HDR & Isocontour help.

Hello.

I am a Macintosh tech at a university. I am helping users that were using a
Windows application that was broken as a result of system updates. The only
thing the users do is shoot a series of pictures, then create a HDR file.

From that HDR file, we want a false color image and an Isocontour image. I

am in the process of setting up a series of scripts for them on OS X. I can
create the false color image without a problem. However, I am having
problems with the Isocontour image.

What are the series of commands that I need to use to create the Iso from
the HDR? I know that I need to create an Illumination file and then
composite that file with the original HDR. How do I do this? I am guessing
it will be 2 different terminal commands.

Any help will be greatly appreciated. I am sorry if this is a simple
problem, I am not a Radiance user so a lot of stuff is greek to me.

Thanks in advance,

Matt Parker
Lab Manager
UNC Charlotte
College of Architecture

Hi Matt,

The falsecolor command will create iso lines using the -cl or -cb options. Try the following sequence:

% rpict -x 512 -y 512 [view and other options] input.oct > rendering.pic
% rpict -i -x 512 -y 512 [same options] intput.oct > luximage.pic
% falsecolor -cl -s 1000 -i luximage.pic -p rendering.pic | ra_tiff - contours.tif

You'll need to play with the falsecolor options to get it like you want. See <http://radsite.lbl.gov/radiance/man_html/falsecolor.1.html> for details.

-Greg

···

From: Matt Parker <[email protected]>
Date: July 25, 2006 10:36:48 PM PDT

Hello.

I am a Macintosh tech at a university. I am helping users that were using a
Windows application that was broken as a result of system updates. The only
thing the users do is shoot a series of pictures, then create a HDR file.
From that HDR file, we want a false color image and an Isocontour image. I
am in the process of setting up a series of scripts for them on OS X. I can
create the false color image without a problem. However, I am having
problems with the Isocontour image.

What are the series of commands that I need to use to create the Iso from
the HDR? I know that I need to create an Illumination file and then
composite that file with the original HDR. How do I do this? I am guessing
it will be 2 different terminal commands.

Any help will be greatly appreciated. I am sorry if this is a simple
problem, I am not a Radiance user so a lot of stuff is greek to me.

Thanks in advance,

Matt Parker
Lab Manager
UNC Charlotte
College of Architecture

Hi Matt,

The falsecolor command will create iso lines using the -cl or -cb
options. Try the following sequence:

% rpict -x 512 -y 512 [view and other options] input.oct > rendering.pic
% rpict -i -x 512 -y 512 [same options] intput.oct > luximage.pic
% falsecolor -cl -s 1000 -i luximage.pic -p rendering.pic | ra_tiff -
contours.tif

You'll need to play with the falsecolor options to get it like you
want. See <http://radsite.lbl.gov/radiance/man_html/falsecolor.
1.html> for details.

-Greg

Greg,

Thanks so much for you very fast reply. All of the commands look simple
enough. My question now is, what is the .oct file and how do I create it? I
have been given a series of .HDR images that were created using PhotoSphere
from a series of shots. What do I need to do to convert this to a .oct file
or do I just substitute my .hdr file where you indicate .oct.

Again, I apologize if this a stupid question.

Thanks for your help.

Matt

Hi Matt.

Answering for Greg here as he may be sound asleep in
another part of the world.

Greg assumed that you had a 3D scene in Radiance format
from which the HDR images have been generated. So his
answer was to use that scene (the input.oct file) to
create a "luximage.pic" from the same viewpoint as the
first HDR image. The "luximage.pic" file contains the
information needed for contour lines showing lux levels.

If you don't have this information you can't create
contour plots of lux level!

However, you still can create contour plots from the
original images. These lines will have "Nits" as unit
and show the "brightness" of an element in the scene
instead of the illuminace on that element (i.e. the
quantity of light reflected from a table vs. the light
falling on that table). The command for this is

$ falsecolor -cl -s 1000 -i rendering.pic -p rendering.pic > cline.pic

As you see input data ("-i" option) and background image
("-p" option) are the same file here. I think you can omit
the "-p" option in this case, but I can't check it now.
You may have to change the value of the "-s" ("scale")
option so it contains all the levels of your image. See
the man page of falsecolor for details and further useful
options.

Regards,
Thomas

···

-----Original Message-----
From: [email protected]
[mailto:[email protected]] On
Behalf Of Matt Parker
Sent: 26 July 2006 13:35
To: [email protected]
Subject: Re: [Radiance-general] HDR & Isocontour help.

> Hi Matt,
>
> The falsecolor command will create iso lines using the -cl or -cb
> options. Try the following sequence:
>
> % rpict -x 512 -y 512 [view and other options] input.oct >
> rendering.pic % rpict -i -x 512 -y 512 [same options] intput.oct >
> luximage.pic % falsecolor -cl -s 1000 -i luximage.pic -p
rendering.pic
> > ra_tiff - contours.tif
>
> You'll need to play with the falsecolor options to get it like you
> want. See <http://radsite.lbl.gov/radiance/man_html/falsecolor.
> 1.html> for details.
>
> -Greg
>

Greg,

Thanks so much for you very fast reply. All of the commands
look simple enough. My question now is, what is the .oct file
and how do I create it? I have been given a series of .HDR
images that were created using PhotoSphere from a series of
shots. What do I need to do to convert this to a .oct file or
do I just substitute my .hdr file where you indicate .oct.

Again, I apologize if this a stupid question.

Thanks for your help.

Matt

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http://www.radiance-online.org/mailman/listinfo/radiance-general

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Hi everybody...again

Im a regular nuisance on here, please dont kick me off Greg!

In addition to my last email, i have a query regarding light measurement within radiance. When viewing an .oct in rvu if i type t and then click on a point, it will give me a few values, the last of which, i assume, is luminance in nits.

Firstly is this assumption correct?

Is there a way to measure illuminance as opposed to luminance?

Thanks in advance

Chris

···

-----Original Message-----
From: [email protected] on behalf of Bleicher, Thomas
Sent: Wed 7/26/2006 2:01 PM
To: Radiance general discussion
Subject: RE: [Radiance-general] HDR & Isocontour help.

Hi Matt.

Answering for Greg here as he may be sound asleep in
another part of the world.

Greg assumed that you had a 3D scene in Radiance format
from which the HDR images have been generated. So his
answer was to use that scene (the input.oct file) to
create a "luximage.pic" from the same viewpoint as the
first HDR image. The "luximage.pic" file contains the
information needed for contour lines showing lux levels.

If you don't have this information you can't create
contour plots of lux level!

However, you still can create contour plots from the
original images. These lines will have "Nits" as unit
and show the "brightness" of an element in the scene
instead of the illuminace on that element (i.e. the
quantity of light reflected from a table vs. the light
falling on that table). The command for this is

$ falsecolor -cl -s 1000 -i rendering.pic -p rendering.pic > cline.pic

As you see input data ("-i" option) and background image
("-p" option) are the same file here. I think you can omit
the "-p" option in this case, but I can't check it now.
You may have to change the value of the "-s" ("scale")
option so it contains all the levels of your image. See
the man page of falsecolor for details and further useful
options.

Regards,
Thomas

-----Original Message-----
From: [email protected]
[mailto:[email protected]] On
Behalf Of Matt Parker
Sent: 26 July 2006 13:35
To: [email protected]
Subject: Re: [Radiance-general] HDR & Isocontour help.

> Hi Matt,
>
> The falsecolor command will create iso lines using the -cl or -cb
> options. Try the following sequence:
>
> % rpict -x 512 -y 512 [view and other options] input.oct >
> rendering.pic % rpict -i -x 512 -y 512 [same options] intput.oct >
> luximage.pic % falsecolor -cl -s 1000 -i luximage.pic -p
rendering.pic
> > ra_tiff - contours.tif
>
> You'll need to play with the falsecolor options to get it like you
> want. See <http://radsite.lbl.gov/radiance/man_html/falsecolor.
> 1.html> for details.
>
> -Greg
>

Greg,

Thanks so much for you very fast reply. All of the commands
look simple enough. My question now is, what is the .oct file
and how do I create it? I have been given a series of .HDR
images that were created using PhotoSphere from a series of
shots. What do I need to do to convert this to a .oct file or
do I just substitute my .hdr file where you indicate .oct.

Again, I apologize if this a stupid question.

Thanks for your help.

Matt

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

***********************************************************************************
This e-mail, (and any attachments) is confidential and may be privileged. It may be read, copied and used by the intended addressee only. If you have received this in error please contact BDP immediately.

If you have any queries, please contact the sender.
***********************************************************************************
Building Design Partnership
Registered in England No 2207415:
Registered Office: Building Design Partnership Ltd, Sunlight House, PO Box 85, Quay Street, Manchester, M60 3JA, http://www.bdp.co.uk
***********************************************************************************

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Hi Chris,

If anyone should be kicked off, it's me -- I've been answering e-mails when I'm rushed and tired and doing a bad job of it, so apologies to everyone.

You are correct that the last value reported (the one with an 'L' next to it) in rvu is the luminance in candelas/meter^2, or nits. To get illuminance instead, turn on the -i option via the "set i y" command in rvu then do the trace again. You can switch irradiance mode off again with "set i n".

I hope this helps!
-Greg

···

From: "Chris Foster" <[email protected]>
Date: July 26, 2006 8:15:42 AM PDT
Hi everybody...again

Im a regular nuisance on here, please dont kick me off Greg!

In addition to my last email, i have a query regarding light measurement within radiance. When viewing an .oct in rvu if i type t and then click on a point, it will give me a few values, the last of which, i assume, is luminance in nits.

Firstly is this assumption correct?

Is there a way to measure illuminance as opposed to luminance?

Thanks in advance

Chris

Chris.

You can find an online version of the rvu man page here:

http://radsite.lbl.gov/radiance/man_html/rvu.1.html

From the description of "trace" I guess your assumption is
correct, for certain values of correct. The man page says the
"value" will be printed as well but I remember vaguely that
it was split in its red, green and blue component. I can't
simply switch to my Radiance machine right now to test it
so you have to figure it out yourself.

For illuminace simply use the "-i" option when you start
rvu. Again I am not sure rvu supports this but I don't see
a reason why it shouldn't.

Thomas

···

_____

From: [email protected]
[mailto:[email protected]] On Behalf Of Chris
Foster
Sent: 26 July 2006 16:16
To: Radiance general discussion; Radiance general discussion
Subject: RE: [Radiance-general] HDR & Isocontour help.

Hi everybody...again

Im a regular nuisance on here, please dont kick me off Greg!

In addition to my last email, i have a query regarding light measurement
within radiance. When viewing an .oct in rvu if i type t and then click
on a point, it will give me a few values, the last of which, i assume,
is luminance in nits.

Firstly is this assumption correct?

Is there a way to measure illuminance as opposed to luminance?

Thanks in advance

Chris

***********************************************************************************
This e-mail, (and any attachments) is confidential and may be privileged. It may be read, copied and used by the intended addressee only. If you have received this in error please contact BDP immediately.

If you have any queries, please contact the sender.
***********************************************************************************
Building Design Partnership
Registered in England No 2207415:
Registered Office: Building Design Partnership Ltd, Sunlight House, PO Box 85, Quay Street, Manchester, M60 3JA, http://www.bdp.co.uk
***********************************************************************************