Recently, anatomical landmark detection has achieved great progresses on single-domain data, which usually assumes training and test sets are from the same domain. However, such an assumption is not always true in practice, which can cause significant performance drop due to domain shift. To tackle this problem, we propose a novel framework for anatomical landmark detection under the setting of unsupervised domain adaptation (UDA), which aims to transfer the knowledge from labeled source domain to unlabeled target domain. The framework leverages self-training and domain adversarial learning to address the domain gap during adaptation. Specifically, a self-training strategy is proposed to select reliable landmark-level pseudo-labels of target domain data with dynamic thresholds, which makes the adaptation more effective. Furthermore, a domain adversarial learning module is designed to handle the unaligned data distributions of two domains by learning domain-invariant features via adversarial training. Our experiments on cephalometric and lung landmark detection show the effectiveness of the method, which reduces the domain gap by a large margin and outperforms other UDA methods consistently. The code is available at https://github.com/jhb86253817/UDA_Med_Landmark.

我们提出了一种基于无监督领域自适应的解剖标志点检测新框架，利用自我训练和领域对抗学习来处理适应过程中的领域差异，通过选择可靠的动态阈值标签进行目标领域数据的自适应，以及通过对抗训练学习领域不变特征来处理两个领域的不对齐数据分布，实验证明该方法在头影测量和肺标志点检测方面有效，显著减小了领域差距并且持续优于其他无监督领域自适应方法。

无监督领域适应在解剖标志检测中的应用