add new rollback inside expansion

Author: Fabien Servant

src/aliceVision/sfm/pipeline/bootstrapping/Bootstrap.cpp

@@ -104,10 +104,11 @@ bool bootstrapMesh(sfmData::SfMData & sfmData,
     std::mt19937 randomNumberGenerator;
     Eigen::Matrix4d pose;
     double threshold;
+    size_t countInliers;
 
     //Compute resection for selected view
     SfmResection resection(50000, std::numeric_limits<double>::infinity());
-    if (!resection.processView(sfmData, tracksMap, tracksPerView, randomNumberGenerator, viewId, pose, threshold))
+    if (!resection.processView(sfmData, tracksMap, tracksPerView, randomNumberGenerator, viewId, pose, threshold, countInliers))
     {
         return false;
     }

src/aliceVision/sfm/pipeline/expanding/ExpansionChunk.cpp

@@ -15,6 +15,7 @@ namespace sfm {
 
 bool ExpansionChunk::process(sfmData::SfMData & sfmData, const track::TracksHandler & tracksHandler, const std::set<IndexT> & viewsChunk)
 {   
+    _ignoredViews.clear();
     ALICEVISION_LOG_INFO("ExpansionChunk::process start");
     ALICEVISION_LOG_INFO("Chunk size : " << viewsChunk.size());
 
@@ -31,6 +32,17 @@ bool ExpansionChunk::process(sfmData::SfMData & sfmData, const track::TracksHand
         return false;
     }
 
+
+    struct IntermediateResectionInfo
+    {
+        IndexT viewId;
+        Eigen::Matrix4d pose;
+        size_t inliersCount;
+        double threshold;
+    };
+
+    std::vector<IntermediateResectionInfo> intermediateInfos;
+
     ALICEVISION_LOG_INFO("Resection start");
     #pragma omp parallel for
     for (int i = 0; i < viewsChunk.size(); i++)
@@ -41,25 +53,52 @@ bool ExpansionChunk::process(sfmData::SfMData & sfmData, const track::TracksHand
 
         if (!sfmData.isPoseAndIntrinsicDefined(viewId))
         {
+            IntermediateResectionInfo iri;
+            iri.viewId = viewId;
+
             SfmResection resection(_resectionIterations, _resectionMaxError);
 
-            Eigen::Matrix4d pose;
-            double threshold = 0.0;
             std::mt19937 randomNumberGenerator;
             if (!resection.processView(sfmData, 
                                 tracksHandler.getAllTracks(), tracksHandler.getTracksPerView(), 
                                 randomNumberGenerator, viewId, 
-                                pose, threshold))
+                                iri.pose, iri.threshold, iri.inliersCount))
             {
                 continue;
             }
 
             #pragma omp critical
             {
-                
-                addPose(sfmData, viewId, pose);
+                intermediateInfos.push_back(iri);
+            }
+        }
+    }
+
+    //Check that at least one view has rich info
+    const int poorInliersCount = 100;
+    int richViews = 0;
+    for (const auto & item : intermediateInfos)
+    {
+        if (item.inliersCount > poorInliersCount)
+        {
+            richViews++;
+        }
+    }
+
+
+    //Add pose only if it match conditions
+    for (const auto & item : intermediateInfos)
+    {
+        if (richViews > 0)
+        {
+            if (item.inliersCount < poorInliersCount)
+            {
+                _ignoredViews.insert(item.viewId);
+                continue;
             }
         }
+        
+        addPose(sfmData, item.viewId, item.pose);
     }
 
     // Get a list of valid views

src/aliceVision/sfm/pipeline/expanding/ExpansionChunk.hpp

@@ -98,6 +98,11 @@ class ExpansionChunk
         _minTriangulationAngleDegrees = angle;
     }
 
+    const std::set<IndexT> & getIgnoredViews()
+    {
+        return _ignoredViews;
+    }
+
 private:
 
     /**
@@ -128,6 +133,7 @@ class ExpansionChunk
     SfmBundle::uptr _bundleHandler;
     ExpansionHistory::sptr _historyHandler;
     PointFetcher::uptr _pointFetcherHandler;
+    std::set<IndexT> _ignoredViews;
 
 private:    
     size_t _resectionIterations = 1024;

src/aliceVision/sfm/pipeline/expanding/ExpansionIteration.cpp

@@ -47,6 +47,10 @@ bool ExpansionIteration::process(sfmData::SfMData & sfmData, track::TracksHandle
             continue;
         }
 
+        //Rollback any views which were ignored (not with errors)
+        _policy->rollback(_chunkHandler->getIgnoredViews());
+        
+        //Save this epoch to history
         _historyHandler->endEpoch(sfmData, _policy->getNextViews());
     }
 

src/aliceVision/sfm/pipeline/expanding/ExpansionPolicy.hpp

@@ -33,6 +33,12 @@ class ExpansionPolicy
      * @return true if the policy succeeded
     */
     virtual bool process(const sfmData::SfMData & sfmData, const track::TracksHandler & tracksHandler) = 0;
+
+    /**
+     * @brief rollback some processed views inside the available views
+     * @param viewsSet the set of views that we want to be able to select again.
+    */
+    virtual void rollback(const std::set<IndexT> & viewsSet) = 0;
 
     /**
      * @brief Retrieve the selected next views

src/aliceVision/sfm/pipeline/expanding/ExpansionPolicyLegacy.cpp

@@ -200,5 +200,14 @@ double ExpansionPolicyLegacy::computeScore(const track::TracksMap & tracksMap,
     return sum;
 }
 
+void ExpansionPolicyLegacy::rollback(const std::set<IndexT> & viewsSet)
+{
+    for (const auto & item : viewsSet)
+    {
+        ALICEVISION_LOG_INFO("rollback view : " << item);
+        _availableViewsIds.insert(item);
+    }
+}
+
 }
 }

src/aliceVision/sfm/pipeline/expanding/ExpansionPolicyLegacy.hpp

@@ -73,6 +73,12 @@ class ExpansionPolicyLegacy : public ExpansionPolicy
         _maxViewsPerGroup = count;
     }
 
+    /**
+     * @brief rollback some processed views inside the available views
+     * @param viewsSet the set of views that we want to be able to select again.
+    */
+    virtual void rollback(const std::set<IndexT> & viewsSet);
+
 private:
 
     // vector of  selected views for this iteration

src/aliceVision/sfm/pipeline/expanding/SfmResection.cpp

@@ -26,7 +26,8 @@ bool SfmResection::processView(
                         std::mt19937 &randomNumberGenerator,
                         const IndexT viewId,
                         Eigen::Matrix4d & updatedPose,
-                        double & updatedThreshold
+                        double & updatedThreshold,
+                        size_t & inliersCount
                         )
 {
     ALICEVISION_LOG_INFO("SfmResection::processView start " << viewId);
@@ -90,6 +91,9 @@ bool SfmResection::processView(
         return false;
     }
 
+    inliersCount = inliers.size();
+    ALICEVISION_LOG_INFO("Resection for view " << viewId << " had " << inliersCount << " inliers.");
+
     //Refine the pose
     if (!internalRefinement(structure, observations, inliers, pose, intrinsic, errorMax))
     {

src/aliceVision/sfm/pipeline/expanding/SfmResection.hpp

@@ -32,6 +32,7 @@ class SfmResection
      * @param viewId the view id to process
      * @param updatedPose output estimated pose
      * @param updatedThreshold estimated threshold
+     * @param inliersCount number of inliers for this resection
      * @return false if a critical error occured
     */
     bool processView(
@@ -41,7 +42,8 @@ class SfmResection
                 std::mt19937 &randomNumberGenerator,
                 const IndexT viewId,
                 Eigen::Matrix4d & updatedPose,
-                double & updatedThreshold
+                double & updatedThreshold,
+                size_t & inliersCount
             );
 
 private: