I have 2 images which are the aggregate data of some participants using an eye tracker in separate groups (the images are attached, R1Active and R1Passive). The images were taken from a facade (R1 and R1_P) so I cannot geo-reference them.
I want to say that the heatmaps (the colorful areas) are almost the same parts of the facade and landscape for both images.
How can I count the number of pixels in colorful areas (i.e. heatmaps) (excluding the black background)?
Do I need to convert .jpg to raster? if so how can I do it?
Can i simply count pixels where R, G, and B are not equal to zero (that is when the color is not black)?
Thank you very much!