通过比较区域面积，初步去除不符合要求的目标,通过求取区域周长，计算偏心率，根据圆形偏心率的标准，去除不符合要求的区域目标-By comparing the size of the area, preliminary removal does not meet the requirements of the target, to obtain the regional perimeter, calculated eccentricity, according to the standard circular eccentricity, remove target non-compliant areas