I have photographed dozens of people in groups of 8 portraits, all with equal illumination, gray background and color calibrated. I need to obtain the color difference inside each group and I'm particularly interested in the skin color.
1 — How to calculate the color difference (comparing photo nr 1 to each one of the other 7)?
2 — Is it possible to obtain the regions of the image in which color changes the most, and by how much?
(see image in attach as example: the 1st one is the control image to which the 2nd and others will be compared)
Thanks in advance for any help provided to this research student with a deadline to accomplish!! Best regards, Teresa.