Visuotactile integration for depth perception in augmented reality

Augmented reality applications using stereo head-mounted displays are not capable of perfectly blending real and virtual objects. For example, depth in the real world is perceived through cues such as accommodation and vergence. However, in stereo head-mounted displays these cues are disconnected since the virtual is generally projected at a static distance, while vergence changes with depth. This conflict can result in biased depth estimation of virtual objects in a real environment. In this research, we examined whether redundant tactile feedback can reduce the bias in perceived depth in a reaching task. In particular, our experiments proved that a tactile mapping of distance to vibration intensity or vibration position on the skin can be used to determine a virtual object's depth. Depth estimation when using only tactile feedback was more accurate than when using only visual feedback, and when using visuotactile feedback it was more precise and occurred faster than when using unimodal feedback. Our work demonstrates the value of multimodal feedback in augmented reality applications that require correct depth perception, and provides insights on various possible visuotactile implementations.