Transform coding of images using fixed-rate and entropy-constrained trellis coded quantization

Abstract

Trellis coded quantization (TCQ) is incorporated into a transform coding structure for encoding monochrome and color images at 1 bit/pixel. Both fixed-rate and entropy-constrained designs are considered. For monochrome images, the fixed-rate TCQ-based systems provide gains in peak-signal-to-noise ratio (PSNR) of up to 3.32 dB over scalar quantizer-based systems, while the entropy-constrained designs provide gains of up to 7.50 dB. Gains in PSNR for color images of up to 1.76 dB and 3.93 dB are achieved for the fixed-rate and entropy-constrained TCQ-based systems, respectively. The high frequency background noise and fuzziness produced by scalar quantizer-based systems are virtually eliminated by the TCQ-based systems.