Shape Numbers

    we can normalize the chain code for starting point by rotating the elements of the chain code until the numbers form an integer of minimum magnitude. Such a normalized difference chain code is called a shape number.

    Example: The difference code of the previous chain code 0 11 2 2 3 0 3 is 1 0 1 0 1 1 3 1, and its shape number is 0 1 0 1 1 3 11.