need to find the density of the black pixels of a binary image which is oval in shape

My image is a Kirlian image which has two ovals, inner one and outer one.there are black pixels in the region between two ovals.The density of the pixels in this region varies in the oval.i need to split the image into sectors by drawing radial lines from the center of the image and need to find the density of black pixels in each segmented area and to find the average density in these regions. i also need to find the region which is more dense than the average density and the region which is less dense than the average density.