fixed error in gcgraph which led to problems in opencv_stitching GC seam finder,…

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/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"