An image coding algorithm combining directional lifting wavelet transform and trellis coded quantization

An image coding algorithm combining the directional lifting wavelet transform(DLWT) and the trellis coded quantization(TCQ) is presented to overcome the drawback of JPEG2000 image compression standard in representing image edges. This algorithm firstly uses a rate-distortion optimization-based quadtree segmentation method to get the optimal transform directions, performs DLWT along the optimal transform directions, then quantizes the wavelet subband coefficients by TCQ, and finally encodes the quantization coefficients outputting the bitstream. Experimental results show that the proposed image coding algorithm outperforms JPEG2000 for the given test images up to 1.49 dB in peak signal-to-noise ratio and 3.98% relatively in multi-scale structural similarity index, and that significant improvement in the subjective visual quality of decoded images is also observed.