The Effect of Varying Latency in a Head-Mounted Display on Task Performance and Motion Sickness

The purpose of this study was to determine how latency in a head-mounted display affects human performance. Virtual environments are used frequently for training, however simulator sickness is a common problem and may affect transfer of training. Aspects of virtual environments that cause simulator sickness are not fully understood, but varying latency has been shown to increase simulator sickness symptoms. The impact of varying latency on task performance and the interaction between performance and simulator sickness symptoms has not been examined. Twenty-nine subjects (15 male) participated in a repeated measures study in which they were exposed to two different latency conditions in a Head-Mounted Display (HMD): constant (70 ms) and varying (70 ms – 270 ms). Experimental sessions were separated by 14-daysto minimize the effects of adaptation. While wearing the HMD, subjects used a laser pointer to repeatedly shoot at 8 laser targets, arrayed in a 180-degree arc around the lab,over the course of 200 trials per session, presented in 5 blocks of 40 trials. Sickness levels, accuracy and time-to-hit data were recorded for analysis. Subjects scored fewer hits and took longer to hit targets in the varying latency condition, F (1,54) = 35.20, p \u3c .01, 2p = .40, than in the constant latency condition F (4,51) = 13.50, p \u3c .01, 2 p = .51. These findings indicate that individuals exposed to varying latency performed worse than individuals exposed to constant latency. However, it is unclear if the performance effects are due mostly to the latency itself or another underlying causal influence such as simulator sickness

THE EFFECT OF 0.2 HZ AND 1.0 HZ FREQUENCY AND 100 MS AND 20 - 100 MS AMPLITUDE OF LATENCY ON SIMULATORY SICKNESS IN A HEAD MOUNTED DISPLAY

The purpose of the current experiment was to contribute to the existing literature on the relationship between frequency of latency and amplitude of latency and simulator sickness experienced in a head mounted display (HMD). Motion sickness has been studied for decades in a variety of vehicles including ships, planes, trains and automobiles. More recently virtual environments, including those utilizing an HMD have been shown to generate significant sickness, often termed simulator sickness. Many studies have linked system latency to simulator sickness and recent research has found that with current technology latency is not a constant; but rather it varies systematically over time due to sensor errors and clock asynchronization. One hundred twenty participants were recruited and randomly assigned to one of four conditions (0.2 Hz frequency of latency with 100 ms fixed amplitude of sinusoidal latency; 0.2 Hz frequency of latency with 20 - 100 ms varying amplitude of sinusoidal latency; 1.0 Hz frequency of latency with 100 ms fixed amplitude of sinusoidal latency; 1.0 Hz frequency of latency with 20 - 100 ms varying amplitude of sinusoidal latency). Collected data were analyzed using analysis of variance. A main effect of frequency of latency was found, and data trended toward a main effect of amplitude of latency. Participants reported greater sickness in 0.2 Hz frequency conditions and in the 1 Hz varying amplitude condition, indicating both frequency and amplitude of latency contribute to simulator sickness and are important factors to consider in regard to system latency. In conclusion, both frequency and amplitude of latency play an important role in simulator sickness

A Tele-Operated Display With a Predictive Display Algorithm

Tele-operated display systems with head mounted displays (HMD) are becoming popular as visual feedback systems for tele-operation systems. However, the users are suffered from time-varying bidirectional delays caused by the latency and limited bandwidth of wireless communication networks. Here, we develop a tele-operated display system and a predictive display algorithm allowing comfortable use of HMDs by operators of tele-operation systems. Inspired by the kinematic model of the human head-neck complex, we built a robot neck-camera system to capture the field of view in any desired orientation. To reduce the negative effects of the time-varying bidirectional communication delay and operation delay of the robot neck, we developed a predictive display algorithm based on a kinematic model of the human/robot neck-camera system, and a geometrical model of a camera. Experimental results showed that the system provide predicted images with high frame rate to the user

Aerospace medicine and biology: A continuing bibliography with indexes, supplement 203

This bibliography lists 150 reports, articles, and other documents introduced into the NASA scientific and technical information system in January 1980

Aerospace Medicine and Biology. A continuing bibliography with indexes

This bibliography lists 244 reports, articles, and other documents introduced into the NASA scientific and technical information system in February 1981. Aerospace medicine and aerobiology topics are included. Listings for physiological factors, astronaut performance, control theory, artificial intelligence, and cybernetics are included

Aerospace medicine and biology: A continuing bibliography with indexes (supplement 355)

This bibliography lists 147 reports, articles and other documents introduced into the NASA Scientific and Technical Information System during October, 1991. Subject coverage includes: aerospace medicine and psychology, life support systems and controlled environments, safety equipment, exobiology and extraterrestrial life, and flight crew behavior and performance

Aerospace medicine and biology: A continuing bibliography with indexes (supplement 375)

This bibliography lists 212 reports, articles, and other documents recently introduced into the NASA Scientific and Technical Information System database. Subject coverage includes the following: aerospace medicine and physiology, life support systems and man/system technology, protective clothing, exobiology and extraterrestrial life, planetary biology, and flight crew behavior and performance

Engineering data compendium. Human perception and performance, volume 3

The concept underlying the Engineering Data Compendium was the product of a research and development program (Integrated Perceptual Information for Designers project) aimed at facilitating the application of basic research findings in human performance to the design of military crew systems. The principal objective was to develop a workable strategy for: (1) identifying and distilling information of potential value to system design from existing research literature, and (2) presenting this technical information in a way that would aid its accessibility, interpretability, and applicability by system designers. The present four volumes of the Engineering Data Compendium represent the first implementation of this strategy. This is Volume 3, containing sections on Human Language Processing, Operator Motion Control, Effects of Environmental Stressors, Display Interfaces, and Control Interfaces (Real/Virtual)

Visually induced motion sickness

At times, people exposed to moving visual scenes may perceive themselves as moving even though they are, in fact, stationary. This sensation is sometimes experienced by people sitting in a railway carriage, in a station, when a neighbouring train slowly pulls away. Rather than sensing that the other train is leaving the station, they have the compelling feeling that their own train is moving in the opposite direction. This phenomenon, the feeling of moving brought about solely by a change in the visual scene, is called vection. Sustained exposure to moving visual scenes may not only produce vection, but can also provoke signs and symptoms of motion sickness such as dizziness, sweating, stomach awareness, and nausea and these adverse effects are now generally termed "visually induced motion sickness" (VIMS). VIMS is frequently reported in a variety of simulated or virtual environments such as flight and driving simulators, as well as in other contexts, such as at the cinema. It not only constitutes a nuisance to the user of these technologies, but also limits the usability of these technologies. Unlike other forms of motion sickness, such as seasickness, little is known about what conditions, or what aspects of moving visual scenes, are particularly provocative. Furthermore, research conducted thus far has generally investigated rotational motion patterns that are not representative of motion typically encountered in the real world. As a consequence, the work presented here has investigated the interrelationship between visual stimulus characteristics, VIMS, and vection during simulated forward and backward selfmotion (Le. along the fore-and-aft axis). In the first study, individuals were exposed to moving visual scenes that induced an illusion of motion in the fore-and-aft axis. These were presented either at a constant speed, or at a sinusoidally varying speed. Although varying the speed was expected to lead to higher levels of VIMS, this was not observed. The absence of an increased level of VIMS was hypothesised to be a consequence of the particular frequency employed (0.025 Hz). The frequency dependence of VI MS was then tested in a series of experiments. Noting that amplitude and acceleration covaried with frequency, it was found that within the range 0.025 - 1.6 Hz, VIMS peaked at 0.2 Hz. Using motion profiles with varying amplitude and acceleration, studies employing angular motion stimulation, on the other hand, had previously shown a peak in VIMS to occur at a frequency of approximately 0.06 Hz. This suggests that results obtained with angular motion stimulation cannot be extrapolated to scenarios involving linear motion stimulation in the fore-and-aft axis. The studies thus far isolated the effect of stimulus characteristics by preventing eye movements from occurring by means of fixation. A further study was conducted with the express purpose of investigating the effect of gaze shifting. It was found that the level of VIMS significantly increased with fixation away from the focus of expansion of a radial display. This suggests that the visual stimulus interacts differently with different portions of the retina. Real-world motion scenarios generally entail motion along different axes simultaneously. Most studies into VIMS have been restricted to single-axis motion and, although VIMS is assumed to increase with more complex motion scenarios, little is known about how VIMS changes with·increasing complexity. Comparing single- versus dual-axis motion, it was unexpectedly found that dualaxis motion did not lead to higher levels of VIMS, challenging the generally held assumption that VIMS is proportional to the degree of sensory conflict. The feasibility of predicting the incidence of VIMS based on an individual's motion sickness history as assessed by the revised Motion Sickness Susceptibility Questionnaire (MSSQ) was finally explored. Correlation coefficients were comparable to those observed with true motion suggestive of a common underlying mechanism between different forms of motion sickness. For the prediction of individual behaviour, the MSSQ was found to be of limited value in its current form. . A general finding was that vection consistently preceded the occurrence of VIMS, in line with the idea that vection is a necessary condition for VIMS to occur. This implies that future displays optimising the simulation of self-motion are likely to result in higher levels of VIMS. In addition, the findings that frequency, gaze direction, and multi-axis motion affected VIMS differently with simulated motion in the fore-and-aft axis as compared to angular motion profiles, indicate that angular motion commonly used to study VIMS may be of limited value.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Visually induced motion sickness

At times, people exposed to moving visual scenes may perceive themselves as moving even though they are, in fact, stationary. This sensation is sometimes experienced by people sitting in a railway carriage, in a station, when a neighbouring train slowly pulls away. Rather than sensing that the other train is leaving the station, they have the compelling feeling that their own train is moving in the opposite direction. This phenomenon, the feeling of moving brought about solely by a change in the visual scene, is called vection. Sustained exposure to moving visual scenes may not only produce vection, but can also provoke signs and symptoms of motion sickness such as dizziness, sweating, stomach awareness, and nausea and these adverse effects are now generally termed "visually induced motion sickness" (VIMS). VIMS is frequently reported in a variety of simulated or virtual environments such as flight and driving simulators, as well as in other contexts, such as at the cinema. It not only constitutes a nuisance to the user of these technologies, but also limits the usability of these technologies. Unlike other forms of motion sickness, such as seasickness, little is known about what conditions, or what aspects of moving visual scenes, are particularly provocative. Furthermore, research conducted thus far has generally investigated rotational motion patterns that are not representative of motion typically encountered in the real world. As a consequence, the work presented here has investigated the interrelationship between visual stimulus characteristics, VIMS, and vection during simulated forward and backward selfmotion (Le. along the fore-and-aft axis). In the first study, individuals were exposed to moving visual scenes that induced an illusion of motion in the fore-and-aft axis. These were presented either at a constant speed, or at a sinusoidally varying speed. Although varying the speed was expected to lead to higher levels of VIMS, this was not observed. The absence of an increased level of VIMS was hypothesised to be a consequence of the particular frequency employed (0.025 Hz). The frequency dependence of VI MS was then tested in a series of experiments. Noting that amplitude and acceleration covaried with frequency, it was found that within the range 0.025 - 1.6 Hz, VIMS peaked at 0.2 Hz. Using motion profiles with varying amplitude and acceleration, studies employing angular motion stimulation, on the other hand, had previously shown a peak in VIMS to occur at a frequency of approximately 0.06 Hz. This suggests that results obtained with angular motion stimulation cannot be extrapolated to scenarios involving linear motion stimulation in the fore-and-aft axis. The studies thus far isolated the effect of stimulus characteristics by preventing eye movements from occurring by means of fixation. A further study was conducted with the express purpose of investigating the effect of gaze shifting. It was found that the level of VIMS significantly increased with fixation away from the focus of expansion of a radial display. This suggests that the visual stimulus interacts differently with different portions of the retina. Real-world motion scenarios generally entail motion along different axes simultaneously. Most studies into VIMS have been restricted to single-axis motion and, although VIMS is assumed to increase with more complex motion scenarios, little is known about how VIMS changes with·increasing complexity. Comparing single- versus dual-axis motion, it was unexpectedly found that dualaxis motion did not lead to higher levels of VIMS, challenging the generally held assumption that VIMS is proportional to the degree of sensory conflict. The feasibility of predicting the incidence of VIMS based on an individual's motion sickness history as assessed by the revised Motion Sickness Susceptibility Questionnaire (MSSQ) was finally explored. Correlation coefficients were comparable to those observed with true motion suggestive of a common underlying mechanism between different forms of motion sickness. For the prediction of individual behaviour, the MSSQ was found to be of limited value in its current form. . A general finding was that vection consistently preceded the occurrence of VIMS, in line with the idea that vection is a necessary condition for VIMS to occur. This implies that future displays optimising the simulation of self-motion are likely to result in higher levels of VIMS. In addition, the findings that frequency, gaze direction, and multi-axis motion affected VIMS differently with simulated motion in the fore-and-aft axis as compared to angular motion profiles, indicate that angular motion commonly used to study VIMS may be of limited value.EThOS - Electronic Theses Online ServiceGBUnited Kingdo