A lossless image compression algorithm using predictive coding based on quantized colors

摘要

Predictive coding has proven to be effective for lossless image compression. Predictive coding estimates a pixel color value based on the pixel color values of its neighboring pixels. To enhance the accuracy of the estimation, we propose a new and simple predictive coding that estimates the pixel color value based on the quantized pixel colors of three neighboring pixels. The prediction scheme can help minimize the upper bound of the residual errors from the prediction. Experiments were conducted on a set of true color 24-bit images, whose pixel colors were quantized into 2, 4, 8 and 16 colors. The experimental results show that the proposed algorithm outperforms some well known lossless image compression algorithms such as JPEG-LS and PNG by factors of 2-3 in terms of bits per pixel. The results also show that the proposed algorithm gives the best compression rates when colors were quantized into two colors.