We examined human perception of head-referenced image motion during concurrent head movement. The visual stimulus was a checkerboard image in a head mounted display that moved from side-to-side. Observers rated the magnitude of the checkerboard motion while either rotating their head about a vertical axis (yaw), about a horizontal axis (pitch), or holding it still. In Experiment 1, we tested four image oscillation frequencies (0.25, 0.5, 1, and 2 Hz) while holding the head motion frequency constant at 0.5 Hz. In Experiment 2, we tested three head motion frequencies (0.25, 0.5, and 1 Hz) while holding the image oscillation frequency constant at 1 Hz. Across all image and head motion frequencies, perceptual sensitivity to image motion was reduced by about 45% during horizontal head movement. During vertical head movement, perceptual sensitivity was reduced by about 25% when head and image motion were of the same frequency. Compared with when the head was still, horizontal and vertical head movements produced a downward shift of about 10% in overall motion magnitude estimation response. Findings from this study provide virtual environment developers with a quantitative description of the influence of concurrent head movement on the perception of frontoparallel image motion.

The experience of motion sickness in a virtual environment may be measured through pre and postexperiment self-reported questionnaires such as the Simulator Sickness Questionnaire (SSQ). Although research provides converging evidence that users of virtual environments can experience motion sickness, there have been no controlled studies to determine to what extent the user's subjective response is a demand characteristic resulting from pre and posttest measures. In this study, subjects were given either SSQ's both pre and postvirtual environment immersion, or only postimmersion. This technique tested for contrast effects due to demand characteristics in which administration of the questionnaire itself suggested to the participant that the virtual environment may produce motion sickness. Results indicate that reports of motion sickness after immersion in a virtual environment are much greater when both pre and postquestionnaires are given than when only a posttest questionnaire is used. The implications for assessments of motion sickness in virtual environments are discussed.

Summary form only for tutorial. As virtual and augmented reality hardware and software have grown more mature over the past decade, the focus of the field is shifting away from the basic engineering technology, and towards the science and applications of VR and AR techniques. Increasingly, virtual and augmented reality researchers are conducting human-subject experiments, both to understand the way humans perceive, manipulate, and cognate with VR and AR information, and to quantify the utility of VR and AR in different application contexts.

The experience of motion sickness in a virtual environment may be measured through pre- and post-experiment self-reported questionnaires such as the Simulator Sickness Questionnaire (SSQ). Although research provides converging evidence that users of virtual environments can experience motion sickness, there have been no controlled studies to determine to what extent the user’s subjective response is a demand characteristic resulting from pre- and post-test measures. In this study, subjects were given either SSQ’s both pre and post virtual environment immersion, or only post immersion. This technique was used to test for contrast effects due to demand characteristics in which administration of the questionnaire itself suggests to the participant that the virtual environment may produce motion sickness. Results indicate that reports of motion sickness after immersion in a virtual environment are much greater when both pre and post questionnaires are given than when only a post test questionnaire is used. The implications for assessments of motion sickness in virtual environments are discussed.

Provides an abstract of the tutorial presentation and a brief professional biography of the presenter. The complete presentation was not made available for publication as part of the conference proceedings.

The natural role of sound in actions involving mechanical impact and vibration suggests the use of auditory display as an augmentation to virtual haptic interfaces. In order to budget available computational resources for sound simulation, the perceptually tolerable asynchrony between paired haptic-auditory sensations must be known. This paper describes a psychophysical study of detectable time delay between a voluntary hammer tap and its auditory consequence (a percussive sound of either 1, 50, or 200 ms duration). The results show Just Noticeable Differences (JNDs) for temporal asynchrony of 24 ms with insignificant response bias. The invariance of JND and response bias as a function of sound duration in this experiment indicates that observers cued on the initial attack of the auditory stimuli.

The contribution to spatial awareness of adding a roll degree-of-freedom (DOF) to telepresence camera platform yaw and pitch was examined in an experiment where subjects judged direction and rotation of stationary target markers in a remote scene. Subjects viewed the scene via head-slaved camera images in a head-mounted display. Elimination of the roll DOF affected rotation judgment, but only at extreme yaw and pitch combinations, and did not affect azimuth and elevation judgement. Systematic azimuth overshoot occurred regardless of roll condition. Observed rotation misjudgments are explained by kinematic models for eye-head direction of gaze.

We examined the effects of human 3D tracking performance of several common defects of immersing virtual environments: spatial sensor distortion, visual latency and low update rates. Results show: removal of relatively small static distortion had minor effects on tracking accuracy; an adapted Cooper-Harper controllability scale proved the most sensitive subjective indicator of simulation degradation; and RMS tracking error and subjective impressions were more influenced by changing visual latency than by update rate.

This paper describes a testbed and method for characterizing the dynamic response of the type of spatial displacement transducers commonly used in virtual environment (VE) applications. The testbed consists of a motorized rotary swing arm that imparts known displacement inputs to the VE sensor. The experimental method involves a series of tests in which the sensor is displaced back and forth at a number of controlled frequencies that span the bandwidth of volitional human movement. During the tests, actual swing arm angle and reported VE sensor displacements are collected and time stamped. Because of the time stamping technique, the response time of the sensor can be measured directly, independent of latencies in data transmission from the sensor unit and any processing by the interface applications running on the host computer. Analysis of these experimental results allows sensor time delay and gain characteristics to be determined as a function of input frequency. Results from tests of several differnt VE spatial sensors (Ascension, Logitech, and Polhemus) are presented here to demonstrate use of the testbed and method.