Content-Preserving Unpaired Translation from Simulated to Realistic Ultrasound Images
This work addresses the problem of generating realistic ultrasound images for sonography training, which is incremental as it builds on existing unpaired translation techniques with specific enhancements.
The paper tackles the appearance gap between simulated and real ultrasound images by introducing a content-preserving image translation framework (ConPres) that maintains anatomical layout while improving realism, achieving superior results in qualitative and quantitative comparisons against state-of-the-art methods.
Interactive simulation of ultrasound imaging greatly facilitates sonography training. Although ray-tracing based methods have shown promising results, obtaining realistic images requires substantial modeling effort and manual parameter tuning. In addition, current techniques still result in a significant appearance gap between simulated images and real clinical scans. Herein we introduce a novel content-preserving image translation framework (ConPres) to bridge this appearance gap, while maintaining the simulated anatomical layout. We achieve this goal by leveraging both simulated images with semantic segmentations and unpaired in-vivo ultrasound scans. Our framework is based on recent contrastive unpaired translation techniques and we propose a regularization approach by learning an auxiliary segmentation-to-real image translation task, which encourages the disentanglement of content and style. In addition, we extend the generator to be class-conditional, which enables the incorporation of additional losses, in particular a cyclic consistency loss, to further improve the translation quality. Qualitative and quantitative comparisons against state-of-the-art unpaired translation methods demonstrate the superiority of our proposed framework.