Addressing inconsistent labeling with cross image matching for scribble-based medical image segmentation.

In recent years, there has been a notable surge in the adoption of weakly-supervised learning for medical image segmentation, utilizing scribble annotation as a means to potentially reduce annotation costs. However, the inherent characteristics of scribble labeling, marked by incompleteness, subjectivity, and a lack of standardization, introduce inconsistencies into the annotations. These inconsistencies become significant challenges for the network's learning process, ultimately affecting the performance of segmentation. To address this challenge, we propose creating a reference set to guide pixel-level feature matching, constructed from class-specific tokens and pixel-level features extracted from variously images. Serving as a repository showcasing diverse pixel styles and classes, the reference set becomes the cornerstone for a pixel-level feature matching strategy. This strategy enables the effective comparison of unlabeled pixels, offering guidance, particularly in learning scenarios characterized by inconsistent and incomplete scribbles. The proposed strategy incorporates smoothing and regression techniques to align pixel-level features across different images. By leveraging the diversity of pixel sources, our matching approach enhances the network's ability to learn consistent patterns from the reference set. This, in turn, mitigates the impact of inconsistent and incomplete labeling, resulting in improved segmentation outcomes. Extensive experiments conducted on three publicly available datasets demonstrate the superiority of our approach over state-of-the-art methods in terms of segmentation accuracy and stability. The code will be made publicly available at https://github.com/jingkunchen/scribble-medical-segmentation.