Joint features-guided linear transformer and CNN for efficient image super-resolution

Integrating convolutional neural networks (CNNs) and transformers has notably improved lightweight single image super-resolution (SISR) tasks. However, existing methods lack the capability to exploit multi-level contextual information, and transformer computations inherently add quadratic complexity. To address these issues, we propose a Joint features-Guided Linear Transformer and CNN Network (JGLTN) for efficient SISR, which is constructed by cascading modules composed of CNN layers and linear transformer layers. Specifically, in the CNN layer, our approach employs an inter-scale feature integration module (IFIM) to extract critical latent information across scales. Then, in the linear transformer layer, we design a joint feature-guided linear attention (JGLA). It jointly considers adjacent and extended regional features, dynamically assigning weights to convolutional kernels for contextual feature selection. This process garners multi-level contextual information, which is used to guide linear attention for effective information interaction. Moreover, we redesign the method of computing feature similarity within the self-attention, reducing its computational complexity to linear. Extensive experiments shows that our proposal outperforms state-of-the-art models while balancing performance and computational costs.