docs: public double computeOverlap( ImageRectangle a , ImageRectangle b ) {
  		if( !a.intersection(b,work) )
  			return 0;
  
  		int areaI = work.area();
  
  		int bottom = a.area() + b.area() - areaI;
  
  		return areaI/ (double)bottom;
  	}