Fix ransac update of the iteration number (#6789)

The update of the iteration number is forced to be non-negative (was negative if corres_inlier_ratio = 0.0)
isl-org · May 23, 2024 · b68eae1 · b68eae1
1 parent 69786b6
commit b68eae1
Show file tree

Hide file tree

Showing 2 changed files with 6 additions and 3 deletions.
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -35,6 +35,7 @@
 -   Fix log error message for `probability` argument validation in `PointCloud::SegmentPlane` (PR #6622)
 -   Fix macOS arm64 builds, add CI runner for macOS arm64 (PR #6695)
 -   Fix KDTreeFlann possibly using a dangling pointer instead of internal storage and simplified its members (PR #6734)
+-   Fix RANSAC early stop if no inliers in a specific iteration (PR #6789)
 -   Fix segmentation fault (infinite recursion) of DetectPlanarPatches if multiple points have same coordinates (PR #6794)
 
 ## 0.13

diff --git a/cpp/open3d/pipelines/registration/Registration.cpp b/cpp/open3d/pipelines/registration/Registration.cpp
@@ -235,13 +235,15 @@ RegistrationResult RegistrationRANSACBasedOnCorrespondence(
                                     max_correspondence_distance,
                                     transformation);
 
-                    // Update exit condition if necessary.
-                    // If confidence is 1.0, then it is safely inf, we always
-                    // consume all the iterations.
+                    // Update exit condition if necessary
                     double est_k_local_d =
                             std::log(1.0 - criteria.confidence_) /
                             std::log(1.0 -
                                      std::pow(corres_inlier_ratio, ransac_n));
+                    // This prevents having a negative number of iterations:
+                    // est_k_local_d = -inf if corres_inlier_ratio = 0.0
+                    est_k_local_d =
+                            est_k_local_d < 0 ? est_k_local : est_k_local_d;
                     est_k_local =
                             est_k_local_d < est_k_global
                                     ? static_cast<int>(std::ceil(est_k_local_d))