Gradient-adjusted prediction of lossless image compression based on block-scan

We propose a new gradient-adjusted prediction method of lossless image compression based on block-scan. Each pixel within a block is predicted by a weighted sum of its different neighbor pixels provided by different scan mode, including horizontal, vertical, right down and left down direction, and the scan mode is selected by an adaptive coding scheme based on the texture property of the image. The experimental results show that the suggested method has a significant reduction of zero-order entropy as compared to only one horizontal scan mode in the same part of image and sequences.