code: protected final boolean touchesBorder( List<Point2D_I32> contour ) {
  		int endX = imageWidth-1;
  		int endY = imageHeight-1;
  
  		for (int j = 0; j < contour.size(); j++) {
  			Point2D_I32 p = contour.get(j);
  			if( p.x == 0 || p.y == 0 || p.x == endX || p.y == endY )
  			{
  				return true;
  			}
  		}
  
  		return false;
  	}
docs: Checks to see if some part of the contour touches the image border.  Most likely cropped