Santiago + Giulio
Thanks for the info, it appears that this has fixed the issue! I have only checked a couple of my images, but so far so good.
Thanks again for sharing your experience/expertise.
Best,
Chris
From: Santiago Torres [mailto:[email protected]]
Sent: Friday, June 03, 2011 9:45 AM
To: High Dynamic Range Imaging
Subject: Re: [HDRI] evalglare changing luminance values??
Hi Chris,
The presentation Giulio is referring to was in fact in 2004 (time flies!)
The script is:
#!/bin/csh -fe
# Undo any exposure to one or more Radiance pictures
foreach i ($*)
set expos=`sed -n -e 's/^EXPOSURE=//p' -e '/^$/q' $i | total -p`
pfilt -1 -e `ev 1/$expos` $i > $i.$$
mv $i.$$ $i
end
This was to solve a problem when mapping the hdr into a source (for ibl), but it could be that evalglare has a similar problem if it is not checking the exposure in order to get the values?
Hope this helps,
Santiago
From: Giugi [mailto:[email protected]]
Sent: 02 June 2011 22:04
To: High Dynamic Range Imaging
Subject: Re: [HDRI] evalglare changing luminance values??
Chris,
My feeling is that it could be an exposure tag issue.
I think Santiago presented at one of the Radiance workshop a script to undo exposure compensation, maybe in 2008
I had a similar issue playing with the files from my camera. (in my case I need to add the aperture tag and play with the multiplier manually (pcomb) to get the right HDR settings, and of course I am using the aforementioned Santiago+Greg script)
I have some more info in the office. WIll come back.
G
On 2 Jun 2011, at 21:37, Chris Coulter wrote:
Good day HDRI list!
I have taken a series of fisheye photos of a completed project in hopes of gathering some data on glare sources as it relates to the special occupancy. So far I have been able to successfully composite them into an HDR with hdrgen. Then, using pcomb, I scaled the luminance values and reduced image size for input into evalglare. The output from evalglare is where I run into problems.
For instance: in my pcomb’d image, I get a local average luminance of 176.3 nits and the same spot in the evalglare image shows 1127 nits. This of course results in false identifications of glare sources by evalglare. Can anyone please explain this phenomenon? Here are my commands used to generate both images:
pcomb –x xmax/4 –y ymax/4 –s 1.175 –o pt2.hdr > pt2_conv.hdr
evalglare –b 2000 –c pt2.glr pt2_conv.hdr (currently interested in glare sources > 2000 nits)
I noticed that hdrgen set the image header to VIEW= -vtv –vh 104.96 –vv 104.16. I’ve tried to use vinfo to edit the header to correctly set VIEW= -vta as evalglare would expect, but achieve the same results as mentioned above.
If anyone is interested, I’ve posted my pcomb image and evalglare image to my GoogleDocs:
pcomb: https://docs.google.com/leaf?id=0Bx321BZMymleNzc5NWRhZjEtZWM5Mi00NjgxLTliZWUtN2RjMTgyMmVjNDhj&hl=en_US&authkey=CJTZnPYI
evalglare: https://docs.google.com/leaf?id=0Bx321BZMymleZmZhNWM0YTEtZTVkZS00ZDA5LWE5ZTAtZjMxOTI4NzRkM2Ey&hl=en_US&authkey=CI6xwfAH.
I appreciate the help I’ve received from the Radiance gurus on the general list and look forward to hearing your thoughts on yet another issue.
Best,
Chris
Chris M. Coulter, LC, IESNA, LEED AP
Associate
Lighting Designer
President, Detroit Section of the Illuminating Engineering Society
……………………………………………………
SmithGroup
www.smithgroup.com
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