Affine-based Deformable Attention and Selective Fusion for Semi-dense Matching

Hongkai Chen, Zixin Luo, Yurun Tian, Xuyang Bai, Ziyu Wang, Lei Zhou, Mingmin Zhen, Tian Fang, David Mckinnon, Yanghai Tsin, Long Quan; Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR) Workshops, 2024, pp. 4254-4263

Identifying robust and accurate correspondences across images is a fundamental problem in computer vision that enables various downstream tasks. Recent semi-dense matching methods emphasize the effectiveness of fusing relevant cross-view information through Transformer. In this paper we propose several improvements upon this paradigm. Firstly we introduce affine-based local attention to model cross-view deformations. Secondly we present selective fusion to merge local and global messages from cross attention. Apart from network structure we also identify the importance of enforcing spatial smoothness in loss design which has been omitted by previous works. Based on these augmentations our network demonstrate strong matching capacity under different settings. The full version of our network achieves state-of-the-art performance among semi-dense matching methods at a similar cost to LoFTR while the slim version reaches LoFTR baseline's performance with only 15% computation cost and 18% parameters.