initial commit

samples/java/tutorial_code/TrackingMotion/harris_detector/CornerHarrisDemo.java

@@ -0,0 +1,142 @@
+import java.awt.BorderLayout;
+import java.awt.Container;
+import java.awt.Image;
+
+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.Point;
+import org.opencv.core.Scalar;
+import org.opencv.highgui.HighGui;
+import org.opencv.imgcodecs.Imgcodecs;
+import org.opencv.imgproc.Imgproc;
+
+class CornerHarris {
+    private Mat srcGray = new Mat();
+    private Mat dst = new Mat();
+    private Mat dstNorm = new Mat();
+    private Mat dstNormScaled = new Mat();
+    private JFrame frame;
+    private JLabel imgLabel;
+    private JLabel cornerLabel;
+    private static final int MAX_THRESHOLD = 255;
+    private int threshold = 200;
+
+    public CornerHarris(String[] args) {
+        /// Load source image and convert it to gray
+        String filename = args.length > 0 ? args[0] : "../data/building.jpg";
+        Mat src = Imgcodecs.imread(filename);
+        if (src.empty()) {
+            System.err.println("Cannot read image: " + filename);
+            System.exit(0);
+        }
+
+        Imgproc.cvtColor(src, srcGray, Imgproc.COLOR_BGR2GRAY);
+
+        // Create and set up the window.
+        frame = new JFrame("Harris corner detector demo");
+        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
+        // Set up the content pane.
+        Image img = HighGui.toBufferedImage(src);
+        addComponentsToPane(frame.getContentPane(), img);
+        // 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));
+
+        sliderPanel.add(new JLabel("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();
+            }
+        });
+        sliderPanel.add(slider);
+        pane.add(sliderPanel, BorderLayout.PAGE_START);
+
+        JPanel imgPanel = new JPanel();
+        imgLabel = new JLabel(new ImageIcon(img));
+        imgPanel.add(imgLabel);
+
+        Mat blackImg = Mat.zeros(srcGray.size(), CvType.CV_8U);
+        cornerLabel = new JLabel(new ImageIcon(HighGui.toBufferedImage(blackImg)));
+        imgPanel.add(cornerLabel);
+
+        pane.add(imgPanel, BorderLayout.CENTER);
+    }
+
+    private void update() {
+        dst = Mat.zeros(srcGray.size(), CvType.CV_32F);
+
+        /// Detector parameters
+        int blockSize = 2;
+        int apertureSize = 3;
+        double k = 0.04;
+
+        /// Detecting corners
+        Imgproc.cornerHarris(srcGray, dst, blockSize, apertureSize, k);
+
+        /// Normalizing
+        Core.normalize(dst, dstNorm, 0, 255, Core.NORM_MINMAX);
+        Core.convertScaleAbs(dstNorm, dstNormScaled);
+
+        /// Drawing a circle around corners
+        float[] dstNormData = new float[(int) (dstNorm.total() * dstNorm.channels())];
+        dstNorm.get(0, 0, dstNormData);
+
+        for (int i = 0; i < dstNorm.rows(); i++) {
+            for (int j = 0; j < dstNorm.cols(); j++) {
+                if ((int) dstNormData[i * dstNorm.cols() + j] > threshold) {
+                    Imgproc.circle(dstNormScaled, new Point(j, i), 5, new Scalar(0), 2, 8, 0);
+                }
+            }
+        }
+
+        cornerLabel.setIcon(new ImageIcon(HighGui.toBufferedImage(dstNormScaled)));
+        frame.repaint();
+    }
+}
+
+public class CornerHarrisDemo {
+    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 CornerHarris(args);
+            }
+        });
+    }
+}