static double pixelSetRectangleness(PixelSet set) {
  L<IntRange> l = pixelSetBoundsByLine(set);
  int[] a = intRangeStarts(l), b = intRangeEnds(l);
  double avgL = doubleAverage(a), avgR = doubleAverage(b);
  double width = avgR-avgL;
  ret max(0, 1-(standardDeviation(b)+standardDeviation(a))/width);
}