var innerStep = 3;

function setup() { 

  createCanvas(320, 240);

  capture = createCapture(VIDEO);

  capture.size(320, 240);

  background(220);

  noStroke();

  frameRate(30);

} 

​

function draw() {

  background(191, 255, 255);

  capture.loadPixels();

    for (var x = 0; x < width; x+= innerStep) {

    for (var y = 0; y < height; y+= innerStep) {

      var i = (y * width + x)*4;

        var r = constrain(capture.pixels[i], 0, 255);

        var g = capture.pixels[i+1];

        var b = capture.pixels[i+2];

      var br = brightness(color(r,g,b));

      var radius = map(br, 0, 255, 1, 8);

      // fill(br, br, br);

      fill(255, 209, 220);

      ellipse(x, y, radius, radius);

    }

  }

}