gistfile1.scala

def computeDifference(in: BufferedImage, compare: BufferedImage): BufferedImage = {
    val w = in.getWidth
    val h = in.getHeight
    var result = new BufferedImage(w,h, BufferedImage.TYPE_INT_ARGB)
    val graphics = result.getGraphics
    graphics.setColor(java.awt.Color.BLACK)
    graphics.clearRect(0,0,w,h)
    for{
      x : Int <- 0 until w
      y : Int <- 0 until h
    }{
      val pixelA = in.getRGB(x, y)
      val pixelB = compare.getRGB(x, y)

      val rA = (pixelA >> 16)& 255
      val gA = (pixelA >> 8) & 255
      val bA =  pixelA & 255
      val rB = (pixelB >> 16)& 255
      val gB = (pixelB >> 8) & 255
      val bB =  pixelB & 255

      val diffsq = ((1 / 3) * (pow(rA - rB, 2) + pow(gA - gB, 2) + pow(bA - bB, 2)))
      result.setRGB(x, y, ((65536 * diffsq) + (256 * diffsq) + diffsq).toInt)
    }
    result
  }