1. A method for post-processing a pixel-classified binary image for determination of a number of objects in the image comprising a material of interest, the method comprising: receiving a binary image containing pixels which have been classified using a pixel classification method, each pixel in said image has an intensity value, each of said pixels has a binary value depending on whether said pixel was classified as a material of interest or not; dividing said image into a plurality of blocks of pixels; manipulating pixel values in each of said blocks according to a threshold-based filtering criteria such that all pixels in a given block have a binary value which is uniform throughout the entire block; grouping together connected pixels having a same binary value to form objects; and counting the number of formed objects in said image.