I have modified source file and add a chart to have distance between keypoint for...

My english is not good so you can change some words in my comment

diff --git a/samples/cpp/matchmethod_orb_akaze_brisk.cpp b/samples/cpp/matchmethod_orb_akaze_brisk.cpp
index 6711ba3..be6bf35 100644 (file)
--- a/samples/cpp/matchmethod_orb_akaze_brisk.cpp
+++ b/samples/cpp/matchmethod_orb_akaze_brisk.cpp
@@ -5,37 +5,73 @@
 using namespace std;
 using namespace cv;
 
+static void help()
+{
+    cout << "\n This program demonstrates how to detect compute and match ORB BRISK and AKAZE descriptors \n"
+        "Usage: \n"
+        "  ./matchmethod_orb_akaze_brisk <image1(../data/basketball1.png as default)> <image2(../data/basketball2.png as default)>\n"
+        "Press a key when image window is active to change algorithm or descriptor";
+}
+
 
-int main(void)
+
+int main(int argc, char *argv[])
 {
+    vector<String> typeDesc;
     vector<String> typeAlgoMatch;
+    vector<String> fileName;
+    help();
+    // This descriptor are going to be detect and compute 
+    typeDesc.push_back("AKAZE");    // see http://docs.opencv.org/trunk/d8/d30/classcv_1_1AKAZE.html
+    typeDesc.push_back("ORB");      // see http://docs.opencv.org/trunk/de/dbf/classcv_1_1BRISK.html
+    typeDesc.push_back("BRISK");    // see http://docs.opencv.org/trunk/db/d95/classcv_1_1ORB.html
+   // This algorithm would be used to match descriptors see http://docs.opencv.org/trunk/db/d39/classcv_1_1DescriptorMatcher.html#ab5dc5036569ecc8d47565007fa518257
     typeAlgoMatch.push_back("BruteForce");
+    typeAlgoMatch.push_back("BruteForce-L1");
     typeAlgoMatch.push_back("BruteForce-Hamming");
     typeAlgoMatch.push_back("BruteForce-Hamming(2)");
+    if (argc==1)
+    {
+        fileName.push_back("../data/basketball1.png");
+        fileName.push_back("../data/basketball2.png");
+    }
+    else if (argc==3)
+    {
+        fileName.push_back(argv[1]);
+        fileName.push_back(argv[2]);
+    }
+    else
+    {
+        help();
+        return(0);
+    }
+    Mat img1 = imread(fileName[0], IMREAD_GRAYSCALE);
+    Mat img2 = imread(fileName[1], IMREAD_GRAYSCALE);
+    if (img1.rows*img1.cols <= 0)
+        {
+        cout << "Image " << fileName[0] << " is empty or cannot be found\n";
+        return(0);
+        }
+    if (img2.rows*img2.cols <= 0)
+        {
+        cout << "Image " << fileName[1] << " is empty or cannot be found\n";
+        return(0);
+        }
 
-    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);
-
+    vector<double> desMethCmp;
     Ptr<Feature2D> b;
 
+    // Descriptor loop
     vector<String>::iterator itDesc;
-// Descriptor loop
-    for (itDesc = typeDesc.begin(); itDesc != typeDesc.end(); itDesc++){
+    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 */
+        // Match between img1 and img2
+        vector<DMatch> matches;                
+        // keypoint  for img1 and img2 
+        vector<KeyPoint> keyImg1, keyImg2;
+        // Descriptor for img1 and img2 
+        Mat descImg1, descImg2;         
         vector<String>::iterator itMatcher = typeAlgoMatch.end();
         if (*itDesc == "AKAZE"){
             b = AKAZE::create();
@@ -47,23 +83,31 @@ int main(void)
             b = BRISK::create();
         }
         try {
+            // We can detect keypoint with detect method
             b->detect(img1, keyImg1, Mat());
+            // and compute their descriptors with method  compute
             b->compute(img1, keyImg1, descImg1);
+            // or detect and compute descriptors in one step
             b->detectAndCompute(img2, Mat(),keyImg2, descImg2,false);
- // Match method loop
-             for (itMatcher = typeAlgoMatch.begin(); itMatcher != typeAlgoMatch.end(); itMatcher++){
+            // 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
+                // Keep best matches only to have a nice drawing.
+                // We sort distance between descriptor matches
                 Mat index;
                 int nbMatch=int(matches.size());
                 Mat tab(nbMatch, 1, CV_32F);
                 for (int i = 0; i<nbMatch; i++)
+                {
                     tab.at<float>(i, 0) = matches[i].distance;
+                }
                 sortIdx(tab, index, SORT_EVERY_COLUMN + SORT_ASCENDING);
                 vector<DMatch> bestMatches;
                 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);
@@ -71,19 +115,45 @@ int main(void)
                 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";
+                cout<<"**********Match results**********\n";
+                cout << "Index \tIndex \tdistance\n";
+                cout << "in img1\tin img2\n";
+                double cumSumDist2=0; // Use to compute distance between keyPoint matches and to evaluate match algorithm
+                for (it = bestMatches.begin(); it != bestMatches.end(); it++)
+                {
+                    cout << it->queryIdx << "\t" <<  it->trainIdx << "\t"  <<  it->distance << "\n";
+                    Point2d p=keyImg1[it->queryIdx].pt-keyImg2[it->trainIdx].pt;
+                    cumSumDist2=p.x*p.x+p.y*p.y;
+                }
+                desMethCmp.push_back(cumSumDist2);
                 waitKey();
             }
         }
-        catch (Exception& e){
+        catch (Exception& e)
+        {
             cout << "Feature : " << *itDesc << "\n";
             if (itMatcher != typeAlgoMatch.end())
+            {
                 cout << "Matcher : " << *itMatcher << "\n";
+            }
             cout<<e.msg<<endl;
         }
     }
+    int i=0;
+    cout << "Cumulative distance between keypoint match for different algorithm and feature detector \n\t";
+    for (vector<String>::iterator itMatcher = typeAlgoMatch.begin(); itMatcher != typeAlgoMatch.end(); itMatcher++)
+    {
+        cout<<*itMatcher<<"\t";
+    }
+    cout << "\n";
+    for (itDesc = typeDesc.begin(); itDesc != typeDesc.end(); itDesc++)
+    {
+        cout << *itDesc << "\t";
+        for (vector<String>::iterator itMatcher = typeAlgoMatch.begin(); itMatcher != typeAlgoMatch.end(); itMatcher++, i++)
+        {
+            cout << desMethCmp[i]<<"\t";
+        }
+        cout<<"\n";
+    }
     return 0;
 }