scan

PImage img;
int edge;

void setup() {
  size(540, 540);
  img = loadImage("pic1.jpg");
  edge = width/5;
  rectMode(CENTER);
}

void draw() {
  background(20);
  noStroke();
  for (int x=edge; x<width-edge; x++) {
    int y = frameCount%height;
    float br = brightness(img.get(x, y));
    float h = map(br, 0, 255, 0, height/2);
    fill(br);
    rect(x, height/2, 1, h);
  }
  //if (frameCount%2==0 && frameCount<500) saveFrame("image-###.gif");
}