A predictive image coding scheme using a smaller codebook

摘要

This paper presents a new scheme in vector quantization (VQ). We call it the peripheral prediction method (PPM). This method assumes that most of the image blocks in VQ are smooth. Therefore, we can use the central area of the image block to predict its peripheral area. According to this assumption, we divide the processing of an image block in VQ into the following two phases. First, we employ a smaller codebook to encode the central area of each image block, and next PPM uses the encoded result to predict the peripheral area of the image block by a prediction method. Experimental comparisons with the other methods show that the smaller codebook of PPM can really help to speed up the encoding time and reduce the bit-rate for the same image quality. Moreover, in some cases, PPM is even ten times faster than the other methods.