Fast algorithm for DCT domain image up-conversion

A great number of data associated with visual information requires usage of the popular DCT (Discrete Cosine Transform) compression. This also suggests the investigation of methods for image processing directly in the DCT domain. This paper presents a fast DCT domain image up-conversion algorithm, and a DCT domain linear filter, which only involves matrix manipulation. By using the separate property of certain spatial filters, we accomplish the DCT domain up-conversion via only matrix products. Because 1) most of the matrices can be calculated beforehand, and 2) common DCT blocks are very sparse; and 3) by avoiding the conventional decode and re-encode scheme, the computational complexities are greatly reduced. Experiments on real images show good results.     

一种加快分形图像解码收敛速度的方法

通过对码本设置阚值的方法来收缩对比度因子,提出了一种新的快速分形图像解码算法.实验结果表明该算法获得了较基本分形算法质量较高的第一次迭代后图像,在图像质量降质较小的情况下较基本分形解码明显地加快了收敛速度,从而可较好地满足需要超高速图像解码的应用场合(如实时视频传输).