使用区域搜索的DCT域分形图像编码方法

为降低ＤＣＴ域分形图像压缩的编码复杂度,文中引入了平坦块的概念,对那些经过ＤＣＴ变换后,能量非常集中的块不做块匹配,而是直接编码输出。同时经统计发现,对于给定的区块,与它匹配最好的域块通常位于这个区块的上方或附近,文中利用这个事实构造了一种优化的自适应搜索方案,大大减少了编码所需要的时间。实验表明,与一般的ＤＣＴ域分形图像压缩方法相比,文中方案在提高了编码速度的同时降低了比特率。

Fractal image coding method using region search in DCT domain

Plain block is introduced to decrease the computational complexity of fractal image coding in DCT domain. Block which energy concentrates highly is called plain block. These blocks are coded directly instead of doing block match. At the same time, it is found that the best-matched main block is always on the top or near the range block, an optimal adaptive search method in block match process based on this fact is proposed. Computer simulations and c omparisons with results of conventional fractal coding method in DCT domain show that this method decreases the complexity greatly with low bit-rate.