Multiscale Residual Alignment Transformer for Remote Sensing Image Change Detection

Deep learning (DL) methods have shown great potential for remote sensing image change detection (CD) recently, but still suffer from several limitations. Within the identical semantic concept, significant but irrelevant changes in surface texture, color, and spatial shifting of building objects resulted from variations in imaging physical factors, cause feature inconsistency of building objects in bitemporal sences. Conventional DL methods lack the capability to effectively distinguish real changes from irrelevant changes, leading to some false detections. This letter propose a novel framework, the multiscale residual alignment transformer (AlignFormer), to mitigate the above issues. Specifically, inspired by deformable attention mechanism, we first design an adaptive feature alignment module (AFAM) to suppress the inconsistency of feature pairs, where the regions of building can be adaptively focused on and the spatial-temporal dependencies of relevant building objects in feature pairs effectively captured, via scheme of flexibly sampling Keys/Values for each given Query. Besides, we utilize an extremely tiny Swin Transformer as the backbone of differencing-based framework for obtaining hierarchical features. Moreover, inspired by residual learning strategy, three AFAMs are integrated into the framework to form the multiscale residual architecture (MRA) for the coarse-to-fine alignment of the paired features. Experimental results confirm the superiority of our proposed method over several state-of-the-art algorithms. Our code will be released at https://github.com/ lilei-aircas/AlignFormer_CD