Circle Detection

I need help developing a circle detection algorithm to detect snooker balls. Does anyone know 开发者_如何学Goany algorithms that can be implemented in C and open cv? I'm having trouble getting this done

OpenCV 2.3 comes with HoughCircles. The C++ API for OpenCV 2.1 also implements the function: http://opencv.willowgarage.com/documentation/cpp/imgproc_feature_detection.html#HoughCircles