[HDRI] HDRI Digest, Vol 86, Issue 1

Iason Konstantzos

2016-11-13 06:29:19 UTC

Greg, Alstan,

You were both right; I just realized that the fact I saw the view info in the header didn't mean that pcomb did recognize it. It was indeed indented therefore ignored. Putting it in back in the third row made everything work like a charm!

Thank you both for your prompt and enlightening responses!

Best

Iason

----------------------------------------------------------------------

Message: 1
Date: Sun, 13 Nov 2016 01:10:03 +0000
From: Iason Konstantzos <***@purdue.edu>
To: "***@radiance-online.org" <***@radiance-online.org>
Subject: [HDRI] Domain errors with incidence and solid angles during
overflow correction
Message-ID:
<***@SN2PR0801MB2255.namprd08.prod.outlook.com>

Content-Type: text/plain; charset="iso-8859-1"

Hello everyone,

I have been doing some tests in order to apply the methodology for overflow correction covered in this year's paper by Jakubiec et al. using pcomb, as for example:

pcomb -e "lo=L ? Sang ? cosCor; L=179 ? li(1);
Sang=S(1); cosCor=Dy(1);" -o masked.hdr
| pvalue -d -b -h -H
| total

However, I keep getting "domain error" messages for both the S(n) and Dy(n) functions in my images. My first thought was something's wrong with the headers, but the view information looks correct having the full 180 degrees span of my Sigma lens.

Images are created by HDRgen using response function obtained by Photosphere, and are square-cropped, and resized to 800x800, and otherwise work fine, in terms of validating luminances or illuminances over Evalglare (at least the ones that don't contain the sun).

I'm getting the same domain errors in terms of solid angles when I try to extract a mapping of solid angles, using something like: cat image.hdr |pcomb -e 'solidangl=S(1); ro=omega; go=omega; bo=omega' -o - > solid_angles.hdr

If anybody has any hints or ideas, I'd greatly appreciate it, as I think that with careful use (no specular reflections etc.), overflow correction can be a great solution over the alternatives for direct sun measurements.

Thanks in advance,

Iason Konstantzos
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Message: 2
Date: Sat, 12 Nov 2016 18:26:51 -0800
From: "Gregory J. Ward" <***@gmail.com>
To: High Dynamic Range Imaging <***@radiance-online.org>
Subject: Re: [HDRI] Domain errors with incidence and solid angles
during overflow correction
Message-ID: <AD1C0F4B-4975-4D40-B4CA-***@gmail.com>
Content-Type: text/plain; charset="utf-8"

Hi Iason,

Can you send the output of "getinfo" for the picture that you are feeding to pcomb? My suspicion is that you performed the cropping operation caused the view parameters are being shifted or modified and are not being recognized by pcomb. This will generate the domain error you are seeing.

Cheers,
-Greg

Date: November 12, 2016 5:10:03 PM PST
Hello everyone,
pcomb ?e "lo=L ? Sang ? cosCor; L=179 ? li(1);
Sang=S(1); cosCor=Dy(1);" ?o masked.hdr
| pvalue ?d ?b ?h ?H
| total
However, I keep getting "domain error" messages for both the S(n) and Dy(n) functions in my images. My first thought was something's wrong with the headers, but the view information looks correct having the full 180 degrees span of my Sigma lens.
Images are created by HDRgen using response function obtained by Photosphere, and are square-cropped, and resized to 800x800, and otherwise work fine, in terms of validating luminances or illuminances over Evalglare (at least the ones that don't contain the sun).
I'm getting the same domain errors in terms of solid angles when I try to extract a mapping of solid angles, using something like: cat image.hdr |pcomb -e 'solidangl=S(1); ro=omega;
go=omega; bo=omega' -o - > solid_angles.hdr
If anybody has any hints or ideas, I'd greatly appreciate it, as I think that with careful use (no specular reflections etc.), overflow correction can be a great solution over the alternatives for direct sun measurements.
Thanks in advance,
Iason Konstantzos

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------------------------------

Message: 3
Date: Sun, 13 Nov 2016 13:34:02 +0800
From: "J. Alstan Jakubiec" <***@jakubiec.net>
To: ***@radiance-online.org
Subject: Re: [HDRI] Domain errors with incidence and solid angles
during overflow correction
Message-ID: <32557636-203d-2a8e-ebf8-***@jakubiec.net>
Content-Type: text/plain; charset="utf-8"; Format="flowed"

Hello Iason,

If you are following the steps in the paper
<http://asd.sutd.edu.sg/dcc/papers/Jakubiec-Inanici-Van-Den-Wymelenberg_2016_Improving-the-Accuracy-of-Measurements-in-Daylit-Interior-Scenes-Using-HDR.pdf>,
Full - Improving the Accuracy of Measurements in Daylit ...<http://asd.sutd.edu.sg/dcc/papers/Jakubiec-Inanici-Van-Den-Wymelenberg_2016_Improving-the-Accuracy-of-Measurements-in-Daylit-Interior-Scenes-Using-HDR.pdf>
asd.sutd.edu.sg
PLEA 2016 Los Angeles - 36th International Conference on Passive and Low Energy Architecture. Cities, Buildings, People: Towards Regenerative Environments

when you mask the image with the command,

pcomb ?e "lo=mask ? li(1); mask=if(li(2)?.1,1,0);" ?o image.hdr ?o
mask.hdr > image_masked.hdr

All of the nice things you put in the header before, like the view type
(-vta -vv 180 -vh 180), get commented out. This keeps the luminance data
but eradicates view information; therefore, the S(1) and Dy(1) functions
don't work as they are view-dependent.

You need to somehow re-add the view information to the image header,
which is a bit of a drag. We were doing everything in the paper with
some really simple Python scripts. In case its helpful to you, I'm
including a code snippet used below. Basically what it does is to write
a new .hdr file with the header information applied on the third line.

# append view information
tmpfile = open("masked.hdr", "rb")
outfile = open("masked_with-view.hdr", "wb")
for (n,line) in enumerate(tmpfile):
outfile.write(line)
if n == 2:
outfile.write("VIEW= -vta -vh 180 -vv 180\n")
tmpfile.close()
outfile.close()

# remove tmp hdr file missing view information
os.remove("masked.hdr")

You can also achieve this manually with a text editor such as Notepad++
or whatever is your favorite as long as it can write in binary formats.
The red part is what I inserted into the images.

#?RADIANCE
CAPDATE= 2015:02:04 09:30:51
GMT= 2015:02:04 01:30:51*
VIEW= -vta -vh 180 -vv 180*

(You will see that the commented information is identified as a
tab indent in the .hdr file.)

Best regards,
Alstan

Hi Iason,
Can you send the output of "getinfo" for the picture that you are
feeding to pcomb? My suspicion is that you performed the cropping
operation caused the view parameters are being shifted or modified and
are not being recognized by pcomb. This will generate the domain
error you are seeing.
Cheers,
-Greg

*Date: *November 12, 2016 5:10:03 PM PST
*
*
Hello everyone,
I have been doing some tests in order to apply the methodology for
overflow correction covered in this year's paper by Jakubiec et al.
pcomb ?e "lo=L ? Sang ? cosCor; L=179 ? li(1);
Sang=S(1); cosCor=Dy(1);" ?o masked.hdr
| pvalue ?d ?b ?h ?H
| total
However, I keep getting "domain error" messages for both the S(n) and
Dy(n) functions in my images. My first thought was something's wrong
with the headers, but the view information looks correct having the
full 180 degrees span of my Sigma lens.
Images are created by HDRgen using response function obtained by
Photosphere, and are square-cropped, and resized to 800x800, and
otherwise work fine, in terms of validating luminances or
illuminances over Evalglare (at least the ones that don't contain the
sun).
I'm getting the same domain errors in terms of solid angles when I
try to extract a mapping of solid angles, using something like: /cat
image.hdr |pcomb -e 'solidangl=S(1); ro=omega; go=omega; bo=omega' -o
- > solid_angles.hdr/
If anybody has any hints or ideas, I'd greatly appreciate it, as I
think that with careful use (no specular reflections etc.), overflow
correction can be a great solution over the alternatives for direct
sun measurements.
Thanks in advance,
Iason Konstantzos

_______________________________________________
HDRI mailing list
http://www.radiance-online.org/mailman/listinfo/hdri

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End of HDRI Digest, Vol 86, Issue 1
***********************************

Gregory J. Ward

2016-11-13 15:26:57 UTC

Permalink

The new getinfo "-a" option in the latest HEAD release (incl. Windows) is a handy way to add information to the header, including VIEW= lines.

Cheers,
-Greg

Date: November 12, 2016 10:29:19 PM PST
Greg, Alstan,
You were both right; I just realized that the fact I saw the view info in the header didn't mean that pcomb did recognize it. It was indeed indented therefore ignored. Putting it in back in the third row made everything work like a charm!
Thank you both for your prompt and enlightening responses!
Best
Iason
----------------------------------------------------------------------
Message: 1
Date: Sun, 13 Nov 2016 01:10:03 +0000
Content-Type: text/plain; charset="iso-8859-1"
Hello everyone,
pcomb -e "lo=L ? Sang ? cosCor; L=179 ? li(1);
Sang=S(1); cosCor=Dy(1);" -o masked.hdr
| pvalue -d -b -h -H
| total
However, I keep getting "domain error" messages for both the S(n) and Dy(n) functions in my images. My first thought was something's wrong with the headers, but the view information looks correct having the full 180 degrees span of my Sigma lens.
Images are created by HDRgen using response function obtained by Photosphere, and are square-cropped, and resized to 800x800, and otherwise work fine, in terms of validating luminances or illuminances over Evalglare (at least the ones that don't contain the sun).
I'm getting the same domain errors in terms of solid angles when I try to extract a mapping of solid angles, using something like: cat image.hdr |pcomb -e 'solidangl=S(1); ro=omega; go=omega; bo=omega' -o - > solid_angles.hdr
If anybody has any hints or ideas, I'd greatly appreciate it, as I think that with careful use (no specular reflections etc.), overflow correction can be a great solution over the alternatives for direct sun measurements.
Thanks in advance,
Iason Konstantzos
-------------- next part --------------
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------------------------------
Message: 2
Date: Sat, 12 Nov 2016 18:26:51 -0800
Subject: Re: [HDRI] Domain errors with incidence and solid angles
during overflow correction
Content-Type: text/plain; charset="utf-8"
Hi Iason,
Can you send the output of "getinfo" for the picture that you are feeding to pcomb? My suspicion is that you performed the cropping operation caused the view parameters are being shifted or modified and are not being recognized by pcomb. This will generate the domain error you are seeing.
Cheers,
-Greg

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.radiance-online.org/pipermail/hdri/attachments/20161112/243b2db9/attachment-0001.html>
------------------------------
Message: 3
Date: Sun, 13 Nov 2016 13:34:02 +0800
Subject: Re: [HDRI] Domain errors with incidence and solid angles
during overflow correction
Content-Type: text/plain; charset="utf-8"; Format="flowed"
Hello Iason,
If you are following the steps in the paper
<http://asd.sutd.edu.sg/dcc/papers/Jakubiec-Inanici-Van-Den-Wymelenberg_2016_Improving-the-Accuracy-of-Measurements-in-Daylit-Interior-Scenes-Using-HDR.pdf>,
Full - Improving the Accuracy of Measurements in Daylit ...
asd.sutd.edu.sg
PLEA 2016 Los Angeles - 36th International Conference on Passive and Low Energy Architecture. Cities, Buildings, People: Towards Regenerative Environments
when you mask the image with the command,
pcomb ?e "lo=mask ? li(1); mask=if(li(2)?.1,1,0);" ?o image.hdr ?o
mask.hdr > image_masked.hdr
All of the nice things you put in the header before, like the view type
(-vta -vv 180 -vh 180), get commented out. This keeps the luminance data
but eradicates view information; therefore, the S(1) and Dy(1) functions
don't work as they are view-dependent.
You need to somehow re-add the view information to the image header,
which is a bit of a drag. We were doing everything in the paper with
some really simple Python scripts. In case its helpful to you, I'm
including a code snippet used below. Basically what it does is to write
a new .hdr file with the header information applied on the third line.
# append view information
tmpfile = open("masked.hdr", "rb")
outfile = open("masked_with-view.hdr", "wb")
outfile.write(line)
outfile.write("VIEW= -vta -vh 180 -vv 180\n")
tmpfile.close()
outfile.close()
# remove tmp hdr file missing view information
os.remove("masked.hdr")
You can also achieve this manually with a text editor such as Notepad++
or whatever is your favorite as long as it can write in binary formats.
The red part is what I inserted into the images.
#?RADIANCE
CAPDATE= 2015:02:04 09:30:51
GMT= 2015:02:04 01:30:51*
VIEW= -vta -vh 180 -vv 180*
(You will see that the commented information is identified as a
tab indent in the .hdr file.)
Best regards,
Alstan

_______________________________________________
HDRI mailing list
http://www.radiance-online.org/mailman/listinfo/hdri

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***********************************
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