Merge pull request #980 from alicevision/dev/crossMatching

[matching] implement cross check for feature matching
alicevision · Feb 19, 2021 · 819608d · 819608d
2 parents 90e4053 + c1dc5d8
commit 819608d
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Showing 5 changed files with 48 additions and 8 deletions.
diff --git a/src/aliceVision/matchingImageCollection/ImageCollectionMatcher_generic.cpp b/src/aliceVision/matchingImageCollection/ImageCollectionMatcher_generic.cpp
@@ -22,9 +22,10 @@ using namespace aliceVision::matching;
 using namespace aliceVision::feature;
 
 ImageCollectionMatcher_generic::ImageCollectionMatcher_generic(
-  float distRatio, EMatcherType matcherType)
+  float distRatio, bool crossMatching, EMatcherType matcherType)
   : IImageCollectionMatcher()
   , _f_dist_ratio(distRatio)
+  , _useCrossMatching(crossMatching)
   , _matcherType(matcherType)
 {
 }
@@ -85,6 +86,37 @@ void ImageCollectionMatcher_generic::Match(
 
       IndMatches vec_putatives_matches;
       matcher.Match(_f_dist_ratio, regionsJ, vec_putatives_matches);
+
+      if (_useCrossMatching)
+      {
+        // Initialize the matching interface
+        matching::RegionsDatabaseMatcher matcherCross(randomNumberGenerator, _matcherType, regionsJ);  
+
+        IndMatches vec_putatives_matches_cross;
+        matcherCross.Match(_f_dist_ratio, regionsI, vec_putatives_matches_cross);
+
+        //Create a dictionnary of matches indexed by their pair of indexes
+        std::map<std::pair<int, int>, IndMatch> check_matches;
+        for (IndMatch & m : vec_putatives_matches_cross)
+        {
+          std::pair<int, int> key = std::make_pair(m._i, m._j);
+          check_matches[key] = m;
+        }
+
+        IndMatches vec_putatives_matches_checked;
+        for (IndMatch & m : vec_putatives_matches)
+        {
+          //Check with reversed key (images are swapped)
+          std::pair<int, int> key = std::make_pair(m._j, m._i);
+          if (check_matches.find(key) != check_matches.end())
+          {
+            vec_putatives_matches_checked.push_back(m);
+          }
+        }
+
+        std::swap(vec_putatives_matches, vec_putatives_matches_checked);
+      }
+
       #pragma omp critical
       {
         ++my_progress_bar;

diff --git a/src/aliceVision/matchingImageCollection/ImageCollectionMatcher_generic.hpp b/src/aliceVision/matchingImageCollection/ImageCollectionMatcher_generic.hpp
@@ -25,6 +25,7 @@ class ImageCollectionMatcher_generic : public IImageCollectionMatcher
   public:
   ImageCollectionMatcher_generic(
     float dist_ratio,
+    bool crossMatching,
     matching::EMatcherType matcherType
   );
 
@@ -40,6 +41,8 @@ class ImageCollectionMatcher_generic : public IImageCollectionMatcher
   private:
   // Distance ratio used to discard spurious correspondence
   float _f_dist_ratio;
+  // Do we use cross matching (Symmetric matching test) ?
+  bool _useCrossMatching;
   // Matcher Type
   matching::EMatcherType _matcherType;
 };

diff --git a/src/aliceVision/matchingImageCollection/matchingCommon.cpp b/src/aliceVision/matchingImageCollection/matchingCommon.cpp
@@ -17,17 +17,17 @@ namespace aliceVision {
 namespace matchingImageCollection {
 
 
-std::unique_ptr<IImageCollectionMatcher> createImageCollectionMatcher(matching::EMatcherType matcherType, float distRatio)
+std::unique_ptr<IImageCollectionMatcher> createImageCollectionMatcher(matching::EMatcherType matcherType, float distRatio, bool crossMatching)
 {
   std::unique_ptr<IImageCollectionMatcher> matcherPtr;
 
   switch(matcherType)
   {
-    case matching::BRUTE_FORCE_L2:          matcherPtr.reset(new ImageCollectionMatcher_generic(distRatio, matching::BRUTE_FORCE_L2)); break;
-    case matching::ANN_L2:                  matcherPtr.reset(new ImageCollectionMatcher_generic(distRatio, matching::ANN_L2)); break;
-    case matching::CASCADE_HASHING_L2:      matcherPtr.reset(new ImageCollectionMatcher_generic(distRatio, matching::CASCADE_HASHING_L2)); break;
+    case matching::BRUTE_FORCE_L2:          matcherPtr.reset(new ImageCollectionMatcher_generic(distRatio, crossMatching, matching::BRUTE_FORCE_L2)); break;
+    case matching::ANN_L2:                  matcherPtr.reset(new ImageCollectionMatcher_generic(distRatio, crossMatching, matching::ANN_L2)); break;
+    case matching::CASCADE_HASHING_L2:      matcherPtr.reset(new ImageCollectionMatcher_generic(distRatio, crossMatching, matching::CASCADE_HASHING_L2)); break;
     case matching::FAST_CASCADE_HASHING_L2: matcherPtr.reset(new ImageCollectionMatcher_cascadeHashing(distRatio)); break;
-    case matching::BRUTE_FORCE_HAMMING:     matcherPtr.reset(new ImageCollectionMatcher_generic(distRatio, matching::BRUTE_FORCE_HAMMING)); break;
+    case matching::BRUTE_FORCE_HAMMING:     matcherPtr.reset(new ImageCollectionMatcher_generic(distRatio, crossMatching, matching::BRUTE_FORCE_HAMMING)); break;
 
     default: throw std::out_of_range("Invalid matcherType enum");
   }

diff --git a/src/aliceVision/matchingImageCollection/matchingCommon.hpp b/src/aliceVision/matchingImageCollection/matchingCommon.hpp
@@ -18,7 +18,7 @@ namespace matchingImageCollection {
  * @param matcherType
  * @return 
  */
-std::unique_ptr<IImageCollectionMatcher> createImageCollectionMatcher(matching::EMatcherType matcherType, float distRatio);
+std::unique_ptr<IImageCollectionMatcher> createImageCollectionMatcher(matching::EMatcherType matcherType, float distRatio, bool crossMatching);
 
 
 } // namespace matching

diff --git a/src/software/pipeline/main_featureMatching.cpp b/src/software/pipeline/main_featureMatching.cpp
@@ -110,6 +110,7 @@ int aliceVision_main(int argc, char **argv)
   double knownPosesGeometricErrorMax = 4.0;
   bool savePutativeMatches = false;
   bool guidedMatching = false;
+  bool crossMatching = false;
   int maxIteration = 2048;
   bool matchFilePerImage = false;
   size_t numMatchesToKeep = 0;
@@ -170,6 +171,8 @@ int aliceVision_main(int argc, char **argv)
       "Save putative matches.")
     ("guidedMatching", po::value<bool>(&guidedMatching)->default_value(guidedMatching),
       "Use the found model to improve the pairwise correspondences.")
+    ("crossMatching", po::value<bool>(&crossMatching)->default_value(crossMatching),
+      "Make sure that the matching process is symmetric (same matches for I->J than fo J->I).")
     ("matchFilePerImage", po::value<bool>(&matchFilePerImage)->default_value(matchFilePerImage),
       "Save matches in a separate file per image.")
     ("distanceRatio", po::value<float>(&distRatio)->default_value(distRatio),
@@ -273,6 +276,8 @@ int aliceVision_main(int argc, char **argv)
   PairSet pairs;
   std::set<IndexT> filter;
 
+
+  // We assume that there is only one pair for (I,J) and (J,I)
   if(predefinedPairList.empty())
   {
     pairs = exhaustivePairs(sfmData.getViews(), rangeStart, rangeSize);
@@ -307,7 +312,7 @@ int aliceVision_main(int argc, char **argv)
 
   // allocate the right Matcher according the Matching requested method
   EMatcherType collectionMatcherType = EMatcherType_stringToEnum(nearestMatchingMethod);
-  std::unique_ptr<IImageCollectionMatcher> imageCollectionMatcher = createImageCollectionMatcher(collectionMatcherType, distRatio);
+  std::unique_ptr<IImageCollectionMatcher> imageCollectionMatcher = createImageCollectionMatcher(collectionMatcherType, distRatio, crossMatching);
 
   const std::vector<feature::EImageDescriberType> describerTypes = feature::EImageDescriberType_stringToEnums(describerTypesName);