I realize there might be a better place to ask this, but I think you all will have some valuable feedback.
People are asked to draw a shape in black on a white cavas. Then their drawing is added to the running average. I’d like to have the parts that the images mostly have in common be shown, and the parts of the drawing that are unlike most of the other drawings disappear.
My two problems are that I’m using ImageMagick to process the images, which means that I can only create a composite of two images at once. So I have the running total image, and the newest one to add. I cannot get a real average this way.
Secondly, I do not fully understand blending modes particularly when different opacities are involved. I’m not sure which is the best to use.
When you add the first two images you blend them equally. But then when you add the 3rd image to the mix you have to change the weight of each image. The two image composite should be blended at 66.6% while the new image should contribute just 33.3%. For the 4th image you will blend at 75% and 25% respectively. In general, if you have n images in the composite, then the new image should contribute 100/(n+1) percent when added.
As you see, the more images you have the less an individual image affects the composite result.