seems to be quite the same thread here
Just for the fun here an example using Variable Pipe (not very fast but it works)
So Generate points on an image, here it is random which is not the best, in you example there is a correlation between the position and radius
generate Circles, one big circle to be white and little circles to be blacks. Circles are moved in Z in order to not overlap.
Transform circle to points and search the brightness of the image
Transform Brightness in radius and make a variable pipe.
Color disk and pipes