Selective splitting approach to entropy-constrained single/multistage vector quantizer design
Hosam Khalil, Kenneth H. Rose · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 2000
A practical tool is proposed to improve the design of various vector quantizer (VQ) structures. Particular emphasis is placed on the design of entropy-constrained VQ (ECVQ), and entropy-constrained multi-stage VQ (EC-MSVQ), whose optimization is notoriously difficult. Traditional design techniques involve an indirect approach where a fixed rate quantizer is gradually modified into a variable rate VQ. We propose a direct design procedure based on selective codevector splitting. The codebooks are grown, using splitting according to a rate-distortion Lagrangian trade-off, to the desired operating point of average bit rate. Extensive simulations in image and video compression are presented and show consistent, significant improvement over standard techniques. For example, in ECVQ design for compression of video residuals, PSNR gains of about 1.0 dB were achieved.