Hi

I have been looking into some of the motion detection scripts around the processing site.

It is quite clear and easy to implement.
My challenge is that I would like to detect the direction of the movement, so the set up is:
A small webcam pointing at a hallway, and each time someone passes by it detects which way they were going.
I have this program that detects the motion, but I need an idea or push in which direction it would be wise to go if I need the direction of the motion.

So suggestions, ideas or pseudo examples is very appreciated :)

import processing.video.*;

Capture cam;


PImage prevFrame;
float threshold = 100;

void setup() {
 size(640,480);
 String[] devices = Capture.list();  
 println(devices);
 cam = new Capture(this, width, height, devices[2], 30);
 //cam.settings();
 prevFrame = createImage(cam.width, cam.height, RGB);
}

void draw() {
 prevFrame = createImage(cam.width, cam.height, RGB);
 if (cam.available()) {
   prevFrame.copy(cam, 0, 0, cam.width, cam.height, 0, 0, cam.width, cam.height); // Before we read the new prevFrame,
   prevFrame.updatePixels();
   println(prevFrame.pixels[9]);
   cam.read();
 }

 cam.loadPixels();
 prevFrame.loadPixels();

 for (int x = 0; x < cam.width; x++ ) {
   for (int y = 100; y < cam.height-100; y++ ) {
     int movementSum = 0;
     int loc = x + y * cam.width;
     color current = cam.pixels[loc];
     color previous = prevFrame.pixels[loc];

     int r1 = (current >> 16) & 0xFF;
     int g1 = (current >> 8) & 0xFF;
     int b1 = current & 0xFF;

     int r2 = (previous >> 16) & 0xFF;
     int g2 = (previous >> 8) & 0xFF;
     int b2 = previous & 0xFF;

     int diffR = abs(r1 - r2);
     int diffG = abs(g1 - g2);
     int diffB = abs(b1 - b2);
     movementSum += diffR + diffG + diffB;

     if (movementSum > threshold) {
       stroke(0);
     }
     else {
       stroke(255);
     }
     point(x,y);
   }
 }
}

Hi Johnny

Thank you, that was just the search term I needed to continue.
I liked your snow example:)