1. float[][] kernel = { { 1, 1, 1 },
2.                      { 1,  0, 1 },
3.                      { 1, 1, 1 } };
4.  
5. PImage img = loadImage("lena2.bmp");
6. int w = img.width;
7. int h = img.height;
8. size(2*w,h);
9. image(img, 0, 0);
10. img.loadPixels();
11. PImage edgeImg = createImage(img.width, img.height, RGB);
12. for (int y = 1; y < img.height-1; y++) {
13.   for (int x = 1; x < img.width-1; x++) {
14.     float sum_red = 0, sum_green = 0, sum_blue = 0;
15.     int pos = x + y*img.height;
16.     int pos_sasiad = (x+1) + y*img.height;
17.     float val_red = red(img.pixels[pos]);
18.     float val_green = green(img.pixels[pos]);
19.     float val_blue = blue(img.pixels[pos]);
20.    
21.    
22.     if ((val_red == 0)) {
23.       for (int ky = -1; ky <= 1; ky++) {
24.         for (int kx = -1; kx <= 1; kx++) {
25.         int pos2 = (y + ky)*img.width + (x + kx);
26.         float val2_red = red(img.pixels[pos2]);
27.         float val2_green = green(img.pixels[pos2]);
28.         float val2_blue = blue(img.pixels[pos2]);
29.         sum_red += kernel[ky+1][kx+1] * val2_red;
30.         sum_green += kernel[ky+1][kx+1] * val2_green;
31.         sum_blue += kernel[ky+1][kx+1] * val2_blue;
32.         val_red = sum_red/8;
33.         val_green = sum_green/8;
34.         val_blue = sum_blue/8;
35.       }
36.     }
37.     }
38.     else if (val_red == 255) {
39.       for (int ky = -1; ky <= 1; ky++) {
40.         for (int kx = -1; kx <= 1; kx++) {
41.         int pos2 = (y + ky)*img.width + (x + kx);
42.         float val2_red = red(img.pixels[pos2]);
43.         float val2_green = green(img.pixels[pos2]);
44.         float val2_blue = blue(img.pixels[pos2]);
45.         sum_red += kernel[ky+1][kx+1] * val2_red;
46.         sum_green += kernel[ky+1][kx+1] * val2_green;
47.         sum_blue += kernel[ky+1][kx+1] * val2_blue;
48.         val_red = sum_red/8;
49.         val_green = sum_green/8;
50.         val_blue = sum_blue/8;
51.       }
52.     }
53.     }
54.     edgeImg.pixels[y*img.width + x] = color(val_red, val_green, val_blue);
55.   }
56. }
57. edgeImg.updatePixels();
58. image(edgeImg, w, 0);