Image coding using wavelet transforms and entropy-constrained trellis coded quantization

The use of entropy-constrained trellis-coded quantization (TCQ) for encoding the wavelet coefficients of both monochrome and color images is investigated. For decomposing images, a separable 2-D discrete wavelet transform in which emphasis is given to the horizontal and vertical directions is used. Nine-tap filters derived from biorthogonal wavelet bases are employed. The lowest-resolution subimage was encoded using a 2-D discrete cosine transform while the other subimages were encoded using TCQ for memoryless data. Excellent peak signal-to-noise ratios are obtained for encoding monochrome and color versions of the 512*512 ´Lenna´ image. Comparisons with other results from the literature reveal that the proposed wavelet coder is quite competitive.<>