Source-free domain adaptation (SFDA) aims to adapt models trained on a labeled source domain to an unlabeled target domain without the access to source data. In medical imaging scenarios, the practical significance of SFDA methods has been emphasized due to privacy concerns. Recent State-of-the-art SFDA methods primarily rely on self-training based on pseudo-labels (PLs). Unfortunately, PLs suffer from accuracy deterioration caused by domain shift, and thus limit the effectiveness of the adaptation process. To address this issue, we propose a Chebyshev confidence guided SFDA framework to accurately assess the reliability of PLs and generate self-improving PLs for self-training. The Chebyshev confidence is estimated by calculating probability lower bound of the PL confidence, given the prediction and the corresponding uncertainty. Leveraging the Chebyshev confidence, we introduce two confidence-guided denoising methods: direct denoising and prototypical denoising. Additionally, we propose a novel teacher-student joint training scheme (TJTS) that incorporates a confidence weighting module to improve PLs iteratively. The TJTS, in collaboration with the denoising methods, effectively prevents the propagation of noise and enhances the accuracy of PLs. Extensive experiments in diverse domain scenarios validate the effectiveness of our proposed framework and establish its superiority over state-of-the-art SFDA methods. Our paper contributes to the field of SFDA by providing a novel approach for precisely estimating the reliability of pseudo-labels and a framework for obtaining high-quality PLs, resulting in improved adaptation performance.

在医学成像场景中，为了解决领域偏移问题导致伪标签准确度下降的限制，我们提出了一个Chebyshev置信度引导的无源域适应框架，准确评估伪标签的可靠性并生成自我改进的伪标签用于自我训练，通过引入直接去噪和原型去噪两种置信度引导的去噪方法，以及结合置信度加权模块的教师-学生联合训练方案，有效防止噪声传播提高伪标签的准确度。在多样化的领域场景中进行的大量实验证实了我们提出框架的有效性，并证明其优于现有最先进的无源域适应方法。

医学图像分割的切比雪夫置信度引导无源领域自适应框架