Progressive transmission in Trellis coded quantization-based image coders

As image coders evolve from DCT-based to wavelet-based designs, the latter must be enhanced to include capabilities currently supported by standards such as JPEG. Recent work [1, 2, 3] has described approaches for incorporating progressive transmission capabilities within wavelet-based coders. All of these coders apply scalar quantization to wavelet transform coefficients, and then apply sophisticated entropy coding methods to the quantized coefficients. In this paper, we present coding techniques that enable progressive transmission when trellis coded quantization (TCQ) is applied to the wavelet coefficients. While the trellis coded quantizer is more complex than the uniform scalar quantizer, comparable PSNR performance is achieved with a simple entropy coder. In addition, our use of sophisticated quantization and bit rate allocation algorithms enables the development of coders that are tuned for improved perceptual image quality.