Regularising disparity estimation via multi task learning with structured light reconstruction

ABSTRACT 3D reconstruction is a useful tool for surgical planning and guidance. Supervised methods for disparity/depth estimation are the state of the art, with demonstrated performances far superior to all alternatives, such as self supervised and traditional geometric methods. However, supervised training requires large datasets, and in this field, data is lacking. In this paper, we investigate the learning of structured light projections to enhance the development of disparity estimation networks. Improving supervised learning on small datasets without needing to collect extra data. We first show that it is possible to learn the projection of structured light on a scene. Secondly, we show that the joint training of structured light and disparity, using a multi-task learning (MTL) framework, improves the learning of disparity. Our MTL setup outperformed the single task learning (STL) network in every validation test. Notably, in the generalisation test, the STL error was 1.4 times worse than that of the best MTL performance. A dataset containing stereoscopic images, disparity maps and structured light projections on medical phantoms and ex vivo tissue was created for evaluation together with virtual scenes. This dataset will be made publicly available in the future.