A block transform coder for arbitrarily shaped image segments

This paper describes a method for coding arbitrarily shaped image segments. The method uses an iterative technique based on the theory of successive projection onto convex sets to determine the best transform coefficients. It uses block transforms with frequency domain region-zeroing and space domain region-enforcing operations for effective coding of image segments of arbitrary shape. A major strength of this method is that it can be implemented in real-time using existing codec hardware at an insignificant additional cost