A new shape-adaptive DCT for coding of arbitrarily shaped image segments

This paper presents a new coding scheme for arbitrarily shaped image segments using a boundary block grouping and merging (BBGM) technique and a modified shape-adaptive discrete cosine transform (SA-DCT). The BBGM technique merges pairs or groups of neighboring blocks satisfying some properties into larger single blocks. The modified SA-DCT is then applied to these blocks as well as to other boundary blocks. The number of transformed coefficients is the same as the number of foreground pixels in the boundary segment. Simulation results show that the proposed algorithm performs better than the conventional SA-DCT first suggested in 1995 and the pseudo-orthonormal SA-DCT published in 1998