Multiscale Spatial-Frequency Learning for Degradation Decoupling in RS Image Restoration

Remote sensing (RS) images are prone to various degradations, which poses challenges to downstream tasks. Although existing single-task remote sensing image restoration methods are effective, they lack generalizability across tasks. All-in-one methods can handle multiple degradation tasks, but they usually focus on spatial information, ignoring the physical properties of the degradation information. To address the above limitations, we propose a Multiscale Spatial-Frequency Degradation Decoupling framework for All-in-One remote sensing image restoration (SFD$^{2}$IR), which decouples degradation features across different tasks to guide the model in performing task-specific image restoration. Specifically, a task-specific instruction generator (TIG) is proposed first to transform degradation features into task-specific prompts. Then, a multi-scale multi-frequency enhancement (MME) module is designed to decouple degradation effects from both spatial and frequency perspectives, thus enhancing the model's adaptability to various degradation types. Finally, a prompt feature refinement (PFR) module is developed to further refine the model's response to degraded tasks. Extensive experiments demonstrate that the proposed method achieves excellent performance on different RSIR tasks, including cloud removal, deblurring, dehazing, and super-resolution. The source code will be publicly available at SFD$^{2}$IR.