ACT-SR: Aggregation Connection Transformer for Remote Sensing Image Super-Resolution

Recently, transformer-based methods have shown impressive performances in remote sensing image super-resolution (RSISR). However, the application of transformer in RSISR frequently results in artifacts and the loss of image detail due to limited information transmission pathways and the constraints of unidimensional self-attention mechanisms. To solve these problems, an aggregation connection transformer (ACT-SR) is proposed for RSISR. ACT-SR employs an advanced attention mechanism designed to enrich information transmission across spatial and channel dimensions, thereby enlarging the receptive fields for more accurate feature extraction. A core component of ACT-SR is the novel aggregation connection attention block, which effectively captures spatial similarities and channel importance, aggregating this information through a combination of series and parallel connections for enhanced feature representation. Furthermore, a new gated feed-forward network is introduced to enhance the nonlinear mapping capabilities of the transformer and control the information flow through the network. In addition, ACT-SR integrates a shifted windows scheme alongside interpolation residual calculation to facilitate efficient detail recovery and artifact elimination. Experimental results confirm the effectiveness of the proposed modules, with ACT-SR outperforming several state-of-the-art RSISR methods in both objective metrics and visual quality.