Xformer: Hybrid X-Shaped Transformer for Image Denoising

TL;DR

Xformer is a novel hybrid X-shaped Transformer architecture that enhances image denoising by capturing multi-scale features through spatial and channel-wise interactions, achieving state-of-the-art results.

Contribution

The paper introduces a hybrid X-shaped Transformer with dual branches and a Bidirectional Connection Unit for improved global and local feature modeling in image denoising.

Findings

Achieves state-of-the-art denoising performance

Effective multi-scale feature extraction

Comparable model complexity with superior results

Abstract

In this paper, we present a hybrid X-shaped vision Transformer, named Xformer, which performs notably on image denoising tasks. We explore strengthening the global representation of tokens from different scopes. In detail, we adopt two types of Transformer blocks. The spatial-wise Transformer block performs fine-grained local patches interactions across tokens defined by spatial dimension. The channel-wise Transformer block performs direct global context interactions across tokens defined by channel dimension. Based on the concurrent network structure, we design two branches to conduct these two interaction fashions. Within each branch, we employ an encoder-decoder architecture to capture multi-scale features. Besides, we propose the Bidirectional Connection Unit (BCU) to couple the learned representations from these two branches while providing enhanced information fusion. The joint designs make our Xformer powerful to conduct global information modeling in both spatial and channel dimensions. Extensive experiments show that Xformer, under the comparable model complexity, achieves state-of-the-art performance on the synthetic and real-world image denoising tasks. We also provide code and models at https://github.com/gladzhang/Xformer.