FindEdgeOfImage

PImage img;

​

void setup(){

  size(192, 144);

  img = loadImage("bunker.png");

}

​

void draw(){

  background(255);

  loadPixels(); 

  img.loadPixels();

  for (int x = 0; x < width; x++){

    for (int y = 0; y < height; y++){

      int loc1 = x     + y*width;

      int loc2 = (x+1) + (y+1)*width;

      float b1 = brightness(img.pixels[loc1]);

      float b2 = brightness(img.pixels[loc2]);

      float diff = abs(b1 - b2);

      pixels[loc1] = color(diff);

    }

  }

  updatePixels();

  //image(img, 0, 0);

}