Recent progress in single-image super-resolution (SISR) has achieved remarkable performance, yet the computational costs of these methods remain a challenge for deployment on resource-constrained devices. Especially for transformer-based methods, the self-attention mechanism in such models brings great breakthroughs while incurring substantial computational costs. To tackle this issue, we introduce the Convolutional Transformer layer (ConvFormer) and the ConvFormer-based Super-Resolution network (CFSR), which offer an effective and efficient solution for lightweight image super-resolution tasks. In detail, CFSR leverages the large kernel convolution as the feature mixer to replace the self-attention module, efficiently modeling long-range dependencies and extensive receptive fields with a slight computational cost. Furthermore, we propose an edge-preserving feed-forward network, simplified as EFN, to obtain local feature aggregation and simultaneously preserve more high-frequency information. Extensive experiments demonstrate that CFSR can achieve an advanced trade-off between computational cost and performance when compared to existing lightweight SR methods. Compared to state-of-the-art methods, e.g. ShuffleMixer, the proposed CFSR achieves 0.39 dB gains on Urban100 dataset for x2 SR task while containing 26% and 31% fewer parameters and FLOPs, respectively. Code and pre-trained models are available at https://github.com/Aitical/CFSR.

通过引入Convolutional Transformer层（ConvFormer）和基于ConvFormer的超分辨率网络（CFSR），提出了一种有效且高效的轻量级图像超分辨率任务解决方案，通过使用大卷积核卷积作为特征混合器替代自注意模块，实现了较长范围依赖关系和广泛接受域的建模，同时在计算成本稍微增加的情况下保留了更多高频信息，并且相对于现有的轻量级SR方法在计算成本和性能之间取得了先进的平衡。

图像超分辨率变换：基于ConvFormer的高效方法