变换运算 meaning in English
commutative operation
Examples
- Discrete fourier transform is a special word for computers to fourier transform , so dft is adapted for computers to caculate . fast fourier transform is a kind of method to decrease the time used in dft . matlab makes matrix and vector as basic data unit
离散傅立叶变换( discretefouriertransform )并非泛指对任意离散信号取傅立叶积分，而是为适应计算机作傅立叶变换运算而引入的一个专用名词，所以dft是适用于数字计算机计算的ft 。 - In this paper , two important modifications in dct - based coding algorithm are suggested after making deep study on the generally used scheme of h . 263 coder . first , we find plenty of invalid computation in the transformation part of the h . 263 coder and an improved scheme based on the pre - transform decision to avoid invalid computation is proposed . second , in the motion estimation part of the coder , we find that normal search algorithms are not effective , which neglects different levels of motion in image sequences , and we suggest a new search algorithm which has variable search region based on the difference of motion level . combining the pre - transform decision scheme with variable search region method in motion estimation , a global decision coding scheme is provided , which greatly increases the coding speed of h . 263 coder
本文对h . 263编码算法的现有实现方法作了深入的分析，首先发现变换部分存在大量无效运算，提出了在变换前加判决的前变换判决的编码方案，以压缩无效的变换运算；其次发现运动估计部分由于忽略了图像场景的分级运动而存在一定的无效搜索运算，提出了基于分级运动的可变搜索域法来压缩无效的搜索运算；最后将前变换判决方案与运动估计的可变搜索域法有机地结合在一起，提出了全局判决编码方案，从而比较全面地改进了现有实现方法，因而能大幅度地提高编码器的编码速度