After reading your comment, deep learning came to mind. A quick search comes up with "Deep Metric Learning for Color Differences" by F Zolotarev: https://lutpu

After reading your comment, deep learning came to mind. A quick search comes up with "Deep Metric Learning for Color Differences" by F Zolotarev: https://lutpub.lut.fi/bitstream/handle/10024/157102/Deep%20Metric%20Learning%20for%20Color%20Differences.pdf https://lutpub.lut.fi/bitstream/handle/10024/157102/Deep%20M... Looks like deep learning works