A New Approach of Image Compression Based on Difference Vector Quantization

For image compression, the better compression rate can be achieved by vector quantization (VQ) scheme, but the quality of the recovered image is about 27 to 30 dB in PSNR, and the methods about quality improvement is limited, so how to improve the VQ decompressed image´s quality is a worth studying issue. In this paper, a new approach of VQ encoding is proposed, that we transform each image into a difference value´s matrix rather than a pixel value´s image before VQ compression. On the other words, we changed the subject of VQ scheme from an image to its corresponding difference value´s matrix. Experimental results show that the better decompressed image quality is achieved by a smaller index table, but some additional recovery data of pixel value from its difference value, should be recorded. However, according to the image characteristics, the recovery data can be compressed into a group of smaller data.