说明：  利用hough变换来进行圆形检测.Function uses Standard Hough Transform to detect circles in a binary image.According to the Hough Transform for circles, each pixel in image space corresponds to a circle in Hough space and vise versa. upper left corner of image is the origin of coordinate system.
(Using hough transform for circle detection. Function uses Standard Hough Transform to detect circles in a binary image.According to the Hough Transform for circles, each pixel in image space corresponds to a circle in Hough space and vise versa. Upper left corner of image is the origin of coordinate system.)