fixed error in gcgraph which led to problems in opencv_stitching GC seam finder, added check for duplication in matches (opencv_stitching)

modules/imgproc/src/gcgraph.hpp

@@ -97,7 +97,7 @@ template <class TWeight>
 void GCGraph<TWeight>::create( unsigned int vtxCount, unsigned int edgeCount )
 {
     vtcs.reserve( vtxCount );
-    edges.reserve( edgeCount );
+    edges.reserve( edgeCount + 2 );
     flow = 0;
 }
 
@@ -118,6 +118,9 @@ void GCGraph<TWeight>::addEdges( int i, int j, TWeight w, TWeight revw )
     CV_Assert( w>=0 && revw>=0 );
     CV_Assert( i != j );
 
+    if( !edges.size() )
+        edges.resize( 2 );
+
     Edge fromI, toI;
     fromI.dst = j;
     fromI.next = vtcs[i].first;

modules/stitching/main.cpp

@@ -71,7 +71,7 @@ void printUsage()
         "  --try_gpu (yes|no)\n"
         "      Try to use GPU. The default value is 'no'. All default values\n"
         "      are for CPU mode.\n"
-        "\nMotion Estimation:\n"
+        "\nMotion Estimation Flags:\n"
         "  --work_megapix <float>\n"
         "      Resolution for image registration step. The default is 0.6 Mpx.\n"
         "  --match_conf <float>\n"
@@ -83,7 +83,7 @@ void printUsage()
         "      Bundle adjustment cost function. The default is 'focal_ray'.\n"
         "  --wave_correct (no|yes)\n"
         "      Perform wave effect correction. The default is 'yes'.\n"
-        "\nCompositing:\n"
+        "\nCompositing Flags:\n"
         "  --warp (plane|cylindrical|spherical)\n" 
         "      Warp surface type. The default is 'spherical'.\n"
         "  --seam_megapix <float>\n"

modules/stitching/matchers.cpp

@@ -257,6 +257,16 @@ void FeaturesMatcher::operator ()(const vector<ImageFeatures> &features, vector<
 
 namespace 
 {
+    class PairLess
+    {
+    public:
+        bool operator()(const pair<int,int>& l, const pair<int,int>& r) const
+        {
+            return l.first < r.first || (l.first == r.first && l.second < r.second);
+        }
+    };
+    typedef set<pair<int,int>,PairLess> MatchesSet;
+
     // These two classes are aimed to find features matches only, not to 
     // estimate homography
 
@@ -289,6 +299,7 @@ namespace
         matches_info.matches.clear();
         FlannBasedMatcher matcher;
         vector< vector<DMatch> > pair_matches;        
+        MatchesSet matches;
 
         // Find 1->2 matches
         matcher.knnMatch(features1.descriptors, features2.descriptors, pair_matches, 2);
@@ -299,7 +310,10 @@ namespace
             const DMatch& m0 = pair_matches[i][0];
             const DMatch& m1 = pair_matches[i][1];
             if (m0.distance < (1.f - match_conf_) * m1.distance)
+            {
                 matches_info.matches.push_back(m0);
+                matches.insert(make_pair(m0.queryIdx, m0.trainIdx));
+            }
         }
 
         // Find 2->1 matches
@@ -312,6 +326,7 @@ namespace
             const DMatch& m0 = pair_matches[i][0];
             const DMatch& m1 = pair_matches[i][1];
             if (m0.distance < (1.f - match_conf_) * m1.distance)
+                if (matches.find(make_pair(m0.trainIdx, m0.queryIdx)) == matches.end())
                     matches_info.matches.push_back(DMatch(m0.trainIdx, m0.queryIdx, m0.distance));
         }
     }
@@ -324,6 +339,7 @@ namespace
         descriptors2_.upload(features2.descriptors);
         BruteForceMatcher_GPU< L2<float> > matcher;
         vector< vector<DMatch> > pair_matches;
+        MatchesSet matches;
 
         // Find 1->2 matches
         matcher.knnMatch(descriptors1_, descriptors2_, train_idx_, distance_, all_dist_, 2);
@@ -335,7 +351,10 @@ namespace
             const DMatch& m0 = pair_matches[i][0];
             const DMatch& m1 = pair_matches[i][1];
             if (m0.distance < (1.f - match_conf_) * m1.distance)
+            {
                 matches_info.matches.push_back(m0);
+                matches.insert(make_pair(m0.queryIdx, m0.trainIdx));
+            }
         }
 
         // Find 2->1 matches
@@ -349,6 +368,7 @@ namespace
             const DMatch& m0 = pair_matches[i][0];
             const DMatch& m1 = pair_matches[i][1];
             if (m0.distance < (1.f - match_conf_) * m1.distance)
+                if (matches.find(make_pair(m0.trainIdx, m0.queryIdx)) == matches.end())
                     matches_info.matches.push_back(DMatch(m0.trainIdx, m0.queryIdx, m0.distance));
         }
     }

modules/stitching/precomp.hpp

@@ -49,6 +49,7 @@
 #include <vector>
 #include <algorithm>
 #include <utility>
+#include <set>
 #include "opencv2/core/core.hpp"
 #include "opencv2/core/internal.hpp"
 #include "opencv2/imgproc/imgproc.hpp"