Semi-supervised learning relaxes the need of large pixel-wise labeled datasets for image segmentation by leveraging unlabeled data. A prominent way to exploit unlabeled data is to regularize model predictions. Since the predictions of unlabeled data can be unreliable, uncertainty-aware schemes are typically employed to gradually learn from meaningful and reliable predictions. Uncertainty estimation methods, however, rely on multiple inferences from the model predictions that must be computed for each training step, which is computationally expensive. Moreover, these uncertainty maps capture pixel-wise disparities and do not consider global information. This work proposes a novel method to estimate segmentation uncertainty by leveraging global information from the segmentation masks. More precisely, an anatomically-aware representation is first learnt to model the available segmentation masks. The learnt representation thereupon maps the prediction of a new segmentation into an anatomically-plausible segmentation. The deviation from the plausible segmentation aids in estimating the underlying pixel-level uncertainty in order to further guide the segmentation network. The proposed method consequently estimates the uncertainty using a single inference from our representation, thereby reducing the total computation. We evaluate our method on two publicly available segmentation datasets of left atria in cardiac MRIs and of multiple organs in abdominal CTs. Our anatomically-aware method improves the segmentation accuracy over the state-of-the-art semi-supervised methods in terms of two commonly used evaluation metrics.

通过利用全局信息来估计分割不确定性的一种新方法，该方法首先学习了一个解剖感知的表示，然后将新分割的预测映射为一个解剖上可信的分割，借助于与可信分割的偏差，估计底层像素级不确定性以进一步指导分割网络，该方法仅使用一次推断从我们的表示中估计不确定性，从而减少了总计算量。该解剖感知方法在心脏磁共振成像的左心房和腹部CT扫描的多个器官这两个公开数据集上改善了分割准确性，以两个常用的评估指标衡量。

解剖学感知的半监督图像分割的不确定性