Self-Paced Sample Selection for Barely-Supervised Medical Image Segmentation
Junming Su, Zhiqiang Shen, Peng Cao, Jinzhu Yang, Osmar R. Zaiane
TL;DR
Barely-supervised medical image segmentation suffers from severely limited pixel-level labels and noisy registration-based pseudo labels. The authors propose SPSS, a self-paced framework combining Self-Paced Uncertainty Sample Selection (SU) and Self-Paced Bidirectional Feature Contrastive Learning (SC) to improve pseudo-label quality in both image and feature spaces. SU creates a voxel-level self-paced mask to select high-confidence voxels, while SC enforces class-discriminative representations through bidirectional contrastive losses, all trained in a self-paced loop. On LA and KiTS, SPSS achieves state-of-the-art performance with substantially fewer labeled slices and is demonstrated to outperform both barely-supervised and SSL baselines; the authors also release their code.
Abstract
The existing barely-supervised medical image segmentation (BSS) methods, adopting a registration-segmentation paradigm, aim to learn from data with very few annotations to mitigate the extreme label scarcity problem. However, this paradigm poses a challenge: pseudo-labels generated by image registration come with significant noise. To address this issue, we propose a self-paced sample selection framework (SPSS) for BSS. Specifically, SPSS comprises two main components: 1) self-paced uncertainty sample selection (SU) for explicitly improving the quality of pseudo labels in the image space, and 2) self-paced bidirectional feature contrastive learning (SC) for implicitly improving the quality of pseudo labels through enhancing the separability between class semantics in the feature space. Both SU and SC are trained collaboratively in a self-paced learning manner, ensuring that SPSS can learn from high-quality pseudo labels for BSS. Extensive experiments on two public medical image segmentation datasets demonstrate the effectiveness and superiority of SPSS over the state-of-the-art. Our code is release at https://github.com/SuuuJM/SPSS.
