THE GEOMETRIC FIELD OF VIEW AND SPEED PERCEPTION IN A DRIVING SIMULATOR

Particularly in the health and rehabilitation sector where cost and space are constraints, practitioners need smaller driving simulators. Because these small-footprint driving simulators have a limited projected field of view (PFOV) it is desirable to extend the virtual or geometric field of view (GFOV) beyond that natively afforded by the PFOV. Changing the PFOV/GFOV ratio has been shown to alter perceived speed. In order for driving simulation to produce realistic experiences, drivers‟ perception of speed should correspond with real world experiences. The purpose of the current research was to better understand the relationship between speed perception and the GFOV/PFOV ratio in a way that would be useful to simulation practitioners using a small-footprint driving simulator. Using the DS-250, a small-footprint simulator, participants performed a speed matching task using six different GFOV conditions while the PFOV was held constant. Target speeds were presented in three appropriate simulated environments: 25mph in a residential area, 45mph in a commercial area, and 65mph on a freeway. In general, perceived speed was found to decrease with larger GFOVs. However, no GFOV tested produced accurate speed perception; on average, all participants underestimated their speeds using all GFOVs. A regression was used to estimate at which GFOV average error in speed production would approach zero. Subjective data regarding participant strategy, perceived accuracy, and their awareness of different GFOV conditions were also collected

Impact of geometric field of view on speed perception

This paper deals with changes of the geometric field of view on speed perception. This study has been carried out using the SAAM dynamic driving simulator (Arts et Métiers ParisTech). SAAM provides motion cues thanks to a 6 DOF electromechanical platform and is equipped with a cylindrical screen of 150°. 20 subjects have reproduced 2 speeds (50 km/h and 90 km/h) without knowing the numerical values of these consigns, and with 5 different visual scale factors: 0.70, 0.85, 1.00, 1.15 and 1.30. This visual scale factor correspond to the ratio between the driver’s field of view covered by the screen (constant) and the geometric field of view. This study shows that this visual scale factor has a significant impact on the speed reached by the subjects and thus shows that perceived speed increases with this visual scale factor. A 0.15 modification of this factor is enough to obtain a significant effect. The modification of the geometric field of view remained unnoticed by all the subjects, which implies that this technique can be easily used to make drivers reduce their speed in driving simulation conditions. However, this technique may also modify perception of distances.Cet article présente l’effet du changement du champ de vision géométrique sur la perception de la vitesse. Cette étude a été réalisée sur le simulateur de conduite dynamique SAAM (Arts et Métiers ParisTech). SAAM utilise une plate-forme électromécanique à 6 DDL et est équipé d’un écran cylindrique de 150° pour restituer la sensation de mouvement. 20 sujets ont reproduit 2 vitesses (50 km/h et 90 km/h), sans connaître les valeurs de ces vitesses, et avec 5 facteurs d’échelle visuelle différents : 0.70, 0.85, 1.00, 1.15 et 1.30. Ces facteurs d’échelle correspondent aux rapports entre le champ de vision du conducteur couvert par l’image (constant) et le champ de vision géométrique. Cette étude montre que ce changement visuel a un impact significatif sur la vitesse qu’atteignent les sujets et montre donc que la vitesse perçue augmente avec ce facteur d’échelle visuelle. Un changement de 0.15 de ce facteur suffit pour obtenir un effet significatif. Les changements de champ de vision géométrique n’ont été détectés par aucun des sujets, ce qui implique que cette technique peut facilement être utilisée pour amener les conducteurs à réduire leur vitesse en conditions de simulation de conduite. Cependant, cette technique pourrait aussi modifier la perception des distances.Le Grand Chalo

Visualization and (Mis)Perceptions in Virtual Reality

Virtual Reality (VR) technologies are now being widely adopted for use in areas as diverse as surgical and military training, architectural design, driving and flight simulation, psychotherapy, and gaming/entertainment. A large range of visual displays (from desktop monitors and head-mounted displays (HMDs) to large projection systems) are all currently being employed where each display technology offers unique advantages as well as disadvantages. In addition to technical considerations involved in choosing a VR interface, it is also critical to consider perceptual and psychophysical factors concerned with visual displays. It is now widely recognized that perceptual judgments of particular spatial properties are different in VR than in the real world. In this paper, we will provide a brief overview of what is currently known about the kinds of perceptual errors that can be observed in virtual environments (VEs). Subsequently we will outline the advantages and disadvantages of particular visual displays by foc using on the perceptual and behavioral constraints that are relevant for each. Overall, the main objective of this paper is to highlight the importance of understanding perceptual issues when evaluating different types of visual simulation in VEs

Human Visual Navigation: Effects of Visual Context, Navigation Mode, and Gender

Abstract This thesis extends research on human visual path integration using optic flow cues. In three experiments, a large-scale path-completion task was contextualised within highly-textured authentic virtual environments. Real-world navigational experience was further simulated, through the inclusion of a large roundabout on the route. Three semi-surrounding screens provided a wide field of view. Participants were able to perform the task, but directional estimates showed characteristic errors, which can be explained with a model of distance misperception on the outbound roads of the route. Display and route layout parameters had very strong effects on performance. Gender and navigation mode were also influential. Participants consistently underestimated the final turn angle when simulated self-motion was viewed passively, on large projection screens in a driving simulator. Error increased with increasing size of the internal angle, on route layouts based on equilateral or isosceles triangles. A compressed range of responses was found. Higher overall accuracy was observed when a display with smaller desktop computer monitors was used; especially when simulated self-motion was actively controlled with a steering wheel and foot pedals, rather than viewed passively. Patterns and levels of error depended on route layout, which included triangles with non-equivalent lengths of the two outbound roads. A powerful effect on performance was exerted by the length of the "approach segment" on the route: that is, the distance travelled on the first outbound road, combined with the distance travelled between the two outbound roads on the roundabout curve. The final turn angle was generally overestimated on routes with a long approach segment (those with a long first road and a 60° or 90° internal angle), and underestimated on routes with a short approach segment (those with a short first road or the 120° internal angle). Accuracy was higher for active participants on routes with longer approach segments and on 90° angle trials, and for passive participants on routes with shorter approach segments and on 120° angle trials. Active participants treated all internal angles as 90° angles. Participants performed with lower overall accuracy when optic flow information was disrupted, through the intermittent presentation of self-motion on the small-screen display, in a sequence of static snapshots of the route. Performance was particularly impaired on routes with a long approach segment, but quite accurate on those with a short approach segment. Consistent overestimation of the final angle was observed, and error decreased with increasing size of the internal angle. Participants treated all internal angles as 120° angles. The level of available visual information did not greatly affect estimates, in general. The degree of curvature on the roundabout mainly influenced estimates by female participants in the Passive condition. Compared with males, females performed less accurately in the driving simulator, and with reduced optic flow cues; but more accurately with the small-screen display on layouts with a short approach segment, and when they had active control of the self-motion. The virtual environments evoked a sense of presence, but this had no effect on task performance, in general. The environments could be used for training navigational skills where high precision is not required

Impact of the geometric field of view on drivers’ speed perception and lateral position in driving simulators

Driving simulators have become an effective tool in road safety research. In recent years, the validity of simulators raised debates concerning the extant to which driving in the simulator resembles driving in the reality. Different types of driving simulators with different characteristics have been developed to study driver behavior, however, the fidelity and reliability of such systems are questionable if no proper validation is conducted. Regarding the visual aspect, the fidelity of the simulators can be assessed based on the field of view of the simulator screens. Drivers’ speed perception and lateral position were compared for two different geometric field of view (GFOV) angles (i.e., 60 and 135 degrees). Results from the ANOVA tests showed that drivers highly underestimate their driving speed while driving for the condition with 60 degrees of GFOV compared to the condition with 135 degrees of GFOV. Furthermore, drivers drove closer to the real-world situations in the condition with 135 degree of GFOV compared to the condition with 60 degree. Results of this study suggest that, using incorrect GFOV for any simulator would generate biased results in speed and lateral position. Therefore, a proper calibration criterion of the GFOV for the simulators is essential. This study recommends using a scale factor (GFOV/FOV) of 1.00 for virtual environment offered by the simulation scenarios such as GFOV of 135 degree for simulators having three screens with 135 degree of field of view (FOV)

Conceptual design study for an advanced cab and visual system, volume 2

The performance, design, construction and testing requirements are defined for developing an advanced cab and visual system. The rotorcraft system integration simulator is composed of the advanced cab and visual system and the rotorcraft system motion generator, and is part of an existing simulation facility. User's applications for the simulator include rotorcraft design development, product improvement, threat assessment, and accident investigation

Visually Guided Control of Movement

The papers given at an intensive, three-week workshop on visually guided control of movement are presented. The participants were researchers from academia, industry, and government, with backgrounds in visual perception, control theory, and rotorcraft operations. The papers included invited lectures and preliminary reports of research initiated during the workshop. Three major topics are addressed: extraction of environmental structure from motion; perception and control of self motion; and spatial orientation. Each topic is considered from both theoretical and applied perspectives. Implications for control and display are suggested

GROUND VEHICLE DRIVING AIDS: ASSESSING DRIVER WORKLOAD AND PERFORMANCE IN DEGRADED VISUAL ENVIRONMENTS

With degraded visual environments being a current priority to the Army, several research programs have been initiated to develop a complete sensor-to-soldier systems to allow operators to see through DVE conditions while conducting ground vehicle tactical operations. To enable indirect-driving maneuverability and threat detection in degraded visual environments (DVEs), CCDC’s ground DVE program developed and tested a range of sensors and driver aid display systems. Six candidate driving aids were identified and tested in three simulator studies and two field tests to examine the effect of driving aids on driver workload and performance in different visibility conditions. The simulator-based testing revealed human factors issues such as the importance of the symbology of the aids used and how obstacles should be presented when designing individual displays. Soldiers were generally accepting of the overall gDVE system in field testing with no costs or benefits revealed using the driving aids. Before future development of the driving aids, a more human-centered design process must be pursued to optimize the human-system interaction to design driving aids that help performance and lower workload in degraded visual environments

CHARACTERISTICS OF HEAD MOUNTED DISPLAYS AND THEIR EFFECTS ON SIMULATOR SICKNESS

Characteristics of head-mounted displays (HMDs) and their effects on simulator sickness (SS) and presence were investigated. Update delay and wide field of views (FOV) have often been thought to elicit SS. With the exception of Draper et al. (2001), previous research that has examined FOV has failed to consider image scale factor, or the ratio between physical FOV of the HMD display and the geometric field of view (GFOV) of the virtual environment (VE). The current study investigated update delay, image scale factor, and peripheral vision on SS and presence when viewing a real-world scene. Participants donned an HMD and performed active head movements to search for objects located throughout the laboratory. Seven out of the first 28 participants withdrew from the study due to extreme responses. These participants experienced faint-like symptoms, confusion, ataxia, nausea, and tunnel vision. Thereafter, the use of a hand-rail was implemented to provide participants something to grasp while performing the experimental task. The 2X2X2 ANOVA revealed a main effect of peripheral vision, F(1,72) = 6.90, p= .01, indicating peak Simulator Sickness Questionnaire (SSQ) scores were significantly higher when peripheral vision was occluded than when peripheral vision was included. No main effects or interaction effects were revealed on Presence Questionnaire (PQ version 4.0) scores. However, a significant negative correlation of peak SSQ scores and PQ scores, r(77) = -.28, p= .013 was revealed. Participants also were placed into \u27sick\u27 and \u27not-sick\u27 groups based on a median split of SSQ scores. A chi-square analysis revealed that participants who were exposed to an additional update delay of ~200 ms were significantly more likely to be in the \u27sick\u27 group than those who were exposed to no additional update delay. To reduce the occurrence of SS, a degree of peripheral vision of the external world should be included and attempts to reduce update delay should continue. Furthermore, participants should be provided with something to grasp while in an HMD VE. Future studies should seek to investigate a critical amount of peripheral vision and update delay necessary to elicit SS

A Simulation-Based Study on Driver Behavior when Negotiating Curves with Sight Limitations

L'abstract è presente nell'allegato / the abstract is in the attachmen