Added base tutorial for using FlannBasedMatcher with SURF detector + descriptor in rst

doc/conf.py

@@ -368,7 +368,10 @@ extlinks = {'cvt_color': ('http://opencv.willowgarage.com/documentation/cpp/imgp
 	    'surf_descriptor_extractor' : ( 'http://opencv.willowgarage.com/documentation/cpp/features2d_common_interfaces_of_descriptor_extractors.html#surfdescriptorextractor%s', None ),
 	    'draw_matches' : ( 'http://opencv.willowgarage.com/documentation/cpp/features2d_drawing_function_of_keypoints_and_matches.html#cv-drawmatches%s', None ),
 	    'find_homography' : ('http://opencv.willowgarage.com/documentation/cpp/calib3d_camera_calibration_and_3d_reconstruction.html?#findHomography%s', None),
-	    'perspective_transform' : ('http://opencv.willowgarage.com/documentation/cpp/core_operations_on_arrays.html?#perspectiveTransform%s', None )			 		 
+	    'perspective_transform' : ('http://opencv.willowgarage.com/documentation/cpp/core_operations_on_arrays.html?#perspectiveTransform%s', None ),
+	    'flann_based_matcher' : ('http://opencv.willowgarage.com/documentation/cpp/features2d_common_interfaces_of_descriptor_matchers.html?#FlannBasedMatcher%s', None),
+	    'brute_force_matcher' : ('http://opencv.willowgarage.com/documentation/cpp/features2d_common_interfaces_of_descriptor_matchers.html?#BruteForceMatcher%s', None ),
+	    'flann' : ('http://opencv.willowgarage.com/documentation/cpp/flann_fast_approximate_nearest_neighbor_search.html?%s', None )			 		 
            }
 
 

doc/tutorials/features2d/feature_description/feature_description.rst

@@ -13,6 +13,7 @@ In this tutorial you will learn how to:
    * Use the :descriptor_extractor:`DescriptorExtractor<>` interface in order to find the feature vector correspondent to the keypoints. Specifically:
 
      * Use :surf_descriptor_extractor:`SurfDescriptorExtractor<>` and its function :descriptor_extractor:`compute<>` to perform the required calculations.
+     * Use a :brute_force_matcher:`BruteForceMatcher<>`	to match the features vector
      * Use the function :draw_matches:`drawMatches<>` to draw the detected matches.
      
 

doc/tutorials/features2d/feature_flann_matcher/feature_flann_matcher.rst

@@ -0,0 +1,132 @@
+.. _feature_flann_matcher:
+
+Feature Matching with FLANN
+****************************
+
+Goal
+=====
+
+In this tutorial you will learn how to:
+
+.. container:: enumeratevisibleitemswithsquare
+
+   * Use the :flann_based_matcher:`FlannBasedMatcher<>` interface in order to perform a quick and efficient matching by using the :flann:`FLANN<>` ( *Fast Approximate Nearest Neighbor Search Library* )
+
+
+Theory
+======
+
+Code
+====
+
+This tutorial code's is shown lines below. You can also download it from `here <https://code.ros.org/svn/opencv/trunk/opencv/samples/cpp/tutorial_code/features2D/SURF_FlannMatcher.cpp>`_
+
+.. code-block:: cpp 
+
+   #include <stdio.h>
+   #include <iostream>
+   #include "opencv2/core/core.hpp"
+   #include "opencv2/features2d/features2d.hpp"
+   #include "opencv2/highgui/highgui.hpp"
+
+   using namespace cv;
+
+   void readme();
+
+   /** @function main */
+   int main( int argc, char** argv )
+   {
+     if( argc != 3 )
+     { readme(); return -1; }
+
+     Mat img_1 = imread( argv[1], CV_LOAD_IMAGE_GRAYSCALE );
+     Mat img_2 = imread( argv[2], CV_LOAD_IMAGE_GRAYSCALE );
+  
+     if( !img_1.data || !img_2.data )
+     { std::cout<< " --(!) Error reading images " << std::endl; return -1; }
+
+     //-- Step 1: Detect the keypoints using SURF Detector
+     int minHessian = 400;
+
+     SurfFeatureDetector detector( minHessian );
+
+     std::vector<KeyPoint> keypoints_1, keypoints_2;
+
+     detector.detect( img_1, keypoints_1 );
+     detector.detect( img_2, keypoints_2 );
+
+     //-- Step 2: Calculate descriptors (feature vectors)
+     SurfDescriptorExtractor extractor;
+
+     Mat descriptors_1, descriptors_2;
+
+     extractor.compute( img_1, keypoints_1, descriptors_1 );
+     extractor.compute( img_2, keypoints_2, descriptors_2 );
+
+     //-- Step 3: Matching descriptor vectors using FLANN matcher
+     FlannBasedMatcher matcher;
+     std::vector< DMatch > matches;
+     matcher.match( descriptors_1, descriptors_2, matches );
+
+     double max_dist = 0; double min_dist = 100;
+
+     //-- Quick calculation of max and min distances between keypoints
+     for( int i = 0; i < descriptors_1.rows; i++ )
+     { double dist = matches[i].distance;
+       if( dist < min_dist ) min_dist = dist;
+       if( dist > max_dist ) max_dist = dist;
+     }
+
+     printf("-- Max dist : %f \n", max_dist );
+     printf("-- Min dist : %f \n", min_dist );
+  
+     //-- Draw only "good" matches (i.e. whose distance is less than 2*min_dist )
+     //-- PS.- radiusMatch can also be used here.
+     std::vector< DMatch > good_matches;
+
+     for( int i = 0; i < descriptors_1.rows; i++ )
+     { if( matches[i].distance < 2*min_dist )
+       { good_matches.push_back( matches[i]); }
+     }  
+
+     //-- Draw only "good" matches
+     Mat img_matches;
+     drawMatches( img_1, keypoints_1, img_2, keypoints_2, 
+                  good_matches, img_matches, Scalar::all(-1), Scalar::all(-1), 
+                  vector<char>(), DrawMatchesFlags::NOT_DRAW_SINGLE_POINTS ); 
+
+     //-- Show detected matches
+     imshow( "Good Matches", img_matches );
+
+     for( int i = 0; i < good_matches.size(); i++ )
+     { printf( "-- Good Match [%d] Keypoint 1: %d  -- Keypoint 2: %d  \n", i, good_matches[i].queryIdx, good_matches[i].trainIdx ); }
+
+     waitKey(0);
+
+     return 0;
+    }
+
+    /** @function readme */
+    void readme()
+    { std::cout << " Usage: ./SURF_FlannMatcher <img1> <img2>" << std::endl; }
+
+Explanation
+============
+
+Result
+======
+ 
+#. Here is the result of the feature detection applied to the first image:
+ 
+   .. image:: images/Featur_FlannMatcher_Result.jpg
+      :align: center
+      :height: 250pt
+
+#. Additionally, we get as console output the keypoints filtered:
+
+   .. image:: images/Feature_FlannMatcher_Keypoints_Result.jpg
+      :align: center
+      :height: 250pt
+
+
+

samples/cpp/tutorial_code/features2D/SURF_FlannMatcher.cpp

@@ -94,4 +94,4 @@ int main( int argc, char** argv )
  * @function readme
  */
 void readme()
-{ std::cout << " Usage: ./SURF_descriptor <img1> <img2>" << std::endl; }
+{ std::cout << " Usage: ./SURF_FlannMatcher <img1> <img2>" << std::endl; }

samples/cpp/tutorial_code/features2D/SURF_Homography.cpp

@@ -119,4 +119,4 @@ int main( int argc, char** argv )
  * @function readme
  */
 void readme()
-{ std::cout << " Usage: ./SURF_descriptor <img1> <img2>" << std::endl; }
+{ std::cout << " Usage: ./SURF_Homography <img1> <img2>" << std::endl; }