Classified vector quantizer technique for image coding employing the linear phase paraunitary M-band filter bank

We propose an efficient classified vector quantizer (CVQ) technique employing the linear phase paraunitary (LPPU) M-band filter bank Based on the asymptotic distortion of VCT, a coding gain, which includes the gain by the correlation in the vector as well as the energy compaction, is first derived. Then we design the LPPU four-band and eight-band filter banks, with various lengths, that maximize the coding gain. Among the designed LPPU filter banks, eye select the LPPU four-band filter bank for the proposed CVQ technique, since we can significantly alleviate the complexity of CVQ and classify the input image more accurately with 4x4 blocks than with 8x8 blocks. However, the side information for the 4x4 blocks Is four times that for the 8x8 blocks. In order to reduce the side information, we propose the quadtree method, which reduces the side information by about 50%. Simulation results demonstrate that the proposed technique yields about 0.8- to 1.0-dB peak-SNR gain over that of the Joint Photographic Experts Group in the range of 0.3 to 0.4 bits per pixel. (C) 1996 Society of Photo-Optical Instrumentation Engineers.