EdgeDetect.java

package javascratch;

import java.awt.Graphics;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.awt.event.WindowStateListener;
import java.awt.image.BufferedImage;
import java.awt.image.Raster;
import java.awt.Color;
import java.util.Arrays;
import java.util.List;
import java.util.stream.Collectors;

import javax.swing.*;
import javax.imageio.ImageIO;

public class EdgeDetect {

	public static void main(String[] args) throws Exception {
		
		final String tim = "20140320_002.jpg";
		final String dog = "penis-dog.jpg";
		
		BufferedImage bi = ImageIO.read(EdgeDetect.class.getResourceAsStream(tim));
		
		JFrame f = new JFrame();
		JPanel mypanel = new MyPanel(bi.getData(), 500, 700);
//		JPanel mypanel = new MyPanel(bi.getData(), 0, 0);
		
		f.getContentPane().add(mypanel);
		f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

		f.setSize(1000, 1000);
		f.setVisible(true);
	}
	
	static class MyPanel extends JPanel {
			
		private Raster r;
		private int ox;
		private int oy;
		

		public MyPanel(Raster r, int ox, int oy) {
			this.r = r;
			this.ox = ox;
			this.oy = oy;
		}
		
		public void paint(Graphics g) {
			int oldValue1, oldValue2, oldValue3, value1 = 0, value2 = 0, value3 = 0;
			Color imgcol;
			
			for (int x = 0; x < Math.min(1000,r.getWidth()-1); x++) {
				for (int y = 0; y < Math.min(1000, r.getHeight()-1); y++) {
					List<Integer> avgs = getAvgForPixels(r, y+oy, x+ox);
					int colour1 = avgs.get(0);
					int colour2 = avgs.get(1);
					int colour3 = avgs.get(2);
					
					oldValue1 = value1;
					oldValue2 = value2;
					oldValue3 = value3;
					
					value1 = colour1;
					value2 = colour2;
					value3 = colour3;
					int delta1 = value1 - oldValue1;
					int delta2 = value2 - oldValue2;
					int delta3 = value3 - oldValue3;
					
					double path1= Math.sqrt(delta1 * delta1 + delta2 * delta2 + delta3 * delta3);
					double avg = (delta1 + delta2 + delta3) / 3;
					double max = Math.max(delta1, Math.max(delta2, delta3));
					
					if (path1>1.2) {
						imgcol = new Color(0, 0, 0);
					} else {
						imgcol = new Color(255,255,255);
					}
					
					g.setColor(imgcol);
					g.drawLine(x, y, x, y);
			
				}
			}
		}
		
		private List<Integer> getAvgForPixels(Raster r, int x, int y) {
			int size = 5;
			int xoffset = (x - ((size -1) / 2)) < 0 ? 0 : (x - ((size -1) / 2));
			int yoffset = (y - ((size -1) / 2)) < 0 ? 0 : (y - ((size -1) / 2));
			
			int width = xoffset + size < r.getWidth() ? size : r.getWidth() - xoffset;			 
			int height = yoffset + size < r.getHeight() ? size : r.getHeight() - yoffset;			 
			
			int[] values = r.getPixels(xoffset, yoffset, width, height, new int[(size* size)*3]);
			
			Integer[] colours = new Integer[] { 0,0,0 };
	
			for (int i =0; i < (size * size)-1; i++) {
				colours[i%3] += values[i];
			}
			
			return Arrays.asList(colours).stream().map(col -> col / (size * size)).collect(Collectors.toList());
			
		}
		
	}
	
}