四步搜索算法对三步算法进行了适当的改进，在一定程度上弥补了TSS算法法在估计细小运动时的不足，并加入了半途中止的策略，进一步提高了搜索精度

-Appropriate improvements to the four-step search algorithm on a three-step algorithm, to a certain extent make up for the deficiencies of the TSS algorithm in estimating the small movement, and joined halfway through the suspension of the strategy to further improve the search accuracy