content: 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.Mat;
  import org.opencv.highgui.HighGui;
  import org.opencv.imgcodecs.Imgcodecs;
  import org.opencv.imgproc.Imgproc;
  
  public class Threshold {
      private static int MAX_VALUE = 255;
      private static int MAX_TYPE = 4;
      private static int MAX_BINARY_VALUE = 255;
      private static final String WINDOW_NAME = "Threshold Demo";
      private static final String TRACKBAR_TYPE = "<html><body>Type: <br> 0: Binary <br> "
              + "1: Binary Inverted <br> 2: Truncate <br> "
              + "3: To Zero <br> 4: To Zero Inverted</body></html>";
      private static final String TRACKBAR_VALUE = "Value";
      private int thresholdValue = 0;
      private int thresholdType = 3;
      private Mat src;
      private Mat srcGray = new Mat();
      private Mat dst = new Mat();
      private JFrame frame;
      private JLabel imgLabel;
  
      public Threshold(String[] args) {
          //! [load]
          String imagePath = "../data/stuff.jpg";
          if (args.length > 0) {
              imagePath = args[0];
          }
          // Load an image
          src = Imgcodecs.imread(imagePath);
          if (src.empty()) {
              System.out.println("Empty image: " + imagePath);
              System.exit(0);
          }
          // Convert the image to Gray
          Imgproc.cvtColor(src, srcGray, Imgproc.COLOR_BGR2GRAY);
          //! [load]
  
          //! [window]
          // Create and set up the window.
          frame = new JFrame(WINDOW_NAME);
          frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
          // Set up the content pane.
          Image img = HighGui.toBufferedImage(srcGray);
          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);
          //! [window]
      }
  
      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(TRACKBAR_TYPE));
          // Create Trackbar to choose type of Threshold
          JSlider sliderThreshType = new JSlider(0, MAX_TYPE, thresholdType);
          sliderThreshType.setMajorTickSpacing(1);
          sliderThreshType.setMinorTickSpacing(1);
          sliderThreshType.setPaintTicks(true);
          sliderThreshType.setPaintLabels(true);
          sliderPanel.add(sliderThreshType);
  
          sliderPanel.add(new JLabel(TRACKBAR_VALUE));
          // Create Trackbar to choose Threshold value
          JSlider sliderThreshValue = new JSlider(0, MAX_VALUE, 0);
          sliderThreshValue.setMajorTickSpacing(50);
          sliderThreshValue.setMinorTickSpacing(10);
          sliderThreshValue.setPaintTicks(true);
          sliderThreshValue.setPaintLabels(true);
          sliderPanel.add(sliderThreshValue);
          //! [trackbar]
  
          //! [on_trackbar]
          sliderThreshType.addChangeListener(new ChangeListener() {
              @Override
              public void stateChanged(ChangeEvent e) {
                  JSlider source = (JSlider) e.getSource();
                  thresholdType = source.getValue();
                  update();
              }
          });
  
          sliderThreshValue.addChangeListener(new ChangeListener() {
              @Override
              public void stateChanged(ChangeEvent e) {
                  JSlider source = (JSlider) e.getSource();
                  thresholdValue = source.getValue();
                  update();
              }
          });
          //! [on_trackbar]
  
          pane.add(sliderPanel, BorderLayout.PAGE_START);
          imgLabel = new JLabel(new ImageIcon(img));
          pane.add(imgLabel, BorderLayout.CENTER);
      }
  
      //! [Threshold_Demo]
      private void update() {
          Imgproc.threshold(srcGray, dst, thresholdValue, MAX_BINARY_VALUE, thresholdType);
          Image img = HighGui.toBufferedImage(dst);
          imgLabel.setIcon(new ImageIcon(img));
          frame.repaint();
      }
      //! [Threshold_Demo]
  
      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 Threshold(args);
              }
          });
      }
  }
  