I am constantly getting errors when running the colour and luminance JND calculations. As you suggested before, I am transforming cone catch to RNL chromaticity first and then running the JND. However, sometimes I get either “NaN” in the JND_diff column or nothing pops up in the Comparison Results window. I have tried to use the cone mapping model that I have created but also one that was already in the toolbox. I am not sure why this happens sometimes. Would you have any idea of what I might be doing wrong here?
If you’re converting to RNL chromaticity space then you will have created XYZ coordinate output (awkwardly this matches the names of the CIE XYZ channel output, which is totally different). You don’t need to use the JND calculator on these RNL chromaticity coordinate data – you just measure the Euclidean distance between any two XYZ values and this is mathematically identical to the JND (or rather delta-S as we should technically call it).
Thank you very much for your reply.
Actually, after I sent this I realized that I was stuck in this question, but I did not need to do anything like that. I was finally able to run the chromatic and achromatic contrasts. Yey!! Thanks again for addressing all my questions!