Localization of a time-delayed, monocular virtual object superimposed on a real environment

Area of Science:

• Human-Computer Interaction
• Virtual Reality
• Perception Psychology

Background:

• Head-mounted displays (HMDs) are increasingly used for virtual reality (VR) applications.
• Accurate spatial perception, particularly distance judgment, is crucial for immersive and effective VR experiences.
• Motion parallax is a key visual cue for depth perception, but its effectiveness in VR can be affected by system latencies.

Purpose of the Study:

• To investigate the impact of system time delay on the accuracy of virtual object distance perception in a see-through HMD.
• To quantify the relationship between time delay, depicted distance, and localization error.
• To develop a model explaining the observed errors in virtual distance judgment.

Main Methods:

• Participants viewed monocular virtual objects in a see-through HMD and adjusted a pointer to match the object's depicted distance.
• Motion parallax was provided by observers rocking side-to-side.
• Experiments were conducted with four time delays (31 ms, 64 ms, 131 ms, 197 ms) and three depicted distances (75 cm, 95 cm, 113 cm).

Main Results:

• Localization errors increased systematically with both increasing time delay and increasing depicted distance.
• A linear relationship was observed between judgment error and time delay.
• The lateral projected position of the virtual object was also found to be linearly related to time delay.

Conclusions:

• System time delay in HMDs significantly degrades the accuracy of virtual object distance perception.
• Both the perceived distance and the accuracy of localization are negatively impacted by latency.
• Minimizing time delay is critical for improving the realism and usability of virtual reality systems.