sclass ChessOCR_Pipeline {
  replace Segmenter with IF1<BufferedImage, L<Rect>>.
  
  transient BufferedImage inputImage;
  SeenAndQueue<Rect> possibleBoardPositions = new(r processPositions);
  new ChessOCR_BoardsFound boardsFound;
  ChessPieceRecognizer pieceRecognizer;

  // segmenters
  SeenAndQueue<Segmenter> segmenters = new(r runSegmenters);

  void addSegmenter(Segmenter s) { segmenters.add(s); }
  void addPossiblePosition(Rect r) { possibleBoardPositions.add(r); }
  
  // internal
  
  void processPositions() {
    for (Rect r : possibleBoardPositions.queueIterator())
      boardsFound.add(pieceRecognizer.recognizeBoard(clipBufferedImage(inputImage, r)));
  }
  
  void runSegmenters() {
    for (Segmenter seg : segmenters.queueIterator())
      possibleBoardPositions.addAll(seg.get(inputImage));
  }
  
  void cleanMeUp { // cancels the threads too
    cleanUpAll(possibleBoardPositions, segmenters);
  }
}