Convolutional neural networks (CNNs) have been previously used as model observers (MO) for the purpose of defect detection in medical images. Due to their limited generalizability, such CNN observers do not possess the ability to recognize whether an input image comes from the same distribution as the data it was trained on, i.e., the ability of having domain awareness. In this paper we propose an adaptive learning approach for training a domain-aware CNN ideal observer (IO). In our approach we use a variant of U-Net CNN which is trained simultaneously for defect localization prediction and for reconstruction of the input image. We demonstrate that the reconstruction mean-squared-error (MSE) by the network can serve as an indicator of how well the observer performs in the defect localization task, which is an important step towards developing a domain-aware MO. Furthermore we propose an adaptive learning approach by automatically selecting datasets on which the model in training has poor reconstruction MSE. Our results show that this adaptive training approach can improve the model performance both in generalization and defect localization compared to a non-adaptive approach, particularly for out-of-distribution images - images that were not seen during the training of the algorithm.
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