Display image using Mat in OpenCV Java

问题

I am writing my first program in OpenCV in Java and I'd like to ask, is it possible to load and display image from file only using Mat? I found solution on this website http://answers.opencv.org/question/31505/how-load-and-display-images-with-java-using-opencv/ but it changes Mat to Image before. I'll be grateful for any tips

回答1:

Nope, there is no imshow equivalent in java. Please refer this link.

回答2:

You can use the next code to transform a cvMat element into a java element: BufferedImage or Image:

 public BufferedImage Mat2BufferedImage(Mat m) {
    // Fastest code
    // output can be assigned either to a BufferedImage or to an Image

    int type = BufferedImage.TYPE_BYTE_GRAY;
    if ( m.channels() > 1 ) {
        type = BufferedImage.TYPE_3BYTE_BGR;
    }
    int bufferSize = m.channels()*m.cols()*m.rows();
    byte [] b = new byte[bufferSize];
    m.get(0,0,b); // get all the pixels
    BufferedImage image = new BufferedImage(m.cols(),m.rows(), type);
    final byte[] targetPixels = ((DataBufferByte) image.getRaster().getDataBuffer()).getData();
    System.arraycopy(b, 0, targetPixels, 0, b.length);  
    return image;
}

And then display it with:

public void displayImage(Image img2) {

    //BufferedImage img=ImageIO.read(new File("/HelloOpenCV/lena.png"));
    ImageIcon icon=new ImageIcon(img2);
    JFrame frame=new JFrame();
    frame.setLayout(new FlowLayout());        
    frame.setSize(img2.getWidth(null)+50, img2.getHeight(null)+50);     
    JLabel lbl=new JLabel();
    lbl.setIcon(icon);
    frame.add(lbl);
    frame.setVisible(true);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}

source: http://answers.opencv.org/question/10344/opencv-java-load-image-to-gui/

来源：https://stackoverflow.com/questions/26515981/display-image-using-mat-in-opencv-java