Hello,
I am trying to figure out a way to use the measure function on some sort of color scale rather than a grayscale or brightness/color-intensity scale. I am combining images in a heatmap using the "Heatmap from Stack" plugin which converts them into a colorscale based off of frequency of pixel appearance from red (being highest frequency among images) to violet (being lowest frequency among images). I want to use the same color scale this plugin uses in order to make measurements on specific regions within my heatmap, so I can quantitatively see which areas were consistently the darkest. Thanks! here is a link to the heatmap plugin I am talking about:
http://www.samuelpean.com/heatmap-from-stack