[software] incrementalSfM : Add the option minNbMatches

src/aliceVision/matching/io.cpp

@@ -99,18 +99,23 @@ void filterMatchesByViews(
 
 void filterTopMatches(
   PairwiseMatches & allMatches,
-  const int limitNum)
+  const int limitNum,
+  const int minNum)
 {
-  if (limitNum <= 0)
+  if (limitNum <= 0 && minNum <=0)
     return;
+  if (minNum > limitNum)
+    throw std::runtime_error("The minimum of matches is higher than the maximum of matches");
 
   for(auto& matchesPerDesc: allMatches)
   {
     for(auto& matches: matchesPerDesc.second)
     {
       IndMatches& m = matches.second;
-      if (m.size() > limitNum)
+      if (limitNum > 0 && m.size() > limitNum)
         m.erase(m.begin()+limitNum, m.end());
+      if (minNum > 0 && m.size() < minNum)
+        m.clear();
     }
   }
 }
@@ -232,7 +237,8 @@ bool Load(
   const std::set<IndexT>& viewsKeysFilter,
   const std::vector<std::string>& folders,
   const std::vector<feature::EImageDescriberType>& descTypesFilter,
-  const int maxNbMatches)
+  const int maxNbMatches,
+  const int minNbMatches)
 {
   std::size_t nbLoadedMatchFiles = 0;
   const std::string pattern = "matches.txt";
@@ -271,8 +277,7 @@ bool Load(
   if(!descTypesFilter.empty())
     filterMatchesByDesc(matches, descTypesFilter);
 
-  if(maxNbMatches > 0)
-    filterTopMatches(matches, maxNbMatches);
+  filterTopMatches(matches, maxNbMatches, minNbMatches);
 
   ALICEVISION_LOG_TRACE("Matches per image pair (after filtering):");
   logMatches(matches);

src/aliceVision/matching/io.hpp

@@ -50,7 +50,8 @@ bool Load(PairwiseMatches& matches,
   const std::set<IndexT>& viewsKeysFilter,
   const std::vector<std::string>& folders,
   const std::vector<feature::EImageDescriberType>& descTypesFilter,
-  const int maxNbMatches = 0);
+  const int maxNbMatches = 0,
+  const int minNbMatches =0);
 
 /**
  * @brief Filter to keep only specific viewIds.

src/aliceVision/sfm/pipeline/pairwiseMatchesIO.hpp

@@ -35,6 +35,7 @@ inline bool loadPairwiseMatches(
     const std::vector<std::string>& folders,
     const std::vector<feature::EImageDescriberType>& descTypes,
     const int maxNbMatches = 0,
+    const int minNbMatches = 0,
     bool useOnlyMatchesFromFolder = false)
 {
   std::vector<std::string> matchesFolders;
@@ -47,7 +48,7 @@ inline bool loadPairwiseMatches(
   matchesFolders.insert(matchesFolders.end(), folders.begin(), folders.end());
 
   ALICEVISION_LOG_DEBUG("Loading matches");
-  if (!matching::Load(out_pairwiseMatches, sfmData.getViewsKeys(), matchesFolders, descTypes, maxNbMatches))
+  if (!matching::Load(out_pairwiseMatches, sfmData.getViewsKeys(), matchesFolders, descTypes, maxNbMatches, minNbMatches))
   {
     std::stringstream ss("Unable to read the matches file(s) from:\n");
     for(const std::string& folder : matchesFolders)

src/software/pipeline/main_incrementalSfM.cpp

@@ -87,6 +87,7 @@ int main(int argc, char **argv)
   sfm::ReconstructionEngine_sequentialSfM::Params sfmParams;
   bool lockScenePreviouslyReconstructed = true;
   int maxNbMatches = 0;
+  int minNbMatches = 0;
   bool useOnlyMatchesFromInputFolder = false;
 
   po::options_description allParams(
@@ -118,6 +119,9 @@ int main(int argc, char **argv)
     ("maxNumberOfMatches", po::value<int>(&maxNbMatches)->default_value(maxNbMatches),
       "Maximum number of matches per image pair (and per feature type). "
       "This can be useful to have a quick reconstruction overview. 0 means no limit.")
+    ("minNumberOfMatches", po::value<int>(&minNbMatches)->default_value(minNbMatches),
+      "Minimum number of matches per image pair (and per feature type). "
+      "This can be useful to have a meaningful reconstruction with accurate keypoints. 0 means no limit.")
     ("minInputTrackLength", po::value<int>(&sfmParams.minInputTrackLength)->default_value(sfmParams.minInputTrackLength),
       "Minimum track length in input of SfM.")
     ("minAngleForTriangulation", po::value<double>(&sfmParams.minAngleForTriangulation)->default_value(sfmParams.minAngleForTriangulation),
@@ -242,7 +246,7 @@ int main(int argc, char **argv)
 
   // matches reading
   matching::PairwiseMatches pairwiseMatches;
-  if(!sfm::loadPairwiseMatches(pairwiseMatches, sfmData, matchesFolders, describerTypes, maxNbMatches, useOnlyMatchesFromInputFolder))
+  if(!sfm::loadPairwiseMatches(pairwiseMatches, sfmData, matchesFolders, describerTypes, maxNbMatches, minNbMatches, useOnlyMatchesFromInputFolder))
   {
     ALICEVISION_LOG_ERROR("Unable to load matches.");
     return EXIT_FAILURE;