Simple Tracking Example

Description:

This example shows how to use keel to track objects by color.

Requirements:

• Linux
• V4L4J (Installing V4L4J)

*This example only works in Linux.

Example:

We will use the ColorFilter to track objects by color.

First we create an Application Class as always

public class SimpleCam extends Application{

    public SimpleCam(int w, int h) {
        super(w, h);
    }

}

Now, we declare the objects

    //The Camera object (a wrap to v4l4j)
    private Camera cam;

    //The filter itself
    private ColorFilter colorFilter;
    
    //This BufferedLayer is needed to flip (horizontally) our Camera image
    private BufferedLayer mirror;
	
    //This is used in filter method to tell filter to search in the whole screen
    private Component screen = new Component(w, h);

    //This is our tracking point
    private Point2D point;

At load() method we initialize our objects (the loadingPhrase says what is happening)

    @Override
    public void load() {
		
        loadingPhrase = "Opening Camera";
	
        cam = new CameraV4L4J(0);

        loadingPhrase = "Setting Filter";

        colorFilter = new ColorFilter();
        colorFilter.setBorder(20);
        colorFilter.setTolerance(20);

        mirror = new BufferedLayer(0, 0);
		
        loading = 100;
    }

In the update method we set the camera image in mirror and flip filter the image

    @Override
    public void update(long now){
	
        //Get the Camera image
        mirror.setBuffer(cam.getBufferedImage());

        //Normally the camera shows the image flipped, but we want to see something like a mirror
        //So we flip the image
        mirror.flipHorizontal();

        //Now we search for the first pixel with the desired color in the whole screen
        point = colorFilter.filterFirst(mirror.getModifiedBuffer(), screen);
    }

Now we draw the Application

    @Override
    public void draw(Graphic g) {

        //Draw the mirror image
        mirror.draw(g);
		
        //Set a Color to our Point
        g.setColor(Color.CYAN);
		
        //Draw our tracking point with radius = 10 pixels
        g.fillCircle((int)point.getX(), (int)point.getY(), 10);

    }

In updateMouse method, we set the color we want to track!

    @Override
    public GUIEvent updateMouse(PointerEvent event) {
		
        if(event.onButtonDown(MouseButton.MOUSE_BUTTON_LEFT)){
            //When mouse clicks with LeftButton, the color filter tries to find
            //The color we are clicking
            colorFilter.setColor(mirror.getModifiedBuffer().getRGB((int)event.getX(), (int)event.getY()));
        }
		
        return GUIEvent.NONE;
    }

Full Source Code

public class SimpleCam extends Application{

	public SimpleCam(int w, int h) {
		super(w, h);
	}

	private Camera cam;
	
	private ColorFilter colorFilter;
	
	private BufferedLayer mirror;
	
	private Component screen = new Component(w, h);
	
	private Point2D point;

	@Override
	public void load() {
		
		loadingPhrase = "Opening Camera";
		
		cam = new CameraV4L4J(0);
				
		loadingPhrase = "Setting Filter";
		
		colorFilter = new ColorFilter();
		colorFilter.setBorder(20);
		colorFilter.setTolerance(20);
		
		mirror = new BufferedLayer(0, 0);
		
		loading = 100;
	}
	
	@Override
	public void update(long now){
		
		mirror.setBuffer(cam.getBufferedImage());
		
		mirror.flipHorizontal();
		
		point = colorFilter.filterFirst(mirror.getModifiedBuffer(), screen);
		
	}

	@Override
	public void draw(Graphic g) {

		mirror.draw(g);
		
		g.setColor(Color.CYAN);
		
		g.fillCircle((int)point.getX(), (int)point.getY(), 10);
		
	}
	
	@Override
	public GUIEvent updateMouse(PointerEvent event) {
		
		if(event.onButtonDown(MouseButton.MOUSE_BUTTON_LEFT)){
			colorFilter.setColor(mirror.getModifiedBuffer().getRGB((int)event.getX(), (int)event.getY()));
		}
		
		return GUIEvent.NONE;
	}

	@Override
	public GUIEvent updateKeyboard(KeyEvent event) {
		// TODO Auto-generated method stub
		return GUIEvent.NONE;
	}

}