src = imread( "../star1.jpg" ,1 );

/// Convert image to gray and blur itcvtColor( src, src_gray, CV_BGR2GRAY );blur( src_gray, src_gray, Size(3,3) );

namedWindow( "image", CV_WINDOW_AUTOSIZE );imshow( "image", src );

Mat canny_output;vector<vector<Point> > contours;vector<Vec4i> hierarchy;

//利用canny算法检测边缘Canny( src_gray, canny_output, thresh, thresh*2, 3 );namedWindow( "canny", CV_WINDOW_AUTOSIZE );imshow( "canny", canny_output );//查找轮廓findContours( canny_output, contours, hierarchy, CV_RETR_TREE, CV_CHAIN_APPROX_SIMPLE, Point(0, 0) );

//计算轮廓矩vector<Moments> mu(contours.size() );for( int i = 0; i < contours.size(); i++ )    { mu[i] = moments( contours[i], false ); }

//计算轮廓的质心vector<Point2f> mc( contours.size() );for( int i = 0; i < contours.size(); i++ )    { mc[i] = Point2f( mu[i].m10/mu[i].m00 , mu[i].m01/mu[i].m00 ); }

//画轮廓及其质心Mat drawing = Mat::zeros( canny_output.size(), CV_8UC3 );for( int i = 0; i< contours.size(); i++ )    {    Scalar color = Scalar( rng.uniform(0, 255), rng.uniform(0,255), rng.uniform(0,255) );    drawContours( drawing, contours, i, color, 2, 8, hierarchy, 0, Point() );    circle( drawing, mc[i], 4, color, -1, 8, 0 );    }

namedWindow( "Contours", CV_WINDOW_AUTOSIZE );imshow( "Contours", drawing );

//打印轮廓面积和轮廓长度printf("\t Info: Area and Contour Length \n");for( int i = 0; i< contours.size(); i++ )    {    printf(" * Contour[%d] - Area (M_00) = %.2f - Area OpenCV: %.2f - Length: %.2f \n", i, mu[i].m00, contourArea(contours[i]), arcLength( contours[i], true ) );    Scalar color = Scalar( rng.uniform(0, 255), rng.uniform(0,255), rng.uniform(0,255) );    drawContours( drawing, contours, i, color, 2, 8, hierarchy, 0, Point() );    circle( drawing, mc[i], 4, color, -1, 8, 0 );    }