OpenCV联通组件扫描

void ccl_demo()
{
  QString appPath = QCoreApplication::applicationDirPath();
  QString imagePath = appPath + "/rice.png";
  Mat img = cv::imread(imagePath.toStdString());
  if (img.empty()) {
    return;
  }
  namedWindow("input", WINDOW_AUTOSIZE);
  imshow("input", img);
  //高斯模糊：降噪
  GaussianBlur(img, img, Size(3, 3),0);
  //To gray image
  Mat gray, binary;
  cvtColor(img, gray, COLOR_BGR2GRAY);
  imshow("gray", gray);
  //OTSU
  double m_otsu = threshold(gray, binary, 0, 255, THRESH_BINARY | THRESH_OTSU);
  imshow("BINARY", binary);
  ccl_stats_demo(binary);
}
void ccl_stats_demo(Mat &image)
{
  Mat labels = Mat::zeros(image.size(), CV_32S);
  Mat stats, centrolds;
  int num_labels = connectedComponentsWithStats(image,labels,stats,centrolds,8, CV_32S, CCL_DEFAULT);
  vector<Vec3b> colorTable(num_labels);
  RNG rng(12345);
  //background color
  colorTable[0] = Vec3b(0, 0, 0);
  
  for (int i = 1; i < num_labels; i++)
  {
    colorTable[i] = Vec3b(rng.uniform(0, 256), rng.uniform(0, 256), rng.uniform(0, 256));
  }
  Mat result = Mat::zeros(image.size(), CV_8UC3);
  int w = result.cols;
  int h = result.rows;
  for (int row = 0; row < h; row++)
  {
    for (int col = 0; col < w; col++)
    {
      int label = labels.at<int>(row, col);
      result.at<Vec3b>(row, col) = colorTable[label];
    }
  }
  for (int i = 1; i < num_labels; i++)
  {
    //center
    int cx = centrolds.at<double>(i, 0);
    int cy = centrolds.at<double>(i, 1);
    //rectangle
    int x = stats.at<int>(i, CC_STAT_LEFT);
    int y = stats.at<int>(i, CC_STAT_TOP);
    int w = stats.at<int>(i, CC_STAT_WIDTH);
    int h = stats.at<int>(i, CC_STAT_HEIGHT);
    int area = stats.at<int>(i, CC_STAT_AREA);
    circle(result, Point(cx, cy), 3, Scalar(0, 0, 255), 2, 8, 0);
    Rect box(x, y, w, h);
    rectangle(result, box, Scalar(0, 255, 0), 2, 8, 0);
    putText(result, format("%d", area), Point(x,y), FONT_HERSHEY_PLAIN, 1.0, Scalar(0, 255, 255), 1);
  }
  putText(result, format("number:%d", num_labels-1), Point(10, 10), FONT_HERSHEY_PLAIN, 1.0, Scalar(0, 0, 255), 1);
  imshow("CCL demo", result);
}