多解析度自适应零块判决算法

在视频会议等应用中,视频编码的速度是保证系统实时性的关键.为了减小视频编码的运算量并提高系统的整体性能,提出了多解析度的自适应零块发现判决算法.多解析度通过对图像的子采样从而大幅度降低了搜索最佳匹配块的次数;而自适应的零块判决算法使得运动搜索速度收敛的更快,在不影响图像质量的前提下提高了编码的效率,并且减少了后续模块(DCT、量化等)所占用的时间.利用H.263算法进行了测试,结果显示在图像主客观质量基本不变的前提下,编码时间最多减少了近40%.

Adaptive Zero-Block Detection Algorithm with Multi-Resolution

In the current applications such as video conferencing, the video codec speed is the key factor to maintain the real-time performance in the whole system. In order to minimize the computations and improve the performance of video coding, an adaptive zero block detection algorithm combined with multi-resolution motion estimation is proposed in this paper. The multi-resolution technique uses down-sampling method on the whole image, which can dramatically reduce the computations in searching for the best candidate block during the motion search period. At the same time, adaptive zero block detection criteria can make the motion search procedure even faster and improve the coding efficiency without any influence on the image quality. Furthermore, the run-time of DCT(discrete cosine transform) and quantization has been singificantly reduced afterwards. Simulation results show that with H.263 codec, the proposed algorithm can obtain 40% savings in computations at most without any losses in the subjective and objective quality of decoded images.