AlexNet CNN how can it be applied to my case?
Potentially what you could do is use a GMM with 3 modes to cluster the image into 3 "partitions". The first would contain all the pixels with blue, the second all the pixels with brown, and the final should contain the background pixels. You would cluster based on the raw RGB values (unless you could calculate some more semantic deep learning based feature for each pixel to cluster). You would then do some form of colour sampling on the pixels assigned to each of the 3 modes to determine which are the brown blobs and which are the blue blobs. You can count easily by computing the binary image from the GMM blobs.