Edge-preserving Image Synthesis for Unsupervised Domain Adaptation in Medical Image Segmentation.

Domain Adaptation is a technique to address the lack of massive amounts of labeled data in different application domains. Unsupervised domain adaptation is the process of adapting a model to an unseen target dataset using solely labeled source data and unlabeled target domain data. Though many image-spaces domain adaptation methods have been proposed to capture pixel-level domain-shift, such techniques may fail to maintain high-level semantic information for the segmentation task. For the case of biomedical images, fine details such as blood vessels can be lost during the image transformation operations between domains. In this work, we propose a model that adapts between domains using cycle-consistent loss while maintaining edge details of the original images by enforcing an edge-based loss during the adaptation process. We demonstrate the effectiveness of our algorithm by comparing it to other approaches on two eye fundus vessels segmentation datasets. We achieve 3.1 % increment in Dice score compared to the SOTA and  ∼  7.02% increment compared to a vanilla CycleGAN implementation. Clinical relevance- The proposed adaptation scheme can provide better performance on unseen data for semantic segmentation, which is widely applied in computer-aided diagnosis. Such robust performance can reduce the reliance of a large amount of labeled data, which is a common problem in the medical domain.