Measuring circular vection speed in a virtual reality headset

Abstract

Understanding the relationship between vection speed and display speed is important to help ensure accurate self-motion experiences in a variety of applications. In the present research, a virtual optokinetic drum was used to induce circular vection at three distinct constant velocities and a method for measuring circular vection speed was developed and examined. In Experiment 1, vection strength was measured using a traditional magnitude estimation rating technique. An optokinetic drum presented on a virtual reality (VR) headset rotated in the yaw axis at slow, medium, and fast speeds. Magnitude estimation ratings were greatest during the fast condition in Experiment 1, replicating previous findings and validating the use of the virtual optokinetic drum in a VR headset. In Experiment 2, participants spun a circular knob in a clockwise or counter-clockwise direction to index their vection speed, direction and duration. The speed at which participants spun the knob increased with drum speed. Vection speed was much faster than the optokinetic drum’s speed, demonstrating that participants may perceive self-motion at faster speeds than intended. It is recommended that indices of vection speed such as the circular knob be used to better understand the relationship between graphic speed and vection speed.