ScribFormer: Transformer Makes CNN Work Better for Scribble-based Medical Image Segmentation
This addresses the challenge of reducing annotation costs for medical image segmentation, though it is an incremental improvement combining existing CNN and Transformer components.
The paper tackles the problem of medical image segmentation with limited scribble annotations by proposing ScribFormer, a CNN-Transformer hybrid model that fuses local and global features to capture shape information, achieving superior performance over state-of-the-art scribble-supervised methods and even outperforming fully-supervised methods on three datasets.
Most recent scribble-supervised segmentation methods commonly adopt a CNN framework with an encoder-decoder architecture. Despite its multiple benefits, this framework generally can only capture small-range feature dependency for the convolutional layer with the local receptive field, which makes it difficult to learn global shape information from the limited information provided by scribble annotations. To address this issue, this paper proposes a new CNN-Transformer hybrid solution for scribble-supervised medical image segmentation called ScribFormer. The proposed ScribFormer model has a triple-branch structure, i.e., the hybrid of a CNN branch, a Transformer branch, and an attention-guided class activation map (ACAM) branch. Specifically, the CNN branch collaborates with the Transformer branch to fuse the local features learned from CNN with the global representations obtained from Transformer, which can effectively overcome limitations of existing scribble-supervised segmentation methods. Furthermore, the ACAM branch assists in unifying the shallow convolution features and the deep convolution features to improve model's performance further. Extensive experiments on two public datasets and one private dataset show that our ScribFormer has superior performance over the state-of-the-art scribble-supervised segmentation methods, and achieves even better results than the fully-supervised segmentation methods. The code is released at https://github.com/HUANGLIZI/ScribFormer.