The thin plate spline robust point matching (TPS-RPM) algorithm: A revisit

This paper reviews the TPS-RPM algorithm (Chui and Rangarajan, 2003) for robustly registering two sets of points and demonstrates from a theoretical point of view its inherent limited performance when outliers are present in both point sets simultaneously. A double-sided outlier handling approach is proposed to overcome this limitation with a rigorous mathematical proof as the underlying theoretical support. This double-sided outlier handling approach is proved to be equivalent to the original formulation of the point matching problem. For a practical application, we also extend the TPS-RPM algorithms to non-rigid image registration by registering two sets of sparse features extracted from images. The intensity information of the extracted features are incorporated into feature matching in order to reduce the impact from outliers. Our experiments demonstrate the double-sided outlier handling approach and the efficiency of intensity information in assisting outlier detection.

Research highlights
► Reviewed the TPS-RPM algorithm in terms of its outlier handling.
► Provided mathematical proof of a double-sided outlier handling approach for the TPS-RPM algorithm.
► Extended the TPS-RPM algorithm to image registration by including an intensity matching term.
► Demonstrated the importance of additional information in robust outlier handling for the TPS-RPM algorithm.