说明：  三步法哪l是一种较好的搜索算法，快速而且高效，它是在对数法的基础上对 其进行了改进，提出在每一步搜索后搜索步长均减半的算法。它基本保持了FS的 性能，但其计算量只有FS的10％左右。TSS在会议电视和可视电话中应用较多， 它通过三步搜索，逐步较小搜索步长。若最大搜索范围为士7，搜索精度取一个像 素，则步长为4、2、1，共需三步即可满足要求，从而得名。
(The three step in which l is a good search algorithm, fast and efficient, it is based on the logarithmic law of It is improved, the search step is halved at each step of the algorithm search. It remained FS TSS commonly used in videoconferencing and videophone, The three step search, gradually smaller search step. If the maximum search range is ± 7, search accuracy, a like If the maximum search range is ± 7, search accuracy, a like Element, the step size for the 4, 2, 1, a total of three steps to meet the requirements, thus its name.)