A Context-aware Locality Measure for Inlier Pool Enrichment in Stepwise Image Registration

We present a feature-based image registration method, the stepwise image registration (SIR), with a closed-form solution. Our SIR creates an inlier pool and a candidate pool as the initialization, and then gradually enriches the inlier pool and refines the transformation. In each step, the enriched correspondence exclusively tunes the transformation coefficient within the confirmed inlier pairs, instead of updating the mapping using the complete putative set. In turn, the refined transformation prunes inconsistent mismatches to alleviate the incoming matching ambiguity. The context-aware locality measure (CALM) is designed for dissimilarity measure. The capability of the CALM can be enhanced by the progressive inlier pool enrichment. Finally, a retrieval process is performed based on the finest CALM and alignment, by which the inlier pool is maximized. Extensive experiments of enrichment evaluation, feature matching, image registration, and image retrieval demonstrate the favorable performance of our SIR against state-of-the-art methods. The code and datasets are available at https://github.com/sucv/SIR.