DescriptorExtractor: added defaultNorm() to return default norm type.

Added the defaultNorm() method to the DescriptorExtractor class. This method returns the default norm type for each descriptor type. The tests and C/C++ samples were updated to get the norm type directly from the DescriptorExtractor inherited classes.

This was reported in feature report #2182 (http://code.opencv.org/issues/2182). It will make it possible to get the norm type usually applied matching method for each descriptor, instead of passing it manually.

samples/cpp/brief_match_test.cpp

@@ -106,7 +106,7 @@ int main(int argc, const char ** argv)
 
   //Do matching using features2d
   cout << "matching with BruteForceMatcher<Hamming>" << endl;
-  BFMatcher matcher_popcount(NORM_HAMMING);
+  BFMatcher matcher_popcount(extractor.defaultNorm());
   vector<DMatch> matches_popcount;
   double pop_time = match(kpts_1, kpts_2, matcher_popcount, desc_1, desc_2, matches_popcount);
   cout << "done BruteForceMatcher<Hamming> matching. took " << pop_time << " seconds" << endl;

samples/cpp/detector_descriptor_evaluation.cpp

@@ -881,9 +881,10 @@ public:
     virtual void readAlgorithm( )
     {
         string classifierFile = data_path + "/features2d/calonder_classifier.rtc";
+        Ptr<DescriptorExtractor> extractor = makePtr<CalonderDescriptorExtractor<float> >( classifierFile );
         defaultDescMatcher = makePtr<VectorDescriptorMatch>(
-            makePtr<CalonderDescriptorExtractor<float> >( classifierFile ),
-            makePtr<BFMatcher>(int(NORM_L2)));
+            extractor,
+            makePtr<BFMatcher>(extractor->defaultNorm()));
         specificDescMatcher = defaultDescMatcher;
     }
 };

samples/cpp/freak_demo.cpp

@@ -96,7 +96,7 @@ int main( int argc, char** argv ) {
     // The standard Hamming distance can be used such as
     // BFMatcher matcher(NORM_HAMMING);
     // or the proposed cascade of hamming distance using SSSE3
-    BFMatcher matcher(NORM_HAMMING);
+    BFMatcher matcher(extractor.defaultNorm());
 
     // detect
     double t = (double)getTickCount();

samples/cpp/matcher_simple.cpp

@@ -44,7 +44,7 @@ int main(int argc, char** argv)
     extractor.compute(img2, keypoints2, descriptors2);
 
     // matching descriptors
-    BFMatcher matcher(NORM_L2);
+    BFMatcher matcher(extractor.defaultNorm());
     vector<DMatch> matches;
     matcher.match(descriptors1, descriptors2, matches);
 

samples/cpp/shape_transformation.cpp

@@ -45,7 +45,7 @@ int main(int argc, char** argv)
     extractor.compute(img2, keypoints2, descriptors2);
 
     // matching descriptors
-    BFMatcher matcher(NORM_L2);
+    BFMatcher matcher(extractor.defaultNorm());
     vector<DMatch> matches;
     matcher.match(descriptors1, descriptors2, matches);
 

samples/cpp/tutorial_code/features2D/SURF_descriptor.cpp

@@ -49,7 +49,7 @@ int main( int argc, char** argv )
   extractor.compute( img_2, keypoints_2, descriptors_2 );
 
   //-- Step 3: Matching descriptor vectors with a brute force matcher
-  BFMatcher matcher(NORM_L2);
+  BFMatcher matcher(extractor.defaultNorm());
   std::vector< DMatch > matches;
   matcher.match( descriptors_1, descriptors_2, matches );
 

samples/cpp/video_homography.cpp

@@ -140,7 +140,7 @@ int main(int ac, char ** av)
 
     vector<DMatch> matches;
 
-    BFMatcher desc_matcher(NORM_HAMMING);
+    BFMatcher desc_matcher(brief.defaultNorm());
 
     vector<Point2f> train_pts, query_pts;
     vector<KeyPoint> train_kpts, query_kpts;