corrected angular difference check in MSER test (thanks to Pieter-Jan Busschaert for the patch)

modules/features2d/test/test_mser.cpp

@@ -107,7 +107,15 @@ int CV_MserTest::CompareBoxes(const vector<CvBox2D>& boxes1,const vector<CvBox2D
         float rel_diff;
         if (!((boxes1[i].angle == 0.0f) && (abs(boxes2[i].angle) < max_rel_diff)))
         {
-			rel_diff = abs(boxes1[i].angle-boxes2[i].angle)/abs(boxes1[i].angle);
+            float angle_diff = (float)fmod(boxes1[i].angle - boxes2[i].angle, 180);
+            // for angular correctness, it makes no sense to use a "relative" error.
+            // a 1-degree error around 5 degrees is equally bas as around 250 degrees.
+            // in correct cases, angle_diff can now be a bit above 0 or a bit below 180
+            if (angle_diff > 90.0f)
+            {
+                    angle_diff -= 180.0f;
+            }
+            rel_diff = (float)fabs(angle_diff);
             if (rel_diff > max_rel_diff)
                 return i;
         }
@@ -173,6 +181,7 @@ void CV_MserTest::run(int)
     }
 
     string boxes_path = string(ts->get_data_path()) + "mser/boxes.txt";
+    string calc_boxes_path = string(ts->get_data_path()) + "mser/boxes.calc.txt";
     
     if (!LoadBoxes(boxes_path.c_str(),boxes_orig))
     {
@@ -190,8 +199,9 @@ void CV_MserTest::run(int)
     }
     else
     {
+        SaveBoxes(calc_boxes_path.c_str(), boxes);
         ts->set_failed_test_info(cvtest::TS::FAIL_BAD_ACCURACY);
-		ts->printf( cvtest::TS::LOG, "Incorrect correspondence in %d box\n",n_box);
+        ts->printf( cvtest::TS::LOG, "Incorrect correspondence in box %d\n",n_box);
     }
 
     cvReleaseMemStorage(&storage);