CNN-Transformer gated fusion network for medical image super-resolution.

To solve the problems of image detail blurring and insufficient utilization of global information in the existing medical image super-resolution reconstruction, this paper proposes a dual-branch fusion network based on residual Transformer network and dynamic convolutional neural network (CTGFSR). The network consists of two branches, one is the global branch based on residual Transformer network, and the other is the local branch based on dynamic convolutional neural network. The global branch uses the self-attention mechanism of Transformer network, which can effectively mine the large-scale global information in the image and improve the overall quality of the image. The local branch uses the characteristic of dynamic convolution to adaptively adjust the convolution kernel parameters, which can enhance the feature extraction ability of convolutional neural network for multi-scale information and improve the detail restoration ability of the image without significantly increasing the network model size. The network uses residual skip connections to preserve the detail information in medical image super-resolution reconstruction. Finally, through the bidirectional gated attention mechanism, the two branches are fused to obtain the final super-resolution reconstruction image. This paper evaluates the performance of the network on two medical image datasets, namely ACDC abdominal MR related to medical image segmentation and L2R2022 lung CT related to registration. The experimental results show that compared with the mainstream super-resolution algorithms, CTGFSR has better overall performance. When the magnification factor is 2 or 4, compared with the convolutional neural network based CFIPC, PDCNCF, ESPCN, FSRCNN, VDSR and the Transformer network based ESRT, SwinIR, the structural similarity SSIM and peak signal-to-noise ratio PSNR have a certain improvement.