中文说明：
meanshift均值平移跟踪算法中核函数窗宽的自动选取代码，根据目标大小变化核窗宽，使得当目标出现大小变化时准确跟踪到目标中心。
English Description：
In meanshift mean shift tracking algorithm, the automatic selection code of kernel window width changes the kernel window width according to the size of the target, so that when the size of the target changes, it can accurately track to the center of the target