Doubt related to image processing

while using image processing of an HDR image RGB pixel value(using 'impixel') obtained from the software doesnot match with the pixel value obtained using photometrics software. Hence it produces a significant variation in luminance value of a specific piont find out using photometics. The value obtained using photometics was correct because it was verified using Konica Minolta luminance meter. I want to know how the actual RGB pixel value of an image can be fing out using MATLAB. I also want to know if it is because of the problem in creating the HDR image using MATLAB.I use 'makehdr' command to create a HDR image in MATLAB from 5 LDR image

[Walter Roberson]

See the similar question at http://www.mathworks.co.uk/matlabcentral/answers/86042-processing-behind-makehdr-and-tone-mapping-algorithm

Very odd: we have never had a question about HDR before, and then within the same hour, two different people ask about the same luminance difficulty.

Answer 1

[Image Analyst]

I don't work with HDR but I would think that whoever or whichever company does it might have their own algorithm, kind of like demosaicing a raw image where different companies use different algorithms. They all start with a raw image and end with an RGB image but they have different algorithms for arriving at the RGB image. Wouldn't HDR be the same way? Correct me if I'm wrong, like there's some ASTM, ISO, CIE, or other de facto industry standard method for the algorithm that you're required to follow. If there's no standard, why would you expect different programs to produce exactly the same output image?