Hi Greg, I am in the midst of trying to get Evalglare to accurately process HDR images. In order to account for light-fall from a Canon + fish-eye generated HDR, I have tried to multiply by the original HDR image with a correction factor using the pcomb command. However, the resulting image does not maintain similar luminance values as the original (as it should particularly for the center part of the image that is only multiplied by a factor of 1).
I am using the following command line and would appreciate any guidance on why the luminance values are so affected: pcomb -e "ro=ri(1)*ri(2);go=gi(1)*gi(2);bo=bi(1)*bi(2);" vignette_283.pic Chauhaus3cr.hdr > Chauhaus3Bvg.hdr My initial attempt actually used the -o function to normalize the values of the image before processing, but the resulting vignetted image was very dark and the luminance values had drastically dropped -- pcomb -e "ro=ri(1)*ri(2);go=gi(1)*gi(2);bo=bi(1)*bi(2);" -o vignette_283.pic Chauhaus3cr.hdr > Chauhaus3vg.hdr As an aside to something Rob mentioned earlier, I do not believe that right now Evalglare automatically only judges the circular view of the fish-eye HDR while being processed. In order to get accurate results, the rectangular images should be cropped (using pcompos) and also the view type should be verified before processing. I have discovered that several of my Photopshere generated HDRs are being judged as a perspective view rather than angular fish-eye as I had assumed it would (vtv instead of vta) and that I had to manually adjust this setting before getting accurate and meaningful Evalglare results. (Greg -- is there anyway to specify the lens type in Photosphere before compiling the HDR so that it follows through from the beginning?) Best, Rashida -- Rashida Mogri | LEED AP Harvard Graduate School of Design MDesS, 2011 | Sustainable Design On Mon, Sep 27, 2010 at 7:35 PM, Gregory J. Ward <[email protected]>wrote: > Try: > > pcomb -e > 's(x):x*x;m=if(xmax*ymax/4-s(x-xmax/2)-s(y-ymax/2),1,0);ro=m*ri(1);go=m*gi(1);bo=m*bi(1)' > input.hdr > output.hdr > > -Greg > > > From: Rob Guglielmetti <[email protected]> > > Date: September 27, 2010 4:00:11 PM PDT > > > > Oh, they are, very low (~2 nits in the HDR), I was just curious because > these corner areas are not truly in the vield of view that we're evaluating. > I ASSume evalglare only is looking at the hemisphere anyway. (?) > > > > Having said all that, does anyone have a masking tip or something like > that to clean up those corners, just out of aesthetic curiosity? > > > > On Mon, Sep 27, 2010 at 4:42 PM, Gregory J. Ward <[email protected]> > wrote: > > Hi Rob, > > > > You need to check what the values of those border pixels are. Chances > are, they are quite low compared to the circular image, and you are only > seeing them because of the tone-mapping compression going on in Photosphere, > assuming that's what you're using. > > > > Best, > > -Greg > > _______________________________________________ > HDRI mailing list > [email protected] > http://www.radiance-online.org/mailman/listinfo/hdri >
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