Morphological image processing techniques are useful for extracting image components that are useful in representing and describing region shapes. The filters can be described using set theoretic notation and implemented using simple computer algorithms based on these. Almost all the material in this chapter has been taken from Digital image processing (Gonzalez and Woods, 1993).
In set theory notation
a 2D image is said to be a member of 
. For simplicity we
assume that the images are gray-scale images with their intensity being
an integer in the range [0,255]. In the following
description we consider
only two gray levels viz. 0 and 255 which correspond to white and black
respectively (it is then called a binary image and belongs to
). However, all the discussion extends easily to
discrete as well as continuous gray-scale images.