A novel quantization scheme for predictive coding

In existing predictive image coding systems, a prediction error is quantized based on the criterion to minimize the mean square value of the coding error. With this quantization scheme, the reduction of the coding error is restricted by the number of the quantization levels and the amplitude distribution of the prediction error, and it is hard to locate more coding errors in less visible areas. In this paper, we present a new quantization scheme to improve the performance of the predictive image coding technique. In the proposed predictive coding system, instead of the prediction error, a contrast measure is generated from a predicted value and the original value of the current image pixel, which is then quantized based on an intuitive concept. Thus, a desirable weighting function is introduced in the coding algorithm such that the coding error is adapted by the pixel intensity and its contrast measure