Faulty fisheye HDR, DGP always 1.0

Hi All,

I am trying to asses visual discomfort using fisheye HDR images. We generated HDR image from a set of 360 degree LDRs and then converted to fisheye HDR ( using a custom made tools). The intension was to use these Fisheye HDRs as input to Evalglare and get DGP value. The Camera used is Ricoh Theta V 360 degree camera.

The problem I am facing is, the DGP calculated from the generated fisheye HDR with Evalglare is always 1.0. We did the calibration but I would like to have expert opinion from you people, what is going wrong with these set of images. Here is the link <https://seafile.rlp.net/f/0212995d110648d38032/?dl=1> to the pictures.

It would be great if anyone could identify the issue.

Best Regards,
Raghu

Hi Raghu,

It looks like your HDR image header is missing the necessary view information. Typically, this might be something like:

VIEW= -vta -vh 180 -vv 180

for a perspective such as yours. You should be sure that your fisheye mapping corresponds to one of the standard Radiance types.

Best,
-Greg

···

From: raghuram kalyanam <[email protected]>
Date: February 6, 2018 5:21:59 AM PST

Hi All,

I am trying to asses visual discomfort using fisheye HDR images. We generated HDR image from a set of 360 degree LDRs and then converted to fisheye HDR ( using a custom made tools). The intension was to use these Fisheye HDRs as input to Evalglare and get DGP value. The Camera used is Ricoh Theta V 360 degree camera.

The problem I am facing is, the DGP calculated from the generated fisheye HDR with Evalglare is always 1.0. We did the calibration but I would like to have expert opinion from you people, what is going wrong with these set of images. Here is the link to the pictures.

It would be great if anyone could identify the issue.

Best Regards,
Raghu

Hi Greg,

I added these options while passing to evalglare like below.

evalglare -vta -vh 180 -vv 180 <hdr file>, and it worked but it always gives 1.0 as DGP (even other parameters are out of bounds).

With out those options evalglare throws an error.

Apart from that

Are all the LDR’s provided, valid to combine into HDR?

I doubt if one or more of the LDR’s is the culprit (especially something to do with over or under exposure).

Best Regards,
Raghu

···

On Feb 6, 2018, at 5:05 PM, Greg Ward <[email protected]> wrote:

Hi Raghu,

It looks like your HDR image header is missing the necessary view information. Typically, this might be something like:

VIEW= -vta -vh 180 -vv 180

for a perspective such as yours. You should be sure that your fisheye mapping corresponds to one of the standard Radiance types.

Best,
-Greg

From: raghuram kalyanam <[email protected] <mailto:[email protected]>>
Date: February 6, 2018 5:21:59 AM PST

Hi All,

I am trying to asses visual discomfort using fisheye HDR images. We generated HDR image from a set of 360 degree LDRs and then converted to fisheye HDR ( using a custom made tools). The intension was to use these Fisheye HDRs as input to Evalglare and get DGP value. The Camera used is Ricoh Theta V 360 degree camera.

The problem I am facing is, the DGP calculated from the generated fisheye HDR with Evalglare is always 1.0. We did the calibration but I would like to have expert opinion from you people, what is going wrong with these set of images. Here is the link <https://seafile.rlp.net/f/0212995d110648d38032/?dl=1> to the pictures.

It would be great if anyone could identify the issue.

Best Regards,
Raghu

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

Hi Raghu,

it is very simple: your HDR image is simply not correct...

The luminance of your blue sky is more than 400000 cd/m2 and the floor has more than 200000 cd/m2� you really have a problem in your hdr generation or calibration... maybe you have used an additional factor 179� in the image???

Of course with these high values DGP gets 1...

good luck
Jan

···

On 06.02.18 14:21, raghuram kalyanam wrote:

Hi All,

I am trying to asses visual discomfort �using fisheye HDR images. We generated HDR image from a set of 360 degree LDRs and then converted to fisheye HDR ( using a custom made tools). The intension was to use these Fisheye HDRs as input to Evalglare and get DGP value. The Camera used is Ricoh Theta V 360 degree camera.

The problem I am facing is, the DGP calculated from the generated fisheye HDR with Evalglare is always 1.0. We did the calibration but I would like to have expert opinion from you people, what is going wrong with these set of images. Here is the link <https://seafile.rlp.net/f/0212995d110648d38032/?dl=1>�to the pictures.

It would be great if anyone could identify the issue.

Best Regards,
Raghu

_______________________________________________
Radiance-general mailing list
[email protected]
https://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 Raghu,

We may need to wait to hear from Jan or someone who understands evalglare better than I do. I don't think there is a problem with your HDR image as you generated it.

-Greg

···

From: raghuram kalyanam <[email protected]>
Date: February 6, 2018 9:05:41 AM PST

Hi Greg,

I added these options while passing to evalglare like below.

evalglare -vta -vh 180 -vv 180 <hdr file>, and it worked but it always gives 1.0 as DGP (even other parameters are out of bounds).

With out those options evalglare throws an error.

Apart from that

Are all the LDR’s provided, valid to combine into HDR?

I doubt if one or more of the LDR’s is the culprit (especially something to do with over or under exposure).

Best Regards,
Raghu

On Feb 6, 2018, at 5:05 PM, Greg Ward <[email protected]> wrote:

Hi Raghu,

It looks like your HDR image header is missing the necessary view information. Typically, this might be something like:

VIEW= -vta -vh 180 -vv 180

for a perspective such as yours. You should be sure that your fisheye mapping corresponds to one of the standard Radiance types.

Best,
-Greg

From: raghuram kalyanam <[email protected]>
Date: February 6, 2018 5:21:59 AM PST

Hi All,

I am trying to asses visual discomfort using fisheye HDR images. We generated HDR image from a set of 360 degree LDRs and then converted to fisheye HDR ( using a custom made tools). The intension was to use these Fisheye HDRs as input to Evalglare and get DGP value. The Camera used is Ricoh Theta V 360 degree camera.

The problem I am facing is, the DGP calculated from the generated fisheye HDR with Evalglare is always 1.0. We did the calibration but I would like to have expert opinion from you people, what is going wrong with these set of images. Here is the link to the pictures.

It would be great if anyone could identify the issue.

Best Regards,
Raghu

was it taken on mercury ? :wink:

the luminances are far off... it sums up to more than 600000 lux
Jan

···

On 06.02.18 18:18, Greg Ward wrote:

Hi Raghu,

We may need to wait to hear from Jan or someone who understands evalglare better than I do. �I don't think there is a problem with your HDR image as you generated it.

-Greg

*From: *raghuram kalyanam <[email protected] <mailto:[email protected]>>

*Date: *February 6, 2018 9:05:41 AM PST

*

Hi Greg,

I added these options while passing to evalglare like below.

evalglare -vta -vh 180 -vv 180 <hdr file>, and it worked but it always gives 1.0 as DGP (even other parameters are out of bounds).

With out those options evalglare throws an error.

Apart from that

Are all the LDR�s provided, valid to combine into HDR?

I doubt if one or more of the LDR�s is the culprit (especially something to do with over or under exposure).

Best Regards,
Raghu

On Feb 6, 2018, at 5:05 PM, Greg Ward <[email protected] >>> <mailto:[email protected]>> wrote:

Hi Raghu,

It looks like your HDR image header is missing the necessary view information. �Typically, this might be something like:

VIEW= -vta -vh 180 -vv 180

for a perspective such as yours. �You should be sure that your fisheye mapping corresponds to one of the standard Radiance types.

Best,
-Greg

*From: *raghuram kalyanam <[email protected] <mailto:[email protected]>>
*Date: *February 6, 2018 5:21:59 AM PST
*
Hi All,

I am trying to asses visual discomfort �using fisheye HDR images. We generated HDR image from a set of 360 degree LDRs and then converted to fisheye HDR ( using a custom made tools). The intension was to use these Fisheye HDRs as input to Evalglare and get DGP value. The Camera used is Ricoh Theta V 360 degree camera.

The problem I am facing is, the DGP calculated from the generated fisheye HDR with Evalglare is always 1.0. We did the calibration but I would like to have expert opinion from you people, what is going wrong with these set of images. Here is the link <https://seafile.rlp.net/f/0212995d110648d38032/?dl=1>�to the pictures.

It would be great if anyone could identify the issue.

Best Regards,
Raghu

_______________________________________________
Radiance-general mailing list
[email protected]
https://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

Ha. Jan is right -- the HDR values are way off. I should have looked at the result more closely and noticed that everything was too bright.

I can take your JPEGs and give them to Photosphere or hdrgen, combining them using a generic response function. I cannot solve for the camera response with these inputs, which likely means that the camera is playing around with the tone curve on the different exposures. This is a no-no, and indicates that the camera is probably not suitable for HDR capture. Nevertheless, hdrgen can create something usable that does not agree at all with your result.

By the way, your shortest exposure is still clipping the sun, which means that your DGP won't be accurate for this scene, even if you can get your HDR builder to work unless you can get a shorter exposure.

Cheers,
-Greg

···

From: Jan Wienold <[email protected]>
Date: February 6, 2018 9:24:54 AM PST
was it taken on mercury ? :wink:
the luminances are far off... it sums up to more than 600000 lux
Jan

On 06.02.18 18:18, Greg Ward wrote:

Hi Raghu,

We may need to wait to hear from Jan or someone who understands evalglare better than I do. I don't think there is a problem with your HDR image as you generated it.

-Greg

From: raghuram kalyanam <[email protected]>
Date: February 6, 2018 9:05:41 AM PST

Hi Greg,

I added these options while passing to evalglare like below.

evalglare -vta -vh 180 -vv 180 <hdr file>, and it worked but it always gives 1.0 as DGP (even other parameters are out of bounds).

With out those options evalglare throws an error.

Apart from that

Are all the LDR’s provided, valid to combine into HDR?

I doubt if one or more of the LDR’s is the culprit (especially something to do with over or under exposure).

Best Regards,
Raghu

On Feb 6, 2018, at 5:05 PM, Greg Ward <[email protected]> wrote:

Hi Raghu,

It looks like your HDR image header is missing the necessary view information. Typically, this might be something like:

VIEW= -vta -vh 180 -vv 180

for a perspective such as yours. You should be sure that your fisheye mapping corresponds to one of the standard Radiance types.

Best,
-Greg

From: raghuram kalyanam <[email protected]>
Date: February 6, 2018 5:21:59 AM PST

Hi All,

I am trying to asses visual discomfort using fisheye HDR images. We generated HDR image from a set of 360 degree LDRs and then converted to fisheye HDR ( using a custom made tools). The intension was to use these Fisheye HDRs as input to Evalglare and get DGP value. The Camera used is Ricoh Theta V 360 degree camera.

The problem I am facing is, the DGP calculated from the generated fisheye HDR with Evalglare is always 1.0. We did the calibration but I would like to have expert opinion from you people, what is going wrong with these set of images. Here is the link to the pictures.

It would be great if anyone could identify the issue.

Best Regards,
Raghu

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

P.S. We should move this discussion to the HDRI mailing list, since it is not a problem with evalglare or any Radiance tools.

···

From: Greg Ward <[email protected]>
Date: February 6, 2018 9:45:19 AM PST

Ha. Jan is right -- the HDR values are way off. I should have looked at the result more closely and noticed that everything was too bright.

I can take your JPEGs and give them to Photosphere or hdrgen, combining them using a generic response function. I cannot solve for the camera response with these inputs, which likely means that the camera is playing around with the tone curve on the different exposures. This is a no-no, and indicates that the camera is probably not suitable for HDR capture. Nevertheless, hdrgen can create something usable that does not agree at all with your result.

By the way, your shortest exposure is still clipping the sun, which means that your DGP won't be accurate for this scene, even if you can get your HDR builder to work unless you can get a shorter exposure.

Cheers,
-Greg

From: Jan Wienold <[email protected]>
Date: February 6, 2018 9:24:54 AM PST
was it taken on mercury ? :wink:
the luminances are far off... it sums up to more than 600000 lux
Jan

On 06.02.18 18:18, Greg Ward wrote:

Hi Raghu,

We may need to wait to hear from Jan or someone who understands evalglare better than I do. I don't think there is a problem with your HDR image as you generated it.

-Greg

From: raghuram kalyanam <[email protected]>
Date: February 6, 2018 9:05:41 AM PST

Hi Greg,

I added these options while passing to evalglare like below.

evalglare -vta -vh 180 -vv 180 <hdr file>, and it worked but it always gives 1.0 as DGP (even other parameters are out of bounds).

With out those options evalglare throws an error.

Apart from that

Are all the LDR’s provided, valid to combine into HDR?

I doubt if one or more of the LDR’s is the culprit (especially something to do with over or under exposure).

Best Regards,
Raghu

On Feb 6, 2018, at 5:05 PM, Greg Ward <[email protected]> wrote:

Hi Raghu,

It looks like your HDR image header is missing the necessary view information. Typically, this might be something like:

VIEW= -vta -vh 180 -vv 180

for a perspective such as yours. You should be sure that your fisheye mapping corresponds to one of the standard Radiance types.

Best,
-Greg

From: raghuram kalyanam <[email protected]>
Date: February 6, 2018 5:21:59 AM PST

Hi All,

I am trying to asses visual discomfort using fisheye HDR images. We generated HDR image from a set of 360 degree LDRs and then converted to fisheye HDR ( using a custom made tools). The intension was to use these Fisheye HDRs as input to Evalglare and get DGP value. The Camera used is Ricoh Theta V 360 degree camera.

The problem I am facing is, the DGP calculated from the generated fisheye HDR with Evalglare is always 1.0. We did the calibration but I would like to have expert opinion from you people, what is going wrong with these set of images. Here is the link to the pictures.

It would be great if anyone could identify the issue.

Best Regards,
Raghu

Hi Jan,

We did the calibration and the results of spot luminance measured and calculated from HDR for the light source (calculated with custom made tool ) is very close.

I want to compare the measured Vertical eye illuminance with the one calculated with evalglare, but the results are out of bounds from evalglare, so i couldn’t even compare.

Could you suggest me anything else i should be taking care of? Any ideas.

Best Regards,

Raghu

···

On Feb 6, 2018 6:24 PM, Jan Wienold [email protected] wrote:

was it taken on mercury ? :wink:

the luminances are far off… it sums up to more than 600000 lux

Jan

On 06.02.18 18:18, Greg Ward wrote:

Hi Raghu,

    We may need to wait to hear from Jan or someone who

understands evalglare better than I do. I don’t think there is
a problem with your HDR image as you generated it.

-Greg

From: raghuram kalyanam
[email protected]

Date: February 6, 2018
9:05:41 AM PST

Hi Greg,

      I added these options while passing to evalglare

like below.

      evalglare -vta -vh 180 -vv 180 <hdr file>,

and it worked but it always gives 1.0 as DGP (even other
parameters are out of bounds).

With out those options evalglare throws an error.

Apart from that

      Are all the LDR’s provided, valid to combine into

HDR?

      I doubt if one or more of the LDR’s is the culprit

(especially something to do with over or under exposure).

Best Regards,

Raghu

On Feb 6, 2018, at 5:05 PM, Greg Ward <[email protected] > > > > > wrote:

Hi Raghu,

              It looks like your HDR image header is

missing the necessary view information. Typically,
this might be something like:

VIEW= -vta -vh 180 -vv 180

              for a perspective such as yours.  You

should be sure that your fisheye mapping corresponds
to one of the standard Radiance types.

Best,

-Greg

From: raghuram
kalyanam [email protected]

Date: February
6, 2018 5:21:59 AM PST

Hi All,

                I am trying to asses visual discomfort

using fisheye HDR images. We generated HDR image
from a set of 360 degree LDRs and then converted to
fisheye HDR ( using a custom made tools). The
intension was to use these Fisheye HDRs as input to
Evalglare and get DGP value. The Camera used is
Ricoh Theta V 360 degree camera.

                The problem I am facing is, the DGP

calculated from the generated fisheye HDR with
Evalglare is always 1.0. We did the calibration but
I would like to have expert opinion from you people,
what is going wrong with these set of images. Here
is the link to the
pictures.

                It would be great if anyone could

identify the issue.

Best Regards,

Raghu

_______________________________________________
Radiance-general mailing list
[email protected]
[https://www.radiance-online.org/mailman/listinfo/radiance-general](https://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](http://people.epfl.ch/jan.wienold)
LE 1 111 (Office)
Phone +41 21 69 30849

Hi Raghu,

What you say does not jibe with what ximage or Photosphere report when probing your HDR image. The values are all quite high for an interior space. What program are you using to look at your result?

Cheers,
-Greg

···

From: Raghuram Kalyanam <[email protected]>
Date: February 6, 2018 9:57:53 AM PST

Hi Jan,

We did the calibration and the results of spot luminance measured and calculated from HDR for the light source (calculated with custom made tool ) is very close.

I want to compare the measured Vertical eye illuminance with the one calculated with evalglare, but the results are out of bounds from evalglare, so i couldn't even compare.

Could you suggest me anything else i should be taking care of? Any ideas.

Best Regards,
Raghu

On Feb 6, 2018 6:24 PM, Jan Wienold <[email protected]> wrote:
was it taken on mercury ? :wink:
the luminances are far off... it sums up to more than 600000 lux
Jan

On 06.02.18 18:18, Greg Ward wrote:
Hi Raghu,

We may need to wait to hear from Jan or someone who understands evalglare better than I do. I don't think there is a problem with your HDR image as you generated it.

-Greg

From: raghuram kalyanam <[email protected]>
Date: February 6, 2018 9:05:41 AM PST

Hi Greg,

I added these options while passing to evalglare like below.

evalglare -vta -vh 180 -vv 180 <hdr file>, and it worked but it always gives 1.0 as DGP (even other parameters are out of bounds).

With out those options evalglare throws an error.

Apart from that

Are all the LDR’s provided, valid to combine into HDR?

I doubt if one or more of the LDR’s is the culprit (especially something to do with over or under exposure).

Best Regards,
Raghu

On Feb 6, 2018, at 5:05 PM, Greg Ward <[email protected]> wrote:

Hi Raghu,

It looks like your HDR image header is missing the necessary view information. Typically, this might be something like:

VIEW= -vta -vh 180 -vv 180

for a perspective such as yours. You should be sure that your fisheye mapping corresponds to one of the standard Radiance types.

Best,
-Greg

From: raghuram kalyanam <[email protected]>
Date: February 6, 2018 5:21:59 AM PST

Hi All,

I am trying to asses visual discomfort using fisheye HDR images. We generated HDR image from a set of 360 degree LDRs and then converted to fisheye HDR ( using a custom made tools). The intension was to use these Fisheye HDRs as input to Evalglare and get DGP value. The Camera used is Ricoh Theta V 360 degree camera.

The problem I am facing is, the DGP calculated from the generated fisheye HDR with Evalglare is always 1.0. We did the calibration but I would like to have expert opinion from you people, what is going wrong with these set of images. Here is the link to the pictures.

It would be great if anyone could identify the issue.

Best Regards,
Raghu

Hi Raghu,

The spot luminance measurements should ideally be done for several ranges for each HDR capturing (e.g. one reference area with 100cd/m2, another one with several thousands) and finally you compare the illuminance of the image with the measured one and you should reject any image with a deviation larger than 25% deviation of the illuminance. With a proper calibration you can be also within 10%.

Definitely the luminances of your image are totally off (=physically impossible, at least factor 50 for the blue sky) - it has nothing to do with evalglare.

BTW. evalglare calculates the illuminance also for that image (617414.88 lux) - there is no limit or "out of bounds". Just that your image has much too high luminances, so you get also an unrealistic illuminance...

It is hard to tell where the problem lies exactly, but definitely it is caused by your applied hdr generation process.

Cheers

Jan

···

On 06.02.18 18:57, Raghuram Kalyanam wrote:

Hi Jan,

We did the calibration and the results of spot luminance measured and calculated from HDR for the light source (calculated with custom made tool ) is very close.

I want to compare the measured Vertical eye illuminance with the one calculated with evalglare, but the results are out of bounds from evalglare, so i couldn't even compare.

Could you suggest me anything else i should be taking care of? Any ideas.

Best Regards,
Raghu

On Feb 6, 2018 6:24 PM, Jan Wienold <[email protected]> wrote:

    was it taken on mercury ? :wink:

    the luminances are far off... it sums up to more than 600000 lux
    Jan

    On 06.02.18 18:18, Greg Ward wrote:

        Hi Raghu,

        We may need to wait to hear from Jan or someone who
        understands evalglare better than I do. I don't think there
        is a problem with your HDR image as you generated it.

        -Greg

            *From: *raghuram kalyanam <[email protected]
            <mailto:[email protected]>>

            *Date: *February 6, 2018 9:05:41 AM PST

            *

            Hi Greg,

            I added these options while passing to evalglare like below.

            evalglare -vta -vh 180 -vv 180 <hdr file>, and it worked
            but it always gives 1.0 as DGP (even other parameters are
            out of bounds).

            With out those options evalglare throws an error.

            Apart from that

            Are all the LDR’s provided, valid to combine into HDR?

            I doubt if one or more of the LDR’s is the culprit
            (especially something to do with over or under exposure).

            Best Regards,
            Raghu

                On Feb 6, 2018, at 5:05 PM, Greg Ward > <[email protected] > <mailto:[email protected]>> wrote:

                Hi Raghu,

                It looks like your HDR image header is missing the
                necessary view information. Typically, this might be
                something like:

                VIEW= -vta -vh 180 -vv 180

                for a perspective such as yours. You should be sure
                that your fisheye mapping corresponds to one of the
                standard Radiance types.

                Best,
                -Greg

                    *From: *raghuram kalyanam <[email protected]
                    <mailto:[email protected]>>
                    *Date: *February 6, 2018 5:21:59 AM PST
                    *

                    Hi All,

                    I am trying to asses visual discomfort using
                    fisheye HDR images. We generated HDR image from a
                    set of 360 degree LDRs and then converted to
                    fisheye HDR ( using a custom made tools). The
                    intension was to use these Fisheye HDRs as input
                    to Evalglare and get DGP value. The Camera used is
                    Ricoh Theta V 360 degree camera.

                    The problem I am facing is, the DGP calculated
                    from the generated fisheye HDR with Evalglare is
                    always 1.0. We did the calibration but I would
                    like to have expert opinion from you people, what
                    is going wrong with these set of images. Here is
                    the link
                    <https://seafile.rlp.net/f/0212995d110648d38032/?dl=1> to
                    the pictures.

                    It would be great if anyone could identify the issue.

                    Best Regards,
                    Raghu

        _______________________________________________
        Radiance-general mailing list
        [email protected]
        <mailto:[email protected]>
        https://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]
https://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

Hi Jan and Greg,

Thank you very much for your suggestions. Finally the issue seems to be solved. It is true that the problem is in HDR generation process. We divided each of the pixel values by 179, then HDR seems to be in radiance compatible format. Now the results of these HDR images from Evalglare are more meaningful.

Once again I thank you for your effort.

Best Regards,
Raghu

···

On Feb 6, 2018, at 7:31 PM, Jan Wienold <[email protected]> wrote:

Hi Raghu,

The spot luminance measurements should ideally be done for several ranges for each HDR capturing (e.g. one reference area with 100cd/m2, another one with several thousands) and finally you compare the illuminance of the image with the measured one and you should reject any image with a deviation larger than 25% deviation of the illuminance. With a proper calibration you can be also within 10%.

Definitely the luminances of your image are totally off (=physically impossible, at least factor 50 for the blue sky) - it has nothing to do with evalglare.
BTW. evalglare calculates the illuminance also for that image (617414.88 lux) - there is no limit or "out of bounds". Just that your image has much too high luminances, so you get also an unrealistic illuminance...
It is hard to tell where the problem lies exactly, but definitely it is caused by your applied hdr generation process.

Cheers
Jan

On 06.02.18 18:57, Raghuram Kalyanam wrote:

Hi Jan,

We did the calibration and the results of spot luminance measured and calculated from HDR for the light source (calculated with custom made tool ) is very close.

I want to compare the measured Vertical eye illuminance with the one calculated with evalglare, but the results are out of bounds from evalglare, so i couldn't even compare.

Could you suggest me anything else i should be taking care of? Any ideas.

Best Regards,
Raghu

On Feb 6, 2018 6:24 PM, Jan Wienold <[email protected]> <mailto:[email protected]> wrote:
was it taken on mercury ? :wink:
the luminances are far off... it sums up to more than 600000 lux
Jan

On 06.02.18 18:18, Greg Ward wrote:
Hi Raghu,

We may need to wait to hear from Jan or someone who understands evalglare better than I do. I don't think there is a problem with your HDR image as you generated it.

-Greg

From: raghuram kalyanam <[email protected] <mailto:[email protected]>>
Date: February 6, 2018 9:05:41 AM PST

Hi Greg,

I added these options while passing to evalglare like below.

evalglare -vta -vh 180 -vv 180 <hdr file>, and it worked but it always gives 1.0 as DGP (even other parameters are out of bounds).

With out those options evalglare throws an error.

Apart from that

Are all the LDR’s provided, valid to combine into HDR?

I doubt if one or more of the LDR’s is the culprit (especially something to do with over or under exposure).

Best Regards,
Raghu

On Feb 6, 2018, at 5:05 PM, Greg Ward <[email protected] <mailto:[email protected]>> wrote:

Hi Raghu,

It looks like your HDR image header is missing the necessary view information. Typically, this might be something like:

VIEW= -vta -vh 180 -vv 180

for a perspective such as yours. You should be sure that your fisheye mapping corresponds to one of the standard Radiance types.

Best,
-Greg

From: raghuram kalyanam <[email protected] <mailto:[email protected]>>
Date: February 6, 2018 5:21:59 AM PST

Hi All,

I am trying to asses visual discomfort using fisheye HDR images. We generated HDR image from a set of 360 degree LDRs and then converted to fisheye HDR ( using a custom made tools). The intension was to use these Fisheye HDRs as input to Evalglare and get DGP value. The Camera used is Ricoh Theta V 360 degree camera.

The problem I am facing is, the DGP calculated from the generated fisheye HDR with Evalglare is always 1.0. We did the calibration but I would like to have expert opinion from you people, what is going wrong with these set of images. Here is the link <https://seafile.rlp.net/f/0212995d110648d38032/?dl=1> to the pictures.

It would be great if anyone could identify the issue.

Best Regards,
Raghu

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

Hi Jan and Greg,

Thank you very much for your suggestions. Finally the issue seems to be solved. It is true that the problem is in HDR generation process. We divided each of the pixel values by 179, then HDR seems to be in radiance compatible format. Now the results of these HDR images from Evalglare are more meaningful.

Once again I thank you for your effort.

Best Regards,
Raghu

···

On Feb 6, 2018, at 7:31 PM, Jan Wienold <[email protected]> wrote:

Hi Raghu,

The spot luminance measurements should ideally be done for several ranges for each HDR capturing (e.g. one reference area with 100cd/m2, another one with several thousands) and finally you compare the illuminance of the image with the measured one and you should reject any image with a deviation larger than 25% deviation of the illuminance. With a proper calibration you can be also within 10%.

Definitely the luminances of your image are totally off (=physically impossible, at least factor 50 for the blue sky) - it has nothing to do with evalglare.
BTW. evalglare calculates the illuminance also for that image (617414.88 lux) - there is no limit or "out of bounds". Just that your image has much too high luminances, so you get also an unrealistic illuminance...
It is hard to tell where the problem lies exactly, but definitely it is caused by your applied hdr generation process.

Cheers
Jan

On 06.02.18 18:57, Raghuram Kalyanam wrote:

Hi Jan,

We did the calibration and the results of spot luminance measured and calculated from HDR for the light source (calculated with custom made tool ) is very close.

I want to compare the measured Vertical eye illuminance with the one calculated with evalglare, but the results are out of bounds from evalglare, so i couldn't even compare.

Could you suggest me anything else i should be taking care of? Any ideas.

Best Regards,
Raghu

On Feb 6, 2018 6:24 PM, Jan Wienold <[email protected]> <mailto:[email protected]> wrote:
was it taken on mercury ? :wink:
the luminances are far off... it sums up to more than 600000 lux
Jan

On 06.02.18 18:18, Greg Ward wrote:
Hi Raghu,

We may need to wait to hear from Jan or someone who understands evalglare better than I do. I don't think there is a problem with your HDR image as you generated it.

-Greg

From: raghuram kalyanam <[email protected] <mailto:[email protected]>>
Date: February 6, 2018 9:05:41 AM PST

Hi Greg,

I added these options while passing to evalglare like below.

evalglare -vta -vh 180 -vv 180 <hdr file>, and it worked but it always gives 1.0 as DGP (even other parameters are out of bounds).

With out those options evalglare throws an error.

Apart from that

Are all the LDR’s provided, valid to combine into HDR?

I doubt if one or more of the LDR’s is the culprit (especially something to do with over or under exposure).

Best Regards,
Raghu

On Feb 6, 2018, at 5:05 PM, Greg Ward <[email protected] <mailto:[email protected]>> wrote:

Hi Raghu,

It looks like your HDR image header is missing the necessary view information. Typically, this might be something like:

VIEW= -vta -vh 180 -vv 180

for a perspective such as yours. You should be sure that your fisheye mapping corresponds to one of the standard Radiance types.

Best,
-Greg

From: raghuram kalyanam <[email protected] <mailto:[email protected]>>
Date: February 6, 2018 5:21:59 AM PST

Hi All,

I am trying to asses visual discomfort using fisheye HDR images. We generated HDR image from a set of 360 degree LDRs and then converted to fisheye HDR ( using a custom made tools). The intension was to use these Fisheye HDRs as input to Evalglare and get DGP value. The Camera used is Ricoh Theta V 360 degree camera.

The problem I am facing is, the DGP calculated from the generated fisheye HDR with Evalglare is always 1.0. We did the calibration but I would like to have expert opinion from you people, what is going wrong with these set of images. Here is the link <https://seafile.rlp.net/f/0212995d110648d38032/?dl=1> to the pictures.

It would be great if anyone could identify the issue.

Best Regards,
Raghu

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