说明：  运动估计的算法源程序,搜索精度为半精度,方法是对整像素搜索到的匹配位置的领域像素进行内查,然后进一步搜索,找到更精确的匹配位置
(motion estimation algorithm source, search for semi-precision accuracy, is the whole pixel search to match the location of the pixel within the field investigation, then further search, find a more precise match position)