blur filter

[Sarah Jose]

following is the code for filtering an image... can somebody please explain the kernel part in the program or the entire program briefly...
actually,i downloaded it...





package thumptrial;



import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.awt.image.BufferedImageOp;
import java.awt.image.ConvolveOp;
import java.awt.image.Kernel;
import java.io.File;
import java.io.IOException;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.imageio.ImageIO;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;

class Surface extends JPanel {

private BufferedImage mshi;
private BufferedImage databuf;

public Surface() {

loadImage();
createBlurredImage();
setSurfaceSize();
}

private void loadImage() {

try {

mshi = ImageIO.read(new File("D://photo//pic//test.jpg"));
} catch (IOException ex) {

Logger.getLogger(Surface.class.getName()).log(Leve l.SEVERE, null, ex);
}
}

private void createBlurredImage() {

databuf = new BufferedImage(mshi.getWidth(null),
mshi.getHeight(null),
BufferedImage.TYPE_INT_BGR);

Graphics g = databuf.getGraphics();
g.drawImage(mshi, 455, 255, null);

float[] blurKernel = {
1 / 9f, 1 / 9f, 1 / 9f,
1 / 9f, 1 / 9f, 1 / 9f,
1 / 9f, 1 / 9f, 1 / 9f
};

BufferedImageOp blur = new ConvolveOp(new Kernel(3, 3, blurKernel));
mshi = blur.filter(mshi, new BufferedImage(mshi.getWidth(),
mshi.getHeight(), mshi.getType()));
g.dispose();
}

private void setSurfaceSize() {

Dimension d = new Dimension();
d.width = mshi.getWidth(null);
d.height = mshi.getHeight(null);
setPreferredSize(d);
}

private void doDrawing(Graphics g) {

Graphics2D g2d = (Graphics2D) g;
g2d.drawImage(mshi, null, 3, 3);
}

@Override
public void paintComponent(Graphics g) {

super.paintComponent(g);
doDrawing(g);
}
}

class FilteredImage extends JFrame {

public FilteredImage() {

setTitle("Filtered image");

add(new Surface());

pack();
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setLocationRelativeTo(null);
}

public static void main(String[] args) {

SwingUtilities.invokeLater(new Runnable() {

@Override
public void run() {

FilteredImage bi = new FilteredImage();
bi.setVisible(true);
}
});
}
}

[Norm]

Please edit your post and wrap your code with code tags:
[code=java]
YOUR CODE HERE
[/code]
to get highlighting and preserve formatting.

What does the code do when executed? What goes in and what comes out?