On a predictive scheme for colour image quantization

摘要

In this paper we proposed an improved colour image quantization scheme based on predictive coding. Since the neighbour-ing colour pixels are quite similar in most colour images, the similarity among the encoded pixels is exploited. In the pro-posed scheme the encoded distinct neighbouring colours are collected to form a smaller state-palette. If the closest colour in the state-palette is quite similar to the current encoding colour pixel, the index of the closest colour in the state-palette is recorded. Otherwise, the closest colour in original colour palette for the current encoding colour pixel is searched and the corresponding index is recorded. The experimental results show that the proposed method achieves good image qualities while requiring much lower bit rates for colour image compression.