Correctly invert two-view geometries when writing swapped image pair …

…to database
colmap · Jul 19, 2018 · 9f70659 · 9f70659
1 parent 885d239
commit 9f70659
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Showing 3 changed files with 43 additions and 15 deletions.
diff --git a/src/base/database.cc b/src/base/database.cc
@@ -516,15 +516,15 @@ TwoViewGeometry Database::ReadTwoViewGeometry(const image_t image_id1,
 
   SQLITE3_CALL(sqlite3_reset(sql_stmt_read_two_view_geometry_));
 
-  if (SwapImagePair(image_id1, image_id2)) {
-    SwapFeatureMatchesBlob(&blob);
-  }
-
   two_view_geometry.inlier_matches = FeatureMatchesFromBlob(blob);
   two_view_geometry.F.transposeInPlace();
   two_view_geometry.E.transposeInPlace();
   two_view_geometry.H.transposeInPlace();
 
+  if (SwapImagePair(image_id1, image_id2)) {
+    two_view_geometry.Invert();
+  }
+
   return two_view_geometry;
 }
 
@@ -695,26 +695,32 @@ void Database::WriteTwoViewGeometry(
   SQLITE3_CALL(
       sqlite3_bind_int64(sql_stmt_write_two_view_geometry_, 1, pair_id));
 
-  // Important: the swapped data must live until the query is executed.
-  FeatureMatchesBlob inlier_matches =
-      FeatureMatchesToBlob(two_view_geometry.inlier_matches);
+  const TwoViewGeometry* two_view_geometry_ptr = &two_view_geometry;
+
+  // Invert the two-view geometry if the image pair has to be swapped.
+  std::unique_ptr<TwoViewGeometry> swapped_two_view_geometry;
   if (SwapImagePair(image_id1, image_id2)) {
-    SwapFeatureMatchesBlob(&inlier_matches);
+    swapped_two_view_geometry.reset(new TwoViewGeometry());
+    *swapped_two_view_geometry = two_view_geometry;
+    swapped_two_view_geometry->Invert();
+    two_view_geometry_ptr = swapped_two_view_geometry.get();
   }
 
+  const FeatureMatchesBlob inlier_matches =
+      FeatureMatchesToBlob(two_view_geometry_ptr->inlier_matches);
   WriteDynamicMatrixBlob(sql_stmt_write_two_view_geometry_, inlier_matches, 2);
 
   SQLITE3_CALL(sqlite3_bind_int64(sql_stmt_write_two_view_geometry_, 5,
-                                  two_view_geometry.config));
+                                  two_view_geometry_ptr->config));
 
   // Transpose the matrices to obtain row-major data layout.
   // Important: Do not move these objects inside the if-statement, because
   // the objects must live until `sqlite3_step` is called on the statement.
-  const Eigen::Matrix3d Ft = two_view_geometry.F.transpose();
-  const Eigen::Matrix3d Et = two_view_geometry.E.transpose();
-  const Eigen::Matrix3d Ht = two_view_geometry.H.transpose();
+  const Eigen::Matrix3d Ft = two_view_geometry_ptr->F.transpose();
+  const Eigen::Matrix3d Et = two_view_geometry_ptr->E.transpose();
+  const Eigen::Matrix3d Ht = two_view_geometry_ptr->H.transpose();
 
-  if (two_view_geometry.inlier_matches.size() > 0) {
+  if (two_view_geometry_ptr->inlier_matches.size() > 0) {
     WriteStaticMatrixBlob(sql_stmt_write_two_view_geometry_, Ft, 6);
     WriteStaticMatrixBlob(sql_stmt_write_two_view_geometry_, Et, 7);
     WriteStaticMatrixBlob(sql_stmt_write_two_view_geometry_, Ht, 8);

diff --git a/src/base/database_test.cc b/src/base/database_test.cc
@@ -304,7 +304,7 @@ BOOST_AUTO_TEST_CASE(TestMatches) {
   BOOST_CHECK_EQUAL(database.NumMatches(), 0);
 }
 
-BOOST_AUTO_TEST_CASE(TestInlierMatches) {
+BOOST_AUTO_TEST_CASE(TestTwoViewGeometry) {
   Database database(kMemoryDatabasePath);
   const image_t image_id1 = 1;
   const image_t image_id2 = 2;
@@ -326,10 +326,32 @@ BOOST_AUTO_TEST_CASE(TestInlierMatches) {
     BOOST_CHECK_EQUAL(two_view_geometry.inlier_matches[i].point2D_idx2,
                       two_view_geometry_read.inlier_matches[i].point2D_idx2);
   }
+
   BOOST_CHECK_EQUAL(two_view_geometry.config, two_view_geometry_read.config);
   BOOST_CHECK_EQUAL(two_view_geometry.F, two_view_geometry_read.F);
   BOOST_CHECK_EQUAL(two_view_geometry.E, two_view_geometry_read.E);
   BOOST_CHECK_EQUAL(two_view_geometry.H, two_view_geometry_read.H);
+
+  const TwoViewGeometry two_view_geometry_read_inv =
+      database.ReadTwoViewGeometry(image_id2, image_id1);
+  BOOST_CHECK_EQUAL(two_view_geometry_read_inv.inlier_matches.size(),
+                    two_view_geometry_read.inlier_matches.size());
+  for (size_t i = 0; i < two_view_geometry_read.inlier_matches.size(); ++i) {
+    BOOST_CHECK_EQUAL(two_view_geometry_read_inv.inlier_matches[i].point2D_idx2,
+                      two_view_geometry_read.inlier_matches[i].point2D_idx1);
+    BOOST_CHECK_EQUAL(two_view_geometry_read_inv.inlier_matches[i].point2D_idx1,
+                      two_view_geometry_read.inlier_matches[i].point2D_idx2);
+  }
+
+  BOOST_CHECK_EQUAL(two_view_geometry_read_inv.config,
+                    two_view_geometry_read.config);
+  BOOST_CHECK_EQUAL(two_view_geometry_read_inv.F.transpose(),
+                    two_view_geometry_read.F);
+  BOOST_CHECK_EQUAL(two_view_geometry_read_inv.E.transpose(),
+                    two_view_geometry_read.E);
+  BOOST_CHECK(two_view_geometry_read_inv.H.inverse().eval().isApprox(
+      two_view_geometry_read.H));
+
   std::vector<image_pair_t> image_pair_ids;
   std::vector<TwoViewGeometry> two_view_geometries;
   database.ReadTwoViewGeometries(&image_pair_ids, &two_view_geometries);

diff --git a/src/feature/matching.cc b/src/feature/matching.cc
@@ -1343,7 +1343,7 @@ void TransitiveFeatureMatcher::Run() {
     std::vector<std::pair<image_t, image_t>> existing_image_pairs;
     std::vector<int> existing_num_inliers;
     database_.ReadTwoViewGeometryNumInliers(&existing_image_pairs,
-                                       &existing_num_inliers);
+                                            &existing_num_inliers);
 
     CHECK_EQ(existing_image_pairs.size(), existing_num_inliers.size());