sclass G22GhostImage is IBWImage {
  int w, h;
  
  public int getWidth() { ret w; }
  public int getHeight() { ret h; }
  
  // number of images averaged
  int imageCount;
  
  // array contains raw sum over images
  // (1 for white pixel, 0 for black pixel)
  int[] pixels;
  
  FloatBWImage toFloatBWImage() {
    float[] floatPixels = new[pixels.length];
    for i over pixels:
      floatPixels[i] = floatRatio(pixels[i], imageCount);
    ret new FloatBWImage(w, h, floatPixels);
  }
  
  public BufferedImage getBufferedImage() {
    ret toFloatBWImage().getBufferedImage();
  }
}