[HDRI] RGB value from 0 to 255

[Mahlab, Seyedeh Farzaneh]

Hello
Im trying to extract RGB value from an HDR image from 0 to 255. I was using : pvalue -o -s $HDR and RGB values are irradiances ? I added -db to the code but still not giving me the result. Any suggestion is appreciated.

[Gregory J. Ward]

Hi Seyedeh,

The "-s" option to pvalue skips the specified number of bytes in the input for non-standard headers. I don't think this is the option you want.

You probably want the "-di" option (or "+di" if you want the pixels positions). The "-o" option removes any exposure that has been applied to the image, so the output will be 255 for 1.0 watts/sr/m^2. If your picture was created using the rpict "-i" or "-I" option, then the output will be irradiance rather than radiance, and 255 will correspond to 1.0 watts/m^2.

I hope this helps.

-Greg

P.S. I had to manually pass your e-mail through the system. Next time, make sure you write from the address you signed up for on the HDRI list, or add this one.

Date: January 27, 2017 2:53:42 PM PST
Hello
Im trying to extract RGB value from an HDR image from 0 to 255. I was using : pvalue –o –s $HDR and RGB values are irradiances ? I added –db to the code but still not giving me the result. Any suggestion is appreciated.