The whole point of HDR is that it doesn't fit in an 8-bit range. The pvalue
program will give you integers if you ask for it, and 256 will correspond to
1.0 in the file, but it doesn't stop at that point, and is happy to give you
integer values up to some very large limit (31 bits, I think).
If that's not what you want, you can use rcalc to clip the output values over
255 to 255, like so:
pvalue -o -h -di $HDR | rcalc -e
'clip(i):if(i-255,255,i);$1=clip($1);$2=clip($2);$3=clip($3)'
Or, if you are trying to squeeze everything in a 0-255 range, making 255 the
maximum and everything else darker, there are ways to do that as well. It's
probably not a good move, though, as you'll usually end up with just a few
white areas around the light sources, with everything else clipped to 0 (or
nearly).
-Greg
> From: "Mahlab, Seyedeh Farzaneh" <[email protected]>
> Subject: [HDRI] RGB extraction
> Date: January 31, 2017 11:56:28 AM PST
> To: "[email protected]" <[email protected]>
> Reply-To: High Dynamic Range Imaging <[email protected]>
>
> Hello
> I am trying to get RGB value of an HDR image captured with Canon camera of a
> light source , in (0-255) scale. I used pvalue –o –h $HDR command but the
> results are not on the desired range (0-255). Any suggestion is appreciated.
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