Compensation for the effects of time delay in a helmet-mounted display: perceptual adaptation versus algorithmic prediction

Virtual environment technologies, such as helmet-mounted displays (HMDs), are challenged by problems involving time delay--the time between an input to a system, and its corresponding output. An experiment was conducted to evaluate two methods of time delay compensation--algorithmic prediction and perceptual adaptation--during a time-delayed, head- slaved tracking task using an HMD. Predictive algorithms attempt to compensate for time delays by predicting future head position in order to update images effectively in the HMD. Perceptual adaptation refers to the ability of humans to adapt to the time delay by modifying their tracking strategies. Subjects were assigned to either a perceptual adaptation or algorithmic prediction condition, and participated in four experimental sessions during which they attempted to center a reticle over a moving circular target using a HMD. Tracking performance was evaluated in terms of RMS error, and the adequacy of the adaptation and prediction solutions was evaluated by several comparisons of tracking efficiency within and between sessions. Results indicated that the algorithmic prediction solution was superior to the perceptual adaptation solution for compensating for the effects of time delay in a head-slaved tracking task.