Effects of Surface Visualizations on Depth Perception in Projective Augmented Reality

Depth perception is a common issue in augmented reality (AR). Projective AR, where the spatial relations between the projection surface and displayed virtual contents need to be represented properly, is particularly affected. This is crucial in the medical domain, e.g., for the distances between the patient's skin and projected inner anatomical structures, but not much research was conducted in this context before. To this end, this work investigates the applicability of surface visualization techniques to support the perception of spatial relations in projective AR. Four methods previously explored in different domains were combined with the projection of inner anatomical structures on a human torso phantom. They were evaluated in a comparative user study (n=21) with respect to a distance estimation and a sorting task. Measures included Task completion time, accuracy, total Head movement and Confidence of the participants. Consistent results across variables show advantages of more occluding surface visualizations for the distance estimation task. Opposite results were obtained for the sorting task. This suggests that the amount of needed surface preservation depends on the use case and individual occlusion compromises need to be explored in future work.