diff --git a/exp/hough.py b/exp/hough.py
--- a/exp/hough.py
+++ b/exp/hough.py
@@ -66,7 +66,7 @@ class HoughTransform:
 				(alphaDeg,d)=keys[k]
 				line=Line(alphaDeg*math.pi/180,d-self._diagLen//2)
 				res[-1].append(self._transformOutput(line))
-			res[-1].sort(key=lambda line: line.d if line.alpha<math.pi else -line.d)
+			res[-1].sort(key=lambda line: line.d)
 			i+=1
 
 		self.show(img)
@@ -82,6 +82,13 @@ class HoughTransform:
 					self._acc[(alphaDeg,d)]+=weight
 		log.debug("Hough updated in %s s",round(datetime.now().timestamp()-start,3))
 
+	def scoreLine(self,line):
+		transformed=self._transformInput(line)
+		alphaDeg=round(transformed.alpha*180/math.pi)%180
+		d=round(transformed.d+self._diagLen//2)
+		if not 0<=d<self._diagLen: return 0
+		return self._acc[(alphaDeg,d)]
+
 	def show(self,img=None):
 		if img is None: img=self._createImg()
 		show(img,"Hough transform accumulator")
@@ -114,6 +121,15 @@ class HoughTransform:
 			res.append((k,i))
 		return res
 
+	def _transformInput(self,line):
+		reflectedLine=Line(math.pi*2-line.alpha,line.d)
+		(x,y)=self._center
+		basis=EPoint(x,-y)
+		shiftedLine=reflectedLine.shiftBasis(basis)
+		if shiftedLine.alpha>=math.pi:
+			shiftedLine=Line(shiftedLine.alpha-math.pi,-shiftedLine.d)
+		return shiftedLine
+
 	def _transformOutput(self,line):
 		(x,y)=self._center
 		basis=EPoint(-x,y)