Am 4/30/15 um 6:04 PM schrieb Jasper Overduin:

Somehow cant use the command pfilt or change the pcomb, does this has
to do with the program Radiance? I have installed the version of windows
from the site, with evalglare v1.11windows . The problem is that I have
composed a .hdr (out of 7 jpg on a mac) and after using the command
c:/HDRI>evalglare -vth -vh 140 -vv 80 image.hdr all the dgp results are
really low, less than 5%. The problem can be in the .hdr (calibrated as
well) or is in the way evalglare is not working as it shoot on my computer.

*.hdr file* (post-it is calibration point 167,98)
https://www.dropbox.com/s/4z69y358yt8ii4z/1_sv_am.hdr?dl=0
*images* original
https://www.dropbox.com/sh/adyyxjkv6eykyek/AAC96QUTpLh_Ef2U8Mppki8ta?dl=0
*command printscreen*
https://www.dropbox.com/s/0pbn105p0z0iinu/Imp%20pan.jpg?dl=0

Need the help!

Greetings Jacobus

*Jasper Overduin*
MSc Building Technology graduate student at Delft University of Technology

*S* Groenhoevelaan 3
*P* 2343 BP Oegstgeest
*T* +31 6 15 64 48 56 (NL)
*T* +56 9 51 11 76 48 (CL)
*E *[email protected]
*Skype *jasper.overduin

_______________________________________________
Radiance-general mailing [email protected]://www.radiance-online.org/mailman/listinfo/radiance-general

--
Dr.-Ing. Jan Wienold
Ecole Polytechnique Fédérale de Lausanne (EPFL)
EPFL ENAC IA LIPID
http://people.epfl.ch/jan.wienold
LE 1 111 (Office)
Phone +41 21 69 30849

_______________________________________________
Radiance-general mailing list
[email protected]
http://www.radiance-online.org/mailman/listinfo/radiance-general

Hi Jasper,

I briefly looked at your image - for sure you get a low DGP value if your illuminance at camera (or eye) level is only about 300lux... It is not the matter of the fish eye lens it is a matter of your lighting condition.
When I remember correctly, for the experiments I did for my PhD, the people adjusted the blinds in a way, that they had 2500-3000 lux at the eye level and they were less than 20% of them dissatisfied. So a value of 300 means one order of magnitude less light at the eye level and a much lower adaptation level.
So I definitely understand the low DGP value in that case. The images themselves look reasonable, so I don't think there is a problem in calibration/processing so far (at least not for these low luminance levels-it might be more tricky to calibrate for the high luminance values when you get stray-light from the multiple lenses).

If all your images are like that it means you have a very low daylight contribution at the place you measure. I'm not sure if DGP is then the right way to measure glare in that case - as I wrote it is made more for the daylight oriented workplace with higher levels and also to take into account very high luminances (e.g. sun or specular reflections of the sun). DGP might be modified in future, but these experiments are just starting.

Jan

···

Am 4/30/15 um 10:41 PM schrieb Jasper Overduin:

    Thank you for the fast reply. We are still having some problems
    with the outcome of Evalglare. With an external luxometre we have
    done some tests now. The DGP is still very low or zero. It seems
    that in almost all the case the DGP is low. In literature we read
    that values above 20% are normal. What do you think? is the data
    much better if we use a full 180 degree lens?

.hdr file https://www.dropbox.com/s/l10x7tri49btr8r/ff.hdr?dl=0
print screen cmd https://www.dropbox.com/s/yv1lamhiirjhvxq/imp%20pan.jpg?dl=0
test.pic https://www.dropbox.com/s/nspdu01477mchsz/test.pic?dl=0

    Greetings Jasper

    *
    *Jasper Overduin*
    MSc Building Technology graduate student at Delft University of
    Technology*
    *

    *S* Groenhoevelaan 3
    *P*2343 BP Oegstgeest
    *T* +31 6 15 64 48 56 (NL)
    *T* +56 9 51 11 76 48 (CL)
    *E *[email protected] <mailto:[email protected]>
    *Skype *jasper.overduin

    On 30 April 2015 at 13:55, Jan Wienold <[email protected] > <mailto:[email protected]>> wrote:

        Hi Jasper,

        why are you using -vth -vh 140 -vv 80 when in your header of
        the HDR image the view is specified as -vtv -vh 98.797409 -vv
        75.402067 ?
        Manipulating the lense type is really dangerous - in that case
        you change from a perspective view to a hemispherical fish eye
        view, without changing the image!!

        If I apply evalglare for your image I get 0.17 as DGP (which
        is still very low, but you have only 2000cd/m2 as maximum
        value, so this can be expected). Be aware, that DGP accounts
        only for glare from a high amount of daylight and/or spots of
        extreme luminances (>50000cd/m2), but not for contrasted glare
        between task (e.g. Monitor) and immediate surroundings for
        lower adaptation levels. This is subject of current research
        (also here at EPFL) and there might be an extension of the DGP
        in future, depending on the outcome of new experiments.

        Back to the lens-type:
        It is extremely important, that the right view type is given
        to evalglare, otherwise ALL calculated values (it doesn't
        matter if this is evalglare or findglare) are wrong. These
        errors could be huge, more than 100% for calculating the
        illuminance out of a 180 degree image.

        If you manipulate an image by pcomb, in general the view is
        marked as "invalid" in the header, because with that tool you
        could manipulate the image in a way, that the original view is
        not valid any more. This is why from evalglare version 1.0 on
        a check on the header was included, because many people were
        creating wrong headers without knowing it and then evalglare
        was calculating wrong values, when the header was invalid.

        In addition for calculating the DGP it is important to have
        the illuminance at camera level. evalglare calculates this
        value out of the image. But if the image does not cover 180
        degree, then the calculated value for the illuminance is too
        low. For that reason, the -i option was included, so you can
        provide the illuminance to evalglare (when you measure it with
        an illuminance sensor).

        So in your case, you should measure the illuminance just
        besides the lens.
        Then (in case this is the right lens description) you should use
        evalglare -i LUXVALUE -vtv -vh 98.797409 -vv 75.402067 IMAGE_NAME
        or better, if your task is always at the same place:
        evalglare -i LUXVALUE -vtv -vh 98.797409 -vv 75.402067 -T 395
        230 .6 -c CHECK_FILE_PICTURE IMAGE_NAME

        good luck!

        Jan

        Am 4/30/15 um 6:04 PM schrieb Jasper Overduin:

        Somehow cant use the command pfilt or change the pcomb, does
        this has to do with the program Radiance? I have installed
        the version of windows from the site, with evalglare
        v1.11windows . The problem is that I have composed a .hdr
        (out of 7 jpg on a mac) and after using the command
        c:/HDRI>evalglare -vth -vh 140 -vv 80 image.hdr all the dgp
        results are really low, less than 5%. The problem can be in
        the .hdr (calibrated as well) or is in the way evalglare is
        not working as it shoot on my computer.

        *.hdr file* (post-it is calibration point 167,98)
        https://www.dropbox.com/s/4z69y358yt8ii4z/1_sv_am.hdr?dl=0
        *images* original
        https://www.dropbox.com/sh/adyyxjkv6eykyek/AAC96QUTpLh_Ef2U8Mppki8ta?dl=0
        *command printscreen*
        https://www.dropbox.com/s/0pbn105p0z0iinu/Imp%20pan.jpg?dl=0

        Need the help!

        Greetings Jacobus

        *
        *Jasper Overduin*
        MSc Building Technology graduate student at Delft University
        of Technology*
        *

        *S* Groenhoevelaan 3
        *P*2343 BP Oegstgeest
        *T* +31 6 15 64 48 56 (NL)
        *T* +56 9 51 11 76 48 (CL)
        *E *[email protected] <mailto:[email protected]>
        *Skype *jasper.overduin

        _______________________________________________
        Radiance-general mailing list
        [email protected] <mailto:[email protected]>
        http://www.radiance-online.org/mailman/listinfo/radiance-general

        -- Dr.-Ing. Jan Wienold
        Ecole Polytechnique F�d�rale de Lausanne (EPFL)
        EPFL ENAC IA LIPID

        http://people.epfl.ch/jan.wienold
        LE 1 111 (Office)
        Phone +41 21 69 30849

        _______________________________________________
        Radiance-general mailing list
        [email protected]
        <mailto:[email protected]>
        http://www.radiance-online.org/mailman/listinfo/radiance-general

_______________________________________________
Radiance-general mailing list
[email protected]
http://www.radiance-online.org/mailman/listinfo/radiance-general

--
Dr.-Ing. Jan Wienold
Ecole Polytechnique F�d�rale de Lausanne (EPFL)
EPFL ENAC IA LIPID

http://people.epfl.ch/jan.wienold
LE 1 111 (Office)
Phone +41 21 69 30849

Dear all,

I have changed my lens to one with 180 circular view to do a contrast
analysis (hdrscope) and meanwhile the glare analysis in evalglare. If i use
the commands in evalglare getinfo i get the (HDR composed with photosphere
on a mac, calibrated with luminance pistol) i get a value for the lens -vv
and -vh which is not over 100, with a lens of 180. I can imagine that the
photo ratio and the lens are not the same and that causes this problem. But
when I enter the external measured Ev, the value the dgp goes somehow to
zero. The fact that the gdp is zero with a maximum luminance of 5600 cd/m2
and Ev of 2500 lux makes me a bit suspicious. How accurate is the result of
the dgp without external vertical lux? is it possible to use this value?

hdr files and printscreens of evalglare
https://www.dropbox.com/sh/ei1y4d2v6hapdsr/AACgVMPd1o0EdK-0q8CFvUGga?dl=0

Greetings Jasper

*Jasper Overduin*
MSc. Building Technology graduate student at Delft University of Technology

*S* Groenhoevelaan 3
*P* 2343 BP Oegstgeest
*T* +31 6 15 64 48 56 (NL)
*T* +56 9 51 11 76 48 (CL)
*E *[email protected]
*Skype *jasper.overduin

···

On 1 May 2015 at 12:15, Jan Wienold <[email protected]> wrote:

Hi Jasper,

I briefly looked at your image - for sure you get a low DGP value if your
illuminance at camera (or eye) level is only about 300lux... It is not the
matter of the fish eye lens it is a matter of your lighting condition.
When I remember correctly, for the experiments I did for my PhD, the
people adjusted the blinds in a way, that they had 2500-3000 lux at the eye
level and they were less than 20% of them dissatisfied. So a value of 300
means one order of magnitude less light at the eye level and a much lower
adaptation level.
So I definitely understand the low DGP value in that case. The images
themselves look reasonable, so I don't think there is a problem in
calibration/processing so far (at least not for these low luminance
levels-it might be more tricky to calibrate for the high luminance values
when you get stray-light from the multiple lenses).

If all your images are like that it means you have a very low daylight
contribution at the place you measure. I'm not sure if DGP is then the
right way to measure glare in that case - as I wrote it is made more for
the daylight oriented workplace with higher levels and also to take into
account very high luminances (e.g. sun or specular reflections of the sun).
DGP might be modified in future, but these experiments are just starting.

Jan

Am 4/30/15 um 10:41 PM schrieb Jasper Overduin:

Thank you for the fast reply. We are still having some problems with the

outcome of Evalglare. With an external luxometre we have done some tests
now. The DGP is still very low or zero. It seems that in almost all the
case the DGP is low. In literature we read that values above 20% are
normal. What do you think? is the data much better if we use a full 180
degree lens?

.hdr file https://www.dropbox.com/s/l10x7tri49btr8r/ff.hdr?dl=0

print screen cmd
https://www.dropbox.com/s/yv1lamhiirjhvxq/imp%20pan.jpg?dl=0
test.pic https://www.dropbox.com/s/nspdu01477mchsz/test.pic?dl=0

Greetings Jasper

*Jasper Overduin*
MSc Building Technology graduate student at Delft University of Technology

*S* Groenhoevelaan 3
*P* 2343 BP Oegstgeest
*T* +31 6 15 64 48 56 (NL)
*T* +56 9 51 11 76 48 (CL)
*E *[email protected]
*Skype *jasper.overduin

On 30 April 2015 at 13:55, Jan Wienold <[email protected]> wrote:

Hi Jasper,

why are you using -vth -vh 140 -vv 80 when in your header of the HDR
image the view is specified as -vtv -vh 98.797409 -vv 75.402067 ?
Manipulating the lense type is really dangerous - in that case you
change from a perspective view to a hemispherical fish eye view, without
changing the image!!

If I apply evalglare for your image I get 0.17 as DGP (which is still
very low, but you have only 2000cd/m2 as maximum value, so this can be
expected). Be aware, that DGP accounts only for glare from a high amount of
daylight and/or spots of extreme luminances (>50000cd/m2), but not for
contrasted glare between task (e.g. Monitor) and immediate surroundings for
lower adaptation levels. This is subject of current research (also here at
EPFL) and there might be an extension of the DGP in future, depending on
the outcome of new experiments.

Back to the lens-type:
It is extremely important, that the right view type is given to
evalglare, otherwise ALL calculated values (it doesn't matter if this is
evalglare or findglare) are wrong. These errors could be huge, more than
100% for calculating the illuminance out of a 180 degree image.

If you manipulate an image by pcomb, in general the view is marked as
"invalid" in the header, because with that tool you could manipulate the
image in a way, that the original view is not valid any more. This is why
from evalglare version 1.0 on a check on the header was included, because
many people were creating wrong headers without knowing it and then
evalglare was calculating wrong values, when the header was invalid.

In addition for calculating the DGP it is important to have the
illuminance at camera level. evalglare calculates this value out of the
image. But if the image does not cover 180 degree, then the calculated
value for the illuminance is too low. For that reason, the -i option was
included, so you can provide the illuminance to evalglare (when you measure
it with an illuminance sensor).

So in your case, you should measure the illuminance just besides the
lens.
Then (in case this is the right lens description) you should use
evalglare -i LUXVALUE -vtv -vh 98.797409 -vv 75.402067 IMAGE_NAME
or better, if your task is always at the same place:
evalglare -i LUXVALUE -vtv -vh 98.797409 -vv 75.402067 -T 395 230 .6 -c
CHECK_FILE_PICTURE IMAGE_NAME

good luck!

Jan

Am 4/30/15 um 6:04 PM schrieb Jasper Overduin:

Somehow cant use the command pfilt or change the pcomb, does this has to
do with the program Radiance? I have installed the version of windows from
the site, with evalglare v1.11windows . The problem is that I have composed
a .hdr (out of 7 jpg on a mac) and after using the command
c:/HDRI>evalglare -vth -vh 140 -vv 80 image.hdr all the dgp results are
really low, less than 5%. The problem can be in the .hdr (calibrated as
well) or is in the way evalglare is not working as it shoot on my computer.

*.hdr file* (post-it is calibration point 167,98)
https://www.dropbox.com/s/4z69y358yt8ii4z/1_sv_am.hdr?dl=0
*images* original
https://www.dropbox.com/sh/adyyxjkv6eykyek/AAC96QUTpLh_Ef2U8Mppki8ta?dl=0
*command printscreen*
https://www.dropbox.com/s/0pbn105p0z0iinu/Imp%20pan.jpg?dl=0

Need the help!

Greetings Jacobus

*Jasper Overduin*
MSc Building Technology graduate student at Delft University of
Technology

*S* Groenhoevelaan 3
*P* 2343 BP Oegstgeest
*T* +31 6 15 64 48 56 (NL)
*T* +56 9 51 11 76 48 (CL)
*E *[email protected]
*Skype *jasper.overduin

_______________________________________________
Radiance-general mailing [email protected]://www.radiance-online.org/mailman/listinfo/radiance-general

--
Dr.-Ing. Jan Wienold
Ecole Polytechnique Fédérale de Lausanne (EPFL)
EPFL ENAC IA LIPID
http://people.epfl.ch/jan.wienold
LE 1 111 (Office)
Phone +41 21 69 30849

_______________________________________________
Radiance-general mailing list
[email protected]
http://www.radiance-online.org/mailman/listinfo/radiance-general

_______________________________________________
Radiance-general mailing [email protected]://www.radiance-online.org/mailman/listinfo/radiance-general

--
Dr.-Ing. Jan Wienold
Ecole Polytechnique Fédérale de Lausanne (EPFL)
EPFL ENAC IA LIPID
http://people.epfl.ch/jan.wienold
LE 1 111 (Office)
Phone +41 21 69 30849

_______________________________________________
Radiance-general mailing list
[email protected]
http://www.radiance-online.org/mailman/listinfo/radiance-general

Hi Jasper,

This is one of the tricky aspects of doing glare analysis with your own HDR images. A couple of pointers are below,

  * You will need to crop your image to a square aspect about the image
    center using the pcompos
    <http://radsite.lbl.gov/radiance/man_html/pcompos.1.html> tool.
    There was a helpful discussion on maintaining image exposure values
    while doing this here
    <http://www.radiance-online.org/pipermail/radiance-general/2011-March/007701.html>.
  * The -vv and -vh parameters are just best guesses according the HDR
    generation software. Once you have cropped the image, you will want
    to open the resulting HDR in a text editor and manually change the
    header 'VIEW' field to include -vta -vv 180 -vh 180. You may also
    specify them via the command line at this point, as you have done. I
    like to keep it associated with the image.
  * After that, unless I am forgetting something (others can chime in),
    you are ready to run evalglare. I would run it with the -d flag,
    which will report a lot of details. Most usefully, it reports
    illuminance as derived from the image, which you can compare to your
    measured Ev value to check the validity of the HDR. If your HDR is
    well-calibrated, not inputting the measured illuminance value should
    be perfectly accurate.
  * I suspect that inputting measured illuminance is somewhat broken in
    the current version of evalglare as I have the same problem that you
    do. One option is to use the -1 option to evalglare, which will
    return only a single DGP value. It seems to avoid this error.
     > evalglare -1 -i 2500 image.hdr

By the way, to avoid some of this cropping and exposure value pain, I use an image-processing tool (like PIL for Python) these days that can maintain EXIF data while cropping the source jpeg files. Though perhaps the cure is worse than the disease in this case..

Best,
Alstan

···

On 8/11/2015 11:08 PM, Jasper Overduin wrote:

Dear all,

I have changed my lens to one with 180 circular view to do a contrast analysis (hdrscope) and meanwhile the glare analysis in evalglare. If i use the commands in evalglare getinfo i get the (HDR composed with photosphere on a mac, calibrated with luminance pistol) i get a value for the lens -vv and -vh which is not over 100, with a lens of 180. I can imagine that the photo ratio and the lens are not the same and that causes this problem. But when I enter the external measured Ev, the value the dgp goes somehow to zero. The fact that the gdp is zero with a maximum luminance of 5600 cd/m2 and Ev of 2500 lux makes me a bit suspicious. How accurate is the result of the dgp without external vertical lux? is it possible to use this value?

hdr files and printscreens of evalglare https://www.dropbox.com/sh/ei1y4d2v6hapdsr/AACgVMPd1o0EdK-0q8CFvUGga?dl=0

Greetings Jasper

*
*Jasper Overduin*
MSc. Building Technology graduate student at Delft University of Technology

*S* Groenhoevelaan 3
*P*2343 BP Oegstgeest
*T* +31 6 15 64 48 56 (NL)
*T* +56 9 51 11 76 48 (CL)
*E *[email protected] <mailto:[email protected]>
*Skype *jasper.overduin

On 1 May 2015 at 12:15, Jan Wienold <[email protected] > <mailto:[email protected]>> wrote:

    Hi Jasper,

    I briefly looked at your image - for sure you get a low DGP value
    if your illuminance at camera (or eye) level is only about
    300lux... It is not the matter of the fish eye lens it is a matter
    of your lighting condition.
    When I remember correctly, for the experiments I did for my PhD,
    the people adjusted the blinds in a way, that they had 2500-3000
    lux at the eye level and they were less than 20% of them
    dissatisfied. So a value of 300 means one order of magnitude less
    light at the eye level and a much lower adaptation level.
    So I definitely understand the low DGP value in that case. The
    images themselves look reasonable, so I don't think there is a
    problem in calibration/processing so far (at least not for these
    low luminance levels-it might be more tricky to calibrate for the
    high luminance values when you get stray-light from the multiple
    lenses).

    If all your images are like that it means you have a very low
    daylight contribution at the place you measure. I'm not sure if
    DGP is then the right way to measure glare in that case - as I
    wrote it is made more for the daylight oriented workplace with
    higher levels and also to take into account very high luminances
    (e.g. sun or specular reflections of the sun). DGP might be
    modified in future, but these experiments are just starting.

    Jan

    Am 4/30/15 um 10:41 PM schrieb Jasper Overduin:

        Thank you for the fast reply. We are still having some
        problems with the outcome of Evalglare. With an external
        luxometre we have done some tests now. The DGP is still very
        low or zero. It seems that in almost all the case the DGP is
        low. In literature we read that values above 20% are normal.
        What do you think? is the data much better if we use a full
        180 degree lens?

    .hdr file https://www.dropbox.com/s/l10x7tri49btr8r/ff.hdr?dl=0
    print screen cmd
    https://www.dropbox.com/s/yv1lamhiirjhvxq/imp%20pan.jpg?dl=0
    test.pic https://www.dropbox.com/s/nspdu01477mchsz/test.pic?dl=0

        Greetings Jasper

        *
        *Jasper Overduin*
        MSc Building Technology graduate student at Delft University
        of Technology*
        *

        *S* Groenhoevelaan 3
        *P*2343 BP Oegstgeest
        *T* +31 6 15 64 48 56 (NL)
        *T* +56 9 51 11 76 48 (CL)
        *E *[email protected] <mailto:[email protected]>
        *Skype *jasper.overduin

        On 30 April 2015 at 13:55, Jan Wienold <[email protected] >> <mailto:[email protected]>> wrote:

            Hi Jasper,

            why are you using -vth -vh 140 -vv 80 when in your header
            of the HDR image the view is specified as -vtv -vh
            98.797409 -vv 75.402067 ?
            Manipulating the lense type is really dangerous - in that
            case you change from a perspective view to a
            hemispherical fish eye view, without changing the image!!

            If I apply evalglare for your image I get 0.17 as DGP
            (which is still very low, but you have only 2000cd/m2 as
            maximum value, so this can be expected). Be aware, that
            DGP accounts only for glare from a high amount of
            daylight and/or spots of extreme luminances
            (>50000cd/m2), but not for contrasted glare between task
            (e.g. Monitor) and immediate surroundings for lower
            adaptation levels. This is subject of current research
            (also here at EPFL) and there might be an extension of
            the DGP in future, depending on the outcome of new
            experiments.

            Back to the lens-type:
            It is extremely important, that the right view type is
            given to evalglare, otherwise ALL calculated values (it
            doesn't matter if this is evalglare or findglare) are
            wrong. These errors could be huge, more than 100% for
            calculating the illuminance out of a 180 degree image.

            If you manipulate an image by pcomb, in general the view
            is marked as "invalid" in the header, because with that
            tool you could manipulate the image in a way, that the
            original view is not valid any more. This is why from
            evalglare version 1.0 on a check on the header was
            included, because many people were creating wrong headers
            without knowing it and then evalglare was calculating
            wrong values, when the header was invalid.

            In addition for calculating the DGP it is important to
            have the illuminance at camera level. evalglare
            calculates this value out of the image. But if the image
            does not cover 180 degree, then the calculated value for
            the illuminance is too low. For that reason, the -i
            option was included, so you can provide the illuminance
            to evalglare (when you measure it with an illuminance
            sensor).

            So in your case, you should measure the illuminance just
            besides the lens.
            Then (in case this is the right lens description) you
            should use
            evalglare -i LUXVALUE -vtv -vh 98.797409 -vv 75.402067
            IMAGE_NAME
            or better, if your task is always at the same place:
            evalglare -i LUXVALUE -vtv -vh 98.797409 -vv 75.402067 -T 395 230 .6 -c CHECK_FILE_PICTURE IMAGE_NAME

            good luck!

            Jan

            Am 4/30/15 um 6:04 PM schrieb Jasper Overduin:

            Somehow cant use the command pfilt or change the pcomb,
            does this has to do with the program Radiance? I have
            installed the version of windows from the site, with
            evalglare v1.11windows . The problem is that I have
            composed a .hdr (out of 7 jpg on a mac) and after using
            the command c:/HDRI>evalglare -vth -vh 140 -vv 80
            image.hdr all the dgp results are really low, less than
            5%. The problem can be in the .hdr (calibrated as well)
            or is in the way evalglare is not working as it shoot on
            my computer.

            *.hdr file* (post-it is calibration point 167,98)
            https://www.dropbox.com/s/4z69y358yt8ii4z/1_sv_am.hdr?dl=0
            *images* original
            https://www.dropbox.com/sh/adyyxjkv6eykyek/AAC96QUTpLh_Ef2U8Mppki8ta?dl=0
            *command printscreen*
            https://www.dropbox.com/s/0pbn105p0z0iinu/Imp%20pan.jpg?dl=0

            Need the help!

            Greetings Jacobus

            *
            *Jasper Overduin*
            MSc Building Technology graduate student at Delft
            University of Technology*
            *

            *S* Groenhoevelaan 3
            *P*2343 BP Oegstgeest
            *T* +31 6 15 64 48 56 (NL)
            *T* +56 9 51 11 76 48 (CL)
            *E *[email protected]
            <mailto:[email protected]>
            *Skype *jasper.overduin

            _______________________________________________
            Radiance-general mailing list
            [email protected] <mailto:[email protected]>
            http://www.radiance-online.org/mailman/listinfo/radiance-general

            -- Dr.-Ing. Jan Wienold
            Ecole Polytechnique Fédérale de Lausanne (EPFL)
            EPFL ENAC IA LIPID

            http://people.epfl.ch/jan.wienold
            LE 1 111 (Office)
            Phone +41 21 69 30849

            _______________________________________________
            Radiance-general mailing list
            [email protected]
            <mailto:[email protected]>
            http://www.radiance-online.org/mailman/listinfo/radiance-general

    _______________________________________________
    Radiance-general mailing list
    [email protected] <mailto:[email protected]>
    http://www.radiance-online.org/mailman/listinfo/radiance-general

    -- Dr.-Ing. Jan Wienold
    Ecole Polytechnique Fédérale de Lausanne (EPFL)
    EPFL ENAC IA LIPID

    http://people.epfl.ch/jan.wienold
    LE 1 111 (Office)
    Phone +41 21 69 30849

    _______________________________________________
    Radiance-general mailing list
    [email protected]
    <mailto:[email protected]>
    http://www.radiance-online.org/mailman/listinfo/radiance-general

_______________________________________________
Radiance-general mailing list
[email protected]
http://www.radiance-online.org/mailman/listinfo/radiance-general

Hi Jasper,
hi Alstan,

I guess there are several issues in that case. First of all, as Alstan wrote, you should crop the image and provide the correct lens specification to evalglare. Be aware that editing the header could be dangerous, because sometimes editors add strange characters or you don't see tabs in the header with marks the view string there as "invalid" . In case the header is interpreted "wrong" in evalglare, the results could be really random and could differ for more than 100% from the right ones (e.g. the calculation of the vertical illuminance, see presentation on the Radiance workshop in 2012). The header treatment is much more robust since the evalglare version 1.08, but still the user should take care of providing a correct header. evalglare is relying on a correct radiance header. To be on the safe side, you should always use the command option to provide the correct view option to evalglare.
Also you should make sure, that you use a view type which really corresponds to your lens. If your real lens is a hemispherical fish eye and you provide -vta as view string, the angles and solid angles are calculated wrong in evalglare and you get wrong results. So make sure that you use -vta only if your lens is a angular fish eye.
And please don't use the -1 option in evalglare!!! This is a special (undocumented) option to get fast results on images calculated without ambient calculations. If you use it for normal images, the glare sources might not detected correctly and you could get big differences. It is working mostly properly in images with large black areas (-ab 0).
Since the -1 option is not robust for normal images, this option is undocumented. There exist also other undocumented options since 2009 for hdr treatment(e.g. pixel overflow correction, image fillup when ccd-array is smaller than the projected image...), but these options are by purpose undocumented because they should be used only in special cases and can cause wrong results when not used properly.

If I look at your image, I guess your calibration is not correct. The sun has a luminance of 2e10 cd/m2. In case of low transmittance glazing you still have a luminance of Xe9 cd/m2, lets say at least 1e9cd/m2, which is factor 200000 higher than you measured!!! And be aware you you might have to deal with blooming effects when you have a pixel overflow (especially when looking into the sun). Not sure about your camera setting, but if you still have an overflow for the shortest exposure, you should think of adding a neutral grey filter to reduce the overall transmittance to the ccd.

Finally I can't reproduce the 0 output of evalglare. I used your image and used as well the 2500lux as input (even if the image is not cropped correctly and the view string is wrong). See here:
/evalglare -i 2500 pmar_sin_03.hdr//
//Notice: Low brightness scene. Vertical illuminance less than 380 lux! dgp might underestimate glare sources//
//dgp,dgi,ugr,vcp,cgi,Lveil: 0.311778 18.132195 21.670120 44.798004 27.925421 58.052605 //

/But I always get an non-0 result, I never experienced this before. I tried the linux ,the mac and also the windows version with your image - it didn't happen. So which version are you using? Which operating system? (type evalglare -v to find out)

@Alstan: Can you provide me another example where this happens as well? Which version are you using? Which operating system?

A zero value should never appear, except your image is completely black.

Best,
Jan

···

Am 8/11/15 um 5:33 PM schrieb J. Alstan Jakubiec:

Hi Jasper,

This is one of the tricky aspects of doing glare analysis with your own HDR images. A couple of pointers are below,

  * You will need to crop your image to a square aspect about the
    image center using the pcompos
    <http://radsite.lbl.gov/radiance/man_html/pcompos.1.html> tool.
    There was a helpful discussion on maintaining image exposure
    values while doing this here
    <http://www.radiance-online.org/pipermail/radiance-general/2011-March/007701.html>.
  * The -vv and -vh parameters are just best guesses according the HDR
    generation software. Once you have cropped the image, you will
    want to open the resulting HDR in a text editor and manually
    change the header 'VIEW' field to include -vta -vv 180 -vh 180.
    You may also specify them via the command line at this point, as
    you have done. I like to keep it associated with the image.
  * After that, unless I am forgetting something (others can chime
    in), you are ready to run evalglare. I would run it with the -d
    flag, which will report a lot of details. Most usefully, it
    reports illuminance as derived from the image, which you can
    compare to your measured Ev value to check the validity of the
    HDR. If your HDR is well-calibrated, not inputting the measured
    illuminance value should be perfectly accurate.
  * I suspect that inputting measured illuminance is somewhat broken
    in the current version of evalglare as I have the same problem
    that you do. One option is to use the -1 option to evalglare,
    which will return only a single DGP value. It seems to avoid this
    error.
    > evalglare -1 -i 2500 image.hdr

By the way, to avoid some of this cropping and exposure value pain, I use an image-processing tool (like PIL for Python) these days that can maintain EXIF data while cropping the source jpeg files. Though perhaps the cure is worse than the disease in this case..

Best,
Alstan

On 8/11/2015 11:08 PM, Jasper Overduin wrote:

Dear all,

I have changed my lens to one with 180 circular view to do a contrast analysis (hdrscope) and meanwhile the glare analysis in evalglare. If i use the commands in evalglare getinfo i get the (HDR composed with photosphere on a mac, calibrated with luminance pistol) i get a value for the lens -vv and -vh which is not over 100, with a lens of 180. I can imagine that the photo ratio and the lens are not the same and that causes this problem. But when I enter the external measured Ev, the value the dgp goes somehow to zero. The fact that the gdp is zero with a maximum luminance of 5600 cd/m2 and Ev of 2500 lux makes me a bit suspicious. How accurate is the result of the dgp without external vertical lux? is it possible to use this value?

hdr files and printscreens of evalglare https://www.dropbox.com/sh/ei1y4d2v6hapdsr/AACgVMPd1o0EdK-0q8CFvUGga?dl=0

Greetings Jasper

*
*Jasper Overduin*
MSc. Building Technology graduate student at Delft University of Technology

*S* Groenhoevelaan 3
*P*2343 BP Oegstgeest
*T* +31 6 15 64 48 56 (NL)
*T* +56 9 51 11 76 48 (CL)
*E *[email protected] <mailto:[email protected]>
*Skype *jasper.overduin

On 1 May 2015 at 12:15, Jan Wienold <[email protected] >> <mailto:[email protected]>> wrote:

    Hi Jasper,

    I briefly looked at your image - for sure you get a low DGP value
    if your illuminance at camera (or eye) level is only about
    300lux... It is not the matter of the fish eye lens it is a
    matter of your lighting condition.
    When I remember correctly, for the experiments I did for my PhD,
    the people adjusted the blinds in a way, that they had 2500-3000
    lux at the eye level and they were less than 20% of them
    dissatisfied. So a value of 300 means one order of magnitude less
    light at the eye level and a much lower adaptation level.
    So I definitely understand the low DGP value in that case. The
    images themselves look reasonable, so I don't think there is a
    problem in calibration/processing so far (at least not for these
    low luminance levels-it might be more tricky to calibrate for the
    high luminance values when you get stray-light from the multiple
    lenses).

    If all your images are like that it means you have a very low
    daylight contribution at the place you measure. I'm not sure if
    DGP is then the right way to measure glare in that case - as I
    wrote it is made more for the daylight oriented workplace with
    higher levels and also to take into account very high luminances
    (e.g. sun or specular reflections of the sun). DGP might be
    modified in future, but these experiments are just starting.

    Jan

    Am 4/30/15 um 10:41 PM schrieb Jasper Overduin:

        Thank you for the fast reply. We are still having some
        problems with the outcome of Evalglare. With an external
        luxometre we have done some tests now. The DGP is still very
        low or zero. It seems that in almost all the case the DGP is
        low. In literature we read that values above 20% are normal.
        What do you think? is the data much better if we use a full
        180 degree lens?

    .hdr file https://www.dropbox.com/s/l10x7tri49btr8r/ff.hdr?dl=0
    print screen cmd
    https://www.dropbox.com/s/yv1lamhiirjhvxq/imp%20pan.jpg?dl=0
    test.pic https://www.dropbox.com/s/nspdu01477mchsz/test.pic?dl=0

        Greetings Jasper

        *
        *Jasper Overduin*
        MSc Building Technology graduate student at Delft University
        of Technology*
        *

        *S* Groenhoevelaan 3
        *P*2343 BP Oegstgeest
        *T* +31 6 15 64 48 56 (NL)
        *T* +56 9 51 11 76 48 (CL)
        *E *[email protected] <mailto:[email protected]>
        *Skype *jasper.overduin

        On 30 April 2015 at 13:55, Jan Wienold <[email protected] >>> <mailto:[email protected]>> wrote:

            Hi Jasper,

            why are you using -vth -vh 140 -vv 80 when in your
            header of the HDR image the view is specified as -vtv
            -vh 98.797409 -vv 75.402067 ?
            Manipulating the lense type is really dangerous - in
            that case you change from a perspective view to a
            hemispherical fish eye view, without changing the image!!

            If I apply evalglare for your image I get 0.17 as DGP
            (which is still very low, but you have only 2000cd/m2 as
            maximum value, so this can be expected). Be aware, that
            DGP accounts only for glare from a high amount of
            daylight and/or spots of extreme luminances
            (>50000cd/m2), but not for contrasted glare between task
            (e.g. Monitor) and immediate surroundings for lower
            adaptation levels. This is subject of current research
            (also here at EPFL) and there might be an extension of
            the DGP in future, depending on the outcome of new
            experiments.

            Back to the lens-type:
            It is extremely important, that the right view type is
            given to evalglare, otherwise ALL calculated values (it
            doesn't matter if this is evalglare or findglare) are
            wrong. These errors could be huge, more than 100% for
            calculating the illuminance out of a 180 degree image.

            If you manipulate an image by pcomb, in general the view
            is marked as "invalid" in the header, because with that
            tool you could manipulate the image in a way, that the
            original view is not valid any more. This is why from
            evalglare version 1.0 on a check on the header was
            included, because many people were creating wrong
            headers without knowing it and then evalglare was
            calculating wrong values, when the header was invalid.

            In addition for calculating the DGP it is important to
            have the illuminance at camera level. evalglare
            calculates this value out of the image. But if the image
            does not cover 180 degree, then the calculated value for
            the illuminance is too low. For that reason, the -i
            option was included, so you can provide the illuminance
            to evalglare (when you measure it with an illuminance
            sensor).

            So in your case, you should measure the illuminance just
            besides the lens.
            Then (in case this is the right lens description) you
            should use
            evalglare -i LUXVALUE -vtv -vh 98.797409 -vv 75.402067
            IMAGE_NAME
            or better, if your task is always at the same place:
            evalglare -i LUXVALUE -vtv -vh 98.797409 -vv 75.402067 -T 395 230 .6 -c CHECK_FILE_PICTURE IMAGE_NAME

            good luck!

            Jan

            Am 4/30/15 um 6:04 PM schrieb Jasper Overduin:

            Somehow cant use the command pfilt or change the pcomb,
            does this has to do with the program Radiance? I have
            installed the version of windows from the site, with
            evalglare v1.11windows . The problem is that I have
            composed a .hdr (out of 7 jpg on a mac) and after using
            the command c:/HDRI>evalglare -vth -vh 140 -vv 80
            image.hdr all the dgp results are really low, less than
            5%. The problem can be in the .hdr (calibrated as well)
            or is in the way evalglare is not working as it shoot
            on my computer.

            *.hdr file* (post-it is calibration point 167,98)
            https://www.dropbox.com/s/4z69y358yt8ii4z/1_sv_am.hdr?dl=0
            *images* original
            https://www.dropbox.com/sh/adyyxjkv6eykyek/AAC96QUTpLh_Ef2U8Mppki8ta?dl=0
            *command printscreen*
            https://www.dropbox.com/s/0pbn105p0z0iinu/Imp%20pan.jpg?dl=0

            Need the help!

            Greetings Jacobus

            *
            *Jasper Overduin*
            MSc Building Technology graduate student at Delft
            University of Technology*
            *

            *S* Groenhoevelaan 3
            *P*2343 BP Oegstgeest
            *T* +31 6 15 64 48 56 (NL)
            *T* +56 9 51 11 76 48 (CL)
            *E *[email protected]
            <mailto:[email protected]>
            *Skype *jasper.overduin

            _______________________________________________
            Radiance-general mailing list
            [email protected]
            <mailto:[email protected]>
            http://www.radiance-online.org/mailman/listinfo/radiance-general

            -- Dr.-Ing. Jan Wienold
            Ecole Polytechnique F�d�rale de Lausanne (EPFL)
            EPFL ENAC IA LIPID

            http://people.epfl.ch/jan.wienold
            LE 1 111 (Office)
            Phone +41 21 69 30849

            _______________________________________________
            Radiance-general mailing list
            [email protected]
            <mailto:[email protected]>
            http://www.radiance-online.org/mailman/listinfo/radiance-general

    _______________________________________________
    Radiance-general mailing list
    [email protected]
    <mailto:[email protected]>
    http://www.radiance-online.org/mailman/listinfo/radiance-general

    -- Dr.-Ing. Jan Wienold
    Ecole Polytechnique F�d�rale de Lausanne (EPFL)
    EPFL ENAC IA LIPID

    http://people.epfl.ch/jan.wienold
    LE 1 111 (Office)
    Phone +41 21 69 30849

    _______________________________________________
    Radiance-general mailing list
    [email protected]
    <mailto:[email protected]>
    http://www.radiance-online.org/mailman/listinfo/radiance-general

_______________________________________________
Radiance-general mailing list
[email protected]
http://www.radiance-online.org/mailman/listinfo/radiance-general

_______________________________________________
Radiance-general mailing list
[email protected]
http://www.radiance-online.org/mailman/listinfo/radiance-general

--
Dr.-Ing. Jan Wienold
Ecole Polytechnique F�d�rale de Lausanne (EPFL)
EPFL ENAC IA LIPID

http://people.epfl.ch/jan.wienold
LE 1 111 (Office)
Phone +41 21 69 30849

Hi Jasper and Alstan,

I just found this in the revision-logging of the evalglare source code(it is such a long time ago that I could not remember...) :

/* evalglare.c, v1.11 2013/01/17 wienold
    - fix output bug of dgp, when using -i or -I
    */

are you using an older version of evalglare than v1.11 which is from January 2013??

best,

Jan

···

Am 8/11/15 um 5:33 PM schrieb J. Alstan Jakubiec:

Hi Jasper,

This is one of the tricky aspects of doing glare analysis with your own HDR images. A couple of pointers are below,

  * You will need to crop your image to a square aspect about the
    image center using the pcompos
    <http://radsite.lbl.gov/radiance/man_html/pcompos.1.html> tool.
    There was a helpful discussion on maintaining image exposure
    values while doing this here
    <http://www.radiance-online.org/pipermail/radiance-general/2011-March/007701.html>.
  * The -vv and -vh parameters are just best guesses according the HDR
    generation software. Once you have cropped the image, you will
    want to open the resulting HDR in a text editor and manually
    change the header 'VIEW' field to include -vta -vv 180 -vh 180.
    You may also specify them via the command line at this point, as
    you have done. I like to keep it associated with the image.
  * After that, unless I am forgetting something (others can chime
    in), you are ready to run evalglare. I would run it with the -d
    flag, which will report a lot of details. Most usefully, it
    reports illuminance as derived from the image, which you can
    compare to your measured Ev value to check the validity of the
    HDR. If your HDR is well-calibrated, not inputting the measured
    illuminance value should be perfectly accurate.
  * I suspect that inputting measured illuminance is somewhat broken
    in the current version of evalglare as I have the same problem
    that you do. One option is to use the -1 option to evalglare,
    which will return only a single DGP value. It seems to avoid this
    error.
    > evalglare -1 -i 2500 image.hdr

By the way, to avoid some of this cropping and exposure value pain, I use an image-processing tool (like PIL for Python) these days that can maintain EXIF data while cropping the source jpeg files. Though perhaps the cure is worse than the disease in this case..

Best,
Alstan

On 8/11/2015 11:08 PM, Jasper Overduin wrote:

Dear all,

I have changed my lens to one with 180 circular view to do a contrast analysis (hdrscope) and meanwhile the glare analysis in evalglare. If i use the commands in evalglare getinfo i get the (HDR composed with photosphere on a mac, calibrated with luminance pistol) i get a value for the lens -vv and -vh which is not over 100, with a lens of 180. I can imagine that the photo ratio and the lens are not the same and that causes this problem. But when I enter the external measured Ev, the value the dgp goes somehow to zero. The fact that the gdp is zero with a maximum luminance of 5600 cd/m2 and Ev of 2500 lux makes me a bit suspicious. How accurate is the result of the dgp without external vertical lux? is it possible to use this value?

hdr files and printscreens of evalglare https://www.dropbox.com/sh/ei1y4d2v6hapdsr/AACgVMPd1o0EdK-0q8CFvUGga?dl=0

Greetings Jasper

*
*Jasper Overduin*
MSc. Building Technology graduate student at Delft University of Technology

*S* Groenhoevelaan 3
*P*2343 BP Oegstgeest
*T* +31 6 15 64 48 56 (NL)
*T* +56 9 51 11 76 48 (CL)
*E *[email protected] <mailto:[email protected]>
*Skype *jasper.overduin

On 1 May 2015 at 12:15, Jan Wienold <[email protected] >> <mailto:[email protected]>> wrote:

    Hi Jasper,

    I briefly looked at your image - for sure you get a low DGP value
    if your illuminance at camera (or eye) level is only about
    300lux... It is not the matter of the fish eye lens it is a
    matter of your lighting condition.
    When I remember correctly, for the experiments I did for my PhD,
    the people adjusted the blinds in a way, that they had 2500-3000
    lux at the eye level and they were less than 20% of them
    dissatisfied. So a value of 300 means one order of magnitude less
    light at the eye level and a much lower adaptation level.
    So I definitely understand the low DGP value in that case. The
    images themselves look reasonable, so I don't think there is a
    problem in calibration/processing so far (at least not for these
    low luminance levels-it might be more tricky to calibrate for the
    high luminance values when you get stray-light from the multiple
    lenses).

    If all your images are like that it means you have a very low
    daylight contribution at the place you measure. I'm not sure if
    DGP is then the right way to measure glare in that case - as I
    wrote it is made more for the daylight oriented workplace with
    higher levels and also to take into account very high luminances
    (e.g. sun or specular reflections of the sun). DGP might be
    modified in future, but these experiments are just starting.

    Jan

    Am 4/30/15 um 10:41 PM schrieb Jasper Overduin:

        Thank you for the fast reply. We are still having some
        problems with the outcome of Evalglare. With an external
        luxometre we have done some tests now. The DGP is still very
        low or zero. It seems that in almost all the case the DGP is
        low. In literature we read that values above 20% are normal.
        What do you think? is the data much better if we use a full
        180 degree lens?

    .hdr file https://www.dropbox.com/s/l10x7tri49btr8r/ff.hdr?dl=0
    print screen cmd
    https://www.dropbox.com/s/yv1lamhiirjhvxq/imp%20pan.jpg?dl=0
    test.pic https://www.dropbox.com/s/nspdu01477mchsz/test.pic?dl=0

        Greetings Jasper

        *
        *Jasper Overduin*
        MSc Building Technology graduate student at Delft University
        of Technology*
        *

        *S* Groenhoevelaan 3
        *P*2343 BP Oegstgeest
        *T* +31 6 15 64 48 56 (NL)
        *T* +56 9 51 11 76 48 (CL)
        *E *[email protected] <mailto:[email protected]>
        *Skype *jasper.overduin

        On 30 April 2015 at 13:55, Jan Wienold <[email protected] >>> <mailto:[email protected]>> wrote:

            Hi Jasper,

            why are you using -vth -vh 140 -vv 80 when in your
            header of the HDR image the view is specified as -vtv
            -vh 98.797409 -vv 75.402067 ?
            Manipulating the lense type is really dangerous - in
            that case you change from a perspective view to a
            hemispherical fish eye view, without changing the image!!

            If I apply evalglare for your image I get 0.17 as DGP
            (which is still very low, but you have only 2000cd/m2 as
            maximum value, so this can be expected). Be aware, that
            DGP accounts only for glare from a high amount of
            daylight and/or spots of extreme luminances
            (>50000cd/m2), but not for contrasted glare between task
            (e.g. Monitor) and immediate surroundings for lower
            adaptation levels. This is subject of current research
            (also here at EPFL) and there might be an extension of
            the DGP in future, depending on the outcome of new
            experiments.

            Back to the lens-type:
            It is extremely important, that the right view type is
            given to evalglare, otherwise ALL calculated values (it
            doesn't matter if this is evalglare or findglare) are
            wrong. These errors could be huge, more than 100% for
            calculating the illuminance out of a 180 degree image.

            If you manipulate an image by pcomb, in general the view
            is marked as "invalid" in the header, because with that
            tool you could manipulate the image in a way, that the
            original view is not valid any more. This is why from
            evalglare version 1.0 on a check on the header was
            included, because many people were creating wrong
            headers without knowing it and then evalglare was
            calculating wrong values, when the header was invalid.

            In addition for calculating the DGP it is important to
            have the illuminance at camera level. evalglare
            calculates this value out of the image. But if the image
            does not cover 180 degree, then the calculated value for
            the illuminance is too low. For that reason, the -i
            option was included, so you can provide the illuminance
            to evalglare (when you measure it with an illuminance
            sensor).

            So in your case, you should measure the illuminance just
            besides the lens.
            Then (in case this is the right lens description) you
            should use
            evalglare -i LUXVALUE -vtv -vh 98.797409 -vv 75.402067
            IMAGE_NAME
            or better, if your task is always at the same place:
            evalglare -i LUXVALUE -vtv -vh 98.797409 -vv 75.402067 -T 395 230 .6 -c CHECK_FILE_PICTURE IMAGE_NAME

            good luck!

            Jan

            Am 4/30/15 um 6:04 PM schrieb Jasper Overduin:

            Somehow cant use the command pfilt or change the pcomb,
            does this has to do with the program Radiance? I have
            installed the version of windows from the site, with
            evalglare v1.11windows . The problem is that I have
            composed a .hdr (out of 7 jpg on a mac) and after using
            the command c:/HDRI>evalglare -vth -vh 140 -vv 80
            image.hdr all the dgp results are really low, less than
            5%. The problem can be in the .hdr (calibrated as well)
            or is in the way evalglare is not working as it shoot
            on my computer.

            *.hdr file* (post-it is calibration point 167,98)
            https://www.dropbox.com/s/4z69y358yt8ii4z/1_sv_am.hdr?dl=0
            *images* original
            https://www.dropbox.com/sh/adyyxjkv6eykyek/AAC96QUTpLh_Ef2U8Mppki8ta?dl=0
            *command printscreen*
            https://www.dropbox.com/s/0pbn105p0z0iinu/Imp%20pan.jpg?dl=0

            Need the help!

            Greetings Jacobus

            *
            *Jasper Overduin*
            MSc Building Technology graduate student at Delft
            University of Technology*
            *

            *S* Groenhoevelaan 3
            *P*2343 BP Oegstgeest
            *T* +31 6 15 64 48 56 (NL)
            *T* +56 9 51 11 76 48 (CL)
            *E *[email protected]
            <mailto:[email protected]>
            *Skype *jasper.overduin

            _______________________________________________
            Radiance-general mailing list
            [email protected]
            <mailto:[email protected]>
            http://www.radiance-online.org/mailman/listinfo/radiance-general

            -- Dr.-Ing. Jan Wienold
            Ecole Polytechnique F�d�rale de Lausanne (EPFL)
            EPFL ENAC IA LIPID

            http://people.epfl.ch/jan.wienold
            LE 1 111 (Office)
            Phone +41 21 69 30849

            _______________________________________________
            Radiance-general mailing list
            [email protected]
            <mailto:[email protected]>
            http://www.radiance-online.org/mailman/listinfo/radiance-general

    _______________________________________________
    Radiance-general mailing list
    [email protected]
    <mailto:[email protected]>
    http://www.radiance-online.org/mailman/listinfo/radiance-general

    -- Dr.-Ing. Jan Wienold
    Ecole Polytechnique F�d�rale de Lausanne (EPFL)
    EPFL ENAC IA LIPID

    http://people.epfl.ch/jan.wienold
    LE 1 111 (Office)
    Phone +41 21 69 30849

    _______________________________________________
    Radiance-general mailing list
    [email protected]
    <mailto:[email protected]>
    http://www.radiance-online.org/mailman/listinfo/radiance-general

_______________________________________________
Radiance-general mailing list
[email protected]
http://www.radiance-online.org/mailman/listinfo/radiance-general

_______________________________________________
Radiance-general mailing list
[email protected]
http://www.radiance-online.org/mailman/listinfo/radiance-general

--
Dr.-Ing. Jan Wienold
Ecole Polytechnique F�d�rale de Lausanne (EPFL)
EPFL ENAC IA LIPID

http://people.epfl.ch/jan.wienold
LE 1 111 (Office)
Phone +41 21 69 30849

Hi Jan,

Apologies for the -1 comment -- I didn't know it did anything special beyond only returning DGP.

As for the version of evalglare, I was using v1.10 -- Doh! I installed Daysim last week to get the source for Linux, and it put an old version in my path. The 0 result issue doesn't happen with version 1.11. Probably the Daysim installer should be updated at some point.

     > /Also you should make sure, that you use a view type which really
    corresponds to your lens. If your real lens is a hemispherical fish
    eye and you provide -vta as view string, the angles and solid
    angles are calculated wrong in evalglare and you get wrong results.
    So make sure that you use -vta only if your lens is a angular fish eye./

I can also second this. I ended up with an equi-solid fisheye lens, and there is no small amount of effort converting the images into a -vta type for Radiance use.

Best,
Alstan

···

On 8/12/2015 5:39 PM, Jan Wienold wrote:

Hi Jasper,
hi Alstan,

I guess there are several issues in that case. First of all, as Alstan wrote, you should crop the image and provide the correct lens specification to evalglare. Be aware that editing the header could be dangerous, because sometimes editors add strange characters or you don't see tabs in the header with marks the view string there as "invalid" . In case the header is interpreted "wrong" in evalglare, the results could be really random and could differ for more than 100% from the right ones (e.g. the calculation of the vertical illuminance, see presentation on the Radiance workshop in 2012). The header treatment is much more robust since the evalglare version 1.08, but still the user should take care of providing a correct header. evalglare is relying on a correct radiance header. To be on the safe side, you should always use the command option to provide the correct view option to evalglare.
Also you should make sure, that you use a view type which really corresponds to your lens. If your real lens is a hemispherical fish eye and you provide -vta as view string, the angles and solid angles are calculated wrong in evalglare and you get wrong results. So make sure that you use -vta only if your lens is a angular fish eye.
And please don't use the -1 option in evalglare!!! This is a special (undocumented) option to get fast results on images calculated without ambient calculations. If you use it for normal images, the glare sources might not detected correctly and you could get big differences. It is working mostly properly in images with large black areas (-ab 0).
Since the -1 option is not robust for normal images, this option is undocumented. There exist also other undocumented options since 2009 for hdr treatment(e.g. pixel overflow correction, image fillup when ccd-array is smaller than the projected image...), but these options are by purpose undocumented because they should be used only in special cases and can cause wrong results when not used properly.

If I look at your image, I guess your calibration is not correct. The sun has a luminance of 2e10 cd/m2. In case of low transmittance glazing you still have a luminance of Xe9 cd/m2, lets say at least 1e9cd/m2, which is factor 200000 higher than you measured!!! And be aware you you might have to deal with blooming effects when you have a pixel overflow (especially when looking into the sun). Not sure about your camera setting, but if you still have an overflow for the shortest exposure, you should think of adding a neutral grey filter to reduce the overall transmittance to the ccd.

Finally I can't reproduce the 0 output of evalglare. I used your image and used as well the 2500lux as input (even if the image is not cropped correctly and the view string is wrong). See here:
/evalglare -i 2500 pmar_sin_03.hdr//
//Notice: Low brightness scene. Vertical illuminance less than 380 lux! dgp might underestimate glare sources//
//dgp,dgi,ugr,vcp,cgi,Lveil: 0.311778 18.132195 21.670120 44.798004 27.925421 58.052605 //

/But I always get an non-0 result, I never experienced this before. I tried the linux ,the mac and also the windows version with your image - it didn't happen. So which version are you using? Which operating system? (type evalglare -v to find out)

@Alstan: Can you provide me another example where this happens as well? Which version are you using? Which operating system?

A zero value should never appear, except your image is completely black.

Best,
Jan

Am 8/11/15 um 5:33 PM schrieb J. Alstan Jakubiec:

Hi Jasper,

This is one of the tricky aspects of doing glare analysis with your own HDR images. A couple of pointers are below,

  * You will need to crop your image to a square aspect about the
    image center using the pcompos
    <http://radsite.lbl.gov/radiance/man_html/pcompos.1.html> tool.
    There was a helpful discussion on maintaining image exposure
    values while doing this here
    <http://www.radiance-online.org/pipermail/radiance-general/2011-March/007701.html>.
  * The -vv and -vh parameters are just best guesses according the
    HDR generation software. Once you have cropped the image, you
    will want to open the resulting HDR in a text editor and manually
    change the header 'VIEW' field to include -vta -vv 180 -vh 180.
    You may also specify them via the command line at this point, as
    you have done. I like to keep it associated with the image.
  * After that, unless I am forgetting something (others can chime
    in), you are ready to run evalglare. I would run it with the -d
    flag, which will report a lot of details. Most usefully, it
    reports illuminance as derived from the image, which you can
    compare to your measured Ev value to check the validity of the
    HDR. If your HDR is well-calibrated, not inputting the measured
    illuminance value should be perfectly accurate.
  * I suspect that inputting measured illuminance is somewhat broken
    in the current version of evalglare as I have the same problem
    that you do. One option is to use the -1 option to evalglare,
    which will return only a single DGP value. It seems to avoid this
    error.
    > evalglare -1 -i 2500 image.hdr

By the way, to avoid some of this cropping and exposure value pain, I use an image-processing tool (like PIL for Python) these days that can maintain EXIF data while cropping the source jpeg files. Though perhaps the cure is worse than the disease in this case..

Best,
Alstan

On 8/11/2015 11:08 PM, Jasper Overduin wrote:

Dear all,

I have changed my lens to one with 180 circular view to do a contrast analysis (hdrscope) and meanwhile the glare analysis in evalglare. If i use the commands in evalglare getinfo i get the (HDR composed with photosphere on a mac, calibrated with luminance pistol) i get a value for the lens -vv and -vh which is not over 100, with a lens of 180. I can imagine that the photo ratio and the lens are not the same and that causes this problem. But when I enter the external measured Ev, the value the dgp goes somehow to zero. The fact that the gdp is zero with a maximum luminance of 5600 cd/m2 and Ev of 2500 lux makes me a bit suspicious. How accurate is the result of the dgp without external vertical lux? is it possible to use this value?

hdr files and printscreens of evalglare https://www.dropbox.com/sh/ei1y4d2v6hapdsr/AACgVMPd1o0EdK-0q8CFvUGga?dl=0

Greetings Jasper

*
*Jasper Overduin*
MSc. Building Technology graduate student at Delft University of Technology

*S* Groenhoevelaan 3
*P*2343 BP Oegstgeest
*T* +31 6 15 64 48 56 (NL)
*T* +56 9 51 11 76 48 (CL)
*E *[email protected]
*Skype *jasper.overduin

On 1 May 2015 at 12:15, Jan Wienold <[email protected] >>> <mailto:[email protected]>> wrote:

    Hi Jasper,

    I briefly looked at your image - for sure you get a low DGP
    value if your illuminance at camera (or eye) level is only about
    300lux... It is not the matter of the fish eye lens it is a
    matter of your lighting condition.
    When I remember correctly, for the experiments I did for my PhD,
    the people adjusted the blinds in a way, that they had 2500-3000
    lux at the eye level and they were less than 20% of them
    dissatisfied. So a value of 300 means one order of magnitude
    less light at the eye level and a much lower adaptation level.
    So I definitely understand the low DGP value in that case. The
    images themselves look reasonable, so I don't think there is a
    problem in calibration/processing so far (at least not for these
    low luminance levels-it might be more tricky to calibrate for
    the high luminance values when you get stray-light from the
    multiple lenses).

    If all your images are like that it means you have a very low
    daylight contribution at the place you measure. I'm not sure if
    DGP is then the right way to measure glare in that case - as I
    wrote it is made more for the daylight oriented workplace with
    higher levels and also to take into account very high luminances
    (e.g. sun or specular reflections of the sun). DGP might be
    modified in future, but these experiments are just starting.

    Jan

    Am 4/30/15 um 10:41 PM schrieb Jasper Overduin:

        Thank you for the fast reply. We are still having some
        problems with the outcome of Evalglare. With an external
        luxometre we have done some tests now. The DGP is still
        very low or zero. It seems that in almost all the case the
        DGP is low. In literature we read that values above 20% are
        normal. What do you think? is the data much better if we
        use a full 180 degree lens?

    .hdr file https://www.dropbox.com/s/l10x7tri49btr8r/ff.hdr?dl=0
    print screen cmd
    https://www.dropbox.com/s/yv1lamhiirjhvxq/imp%20pan.jpg?dl=0
    test.pic https://www.dropbox.com/s/nspdu01477mchsz/test.pic?dl=0

        Greetings Jasper

        *
        *Jasper Overduin*
        MSc Building Technology graduate student at Delft
        University of Technology*
        *

        *S* Groenhoevelaan 3
        *P*2343 BP Oegstgeest
        *T* +31 6 15 64 48 56 (NL)
        *T* +56 9 51 11 76 48 (CL)
        *E *[email protected]
        *Skype *jasper.overduin

        On 30 April 2015 at 13:55, Jan Wienold >>>> <[email protected]> wrote:

            Hi Jasper,

            why are you using -vth -vh 140 -vv 80 when in your
            header of the HDR image the view is specified as -vtv
            -vh 98.797409 -vv 75.402067 ?
            Manipulating the lense type is really dangerous - in
            that case you change from a perspective view to a
            hemispherical fish eye view, without changing the image!!

            If I apply evalglare for your image I get 0.17 as DGP
            (which is still very low, but you have only 2000cd/m2
            as maximum value, so this can be expected). Be aware,
            that DGP accounts only for glare from a high amount of
            daylight and/or spots of extreme luminances
            (>50000cd/m2), but not for contrasted glare between
            task (e.g. Monitor) and immediate surroundings for
            lower adaptation levels. This is subject of current
            research (also here at EPFL) and there might be an
            extension of the DGP in future, depending on the
            outcome of new experiments.

            Back to the lens-type:
            It is extremely important, that the right view type is
            given to evalglare, otherwise ALL calculated values (it
            doesn't matter if this is evalglare or findglare) are
            wrong. These errors could be huge, more than 100% for
            calculating the illuminance out of a 180 degree image.

            If you manipulate an image by pcomb, in general the
            view is marked as "invalid" in the header, because with
            that tool you could manipulate the image in a way, that
            the original view is not valid any more. This is why
            from evalglare version 1.0 on a check on the header was
            included, because many people were creating wrong
            headers without knowing it and then evalglare was
            calculating wrong values, when the header was invalid.

            In addition for calculating the DGP it is important to
            have the illuminance at camera level. evalglare
            calculates this value out of the image. But if the
            image does not cover 180 degree, then the calculated
            value for the illuminance is too low. For that reason,
            the -i option was included, so you can provide the
            illuminance to evalglare (when you measure it with an
            illuminance sensor).

            So in your case, you should measure the illuminance
            just besides the lens.
            Then (in case this is the right lens description) you
            should use
            evalglare -i LUXVALUE -vtv -vh 98.797409 -vv 75.402067
            IMAGE_NAME
            or better, if your task is always at the same place:
            evalglare -i LUXVALUE -vtv -vh 98.797409 -vv 75.402067
            -T 395 230 .6 -c CHECK_FILE_PICTURE IMAGE_NAME

            good luck!

            Jan

            Am 4/30/15 um 6:04 PM schrieb Jasper Overduin:

            Somehow cant use the command pfilt or change the
            pcomb, does this has to do with the program Radiance?
            I have installed the version of windows from the site,
            with evalglare v1.11windows . The problem is that I
            have composed a .hdr (out of 7 jpg on a mac) and after
            using the command c:/HDRI>evalglare -vth -vh 140 -vv
            80 image.hdr all the dgp results are really low, less
            than 5%. The problem can be in the .hdr (calibrated as
            well) or is in the way evalglare is not working as it
            shoot on my computer.

            *.hdr file* (post-it is calibration point 167,98)
            https://www.dropbox.com/s/4z69y358yt8ii4z/1_sv_am.hdr?dl=0
            *images* original
            https://www.dropbox.com/sh/adyyxjkv6eykyek/AAC96QUTpLh_Ef2U8Mppki8ta?dl=0
            *command printscreen*
            https://www.dropbox.com/s/0pbn105p0z0iinu/Imp%20pan.jpg?dl=0

            Need the help!

            Greetings Jacobus

            *
            *Jasper Overduin*
            MSc Building Technology graduate student at Delft
            University of Technology*
            *

            *S* Groenhoevelaan 3
            *P*2343 BP Oegstgeest
            *T* +31 6 15 64 48 56 (NL)
            *T* +56 9 51 11 76 48 (CL)
            *E *[email protected]
            *Skype *jasper.overduin

            _______________________________________________
            Radiance-general mailing list
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            Ecole Polytechnique Fédérale de Lausanne (EPFL)
            EPFL ENAC IA LIPID

            http://people.epfl.ch/jan.wienold
            LE 1 111 (Office)
            Phone +41 21 69 30849

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    -- Dr.-Ing. Jan Wienold
    Ecole Polytechnique Fédérale de Lausanne (EPFL)
    EPFL ENAC IA LIPID

    http://people.epfl.ch/jan.wienold
    LE 1 111 (Office)
    Phone +41 21 69 30849

    _______________________________________________
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--
Dr.-Ing. Jan Wienold
Ecole Polytechnique Fédérale de Lausanne (EPFL)
EPFL ENAC IA LIPID

http://people.epfl.ch/jan.wienold
LE 1 111 (Office)
Phone +41 21 69 30849

_______________________________________________
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Im using evalglare 1.10 release 30.09.2012 with windows 7
The photos are calibrated with a (il)lumination pistol with 4 different
measurements (with maximum deviation of 0.4 cd/m2)
There is a certain coating on the window, not sure what kind. but as you
said the difference is huge.

Within the program of HDRscope there is a similar function and gives and
errer as well if i use an external Ev value.

Greetings,
Jasper

*Jasper Overduin*
MSc. Building Technology graduate student at Delft University of Technology

*S* Groenhoevelaan 3
*P* 2343 BP Oegstgeest
*T* +31 6 15 64 48 56 (NL)
*T* +56 9 51 11 76 48 (CL)
*E *[email protected]
*Skype *jasper.overduin

···

On 12 August 2015 at 06:39, Jan Wienold <[email protected]> wrote:

Hi Jasper,
hi Alstan,

I guess there are several issues in that case. First of all, as Alstan
wrote, you should crop the image and provide the correct lens specification
to evalglare. Be aware that editing the header could be dangerous, because
sometimes editors add strange characters or you don't see tabs in the
header with marks the view string there as "invalid" . In case the header
is interpreted "wrong" in evalglare, the results could be really random and
could differ for more than 100% from the right ones (e.g. the calculation
of the vertical illuminance, see presentation on the Radiance workshop in
2012). The header treatment is much more robust since the evalglare version
1.08, but still the user should take care of providing a correct header.
evalglare is relying on a correct radiance header. To be on the safe side,
you should always use the command option to provide the correct view option
to evalglare.
Also you should make sure, that you use a view type which really
corresponds to your lens. If your real lens is a hemispherical fish eye and
you provide -vta as view string, the angles and solid angles are
calculated wrong in evalglare and you get wrong results. So make sure that
you use -vta only if your lens is a angular fish eye.
And please don't use the -1 option in evalglare!!! This is a special
(undocumented) option to get fast results on images calculated without
ambient calculations. If you use it for normal images, the glare sources
might not detected correctly and you could get big differences. It is
working mostly properly in images with large black areas (-ab 0).
Since the -1 option is not robust for normal images, this option is
undocumented. There exist also other undocumented options since 2009 for
hdr treatment(e.g. pixel overflow correction, image fillup when ccd-array
is smaller than the projected image...), but these options are by purpose
undocumented because they should be used only in special cases and can
cause wrong results when not used properly.

If I look at your image, I guess your calibration is not correct. The sun
has a luminance of 2e10 cd/m2. In case of low transmittance glazing you
still have a luminance of Xe9 cd/m2, lets say at least 1e9cd/m2, which is
factor 200000 higher than you measured!!! And be aware you you might have
to deal with blooming effects when you have a pixel overflow (especially
when looking into the sun). Not sure about your camera setting, but if you
still have an overflow for the shortest exposure, you should think of
adding a neutral grey filter to reduce the overall transmittance to the ccd.

Finally I can't reproduce the 0 output of evalglare. I used your image and
used as well the 2500lux as input (even if the image is not cropped
correctly and the view string is wrong). See here:
*evalglare -i 2500 pmar_sin_03.hdr*
*Notice: Low brightness scene. Vertical illuminance less than 380 lux! dgp
might underestimate glare sources*
*dgp,dgi,ugr,vcp,cgi,Lveil: 0.311778 18.132195 21.670120 44.798004
27.925421 58.052605 *

But I always get an non-0 result, I never experienced this before. I tried
the linux ,the mac and also the windows version with your image - it didn't
happen. So which version are you using? Which operating system? (type
evalglare -v to find out)

@Alstan: Can you provide me another example where this happens as well?
Which version are you using? Which operating system?

A zero value should never appear, except your image is completely black.

Best,
Jan

Am 8/11/15 um 5:33 PM schrieb J. Alstan Jakubiec:

Hi Jasper,

This is one of the tricky aspects of doing glare analysis with your own
HDR images. A couple of pointers are below,

   - You will need to crop your image to a square aspect about the image
   center using the pcompos
   <http://radsite.lbl.gov/radiance/man_html/pcompos.1.html> tool. There
   was a helpful discussion on maintaining image exposure values while doing
   this here
   <http://www.radiance-online.org/pipermail/radiance-general/2011-March/007701.html>
   .
   - The -vv and -vh parameters are just best guesses according the HDR
   generation software. Once you have cropped the image, you will want to open
   the resulting HDR in a text editor and manually change the header 'VIEW'
   field to include -vta -vv 180 -vh 180. You may also specify them via
   the command line at this point, as you have done. I like to keep it
   associated with the image.
   - After that, unless I am forgetting something (others can chime in),
   you are ready to run evalglare. I would run it with the -d flag, which
   will report a lot of details. Most usefully, it reports illuminance as
   derived from the image, which you can compare to your measured Ev value to
   check the validity of the HDR. If your HDR is well-calibrated, not
   inputting the measured illuminance value should be perfectly accurate.
   - I suspect that inputting measured illuminance is somewhat broken in
   the current version of evalglare as I have the same problem that you do.
   One option is to use the -1 option to evalglare, which will return
   only a single DGP value. It seems to avoid this error.
   > evalglare -1 -i 2500 image.hdr

By the way, to avoid some of this cropping and exposure value pain, I use
an image-processing tool (like PIL for Python) these days that can maintain
EXIF data while cropping the source jpeg files. Though perhaps the cure is
worse than the disease in this case..

Best,
Alstan

On 8/11/2015 11:08 PM, Jasper Overduin wrote:

Dear all,

I have changed my lens to one with 180 circular view to do a contrast
analysis (hdrscope) and meanwhile the glare analysis in evalglare. If i use
the commands in evalglare getinfo i get the (HDR composed with photosphere
on a mac, calibrated with luminance pistol) i get a value for the lens -vv
and -vh which is not over 100, with a lens of 180. I can imagine that the
photo ratio and the lens are not the same and that causes this problem. But
when I enter the external measured Ev, the value the dgp goes somehow to
zero. The fact that the gdp is zero with a maximum luminance of 5600 cd/m2
and Ev of 2500 lux makes me a bit suspicious. How accurate is the result of
the dgp without external vertical lux? is it possible to use this value?

hdr files and printscreens of evalglare
<https://www.dropbox.com/sh/ei1y4d2v6hapdsr/AACgVMPd1o0EdK-0q8CFvUGga?dl=0>
https://www.dropbox.com/sh/ei1y4d2v6hapdsr/AACgVMPd1o0EdK-0q8CFvUGga?dl=0

Greetings Jasper

*Jasper Overduin*
MSc. Building Technology graduate student at Delft University of Technology

*S* Groenhoevelaan 3
*P* 2343 BP Oegstgeest
*T* +31 6 15 64 48 56 (NL)
*T* +56 9 51 11 76 48 (CL)
*E * <[email protected]>[email protected]
*Skype *jasper.overduin

On 1 May 2015 at 12:15, Jan Wienold <[email protected]> wrote:

Hi Jasper,

I briefly looked at your image - for sure you get a low DGP value if your
illuminance at camera (or eye) level is only about 300lux... It is not the
matter of the fish eye lens it is a matter of your lighting condition.
When I remember correctly, for the experiments I did for my PhD, the
people adjusted the blinds in a way, that they had 2500-3000 lux at the eye
level and they were less than 20% of them dissatisfied. So a value of 300
means one order of magnitude less light at the eye level and a much lower
adaptation level.
So I definitely understand the low DGP value in that case. The images
themselves look reasonable, so I don't think there is a problem in
calibration/processing so far (at least not for these low luminance
levels-it might be more tricky to calibrate for the high luminance values
when you get stray-light from the multiple lenses).

If all your images are like that it means you have a very low daylight
contribution at the place you measure. I'm not sure if DGP is then the
right way to measure glare in that case - as I wrote it is made more for
the daylight oriented workplace with higher levels and also to take into
account very high luminances (e.g. sun or specular reflections of the sun).
DGP might be modified in future, but these experiments are just starting.

Jan

Am 4/30/15 um 10:41 PM schrieb Jasper Overduin:

Thank you for the fast reply. We are still having some problems with the

outcome of Evalglare. With an external luxometre we have done some tests
now. The DGP is still very low or zero. It seems that in almost all the
case the DGP is low. In literature we read that values above 20% are
normal. What do you think? is the data much better if we use a full 180
degree lens?

.hdr file https://www.dropbox.com/s/l10x7tri49btr8r/ff.hdr?dl=0

print screen cmd
<https://www.dropbox.com/s/yv1lamhiirjhvxq/imp%20pan.jpg?dl=0>
https://www.dropbox.com/s/yv1lamhiirjhvxq/imp%20pan.jpg?dl=0
test.pic https://www.dropbox.com/s/nspdu01477mchsz/test.pic?dl=0

Greetings Jasper

*Jasper Overduin*
MSc Building Technology graduate student at Delft University of
Technology

*S* Groenhoevelaan 3
*P* 2343 BP Oegstgeest
*T* +31 6 15 64 48 56 (NL)
*T* +56 9 51 11 76 48 (CL)
*E * <[email protected]>[email protected]
*Skype *jasper.overduin

On 30 April 2015 at 13:55, Jan Wienold < <[email protected]> >>> [email protected]> wrote:

Hi Jasper,

why are you using -vth -vh 140 -vv 80 when in your header of the HDR
image the view is specified as -vtv -vh 98.797409 -vv 75.402067 ?
Manipulating the lense type is really dangerous - in that case you
change from a perspective view to a hemispherical fish eye view, without
changing the image!!

If I apply evalglare for your image I get 0.17 as DGP (which is still
very low, but you have only 2000cd/m2 as maximum value, so this can be
expected). Be aware, that DGP accounts only for glare from a high amount of
daylight and/or spots of extreme luminances (>50000cd/m2), but not for
contrasted glare between task (e.g. Monitor) and immediate surroundings for
lower adaptation levels. This is subject of current research (also here at
EPFL) and there might be an extension of the DGP in future, depending on
the outcome of new experiments.

Back to the lens-type:
It is extremely important, that the right view type is given to
evalglare, otherwise ALL calculated values (it doesn't matter if this is
evalglare or findglare) are wrong. These errors could be huge, more than
100% for calculating the illuminance out of a 180 degree image.

If you manipulate an image by pcomb, in general the view is marked as
"invalid" in the header, because with that tool you could manipulate the
image in a way, that the original view is not valid any more. This is why
from evalglare version 1.0 on a check on the header was included, because
many people were creating wrong headers without knowing it and then
evalglare was calculating wrong values, when the header was invalid.

In addition for calculating the DGP it is important to have the
illuminance at camera level. evalglare calculates this value out of the
image. But if the image does not cover 180 degree, then the calculated
value for the illuminance is too low. For that reason, the -i option was
included, so you can provide the illuminance to evalglare (when you measure
it with an illuminance sensor).

So in your case, you should measure the illuminance just besides the
lens.
Then (in case this is the right lens description) you should use
evalglare -i LUXVALUE -vtv -vh 98.797409 -vv 75.402067 IMAGE_NAME
or better, if your task is always at the same place:
evalglare -i LUXVALUE -vtv -vh 98.797409 -vv 75.402067 -T 395 230 .6
-c CHECK_FILE_PICTURE IMAGE_NAME

good luck!

Jan

Am 4/30/15 um 6:04 PM schrieb Jasper Overduin:

Somehow cant use the command pfilt or change the pcomb, does this has
to do with the program Radiance? I have installed the version of windows
from the site, with evalglare v1.11windows . The problem is that I have
composed a .hdr (out of 7 jpg on a mac) and after using the command
c:/HDRI>evalglare -vth -vh 140 -vv 80 image.hdr all the dgp results are
really low, less than 5%. The problem can be in the .hdr (calibrated as
well) or is in the way evalglare is not working as it shoot on my computer.

*.hdr file* (post-it is calibration point 167,98)
<https://www.dropbox.com/s/4z69y358yt8ii4z/1_sv_am.hdr?dl=0>
https://www.dropbox.com/s/4z69y358yt8ii4z/1_sv_am.hdr?dl=0
*images* original
<https://www.dropbox.com/sh/adyyxjkv6eykyek/AAC96QUTpLh_Ef2U8Mppki8ta?dl=0>
https://www.dropbox.com/sh/adyyxjkv6eykyek/AAC96QUTpLh_Ef2U8Mppki8ta?dl=0
*command printscreen*
<https://www.dropbox.com/s/0pbn105p0z0iinu/Imp%20pan.jpg?dl=0>
https://www.dropbox.com/s/0pbn105p0z0iinu/Imp%20pan.jpg?dl=0

Need the help!

Greetings Jacobus

*Jasper Overduin*
MSc Building Technology graduate student at Delft University of
Technology

*S* Groenhoevelaan 3
*P* 2343 BP Oegstgeest
*T* +31 6 15 64 48 56 (NL)
*T* +56 9 51 11 76 48 (CL)
*E * <[email protected]>[email protected]
*Skype *jasper.overduin

_______________________________________________
Radiance-general mailing [email protected]://www.radiance-online.org/mailman/listinfo/radiance-general

--
Dr.-Ing. Jan Wienold
Ecole Polytechnique Fédérale de Lausanne (EPFL)
EPFL ENAC IA LIPID
http://people.epfl.ch/jan.wienold
LE 1 111 (Office)
Phone +41 21 69 30849

_______________________________________________
Radiance-general mailing list
[email protected]
http://www.radiance-online.org/mailman/listinfo/radiance-general

_______________________________________________
Radiance-general mailing [email protected]://www.radiance-online.org/mailman/listinfo/radiance-general

--
Dr.-Ing. Jan Wienold
Ecole Polytechnique Fédérale de Lausanne (EPFL)
EPFL ENAC IA LIPID
http://people.epfl.ch/jan.wienold
LE 1 111 (Office)
Phone +41 21 69 30849

_______________________________________________
Radiance-general mailing list
[email protected]
http://www.radiance-online.org/mailman/listinfo/radiance-general

_______________________________________________
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_______________________________________________
Radiance-general mailing [email protected]://www.radiance-online.org/mailman/listinfo/radiance-general

--
Dr.-Ing. Jan Wienold
Ecole Polytechnique Fédérale de Lausanne (EPFL)
EPFL ENAC IA LIPID
http://people.epfl.ch/jan.wienold
LE 1 111 (Office)
Phone +41 21 69 30849

_______________________________________________
Radiance-general mailing list
[email protected]
http://www.radiance-online.org/mailman/listinfo/radiance-general

Hi Jasper,

you definitely should use a newer version of evalglare.
If you go to the website:
http://www.ise.fraunhofer.de/radiance
you can at least download the 1.11 version-which doesn't have this bug.

The will be a new version of evalglare coming out in the next days/weeks (version 1.17) - this will be announced separately here in that group.

Regarding your image: Your calibration must span the luminance-range you want to measure.
If you calibrate between 1cd/m2-1000 cd/m2 it does not tell you anything how accurate you are when measuring 100000cd/m2!
So if you want to measure the luminance of the sun, then you have to make sure your camera is calibrated for such high luminances as well.
I guess when you want to measure several million cd/m2 you might need a grey filter. At ISE we had several filters down to 0.0001 transmittance, so it was easy to measure also towards the sun and the increase of noise for the lower luminaces doesn't hurt so much.
Your coating on the window play a minor role in that case... honestly for the sun you can be lucky to measure with one or 2 orders of magnitude, so if your glazing is 0.75 or 0.4 in light transmittance is negligible compared to the difference between 5000 and 200000000 cd/m2 !

The picture you have in dropbox is also difficult to check with an illuminance meter when you integrate the values to an illuminance value, because the sun is so much on the side and has a very flat angle of incidence to your measuring plane. For example when your angle of incidence for the light source (here sun) is 80� and your "uncertainty" for putting the sensor in the right plane wold be 2.5 degree (it is very difficult to put it more accurate), then you have automatically an uncertainty in your sensor reading of 25% (of the illuminance)! (because illuminance is cos-weighted and a difference in angle for large angles is big for the cosinus).

Good luck!

best,
Jan

···

Am 8/12/15 um 3:21 PM schrieb Jasper Overduin:

Im using evalglare 1.10 release 30.09.2012 with windows 7
The photos are calibrated with a (il)lumination pistol with 4 different measurements (with maximum deviation of 0.4 cd/m2)
There is a certain coating on the window, not sure what kind. but as you said the difference is huge.

Within the program of HDRscope there is a similar function and gives and errer as well if i use an external Ev value.

Greetings,
Jasper

*
*Jasper Overduin*
MSc. Building Technology graduate student at Delft University of Technology

*S* Groenhoevelaan 3
*P*2343 BP Oegstgeest
*T* +31 6 15 64 48 56 (NL)
*T* +56 9 51 11 76 48 (CL)
*E *[email protected] <mailto:[email protected]>
*Skype *jasper.overduin

On 12 August 2015 at 06:39, Jan Wienold <[email protected] > <mailto:[email protected]>> wrote:

    Hi Jasper,
    hi Alstan,

    I guess there are several issues in that case. First of all, as
    Alstan wrote, you should crop the image and provide the correct
    lens specification to evalglare. Be aware that editing the header
    could be dangerous, because sometimes editors add strange
    characters or you don't see tabs in the header with marks the view
    string there as "invalid" . In case the header is interpreted
    "wrong" in evalglare, the results could be really random and could
    differ for more than 100% from the right ones (e.g. the
    calculation of the vertical illuminance, see presentation on the
    Radiance workshop in 2012). The header treatment is much more
    robust since the evalglare version 1.08, but still the user should
    take care of providing a correct header. evalglare is relying on a
    correct radiance header. To be on the safe side, you should always
    use the command option to provide the correct view option to
    evalglare.
    Also you should make sure, that you use a view type which really
    corresponds to your lens. If your real lens is a hemispherical
    fish eye and you provide -vta as view string, the angles and
    solid angles are calculated wrong in evalglare and you get wrong
    results. So make sure that you use -vta only if your lens is a
    angular fish eye.
    And please don't use the -1 option in evalglare!!! This is a
    special (undocumented) option to get fast results on images
    calculated without ambient calculations. If you use it for normal
    images, the glare sources might not detected correctly and you
    could get big differences. It is working mostly properly in images
    with large black areas (-ab 0).
    Since the -1 option is not robust for normal images, this option
    is undocumented. There exist also other undocumented options since
    2009 for hdr treatment(e.g. pixel overflow correction, image
    fillup when ccd-array is smaller than the projected image...), but
    these options are by purpose undocumented because they should be
    used only in special cases and can cause wrong results when not
    used properly.

    If I look at your image, I guess your calibration is not correct.
    The sun has a luminance of 2e10 cd/m2. In case of low
    transmittance glazing you still have a luminance of Xe9 cd/m2,
    lets say at least 1e9cd/m2, which is factor 200000 higher than you
    measured!!! And be aware you you might have to deal with blooming effects when you have a pixel overflow (especially when looking
    into the sun). Not sure about your camera setting, but if you
    still have an overflow for the shortest exposure, you should think
    of adding a neutral grey filter to reduce the overall
    transmittance to the ccd.

    Finally I can't reproduce the 0 output of evalglare. I used your
    image and used as well the 2500lux as input (even if the image is
    not cropped correctly and the view string is wrong). See here:
    /evalglare -i 2500 pmar_sin_03.hdr//
    //Notice: Low brightness scene. Vertical illuminance less than 380
    lux! dgp might underestimate glare sources//
    //dgp,dgi,ugr,vcp,cgi,Lveil: 0.311778 18.132195 21.670120
    44.798004 27.925421 58.052605 //

    /But I always get an non-0 result, I never experienced this
    before. I tried the linux ,the mac and also the windows version
    with your image - it didn't happen. So which version are you
    using? Which operating system? (type evalglare -v to find out)

    @Alstan: Can you provide me another example where this happens as
    well? Which version are you using? Which operating system?

    A zero value should never appear, except your image is completely
    black.

    Best,
    Jan

    Am 8/11/15 um 5:33 PM schrieb J. Alstan Jakubiec:

    Hi Jasper,

    This is one of the tricky aspects of doing glare analysis with
    your own HDR images. A couple of pointers are below,

      * You will need to crop your image to a square aspect about the
        image center using the pcompos
        <http://radsite.lbl.gov/radiance/man_html/pcompos.1.html>
        tool. There was a helpful discussion on maintaining image
        exposure values while doing this here
        <http://www.radiance-online.org/pipermail/radiance-general/2011-March/007701.html>.
      * The -vv and -vh parameters are just best guesses according
        the HDR generation software. Once you have cropped the image,
        you will want to open the resulting HDR in a text editor and
        manually change the header 'VIEW' field to include -vta -vv
        180 -vh 180. You may also specify them via the command line
        at this point, as you have done. I like to keep it associated
        with the image.
      * After that, unless I am forgetting something (others can
        chime in), you are ready to run evalglare. I would run it
        with the -d flag, which will report a lot of details. Most
        usefully, it reports illuminance as derived from the image,
        which you can compare to your measured Ev value to check the
        validity of the HDR. If your HDR is well-calibrated, not
        inputting the measured illuminance value should be perfectly
        accurate.
      * I suspect that inputting measured illuminance is somewhat
        broken in the current version of evalglare as I have the same
        problem that you do. One option is to use the -1 option to
        evalglare, which will return only a single DGP value. It
        seems to avoid this error.
        > evalglare -1 -i 2500 image.hdr

    By the way, to avoid some of this cropping and exposure value
    pain, I use an image-processing tool (like PIL for Python) these
    days that can maintain EXIF data while cropping the source jpeg
    files. Though perhaps the cure is worse than the disease in this
    case..

    Best,
    Alstan

    On 8/11/2015 11:08 PM, Jasper Overduin wrote:

    Dear all,

    I have changed my lens to one with 180 circular view to do a
    contrast analysis (hdrscope) and meanwhile the glare analysis in
    evalglare. If i use the commands in evalglare getinfo i get the
    (HDR composed with photosphere on a mac, calibrated with
    luminance pistol) i get a value for the lens -vv and -vh which
    is not over 100, with a lens of 180. I can imagine that the
    photo ratio and the lens are not the same and that causes this
    problem. But when I enter the external measured Ev, the value
    the dgp goes somehow to zero. The fact that the gdp is zero with
    a maximum luminance of 5600 cd/m2 and Ev of 2500 lux makes me a
    bit suspicious. How accurate is the result of the dgp without
    external vertical lux? is it possible to use this value?

    hdr files and printscreens of evalglare
    https://www.dropbox.com/sh/ei1y4d2v6hapdsr/AACgVMPd1o0EdK-0q8CFvUGga?dl=0

    Greetings Jasper

    *
    *Jasper Overduin*
    MSc. Building Technology graduate student at Delft University of
    Technology

    *S* Groenhoevelaan 3
    *P*2343 BP Oegstgeest
    *T* +31 6 15 64 48 56 (NL)
    *T* +56 9 51 11 76 48 (CL)
    *E *[email protected] <mailto:[email protected]>
    *Skype *jasper.overduin

    On 1 May 2015 at 12:15, Jan Wienold <[email protected] >>> <mailto:[email protected]>> wrote:

        Hi Jasper,

        I briefly looked at your image - for sure you get a low DGP
        value if your illuminance at camera (or eye) level is only
        about 300lux... It is not the matter of the fish eye lens it
        is a matter of your lighting condition.
        When I remember correctly, for the experiments I did for my
        PhD, the people adjusted the blinds in a way, that they had
        2500-3000 lux at the eye level and they were less than 20%
        of them dissatisfied. So a value of 300 means one order of
        magnitude less light at the eye level and a much lower
        adaptation level.
        So I definitely understand the low DGP value in that case.
        The images themselves look reasonable, so I don't think
        there is a problem in calibration/processing so far (at
        least not for these low luminance levels-it might be more
        tricky to calibrate for the high luminance values when you
        get stray-light from the multiple lenses).

        If all your images are like that it means you have a very
        low daylight contribution at the place you measure. I'm not
        sure if DGP is then the right way to measure glare in that
        case - as I wrote it is made more for the daylight oriented
        workplace with higher levels and also to take into account
        very high luminances (e.g. sun or specular reflections of
        the sun). DGP might be modified in future, but these
        experiments are just starting.

        Jan

        Am 4/30/15 um 10:41 PM schrieb Jasper Overduin:

            Thank you for the fast reply. We are still having some
            problems with the outcome of Evalglare. With an
            external luxometre we have done some tests now. The DGP
            is still very low or zero. It seems that in almost all
            the case the DGP is low. In literature we read that
            values above 20% are normal. What do you think? is the
            data much better if we use a full 180 degree lens?

        .hdr file https://www.dropbox.com/s/l10x7tri49btr8r/ff.hdr?dl=0
        print screen cmd
        https://www.dropbox.com/s/yv1lamhiirjhvxq/imp%20pan.jpg?dl=0
        test.pic
        https://www.dropbox.com/s/nspdu01477mchsz/test.pic?dl=0

            Greetings Jasper

            *
            *Jasper Overduin*
            MSc Building Technology graduate student at Delft
            University of Technology*
            *

            *S* Groenhoevelaan 3
            *P*2343 BP Oegstgeest
            *T* +31 6 15 64 48 56 (NL)
            *T* +56 9 51 11 76 48 (CL)
            *E *[email protected]
            <mailto:[email protected]>
            *Skype *jasper.overduin

            On 30 April 2015 at 13:55, Jan Wienold >>>> <[email protected] <mailto:[email protected]>> wrote:

                Hi Jasper,

                why are you using -vth -vh 140 -vv 80 when in your
                header of the HDR image the view is specified as
                -vtv -vh 98.797409 -vv 75.402067 ?
                Manipulating the lense type is really dangerous -
                in that case you change from a perspective view to
                a hemispherical fish eye view, without changing the
                image!!

                If I apply evalglare for your image I get 0.17 as
                DGP (which is still very low, but you have only
                2000cd/m2 as maximum value, so this can be
                expected). Be aware, that DGP accounts only for
                glare from a high amount of daylight and/or spots
                of extreme luminances (>50000cd/m2), but not for
                contrasted glare between task (e.g. Monitor) and
                immediate surroundings for lower adaptation levels.
                This is subject of current research (also here at
                EPFL) and there might be an extension of the DGP in
                future, depending on the outcome of new experiments.

                Back to the lens-type:
                It is extremely important, that the right view type
                is given to evalglare, otherwise ALL calculated
                values (it doesn't matter if this is evalglare or
                findglare) are wrong. These errors could be huge,
                more than 100% for calculating the illuminance out
                of a 180 degree image.

                If you manipulate an image by pcomb, in general the
                view is marked as "invalid" in the header, because
                with that tool you could manipulate the image in a
                way, that the original view is not valid any more.
                This is why from evalglare version 1.0 on a check
                on the header was included, because many people
                were creating wrong headers without knowing it and
                then evalglare was calculating wrong values, when
                the header was invalid.

                In addition for calculating the DGP it is important
                to have the illuminance at camera level. evalglare
                calculates this value out of the image. But if the
                image does not cover 180 degree, then the
                calculated value for the illuminance is too low.
                For that reason, the -i option was included, so you
                can provide the illuminance to evalglare (when you
                measure it with an illuminance sensor).

                So in your case, you should measure the illuminance
                just besides the lens.
                Then (in case this is the right lens description)
                you should use
                evalglare -i LUXVALUE -vtv -vh 98.797409 -vv
                75.402067 IMAGE_NAME
                or better, if your task is always at the same place:
                evalglare -i LUXVALUE -vtv -vh 98.797409 -vv
                75.402067 -T 395 230 .6 -c CHECK_FILE_PICTURE
                IMAGE_NAME

                good luck!

                Jan

                Am 4/30/15 um 6:04 PM schrieb Jasper Overduin:

                Somehow cant use the command pfilt or change the
                pcomb, does this has to do with the program
                Radiance? I have installed the version of windows
                from the site, with evalglare v1.11windows . The
                problem is that I have composed a .hdr (out of 7
                jpg on a mac) and after using the command
                c:/HDRI>evalglare -vth -vh 140 -vv 80 image.hdr
                all the dgp results are really low, less than 5%.
                The problem can be in the .hdr (calibrated as
                well) or is in the way evalglare is not working as
                it shoot on my computer.

                *.hdr file* (post-it is calibration point 167,98)
                https://www.dropbox.com/s/4z69y358yt8ii4z/1_sv_am.hdr?dl=0
                *images* original
                https://www.dropbox.com/sh/adyyxjkv6eykyek/AAC96QUTpLh_Ef2U8Mppki8ta?dl=0
                *command printscreen*
                https://www.dropbox.com/s/0pbn105p0z0iinu/Imp%20pan.jpg?dl=0

                Need the help!

                Greetings Jacobus

                *
                *Jasper Overduin*
                MSc Building Technology graduate student at Delft
                University of Technology*
                *

                *S* Groenhoevelaan 3
                *P*2343 BP Oegstgeest
                *T* +31 6 15 64 48 56 (NL)
                *T* +56 9 51 11 76 48 (CL)
                *E *[email protected]
                <mailto:[email protected]>
                *Skype *jasper.overduin

                _______________________________________________
                Radiance-general mailing list
                [email protected]
                <mailto:[email protected]>
                http://www.radiance-online.org/mailman/listinfo/radiance-general

                -- Dr.-Ing. Jan Wienold
                Ecole Polytechnique F�d�rale de Lausanne (EPFL)
                EPFL ENAC IA LIPID

                http://people.epfl.ch/jan.wienold
                LE 1 111 (Office)
                Phone +41 21 69 30849

                _______________________________________________
                Radiance-general mailing list
                [email protected]
                <mailto:[email protected]>
                http://www.radiance-online.org/mailman/listinfo/radiance-general

        _______________________________________________
        Radiance-general mailing list
        [email protected]
        <mailto:[email protected]>
        http://www.radiance-online.org/mailman/listinfo/radiance-general

        -- Dr.-Ing. Jan Wienold
        Ecole Polytechnique F�d�rale de Lausanne (EPFL)
        EPFL ENAC IA LIPID

        http://people.epfl.ch/jan.wienold
        LE 1 111 (Office)
        Phone +41 21 69 30849

        _______________________________________________
        Radiance-general mailing list
        [email protected]
        <mailto:[email protected]>
        http://www.radiance-online.org/mailman/listinfo/radiance-general

    _______________________________________________
    Radiance-general mailing list
    [email protected]
    <mailto:[email protected]>
    http://www.radiance-online.org/mailman/listinfo/radiance-general

    _______________________________________________
    Radiance-general mailing list
    [email protected]
    <mailto:[email protected]>
    http://www.radiance-online.org/mailman/listinfo/radiance-general

    -- Dr.-Ing. Jan Wienold
    Ecole Polytechnique F�d�rale de Lausanne (EPFL)
    EPFL ENAC IA LIPID

    http://people.epfl.ch/jan.wienold
    LE 1 111 (Office)
    Phone +41 21 69 30849

    _______________________________________________
    Radiance-general mailing list
    [email protected]
    <mailto:[email protected]>
    http://www.radiance-online.org/mailman/listinfo/radiance-general

_______________________________________________
Radiance-general mailing list
[email protected]
http://www.radiance-online.org/mailman/listinfo/radiance-general

--
Dr.-Ing. Jan Wienold
Ecole Polytechnique F�d�rale de Lausanne (EPFL)
EPFL ENAC IA LIPID

http://people.epfl.ch/jan.wienold
LE 1 111 (Office)
Phone +41 21 69 30849

Thanks a lot for the help so far. I've updated the evalglare to 1.11.
Getting the same results as Jan showed.

I've desinstalled and reinstalled everything, and now the pcompos and other
functions are not recognized. With a google search I couldnt find the
problem.

any ideas?

installed
radiance 2.01
daysim 4.0
ecotect 2011
evalglare 1.11

As far as the picture. This is the only photo with an almost direct sun.
Other photos (160) are within a more sober spectrum. The idea is to to an
analysis of cd/m2 ratios, with the evalglare as indicator, not as main
target. Do you think it is possible to use the data?

Greetings,
Jasper

*Jasper Overduin*
MSc. Building Technology graduate student at Delft University of Technology

*S* Groenhoevelaan 3
*P* 2343 BP Oegstgeest
*T* +31 6 15 64 48 56 (NL)
*T* +56 9 51 11 76 48 (CL)
*E *[email protected]
*Skype *jasper.overduin

···

On 13 August 2015 at 11:23, Jan Wienold <[email protected]> wrote:

Hi Jasper,

you definitely should use a newer version of evalglare.
If you go to the website:
http://www.ise.fraunhofer.de/radiance
you can at least download the 1.11 version-which doesn't have this bug.

The will be a new version of evalglare coming out in the next days/weeks
(version 1.17) - this will be announced separately here in that group.

Regarding your image: Your calibration must span the luminance-range you
want to measure.
If you calibrate between 1cd/m2-1000 cd/m2 it does not tell you anything
how accurate you are when measuring 100000cd/m2!
So if you want to measure the luminance of the sun, then you have to make
sure your camera is calibrated for such high luminances as well.
I guess when you want to measure several million cd/m2 you might need a
grey filter. At ISE we had several filters down to 0.0001 transmittance, so
it was easy to measure also towards the sun and the increase of noise for
the lower luminaces doesn't hurt so much.
Your coating on the window play a minor role in that case... honestly for
the sun you can be lucky to measure with one or 2 orders of magnitude, so
if your glazing is 0.75 or 0.4 in light transmittance is negligible
compared to the difference between 5000 and 200000000 cd/m2 !

The picture you have in dropbox is also difficult to check with an
illuminance meter when you integrate the values to an illuminance value,
because the sun is so much on the side and has a very flat angle of
incidence to your measuring plane. For example when your angle of incidence
for the light source (here sun) is 80° and your "uncertainty" for putting
the sensor in the right plane wold be 2.5 degree (it is very difficult to
put it more accurate), then you have automatically an uncertainty in your
sensor reading of 25% (of the illuminance)! (because illuminance is
cos-weighted and a difference in angle for large angles is big for the
cosinus).

Good luck!

best,
Jan

Am 8/12/15 um 3:21 PM schrieb Jasper Overduin:

Im using evalglare 1.10 release 30.09.2012 with windows 7
The photos are calibrated with a (il)lumination pistol with 4 different
measurements (with maximum deviation of 0.4 cd/m2)
There is a certain coating on the window, not sure what kind. but as you
said the difference is huge.

Within the program of HDRscope there is a similar function and gives and
errer as well if i use an external Ev value.

Greetings,
Jasper

*Jasper Overduin*
MSc. Building Technology graduate student at Delft University of Technology

*S* Groenhoevelaan 3
*P* 2343 BP Oegstgeest
*T* +31 6 15 64 48 56 (NL)
*T* +56 9 51 11 76 48 (CL)
*E * <[email protected]>[email protected]
*Skype *jasper.overduin

On 12 August 2015 at 06:39, Jan Wienold <[email protected]> wrote:

Hi Jasper,
hi Alstan,

I guess there are several issues in that case. First of all, as Alstan
wrote, you should crop the image and provide the correct lens specification
to evalglare. Be aware that editing the header could be dangerous, because
sometimes editors add strange characters or you don't see tabs in the
header with marks the view string there as "invalid" . In case the header
is interpreted "wrong" in evalglare, the results could be really random and
could differ for more than 100% from the right ones (e.g. the calculation
of the vertical illuminance, see presentation on the Radiance workshop in
2012). The header treatment is much more robust since the evalglare version
1.08, but still the user should take care of providing a correct header.
evalglare is relying on a correct radiance header. To be on the safe side,
you should always use the command option to provide the correct view option
to evalglare.
Also you should make sure, that you use a view type which really
corresponds to your lens. If your real lens is a hemispherical fish eye and
you provide -vta as view string, the angles and solid angles are
calculated wrong in evalglare and you get wrong results. So make sure that
you use -vta only if your lens is a angular fish eye.
And please don't use the -1 option in evalglare!!! This is a special
(undocumented) option to get fast results on images calculated without
ambient calculations. If you use it for normal images, the glare sources
might not detected correctly and you could get big differences. It is
working mostly properly in images with large black areas (-ab 0).
Since the -1 option is not robust for normal images, this option is
undocumented. There exist also other undocumented options since 2009 for
hdr treatment(e.g. pixel overflow correction, image fillup when ccd-array
is smaller than the projected image...), but these options are by purpose
undocumented because they should be used only in special cases and can
cause wrong results when not used properly.

If I look at your image, I guess your calibration is not correct. The sun
has a luminance of 2e10 cd/m2. In case of low transmittance glazing you
still have a luminance of Xe9 cd/m2, lets say at least 1e9cd/m2, which is
factor 200000 higher than you measured!!! And be aware you you might have
to deal with blooming effects when you have a pixel overflow (especially
when looking into the sun). Not sure about your camera setting, but if you
still have an overflow for the shortest exposure, you should think of
adding a neutral grey filter to reduce the overall transmittance to the ccd.

Finally I can't reproduce the 0 output of evalglare. I used your image
and used as well the 2500lux as input (even if the image is not cropped
correctly and the view string is wrong). See here:
*evalglare -i 2500 pmar_sin_03.hdr*
*Notice: Low brightness scene. Vertical illuminance less than 380 lux!
dgp might underestimate glare sources*
*dgp,dgi,ugr,vcp,cgi,Lveil: 0.311778 18.132195 21.670120 44.798004
27.925421 58.052605 *

But I always get an non-0 result, I never experienced this before. I
tried the linux ,the mac and also the windows version with your image - it
didn't happen. So which version are you using? Which operating system?
(type evalglare -v to find out)

@Alstan: Can you provide me another example where this happens as well?
Which version are you using? Which operating system?

A zero value should never appear, except your image is completely black.

Best,
Jan

Am 8/11/15 um 5:33 PM schrieb J. Alstan Jakubiec:

Hi Jasper,

This is one of the tricky aspects of doing glare analysis with your own
HDR images. A couple of pointers are below,

   - You will need to crop your image to a square aspect about the image
   center using the pcompos
   <http://radsite.lbl.gov/radiance/man_html/pcompos.1.html> tool. There
   was a helpful discussion on maintaining image exposure values while doing
   this here
   <http://www.radiance-online.org/pipermail/radiance-general/2011-March/007701.html>
   .
   - The -vv and -vh parameters are just best guesses according the HDR
   generation software. Once you have cropped the image, you will want to open
   the resulting HDR in a text editor and manually change the header 'VIEW'
   field to include -vta -vv 180 -vh 180. You may also specify them via
   the command line at this point, as you have done. I like to keep it
   associated with the image.
   - After that, unless I am forgetting something (others can chime in),
   you are ready to run evalglare. I would run it with the -d flag,
   which will report a lot of details. Most usefully, it reports illuminance
   as derived from the image, which you can compare to your measured Ev value
   to check the validity of the HDR. If your HDR is well-calibrated, not
   inputting the measured illuminance value should be perfectly accurate.
   - I suspect that inputting measured illuminance is somewhat broken in
   the current version of evalglare as I have the same problem that you do.
   One option is to use the -1 option to evalglare, which will return
   only a single DGP value. It seems to avoid this error.
   > evalglare -1 -i 2500 image.hdr

By the way, to avoid some of this cropping and exposure value pain, I use
an image-processing tool (like PIL for Python) these days that can maintain
EXIF data while cropping the source jpeg files. Though perhaps the cure is
worse than the disease in this case..

Best,
Alstan

On 8/11/2015 11:08 PM, Jasper Overduin wrote:

Dear all,

I have changed my lens to one with 180 circular view to do a contrast
analysis (hdrscope) and meanwhile the glare analysis in evalglare. If i use
the commands in evalglare getinfo i get the (HDR composed with photosphere
on a mac, calibrated with luminance pistol) i get a value for the lens -vv
and -vh which is not over 100, with a lens of 180. I can imagine that the
photo ratio and the lens are not the same and that causes this problem. But
when I enter the external measured Ev, the value the dgp goes somehow to
zero. The fact that the gdp is zero with a maximum luminance of 5600 cd/m2
and Ev of 2500 lux makes me a bit suspicious. How accurate is the result of
the dgp without external vertical lux? is it possible to use this value?

hdr files and printscreens of evalglare
<https://www.dropbox.com/sh/ei1y4d2v6hapdsr/AACgVMPd1o0EdK-0q8CFvUGga?dl=0>
https://www.dropbox.com/sh/ei1y4d2v6hapdsr/AACgVMPd1o0EdK-0q8CFvUGga?dl=0

Greetings Jasper

*Jasper Overduin*
MSc. Building Technology graduate student at Delft University of
Technology

*S* Groenhoevelaan 3
*P* 2343 BP Oegstgeest
*T* +31 6 15 64 48 56 (NL)
*T* +56 9 51 11 76 48 (CL)
*E * <[email protected]>[email protected]
*Skype *jasper.overduin

On 1 May 2015 at 12:15, Jan Wienold < <[email protected]> >> [email protected]> wrote:

Hi Jasper,

I briefly looked at your image - for sure you get a low DGP value if
your illuminance at camera (or eye) level is only about 300lux... It is not
the matter of the fish eye lens it is a matter of your lighting condition.
When I remember correctly, for the experiments I did for my PhD, the
people adjusted the blinds in a way, that they had 2500-3000 lux at the eye
level and they were less than 20% of them dissatisfied. So a value of 300
means one order of magnitude less light at the eye level and a much lower
adaptation level.
So I definitely understand the low DGP value in that case. The images
themselves look reasonable, so I don't think there is a problem in
calibration/processing so far (at least not for these low luminance
levels-it might be more tricky to calibrate for the high luminance values
when you get stray-light from the multiple lenses).

If all your images are like that it means you have a very low daylight
contribution at the place you measure. I'm not sure if DGP is then the
right way to measure glare in that case - as I wrote it is made more for
the daylight oriented workplace with higher levels and also to take into
account very high luminances (e.g. sun or specular reflections of the sun).
DGP might be modified in future, but these experiments are just starting.

Jan

Am 4/30/15 um 10:41 PM schrieb Jasper Overduin:

Thank you for the fast reply. We are still having some problems with the

outcome of Evalglare. With an external luxometre we have done some tests
now. The DGP is still very low or zero. It seems that in almost all the
case the DGP is low. In literature we read that values above 20% are
normal. What do you think? is the data much better if we use a full 180
degree lens?

.hdr file <https://www.dropbox.com/s/l10x7tri49btr8r/ff.hdr?dl=0>

https://www.dropbox.com/s/l10x7tri49btr8r/ff.hdr?dl=0
print screen cmd
<https://www.dropbox.com/s/yv1lamhiirjhvxq/imp%20pan.jpg?dl=0>
https://www.dropbox.com/s/yv1lamhiirjhvxq/imp%20pan.jpg?dl=0
test.pic <https://www.dropbox.com/s/nspdu01477mchsz/test.pic?dl=0>
https://www.dropbox.com/s/nspdu01477mchsz/test.pic?dl=0

Greetings Jasper

*Jasper Overduin*
MSc Building Technology graduate student at Delft University of
Technology

*S* Groenhoevelaan 3
*P* 2343 BP Oegstgeest
*T* +31 6 15 64 48 56 (NL)
*T* +56 9 51 11 76 48 (CL)
*E * <[email protected]>[email protected]
*Skype *jasper.overduin

On 30 April 2015 at 13:55, Jan Wienold < <[email protected]> >>>> [email protected]> wrote:

Hi Jasper,

why are you using -vth -vh 140 -vv 80 when in your header of the HDR
image the view is specified as -vtv -vh 98.797409 -vv 75.402067 ?
Manipulating the lense type is really dangerous - in that case you
change from a perspective view to a hemispherical fish eye view, without
changing the image!!

If I apply evalglare for your image I get 0.17 as DGP (which is still
very low, but you have only 2000cd/m2 as maximum value, so this can be
expected). Be aware, that DGP accounts only for glare from a high amount of
daylight and/or spots of extreme luminances (>50000cd/m2), but not for
contrasted glare between task (e.g. Monitor) and immediate surroundings for
lower adaptation levels. This is subject of current research (also here at
EPFL) and there might be an extension of the DGP in future, depending on
the outcome of new experiments.

Back to the lens-type:
It is extremely important, that the right view type is given to
evalglare, otherwise ALL calculated values (it doesn't matter if this is
evalglare or findglare) are wrong. These errors could be huge, more than
100% for calculating the illuminance out of a 180 degree image.

If you manipulate an image by pcomb, in general the view is marked as
"invalid" in the header, because with that tool you could manipulate the
image in a way, that the original view is not valid any more. This is why
from evalglare version 1.0 on a check on the header was included, because
many people were creating wrong headers without knowing it and then
evalglare was calculating wrong values, when the header was invalid.

In addition for calculating the DGP it is important to have the
illuminance at camera level. evalglare calculates this value out of the
image. But if the image does not cover 180 degree, then the calculated
value for the illuminance is too low. For that reason, the -i option was
included, so you can provide the illuminance to evalglare (when you measure
it with an illuminance sensor).

So in your case, you should measure the illuminance just besides the
lens.
Then (in case this is the right lens description) you should use
evalglare -i LUXVALUE -vtv -vh 98.797409 -vv 75.402067 IMAGE_NAME
or better, if your task is always at the same place:
evalglare -i LUXVALUE -vtv -vh 98.797409 -vv 75.402067 -T 395 230 .6
-c CHECK_FILE_PICTURE IMAGE_NAME

good luck!

Jan

Am 4/30/15 um 6:04 PM schrieb Jasper Overduin:

Somehow cant use the command pfilt or change the pcomb, does this has
to do with the program Radiance? I have installed the version of windows
from the site, with evalglare v1.11windows . The problem is that I have
composed a .hdr (out of 7 jpg on a mac) and after using the command
c:/HDRI>evalglare -vth -vh 140 -vv 80 image.hdr all the dgp results are
really low, less than 5%. The problem can be in the .hdr (calibrated as
well) or is in the way evalglare is not working as it shoot on my computer.

*.hdr file* (post-it is calibration point 167,98)
<https://www.dropbox.com/s/4z69y358yt8ii4z/1_sv_am.hdr?dl=0>
https://www.dropbox.com/s/4z69y358yt8ii4z/1_sv_am.hdr?dl=0
*images* original
<https://www.dropbox.com/sh/adyyxjkv6eykyek/AAC96QUTpLh_Ef2U8Mppki8ta?dl=0>
https://www.dropbox.com/sh/adyyxjkv6eykyek/AAC96QUTpLh_Ef2U8Mppki8ta?dl=0
*command printscreen*
<https://www.dropbox.com/s/0pbn105p0z0iinu/Imp%20pan.jpg?dl=0>
https://www.dropbox.com/s/0pbn105p0z0iinu/Imp%20pan.jpg?dl=0

Need the help!

Greetings Jacobus

*Jasper Overduin*
MSc Building Technology graduate student at Delft University of
Technology

*S* Groenhoevelaan 3
*P* 2343 BP Oegstgeest
*T* +31 6 15 64 48 56 (NL)
*T* +56 9 51 11 76 48 (CL)
*E * <[email protected]>[email protected]
*Skype *jasper.overduin

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Radiance-general mailing [email protected]://www.radiance-online.org/mailman/listinfo/radiance-general

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Dr.-Ing. Jan Wienold
Ecole Polytechnique Fédérale de Lausanne (EPFL)
EPFL ENAC IA LIPID
http://people.epfl.ch/jan.wienold
LE 1 111 (Office)
Phone +41 21 69 30849

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_______________________________________________
Radiance-general mailing [email protected]://www.radiance-online.org/mailman/listinfo/radiance-general

--
Dr.-Ing. Jan Wienold
Ecole Polytechnique Fédérale de Lausanne (EPFL)
EPFL ENAC IA LIPID
http://people.epfl.ch/jan.wienold
LE 1 111 (Office)
Phone +41 21 69 30849

_______________________________________________
Radiance-general mailing list
[email protected]
http://www.radiance-online.org/mailman/listinfo/radiance-general

_______________________________________________
Radiance-general mailing [email protected]://www.radiance-online.org/mailman/listinfo/radiance-general

_______________________________________________
Radiance-general mailing [email protected]://www.radiance-online.org/mailman/listinfo/radiance-general

--
Dr.-Ing. Jan Wienold
Ecole Polytechnique Fédérale de Lausanne (EPFL)
EPFL ENAC IA LIPID
http://people.epfl.ch/jan.wienold
LE 1 111 (Office)
Phone +41 21 69 30849

_______________________________________________
Radiance-general mailing list
[email protected]
http://www.radiance-online.org/mailman/listinfo/radiance-general

_______________________________________________
Radiance-general mailing [email protected]://www.radiance-online.org/mailman/listinfo/radiance-general

--
Dr.-Ing. Jan Wienold
Ecole Polytechnique Fédérale de Lausanne (EPFL)
EPFL ENAC IA LIPID
http://people.epfl.ch/jan.wienold
LE 1 111 (Office)
Phone +41 21 69 30849

_______________________________________________
Radiance-general mailing list
[email protected]
http://www.radiance-online.org/mailman/listinfo/radiance-general