- Some japanese pornography has been "censored".  Some of the censoring is done by simply inverting
  pixel-aligned boxes, intended to, like ROT13, be trivial to undo.  However, it's still usually a
  manual process.  Is it possible to automatically identify the bounding boxes for these areas?
  Hints:

        - brightness is obviously inverted...  and while a good clue, there are often abrupt
          brightness changes...  ESPECIALLY in hentai, where black lines bound brighter areas

        - more clearly, hue is shifted in a very specific manner