sinterface IIntegralImage extends MakesBufferedImage {
  public int getWidth();
  public int getHeight();

  // get value for 1 channel
  // range [0; pixelCount*256)
  public double getIntegralValue(int x, int y, int channel);
    
  // gets value of the 3 channels
  // range [0; pixelCount*256*3)
  public double getIntegralValue(int x, int y);
}