所有灰度大于或等于阀值的像素被判定为属于特定物体，其灰度值为255表示，否则这些像素点被排除在物体区域以外，灰度值为0，表示背景或者例外的物体区域-All the gray pixels is greater than or equal to the threshold has been determined as belonging to a particular object, the gray value of 255 that would otherwise be excluded fr