Desktop : OpenCV Robinson Filter

<h5>Goal</h5>
Test OpenCV robinson filter.

```OpenCV_Robinson_Filter.java
import org.opencv.core.Core;
import org.opencv.core.CvType;
import org.opencv.core.Mat;
import org.opencv.imgcodecs.Imgcodecs;
import org.opencv.imgproc.Imgproc;

import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.image.BufferedImage;

public class OpenCV_Robinson_Filter {

    static {System.loadLibrary(Core.NATIVE_LIBRARY_NAME);}
    private JFrame frmjavaSwing;

    /**
        * Lunch the application.
        */
    public static void main(String[] args){
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    OpenCV_Robinson_Filter window = new OpenCV_Robinson_Filter();
                    window.frmjavaSwing.setVisible(true);
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        });
    }

    /**
        * Create the application.
        */
    public OpenCV_Robinson_Filter(){
        init();
    }

    /**
        * Init the contents of the frame.
        */
    private void init(){
        final Mat source = Imgcodecs.imread(
                "D:\\projects\\Java\\OpenCV_Samples\\resource\\imgs\\lena.jpg");

        BufferedImage image=matToBufferedImage(source);

        frmjavaSwing = new JFrame();
        frmjavaSwing.setTitle("opencv Robinson filter練習");
        frmjavaSwing.setBounds(100, 100, 560, 620);
        frmjavaSwing.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frmjavaSwing.getContentPane().setLayout(null);

        final JLabel lblNewLabel = new JLabel("");
        lblNewLabel.setBounds(5, 60, image.getHeight()+10, image.getWidth()+10);
        lblNewLabel.setIcon(new ImageIcon(image));
        frmjavaSwing.getContentPane().add(lblNewLabel);

        JButton btnR0 = new JButton("R0");
        btnR0.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent arg0) {
                BufferedImage newImage=matToBufferedImage(Convolution(source,0));
                lblNewLabel.setIcon(new ImageIcon(newImage));
            }
        });
        btnR0.setBounds(5, 10, 63, 23);
        frmjavaSwing.getContentPane().add(btnR0);

        JButton btnR1 = new JButton("R1");
        btnR1.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent arg0) {
                BufferedImage newImage=matToBufferedImage(Convolution(source,1));
                lblNewLabel.setIcon(new ImageIcon(newImage));
            }
        });
        btnR1.setBounds(72, 10, 63, 23);
        frmjavaSwing.getContentPane().add(btnR1);

        JButton btnR2 = new JButton("R2");
        btnR2.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent arg0) {
                BufferedImage newImage=matToBufferedImage(Convolution(source,2));
                lblNewLabel.setIcon(new ImageIcon(newImage));
            }
        });
        btnR2.setBounds(136, 10, 63, 23);
        frmjavaSwing.getContentPane().add(btnR2);

        JButton btnR3 = new JButton("R3");
        btnR3.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent arg0) {
                BufferedImage newImage=matToBufferedImage(Convolution(source,3));
                lblNewLabel.setIcon(new ImageIcon(newImage));
            }
        });
        btnR3.setBounds(202, 10, 63, 23);
        frmjavaSwing.getContentPane().add(btnR3);

        JButton btnR4 = new JButton("R4");
        btnR4.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent arg0) {
                BufferedImage newImage=matToBufferedImage(Convolution(source,4));
                lblNewLabel.setIcon(new ImageIcon(newImage));
            }
        });
        btnR4.setBounds(268, 10, 63, 23);
        frmjavaSwing.getContentPane().add(btnR4);

        JButton btnR5 = new JButton("R5");
        btnR5.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent arg0) {
                BufferedImage newImage=matToBufferedImage(Convolution(source,5));
                lblNewLabel.setIcon(new ImageIcon(newImage));
            }
        });
        btnR5.setBounds(336, 10, 63, 23);
        frmjavaSwing.getContentPane().add(btnR5);

        JButton btnR6 = new JButton("R6");
        btnR6.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent arg0) {
                BufferedImage newImage=matToBufferedImage(Convolution(source,6));
                lblNewLabel.setIcon(new ImageIcon(newImage));
            }
        });
        btnR6.setBounds(403, 10, 63, 23);
        frmjavaSwing.getContentPane().add(btnR6);

        JButton btnR7 = new JButton("R7");
        btnR7.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent arg0) {
                BufferedImage newImage=matToBufferedImage(Convolution(source,7));
                lblNewLabel.setIcon(new ImageIcon(newImage));
            }
        });
        btnR7.setBounds(476, 10, 63, 23);
        frmjavaSwing.getContentPane().add(btnR7);
    }

    public Mat Convolution(Mat source,int type){
        Mat kernel =new Mat(3,3, CvType.CV_32F);
        if (type==0){
            kernel.put(0, 0, new float[]{-1,0,1});
            kernel.put(1, 0, new float[]{-2,0,2});
            kernel.put(2, 0, new float[]{-1,0,1});

        }else if (type==1){
            kernel.put(0, 0, new float[]{0,1,2});
            kernel.put(1, 0, new float[]{-1,0,1});
            kernel.put(2, 0, new float[]{-2,-1,0});


        }else if (type==2){
            kernel.put(0, 0, new float[]{1,2,1});
            kernel.put(1, 0, new float[]{0,0,0});
            kernel.put(2, 0, new float[]{-1,-2,-1});


        }else if (type==3){
            kernel.put(0, 0, new float[]{2,1,0});
            kernel.put(1, 0, new float[]{1,0,-1});
            kernel.put(2, 0, new float[]{0,-1,-2});


        }else if (type==4){
            kernel.put(0, 0, new float[]{1,0,-1});
            kernel.put(1, 0, new float[]{2,0,-2});
            kernel.put(2, 0, new float[]{1,0,-1});


        }else if (type==5){
            kernel.put(0, 0, new float[]{0,-1,-2});
            kernel.put(1, 0, new float[]{1,0,-1});
            kernel.put(2, 0, new float[]{2,1,0});


        }else if (type==6){
            kernel.put(0, 0, new float[]{-1,-2,-1});
            kernel.put(1, 0, new float[]{0,0,0});
            kernel.put(2, 0, new float[]{1,2,1});


        }else if (type==7){
            kernel.put(0, 0, new float[]{-2,-1,0});
            kernel.put(1, 0, new float[]{-1,0,1});
            kernel.put(2, 0, new float[]{0,1,2});
        }
        Mat destination=new Mat(source.rows(),source.cols(),source.type());
        Imgproc.filter2D(source, destination, -1, kernel);
        return destination;

    }

    public BufferedImage matToBufferedImage(Mat matrix) {
        int cols = matrix.cols();
        int rows = matrix.rows();
        int elemSize = (int)matrix.elemSize();
        byte[] data = new byte[cols * rows * elemSize];
        int type;
        matrix.get(0, 0, data);
        switch (matrix.channels()) {
            case 1:
                type = BufferedImage.TYPE_BYTE_GRAY;
                break;
            case 3:
                type = BufferedImage.TYPE_3BYTE_BGR;
                // bgr to rgb
                byte b;
                for(int i=0; i<data.length; i=i+3) {
                    b = data[i];
                    data[i] = data[i+2];
                    data[i+2] = b;
                }
                break;
            default:
                return null;
        }
        BufferedImage image2 = new BufferedImage(cols, rows, type);
        image2.getRaster().setDataElements(0, 0, cols, rows, data);
        return image2;
    }
}
```
<h5>Result</h5>
![opencv_robinson_filter.JPG](https://qiita-image-store.s3.ap-northeast-1.amazonaws.com/0/276243/23317a56-4f32-58ca-d2d2-436066faab08.jpeg)