Subjective Perception and Objective Measurements in Perceiving Object Softness for VR Surgical Systems

A critical issue of virtual reality (VR) surgical systems is to correctly represent both haptic and visual information for distinguishing the softness of organs/tissues. We investigated the relationship between subjective perception of object softness and objective measurements of haptic and visual information. On a co-location VR setup, human subjects pressed deformable balls (simulating organs/tissues) under the conditions of both haptic and visual information available and only haptic (or visual) information available. We recorded and analyzed the subject's selection (subjective perception) of the harder object between two balls and objective measurements of maximum force (haptic) and pressing depth (visual). The results preliminarily indicated that subjective perception behaves differently from objective measurements in perceiving object softness. This has implications for creating accurate simulation in VR surgical systems.