Example for the calculation of texture features from a grey-level co-occurrence matrix (GLCM). For the sake of simplicity, a 4 × 4 pixel grey-scale image with only three grey-levels (i.e. white, grey, and black) was chosen. In Step 1, a GLCM is deducted from this image by considering the relationship of every pixel to its neighborhood. We start with the co-occurrence of ‘black + black’, which occurs twice in the image, as indicated by the red circles. The absolute count of the different co-occurrences is recorded in a table, which - after its completion - is named the GLCM. In Step 2, the GLCM is normalized so that each cell doesn’t contain a count but the probability of every possible co-occurrence. These probabilities provide the basis for the calculation of the various ‘texture features’ according to the equations shown (Step 3).