ETO+: Revisit the Refinement Stage in Efficient Feature Matching

Abstract

Recent feature matching approaches like ETO have focused on developing lightweight matching algorithms for real-time applications. However, their lack of cross-image feature interaction and sufficient refinement often lead to a decline in matching accuracy. To address these challenges, we propose ETO+, a novel and accurate feature matching algorithm that incorporates a lightweight yet efficient bidirectional interaction module and multi-stage refinement. Specifically, we introduce Trans-CNN, a bidirectional feature interaction module that integrates CNN- and transformer-based techniques to enhance both intra-image feature refinement and inter-image feature fusion, all while maintaining a comparable computational cost. Furthermore, by leveraging the inherent sparsity of local feature matching, we propose an efficient strategy to adaptively reallocate computational resources within the network. Additionally, we design an adaptive loss function that mitigates the impact of large matching errors, thereby improving overall robustness. Extensive experiments on widely used datasets demonstrate that our approach achieves a strong balance between accuracy and computational efficiency. It outperforms ETO by 7.9 in AUC@5 on MegaDepth, respectively, while being about 40% faster than E-LoFTR.