  Transformer-based image denoising methods have achieved encouraging results
in the past year. However, it must uses linear operations to model long-range
dependencies, which greatly increases model inference time and consumes GPU
storage space. Compared with convolutional neural network-based methods,
current Transformer-based image denoising methods cannot achieve a balance
between performance improvement and resource consumption. In this paper, we
propose an Efficient Wavelet Transformer (EWT) for image denoising.
Specifically, we use Discrete Wavelet Transform (DWT) and Inverse Wavelet
Transform (IWT) for downsampling and upsampling, respectively. This method can
fully preserve the image features while reducing the image resolution, thereby
greatly reducing the device resource consumption of the Transformer model.
Furthermore, we propose a novel Dual-stream Feature Extraction Block (DFEB) to
extract image features at different levels, which can further reduce model
inference time and GPU memory usage. Experiments show that our method speeds up
the original Transformer by more than 80%, reduces GPU memory usage by more
than 60%, and achieves excellent denoising results. All code will be public.
