samples/java/tutorial_code/ShapeDescriptors/moments/MomentsDemo.java - 4.x - Alx89/OpenCV

samples/java/tutorial_code/ShapeDescriptors/moments/MomentsDemo.java
178 строк6 KB
catree
Add Java and Python code for the following imgproc tutorials: Finding contours in your image, Convex Hull, Creating Bounding boxes and circles for contours, Creating Bounding rotated boxes and ellipses for contours, Image Moments, Point Polygon Test.
11 июн 2018, 00:57
11 июн 2018, 00:57a11ef26
import java.awt.BorderLayout;
import java.awt.Container;
import java.awt.Image;
import java.util.ArrayList;
import java.util.List;
import java.util.Random;

import javax.swing.BoxLayout;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JSlider;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;

import org.opencv.core.Core;
import org.opencv.core.CvType;
import org.opencv.core.Mat;
import org.opencv.core.MatOfPoint;
import org.opencv.core.MatOfPoint2f;
import org.opencv.core.Point;
import org.opencv.core.Scalar;
import org.opencv.core.Size;
import org.opencv.highgui.HighGui;
import org.opencv.imgcodecs.Imgcodecs;
import org.opencv.imgproc.Imgproc;
import org.opencv.imgproc.Moments;

class MomentsClass {
    private Mat srcGray = new Mat();
    private JFrame frame;
    private JLabel imgSrcLabel;
    private JLabel imgContoursLabel;
    private static final int MAX_THRESHOLD = 255;
    private int threshold = 100;
    private Random rng = new Random(12345);

    public MomentsClass(String[] args) {
        //! [setup]
        /// Load source image
        String filename = args.length > 0 ? args[0] : "../data/stuff.jpg";
        Mat src = Imgcodecs.imread(filename);
        if (src.empty()) {
            System.err.println("Cannot read image: " + filename);
            System.exit(0);
        }

        /// Convert image to gray and blur it
        Imgproc.cvtColor(src, srcGray, Imgproc.COLOR_BGR2GRAY);
        Imgproc.blur(srcGray, srcGray, new Size(3, 3));
        //! [setup]

        //! [createWindow]
        // Create and set up the window.
        frame = new JFrame("Image Moments demo");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        // Set up the content pane.
        Image img = HighGui.toBufferedImage(src);
        addComponentsToPane(frame.getContentPane(), img);
        //! [createWindow]
        // Use the content pane's default BorderLayout. No need for
        // setLayout(new BorderLayout());
        // Display the window.
        frame.pack();
        frame.setVisible(true);
        update();
    }

    private void addComponentsToPane(Container pane, Image img) {
        if (!(pane.getLayout() instanceof BorderLayout)) {
            pane.add(new JLabel("Container doesn't use BorderLayout!"));
            return;
        }

        JPanel sliderPanel = new JPanel();
        sliderPanel.setLayout(new BoxLayout(sliderPanel, BoxLayout.PAGE_AXIS));

        //! [trackbar]
        sliderPanel.add(new JLabel("Canny threshold: "));
        JSlider slider = new JSlider(0, MAX_THRESHOLD, threshold);
        slider.setMajorTickSpacing(20);
        slider.setMinorTickSpacing(10);
        slider.setPaintTicks(true);
        slider.setPaintLabels(true);
        slider.addChangeListener(new ChangeListener() {
            @Override
            public void stateChanged(ChangeEvent e) {
                JSlider source = (JSlider) e.getSource();
                threshold = source.getValue();
                update();
            }
        });
        //! [trackbar]
        sliderPanel.add(slider);
        pane.add(sliderPanel, BorderLayout.PAGE_START);

        JPanel imgPanel = new JPanel();
        imgSrcLabel = new JLabel(new ImageIcon(img));
        imgPanel.add(imgSrcLabel);

        Mat blackImg = Mat.zeros(srcGray.size(), CvType.CV_8U);
        imgContoursLabel = new JLabel(new ImageIcon(HighGui.toBufferedImage(blackImg)));
        imgPanel.add(imgContoursLabel);

        pane.add(imgPanel, BorderLayout.CENTER);
    }

    private void update() {
        //! [Canny]
        /// Detect edges using Canny
        Mat cannyOutput = new Mat();
        Imgproc.Canny(srcGray, cannyOutput, threshold, threshold * 2);
        //! [Canny]

        //! [findContours]
        /// Find contours
        List<MatOfPoint> contours = new ArrayList<>();
        Mat hierarchy = new Mat();
        Imgproc.findContours(cannyOutput, contours, hierarchy, Imgproc.RETR_TREE, Imgproc.CHAIN_APPROX_SIMPLE);
        //! [findContours]

        /// Get the moments
        List<Moments> mu = new ArrayList<>(contours.size());
        for (int i = 0; i < contours.size(); i++) {
            mu.add(Imgproc.moments(contours.get(i)));
        }

        /// Get the mass centers
        List<Point> mc = new ArrayList<>(contours.size());
        for (int i = 0; i < contours.size(); i++) {
            //add 1e-5 to avoid division by zero
            mc.add(new Point(mu.get(i).m10 / (mu.get(i).m00 + 1e-5), mu.get(i).m01 / (mu.get(i).m00 + 1e-5)));
        }

        //! [zeroMat]
        /// Draw contours
        Mat drawing = Mat.zeros(cannyOutput.size(), CvType.CV_8UC3);
        //! [zeroMat]
        //! [forContour]
        for (int i = 0; i < contours.size(); i++) {
            Scalar color = new Scalar(rng.nextInt(256), rng.nextInt(256), rng.nextInt(256));
            Imgproc.drawContours(drawing, contours, i, color, 2);
            Imgproc.circle(drawing, mc.get(i), 4, color, -1);
        }
        //! [forContour]

        //! [showDrawings]
        /// Show in a window
        imgContoursLabel.setIcon(new ImageIcon(HighGui.toBufferedImage(drawing)));
        frame.repaint();
        //! [showDrawings]

        /// Calculate the area with the moments 00 and compare with the result of the OpenCV function
        System.out.println("\t Info: Area and Contour Length \n");
        for (int i = 0; i < contours.size(); i++) {
            System.out.format(" * Contour[%d] - Area (M_00) = %.2f - Area OpenCV: %.2f - Length: %.2f\n", i,
                    mu.get(i).m00, Imgproc.contourArea(contours.get(i)),
                    Imgproc.arcLength(new MatOfPoint2f(contours.get(i).toArray()), true));
        }
    }
}

public class MomentsDemo {
    public static void main(String[] args) {
        // Load the native OpenCV library
        System.loadLibrary(Core.NATIVE_LIBRARY_NAME);

        // Schedule a job for the event dispatch thread:
        // creating and showing this application's GUI.
        javax.swing.SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                new MomentsClass(args);
            }
        });
    }
}