[opencv] image morphological operation opencv marks the positions of different connected domains

【opencv】 Image morphology operation -opencv Mark the location of different connected domains

/** @overload
@param image the 8-bit single-channel image to be labeled
@param labels destination labeled image
@param stats statistics output for each label, including the background label.
Statistics are accessed via stats(label, COLUMN) where COLUMN is one of
#ConnectedComponentsTypes, selecting the statistic. The data type is CV_32S.
@param centroids centroid output for each label, including the background label. Centroids are
accessed via centroids(label, 0) for x and centroids(label, 1) for y. The data type CV_64F.
@param connectivity 8 or 4 for 8-way or 4-way connectivity respectively
@param ltype output image label type. Currently CV_32S and CV_16U are supported.
*/
CV_EXPORTS_W int connectedComponentsWithStats(InputArray image, OutputArray labels,
                                              OutputArray stats, OutputArray centroids,
                                              int connectivity = 8, int ltype = CV_32S);

 

 

 

   system("color F0");

    Mat img = imread("D:/image/ml2.png");
    if (img.empty()) {
        cout << "img is empty." << endl;
        return;
    }
    //imshow("srcImg", img);
    Mat rice, riceBW;

    cvtColor(img, rice, COLOR_BGR2GRAY);
    imshow("rice", rice);
    threshold(rice, riceBW, 50, 255, THRESH_BINARY);
    imshow("riceBW", riceBW);
    RNG rng(10086);
    Mat out, stats, centroids;
    //
    int number = connectedComponentsWithStats(riceBW, out, stats, centroids, 8, CV_16U);
    vector<Vec3b> colors;
    for (int i = 0; i < number; i++) {
        Vec3b vec3 = Vec3b(rng.uniform(0, 256), rng.uniform(0, 256), rng.uniform(0, 256));
        colors.push_back(vec3);
    }
    Mat result = Mat::zeros(rice.size(), img.type());
    int w = result.cols;
    int h = result.rows;
    for (int i = 1; i < number; i++) {
        int center_x = centroids.at<double>(i, 0);
        int center_y = centroids.at<double>(i, 1);
        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(img, Point(center_x, center_y), 2, Scalar(0, 255, 0), 2, 8, 0);

        Rect rect(x, y, w, h);
        rectangle(img, rect, colors[i], 1, 8, 0);
        putText(img, format("%d", i), Point(center_x, center_y),
                FONT_HERSHEY_SIMPLEX, 0.5, Scalar(0, 0, 255), 1);
        cout << "number: " << i << ",area: " << area << endl;
    }

    imshow("result:", img);
    waitKey(0);

  result ：