A sample program : how to use ORB AKAZE BRISK descriptors for matching.

see http://answers.opencv.org/question/61062/features2d-example/

samples/cpp/matchmethod_orb_akaze_brisk.cpp

@@ -0,0 +1,92 @@
+#include <opencv2/opencv.hpp>
+#include <vector>
+#include <iostream>
+
+using namespace std;
+using namespace cv;
+
+
+int main(void)
+{
+    vector<String> typeAlgoMatch;
+    typeAlgoMatch.push_back("BruteForce");
+    typeAlgoMatch.push_back("BruteForce-Hamming");
+    typeAlgoMatch.push_back("BruteForce-Hamming(2)");
+    
+    vector<String> typeDesc;
+    typeDesc.push_back("AKAZE");
+    typeDesc.push_back("ORB");
+    typeDesc.push_back("BRISK");
+
+    String  dataFolder("../data/");
+    vector<String> fileName;
+    fileName.push_back("basketball1.png");
+    fileName.push_back("basketball2.png");
+    
+    Mat img1 = imread(dataFolder+fileName[0], IMREAD_GRAYSCALE);
+    Mat img2 = imread(dataFolder+fileName[1], IMREAD_GRAYSCALE);
+
+    Ptr<Feature2D> b;
+
+    vector<String>::iterator itDesc;
+// Descriptor loop
+    for (itDesc = typeDesc.begin(); itDesc != typeDesc.end(); itDesc++){
+        Ptr<DescriptorMatcher> descriptorMatcher;
+        vector<DMatch> matches;	        /*<! Match between img and img2*/
+        vector<KeyPoint> keyImg1;		/*<! keypoint  for img1 */
+        vector<KeyPoint> keyImg2;		/*<! keypoint  for img2 */
+        Mat descImg1, descImg2;         /*<! Descriptor for img1 and img2 */
+        vector<String>::iterator itMatcher = typeAlgoMatch.end();
+        if (*itDesc == "AKAZE"){
+            b = AKAZE::create();
+        }
+        if (*itDesc == "ORB"){
+            b = ORB::create();
+        }
+        else if (*itDesc == "BRISK"){
+            b = BRISK::create();
+        }
+        try {
+            b->detect(img1, keyImg1, Mat());
+            b->compute(img1, keyImg1, descImg1);
+            b->detectAndCompute(img2, Mat(),keyImg2, descImg2,false);
+ // Match method loop
+             for (itMatcher = typeAlgoMatch.begin(); itMatcher != typeAlgoMatch.end(); itMatcher++){
+                descriptorMatcher = DescriptorMatcher::create(*itMatcher);
+                descriptorMatcher->match(descImg1, descImg2, matches, Mat());
+ // Keep best matches only to have a nice drawing 
+                Mat index;
+                Mat tab(matches.size(), 1, CV_32F);
+                for (int i = 0; i<matches.size(); i++)
+                    tab.at<float>(i, 0) = matches[i].distance;
+                sortIdx(tab, index, SORT_EVERY_COLUMN + SORT_ASCENDING);
+                vector<DMatch> bestMatches;	/*<! best match */
+            
+                for (int i = 0; i<30; i++)
+                    bestMatches.push_back(matches[index.at<int>(i, 0)]);
+
+                Mat result;
+                drawMatches(img1, keyImg1, img2, keyImg2, bestMatches, result);
+                namedWindow(*itDesc+": "+*itMatcher, WINDOW_AUTOSIZE);
+                imshow(*itDesc + ": " + *itMatcher, result);
+                FileStorage fs(*itDesc+"_"+*itMatcher+"_"+fileName[0]+"_"+fileName[1]+".xml", FileStorage::WRITE);
+                fs<<"Matches"<<matches;
+
+                vector<DMatch>::iterator it;
+
+                cout << "Index \tIndex \tindex \tdistance\n";
+                cout << "in img1\tin img2\timage\t\n";
+                for (it = matches.begin(); it != matches.end(); it++)
+                    cout << it->queryIdx << "\t" << it->trainIdx << "\t" << it->imgIdx << "\t" << it->distance<<"\n";
+                waitKey();
+            }
+        }
+        catch (Exception& e){
+            cout << "Feature : " << *itDesc << "\n";
+            if (itMatcher != typeAlgoMatch.end())
+                cout << "Matcher : " << *itMatcher << "\n";
+            cout<<e.msg<<endl;
+        }
+    }
+    return 0;
+}