Detecta movimento na camera e cria rastro dinâmico em video de webcam.

traildentes.java

package traildentes;

import processing.core.*;
import processing.video.*;
import java.util.ArrayList;

public class Traildentes extends PApplet {
	private static final long serialVersionUID = 1L;
	
	int rastroSize = 10;		
	float threshold = 100;
	
	Capture video;
	PImage prevFrame;
	ArrayList<ArrayList<Integer>> rastros = new ArrayList<ArrayList<Integer>>();
	
	int t = 0;
	
	public void setup() {
		size(800, 600);
		video = new Capture(this, width, height, 30);
		prevFrame = createImage(video.width, video.height, RGB);
	}

	public void draw() {
		t++;
		if (video.available()) {
			prevFrame.copy(video, 0, 0, video.width, video.height, 0, 0,
					video.width, video.height);
			prevFrame.updatePixels();
			video.read();
		}

		loadPixels();
		video.loadPixels();
		prevFrame.loadPixels();

		ArrayList<Integer> motionAtual = new ArrayList<Integer>();
		for (int x = 0; x < video.width; x++) {
			for (int y = 0; y < video.height; y++) {
				int loc = x + y * video.width; 												
				int current = video.pixels[loc]; 												
				int previous = prevFrame.pixels[loc];

				float r1 = red(current);
				float g1 = green(current);
				float b1 = blue(current);
				float r2 = red(previous);
				float g2 = green(previous);
				float b2 = blue(previous);
				float diff = dist(r1, g1, b1, r2, g2, b2);

				// How different are the colors?
				if (diff > threshold) {									
					motionAtual.add(loc);
				} else {
					pixels[loc] = color(0);
				}
			}
		}
		
		if (t > 10) { // after 50 draws
			rastros.add(motionAtual);
			if(rastros.size()==rastroSize){ // array completo? excluir rastro 0
				rastros = new ArrayList<ArrayList<Integer>>(rastros.subList(1, rastros.size()));				
			}			

			// aplicar rastro
			for (int x = 0; x < rastros.size(); x++) {
				ArrayList<Integer> motion = rastros.get(x);
				// para cada motion
				for (int y = 0; y < motion.size(); y++) {
					// para cada ponto
					int ponto = motion.get(y);
					Float R = (new Float(-x*x*10 +255) / rastroSize) * 255;
					Float G = (new Float(-(x-rastroSize/2)*(x-rastroSize/2)*10+255) / rastroSize) * 105;
					Float B = (new Float(-(x-rastroSize)*(x-rastroSize)*20+255) / rastroSize) * 55;
					//Float A = R;
					pixels[ponto] = color(R,G,B);
				}
			}
		}

		updatePixels();
	}
}

http://vimeo.com/49355849