A Novel Adaptive Decimation/Interpolation Methodwith Contour Preserving Property
一种保护图象轮廓细节的自适应亚抽样和插值方法

A novel adaptive decimation/interpolation algorithm, which can be applied in all kinds of blocking image coding algorithm, is proposed. The image is first divided into non overlapping blocks. Then the horizontal and the vertical gradients of each block are calculated. According to the two gradient values, the image blocks are classified into four groups, namely smooth block, horizontal contour block, vertical contour block and high detail block. Then different decimation methods are applied to different class of blocks to reduce the original data quantity. Experimental results show, compared to other decimation/interpolation algorithms, the proposed algorithm can well preserve the contour and other detail information, thus substantially improve the quality of the reconstructed images, especially the subjective quality. The proposed method increases the PSNR by 3 9 dB while keeping comparable compression ratio for high detailed images. For low detailed images, compression ratio and PSNR are all slightly improved.