Perceptual issues in the use of head-mounted visual displays

New horizons in dermatological education: Skin cancer screening with virtual reality

BACKGROUND

Technological advances in the field of virtual reality (VR) offer new opportunities in many areas of life, including medical education. The University of Münster has been using VR scenarios in the education of medical students for several years, especially for situations that are difficult to reproduce in reality (e.g., brain death). Due to the consistently positive feedback from students, a dermatological VR scenario for skin cancer screening was developed.

OBJECTIVES

Presentation and first evaluation of the skin cancer screening VR scenario to determine to what extent the technical implementation of the scenario was evaluated overall by the students and how their subjective competence to perform a skin cancer screening changed over the course of the teaching unit (theory seminar, VR scenario, theoretical debriefing).

METHODS

Students (n = 140) participating in the curricular pilot project during the 2023 summer term were surveyed throughout the teaching unit using several established questionnaires (System Usability Scale, Simulation Task-Load-Index, Realism and Presence Questionnaire) as well as additional questions on cybersickness and subjective learning.

RESULTS

(i) The use of VR is technically feasible, (ii) students evaluate the VR scenario as a useful curricular supplement, and (iii) from the students' subjective perspective, a good learning outcome is achieved. Although preparation and follow-up appear to be important for overall learning, the greatest increase in subjective competence to perform a skin cancer screening is achieved by the VR scenario.

CONCLUSIONS

Technically feasible and positively evaluated by students, VR can already be a useful addition to dermatology education, although costs are still high. As a visual discipline, dermatology offers special opportunities to create VR scenarios that are not always available or comfortable for patients in reality. Additionally, VR scenarios guarantee the same conditions for all students, which is essential for a high-quality education.

Helicopter Pilot Performance and Workload in a Following Task in a Degraded Visual Environment

BACKGROUND: In this study, we investigated the impact of a loss of horizon due to atmospheric conditions on flight performance and workload of helicopter pilots during a low-altitude, dynamic flight task in windy conditions at sea. We also examined the potential benefits of a helmet-mounted display (HMD) for this specific task.METHODS: In a fixed-based helicopter simulator, 16 military helicopter pilots were asked to follow a maneuvering go-fast vessel in a good visual environment (GVE) and in a degraded visual environment (DVE). DVE was simulated by fog, obscuring the horizon and reducing contrast. Both visual conditions were performed once with and once without an HMD, which was simulated by projecting head-slaved symbology in the outside visuals. Objective measures included flight performance, control inputs, gaze direction, and relative positioning. Subjective measures included self-ratings on performance, situation awareness, and workload.RESULTS: The results showed that in DVE the pilots perceived higher workload and were flying closer to the go-fast vessel than in GVE. Consequently, they responded with larger control inputs to maneuvers of the vessel. The availability of an HMD hardly improved flight performance but did allow the pilots to focus their attention more outside, significantly improving their situation awareness and reducing workload. These benefits were found in DVE as well as GVE conditions.DISCUSSION: DVE negatively affects workload and flight performance of helicopter pilots in a dynamic, low-altitude following task. An HMD can help improve situation awareness and lower the workload during such a task, irrespective of the visual conditions.Ledegang WD, van der Burg E, Valk PJL, Houben MMJ, Groen EL. Helicopter pilot performance and workload in a following task in a degraded visual environment. Aerosp Med Hum Perform. 2024; 95(1):16-24.

A workflow for viewing biomedical computational fluid dynamics results and corresponding data within virtual and augmented reality environments

Researchers conducting computational fluid dynamics (CFD) modeling can spend weeks obtaining imaging data, determining boundary conditions, running simulations and post-processing files. However, results are typically viewed on a 2D display and often at one point in time thus reducing the dynamic and inherently three-dimensional data to a static image. Results from different pathologic states or cases are rarely compared in real-time, and supplementary data are seldom included. Therefore, only a fraction of CFD results are typically studied in detail, and associations between mechanical stimuli and biological response may be overlooked. Virtual and augmented reality facilitate stereoscopic viewing that may foster extraction of more information from CFD results by taking advantage of improved depth cues, as well as custom content development and interactivity, all within an immersive approach. Our objective was to develop a straightforward, semi-automated workflow for enhanced viewing of CFD results and associated data in an immersive virtual environment (IVE). The workflow supports common CFD software and has been successfully completed by novice users in about an hour, demonstrating its ease of use. Moreover, its utility is demonstrated across clinical research areas and IVE platforms spanning a range of cost and development considerations. We are optimistic that this advancement, which decreases and simplifies the steps to facilitate more widespread use of immersive CFD viewing, will foster more efficient collaboration between engineers and clinicians. Initial clinical feedback is presented, and instructional videos, manuals, templates and sample data are provided online to facilitate adoption by the community.

Interface Design of Head-Worn Display Application on Condition Monitoring in Aviation

Head-worn displays (HWDs) as timely condition monitoring are increasingly used in aviation. However, interface design characteristics that mainly affect HWD use have not been fully investigated. The aim of this study was to examine the effects of several important interface design characteristics (i.e., the distance between calibration lines and the layouts of vertical and horizontal scale belts) on task performance and user preference between different conditions of display, i.e., HWD or head-up display (HUD). Thirty participants joined an experiment in which they performed flight tasks. In the experiment, the calibration lines' distance was set to three different levels (7, 9 and 11 mrad), and the scale belt layouts included horizontal and vertical scale belt layouts. The scale belts were set as follows: the original vertical scale belt width was set as L, and the horizontal scale belt height as H. The three layouts of the vertical calibration scale belt used were 3/4H, H and 3H/2. Three layouts of horizontal calibration scale belts were selected as 3L/4, L and 3L/2. The results indicated that participants did better with the HWD compared to the HUD. Both layouts of vertical and horizontal scale belts yielded significant effects on the users' task performance and preference. Users showed the best task performance while the vertical calibration scale belts were set as H and horizontal calibration scale belts were set as L, and users generally preferred interface design characteristics that could yield an optimal performance. These findings could facilitate the optimal design of usable head-worn-display technology.

Comparison between wrap around screens and a head mounted display on driver muscle and kinematic responses to a pedestrian hazard

As driving performance relies heavily on the interpretation of visual information, driving simulators require a visual display that can effectively communicate the virtual environment to the driver. Most high-fidelity visual displays include an expensive system of high-definition projectors and wraparound screens. To reduce the overall cost of a driving simulator while preserving the generalizability of results to naturalistic driving, head mounted displays (HMD) are being considered as a substitute visual cueing system. Recent innovations to virtual reality technologies are encouraging, however, differences between HMDs and more traditional visual displays have not been explored for all types of driving measures. In particular, while existing literature provides insight into the validity of HMDs as a substitute for higher fidelity visual displays in tests of driver behaviour and performance, there is a gap in the literature regarding differences in physiological responses. In the current study, upper body muscle activation and joint angle ranges were compared between an Oculus™ Rift Development Kit 2 HMD and a system of wrap around screens. Twenty-one participants each completed two simulated drives, one per display, in a counterbalanced order. During the simulation, drivers encountered unanticipated pedestrian crossings during which peak surface electromyography, root-mean-square of the surface electromyography signal and joint angles were determined bilaterally on the upper limbs. No significant differences (p ≤ 0.05) were observed between the Oculus™ Rift HMD and the wrap around screens for all dependent variables with the exception of left joint range of motion in female participants, suggesting that the HMD reduced field of view had a minimal effect on driver kinematics and no effect on muscle activation levels. Upper body bracing was observed during the hazard response time segments characterized by significantly increased muscle activity during hazard response time segments and minimal joint movement. Considering the lack of significant kinematic and muscle activation differences between the two visual inputs, HMD technology for hazard response may provide a suitable alternative to wrap around screens for studying kinematic responses during hazardous driving scenarios.

Effects of using immersive virtual reality on time and steps during a locomotor task in young adults

Immersive virtual reality makes possible to perceive and interact in a standardized, reproductible and digital environment, with a wide range of simulated situations possibilities. This study aimed to measure the potential effect of virtual reality on time and number of steps when performing a locomotor task, in a young adult’s population. Sixty young adults (32W, 28M, mean age 21.55 ± 1.32), who had their first immersive virtual reality experience, performed a locomotor task based on "Timed Up and Go" (TUG) task in real, in virtual reality in a stopped train and in virtual reality in a moving train. Time and number of steps variables representing primary locomotion indicators were measured and compared between each condition. Results showed significant increases in time and number of steps in the two virtual reality conditions compared to real but not between the two virtual reality conditions. There was an effect of virtual reality in young adults when performing the locomotor task. It means that technological and digital characteristics of the immersive virtual reality experience led to modify motor strategies employed. Adding a plausible visual optic flow did not appear to affect motor control further when the information is negligible and not essential for performing the task.

A Stray Light Detection Model for VR Head-Mounted Display Based on Visual Perception

In recent years, the general public and the technology industry have favored stereoscopic vision, immersive experience, and real-time visual information reception of virtual reality (VR) and augmented reality (AR). The device carrier, the Head-Mounted Display (HMD), is recognized as one of the next generation’s most promising computing and communication platforms. HMD is a virtual image optical display device that combines optical lens modules and binocular displays. The visual impact it brings is much more complicated than the traditional display and also influences the performance of image quality. This research investigated the visual threshold of stray light for three kinds of VR HMD devices, and proposes a qualitative model, derived from psychophysical experiments and the measurement of images on VR devices. The recorded threshold data of the psychophysical stray light perception experiment was used as the target when training. VR display image captured by a wide-angle camera was processed, through a series of image processing procedures, to extract variables in the range of interest. The machine learning algorithm established an evaluation method for human eye-perceived stray light in the study. Four supervised learning algorithms, including K-Nearest Neighbor (KNN), Logistic Regression (LR), Support Vector Machine (SVM), and Random Forest (RF), were compared. The established model’s accuracy was about 90% in all four algorithms. It also proved that different percentages of thresholds could be used to label data according to demand to predict the feasibility of various subdivision inspection specifications in the future. This research aimed to provide a fast and effective stray light qualitative evaluation method to be used as a basis for future HMD optical system design and quality control. Thus, stray light evaluation will become one of the critical indicators of image quality and will be applicable to VR or AR content design.

Key Ergonomics Requirements and Possible Mechanical Solutions for Augmented Reality Head-Mounted Displays in Surgery

In the context of a European project, we identified over 150 requirements for the development of an augmented reality (AR) head-mounted display (HMD) specifically tailored to support highly challenging manual surgical procedures. The requirements were established by surgeons from different specialties and by industrial players working in the surgical field who had strong commitments to the exploitation of this technology. Some of these requirements were specific to the project, while others can be seen as key requirements for the implementation of an efficient and reliable AR headset to be used to support manual activities in the peripersonal space. The aim of this work is to describe these ergonomic requirements that impact the mechanical design of the HMDs, the possible innovative solutions to these requirements, and how these solutions have been used to implement the AR headset in surgical navigation. We also report the results of a preliminary qualitative evaluation of the AR headset by three surgeons.

A review of the effects of head-worn displays on teamwork for emergency response

Head-Worn Displays (HWD) can potentially support the mobile work of emergency responders, but it remains unclear whether teamwork is affected when emergency responders use HWDs. We reviewed studies that examined HWDs in emergency response contexts to evaluate the impact of HWDs on team performance and on team processes of situation awareness, communication, and coordination. Sixteen studies were identified through manual and systematic literature searches. HWDs appeared to improve the quality of team performance but they increased time to perform under some conditions; effects on team processes were mixed. We identify five challenges to explain the mixed results. We discuss four theoretical perspectives that might address the challenges and guide research needs-joint cognitive systems, distributed cognition, common ground, and dynamical systems. Researchers and designers should use process-based measures and apply greater theoretical guidance to uncover mechanisms by which HWDs shape team processes, and to understand the impact on team performance. Practitioner Summary: This review examines the effects of head-worn displays on teamwork performance and team processes for emergency response. Results are mixed, but study diversity challenges the search for underlying mechanisms. Guidance from perspectives such as joint cognitive systems, distributed cognition, common ground, and dynamical systems may advance knowledge in the area. Abbreviations: HWD: head-worn display; RC: remote collaboration; DD: data display; ARC: augmented remote collaboration; ACC: augmented collocated collaboration; SA: situation awareness; TSA: team situation awareness; CPR: cardiopulmonary resuscitation; SAGAT: situation awareness global assessment technique; SART: situation awareness rating technique.

Cyber sickness in low-immersive, semi-immersive, and fully immersive virtual reality

It is known that virtual reality (VR) experience may cause cyber sickness. One aspect of VR is an immersion or otherwise sense of presence, the sense of feeling oneself in a virtual world. In this paper an experiment which was conducted in order to find the link between level of immersion and cyber sickness felt by participants is presented. Eighty-nine participants aged between 19 and 36 years have been equally divided into four groups with different level of VR immersion. The low-immersive group was represented by PC with monoscopic screen, the semi-immersive group was represented by CAVE with stereoscopic projector, the fully immersive group was represented by VR head-mounted display, and the last group was the control group without any kind of immersion. The task for the participants was to navigate through the maze for a specified amount of time (10 min). The Simulator Sickness Questionnaire was used as a subjective measure tool for cyber sickness level and Grooved Pegboard Test for assessing the fine dexterity, both before and after the experiment. Regarding the time spend in VR the fully immersive environment had the biggest problems as more than half of the participants had to stop before 10 min (p < 0.001). Concerning the cyber sickness, the significant increase in nausea score between pre-test and post-test scores has been observed in semi-immersive group (p = 0.0018) and fully immersive group (p < 0.0001). The increase in oculomotor score was smaller. The significant difference was noted only in fully immersive group (p = 0.0449). In spite of great nausea factor after the VR immersion the participants did not show a decrease of fine dexterity in any group (p < 0.001).

Interocular conflict from a monocular augmented reality display: Impact of visual characteristics on performance

In monocular see-through augmented reality systems, each eye is stimulated differently by a monocular image that is superimposed on the binocular background. This can impair binocular fusion, due to interocular conflict. As a function of visual characteristics, the latter can have a greater or lesser impact on user comfort and performance. This study tested several visual characteristics of a binocular background and a monocular element during an exposure that reproduced the interocular conflict induced by a monocular see-through near-eye display. The aim was to identify which factors impact the user’s performance. Performance was measured as target tracking and event detection, identification, fixation time, and latency. Our results demonstrate that performance is a function of the binocular background. Furthermore, exogenous attentional stimulation, in the form of a pulse with different levels of contrast applied to the monocular display, appears to preserve performance in most background conditions.

Effects of wearing a head-mounted display during a standard clinical test of dynamic balance

BACKGROUND

The use of virtual reality (VR) in clinical settings has increased with the introduction of affordable, easy-to-use head-mounted displays (HMDs). However, some have raised concerns about the effects that HMDs have on posture and locomotion, even without the projection of a virtual scene, which may be different across ages.

RESEARCH QUESTION

How does HMD wear impact the kinematic measures in younger and older adults?

METHODS

Twelve healthy young and sixteen older adults participated in two testing conditions: 1) TUG with no HMD and 2) TUG with an HMD displaying a scene of the actual environment (TUG_HMD). The dependent variables were the pitch, yaw, and roll peak trunk velocities (PTVs) in each TUG component, turning cadence, and the time to complete the TUG and its components - SIT-TO-STAND, TURN, WALK, and STAND-TO-SIT.

RESULTS

Wearing the HMD decreased turning cadence and pitch and yaw PTVs in all TUG components, decreased roll PTV in SIT-TO-STAND and TURN, and increased the time taken to complete all TUG components in all participants. Wearing the HMD decreased the pitch PTV in SIT-TO-STAND in older relative to younger adults. Wearing an HMD affected TUG performance in younger and older adults, which should be considered when an HMD is used for VR applications in rehabilitation.

SIGNIFICANCE

Our findings highlight the importance of considering the physical effect of HMD wear in clinical testing, which may not be present with non-wearable VR technologies.

Virtual and augmented reality in a simulated naval engagement: Preliminary comparisons of simulator sickness and human performance

The aim of this study was to compare simulator sickness symptoms while participants wore either a virtual reality (VR) or augmented reality (AR) headset. A secondary aim involved comparing how physical motion affects symptoms. During a simulation, participants wore VR and AR headsets while standing on a motion platform and firing at hostile ships under three motion conditions: No Physical Motion; Synchronous Motion, in which the physical and displayed motion were coupled; and Asynchronous Motion, in which the physical motion did not match the display. Symptoms increased over time but were not different with respect to headset or motion. The VR condition had higher accuracy and faster response time to the commence fire instruction. Further research is necessary to determine if this holds under more extreme motion. The use of VR or AR headsets for training under gentle motion conditions is practicable and should be permissible under normal conditions during deployment.

A Comparative Usability Study of Bare Hand Three-Dimensional Object Selection Techniques in Virtual Environment

Object selection is the basis of natural user–computer interaction (NUI) in a virtual environment (VE). Among the three-dimensional object selection techniques employed in virtual reality (VR), bare hand-based finger clicking interaction and ray-casting are two convenient approaches with a high level of acceptance. This study involved 14 participants, constructed a virtual laboratory environment in VR, and compared the above two finger-based interaction techniques in terms of aspects of the task performance, including the success rate, total reaction time, operational deviation, and accuracy, at different spatial positions. The results indicated that the applicable distance range of finger clicking interaction and finger ray-casting was 0.2 to 1.4 m and over 0.4 m, respectively. Within the shared applicable distance, the finger clicking interaction achieved a shorter total reaction time and higher clicking accuracy. The performance of finger clicking interaction varied remarkably at the center and edge of the horizontal field of view, while no significant difference was found among ray-casting at various horizontal azimuths. The current findings could be directly applied to the application of bare-hand interaction in VR environments.

Performance and Usability of Smartglasses for Augmented Reality in Precision Livestock Farming Operations

In recent years, smartglasses for augmented reality are becoming increasingly popular in professional contexts. However, no commercial solutions are available for the agricultural field, despite the potential of this technology to help farmers. Many head-wearable devices in development possess a variety of features that may affect the smartglasses wearing experience. Over the last decades, dairy farms have adopted new technologies to improve their productivity and profit. However, there remains a gap in the literature as regards the application of augmented reality in livestock farms. Head-wearable devices may offer invaluable benefits to farmers, allowing real-time information monitoring of each animal during on-farm activities. The aim of this study was to expand the knowledge base on how augmented reality devices (smartglasses) interact with farming environments, focusing primarily on human perception and usability. Research has been conducted examining the GlassUp F4 smartglasses during animal selection process. Sixteen participants performed the identification and grouping trials in the milking parlor, reading different types of contents on the augmented reality device optical display. Two questionnaires were used to evaluate the perceived workload and usability of the device. Results showed that the information type could influence the perceived workload and the animal identification process. Smart glasses for augmented reality were a useful tool in the animal genetic improvement program offering promising opportunities for adoption in livestock operations in terms of assessing data consultation and information about animals.

Comparison of in-sight and handheld navigation devices toward supporting industry 4.0 supply chains: First and last mile deliveries at the human level

Last (and First) mile deliveries are an increasingly important and costly component of supply chains especially those that require transport within city centres. With reduction in anticipated manufacturing and delivery timescales, logistics personnel are expected to identify the correct location (accurately) and supply the goods in appropriate condition (safe delivery). Moving towards more environmentally sustainable supply chains, the last/first mile of deliveries may be completed by a cyclist courier which could result in significant reductions in congestion and emissions in cities. In addition, the last metres of an increasing number of deliveries are completed on foot i.e. as a pedestrian. Although research into new technologies to support enhanced navigation capabilities is ongoing, the focus to date has been on technical implementations with limited studies addressing how information is perceived and actioned by a human courier. In the research reported in this paper a comparison study has been conducted with 24 participants evaluating two examples of state-of-the-art navigation aids to support accurate (right time and place) and safe (right condition) navigation. Participants completed 4 navigation tasks, 2 whilst cycling and 2 whilst walking. The navigation devices under investigation were a handheld display presenting a map and instructions and an in-sight monocular display presenting text and arrow instructions. Navigation was conducted in a real-world environment in which eye movements and device interaction were recorded using Tobii-Pro 2 eye tracking glasses. The results indicate that the handheld device provided better support for accurate navigation (right time and place), with longer but less frequent gaze interactions and higher perceived usability. The in-sight display supported improved situation awareness with a greater number of hazards acknowledged. The benefits and drawbacks of each device and use of visual navigation support tools are discussed.

Visual dependence affects the motor behavior of older adults during the Timed Up and Go (TUG) test

BACKGROUND

Older adults show greater postural instabilities under misleading visual cues relative to younger adults. We investigated the effects of age-related visual dependence on motor performance under increased attention demands by adding a motor task and visual stimulus to the Timed Up and Go (TUG) test sub-components.

METHOD

We designed a cross-sectional quantitative study. Twenty-eight younger (n = 12) and older (n = 16) adults completed the TUG test while wearing a head-mounted display (HMD) that presented a visual stimulus and/or carrying a cup of water. Outcome measures were turning cadence; gait speed; pitch, yaw, and roll peak trunk velocities (PTVs); and acceleration ranges of sit-to-stand and stand-to-sit.

RESULTS

Wearing the HMD caused significant performance differences in the TUG test tasks due to age and visual dependence, although performance was lower across all groups with the HMD (p < 0.01). Older adults showed lower roll PTV in turning compared to younger adults (p = 0.03). Visually dependent older adults showed smaller mediolateral and vertical acceleration ranges (p < 0.04) in sit-to-stand compared to visually independent older adults.

CONCLUSION

The demand for orienting posture to a vertical position during sit-to-stand may differentiate older adults who are more visually dependent-and thus at greater fall risk- from those who are more visually independent. Age-related differences in turning behavior suggest a relationship with fall risk that warrants further investigation.

Supporting multiple patient monitoring with head-worn displays and spearcons

In hospitals, clinicians often need to monitor several patients while performing other tasks. However, visual displays that show patients' vital signs are in fixed locations and auditory alarms intended to alert clinicians may be missed. Information such as spearcons (time-compressed speech earcons) that 'travels' with the clinician and is delivered by earpiece and/or head-worn displays (HWDs), might overcome these problems. In this study, non-clinicians monitored five simulated patients in three 10-min scenarios while performing a demanding tracking task. Monitoring accuracy was better for participants using spearcons and a HWD (88.7%) or a HWD alone (86.2%) than for participants using spearcons alone (74.1%). Participants using the spearcons and HWD (37.7%) performed the tracking task no differently from participants using spearcons alone (37.1%) but participants using the HWD alone performed worse overall (33.1%). The combination of both displays may be a suitable solution for monitoring multiple patients.

The Impact of Head-Worn Displays on Strategic Alarm Management and Situation Awareness

OBJECTIVE

To investigate whether head-worn displays (HWDs) help mobile participants make better alarm management decisions and achieve better situation awareness than alarms alone.

BACKGROUND

Patient alarms occur frequently in hospitals but often do not require clinical intervention. Clinicians may become desensitized to alarms and fail to respond to clinically relevant alarms. HWDs could make patient information continuously accessible, support situation awareness, and help clinicians prioritize alarms.

METHOD

Experiment 1 ( n = 76) tested whether nonclinicians monitoring simulated patients benefited from vital sign information continuously displayed on an HWD while they performed a secondary calculation task. Experiment 2 ( n = 13) tested, across three separate experimental sessions, how effectively nursing trainees monitored simulated patients' vital signs under three different display conditions while they assessed a simulated patient.

RESULTS

In Experiment 1, participants who had access to continuous patient information on an HWD responded to clinically important alarms 25.9% faster and were 6.7 times less likely to miss alarms compared to participants who only heard alarms. In Experiment 2, participants using an HWD answered situation awareness questions 18.9% more accurately overall than when they used alarms only. However, the effect was significant in only two of the three experimental sessions.

CONCLUSION

HWDs may help users maintain continuous awareness of multiple remote processes without affecting their performance on ongoing tasks.

APPLICATION

The outcomes may apply to contexts where access to continuous streams of information from remote locations is useful, such as patient monitoring or clinical supervision.

Influences of augmented reality head-worn display type and user interface design on performance and usability in simulated warehouse order picking

Limited information is available regarding the effective use of workplace head-worn displays (HWD), especially the choices of HWD types and user interface (UI) designs. We explored how different HWD types and UI designs affect perceived workload, usability, visual discomfort, and job performance during a simulated warehouse job involving order picking and part assembly. Sixteen gender-balanced participants completed the simulated job in all combinations of two HWD types (binocular vs. monocular) and four UIs, the latter of which manipulated information mode (text-vs. graphic-based) and information availability (always-on vs. on-demand); a baseline condition was also completed (paper pick list). Job performance, workload, and usability were more affected by UI designs than HWD type. For example, the graphic-based UI reduced job completion time and number of errors by ∼13% and ∼59%, respectively. Participants had no strong preference for either of the HWD types, suggesting that the physical HWD designs tested are suboptimal.

Use of cues in virtual reality depends on visual feedback

3D motion perception is of central importance to daily life. However, when tested in laboratory settings, sensitivity to 3D motion signals is found to be poor, leading to the view that heuristics and prior assumptions are critical for 3D motion perception. Here we explore an alternative: sensitivity to 3D motion signals is context-dependent and must be learned based on explicit visual feedback in novel environments. The need for action-contingent visual feedback is well-established in the developmental literature. For example, young kittens that are passively moved through an environment, but unable to move through it themselves, fail to develop accurate depth perception. We find that these principles also obtain in adult human perception. Observers that do not experience visual consequences of their actions fail to develop accurate 3D motion perception in a virtual reality environment, even after prolonged exposure. By contrast, observers that experience the consequences of their actions improve performance based on available sensory cues to 3D motion. Specifically, we find that observers learn to exploit the small motion parallax cues provided by head jitter. Our findings advance understanding of human 3D motion processing and form a foundation for future study of perception in virtual and natural 3D environments.

Simulation of Driving in Low-Visibility Conditions: Does Stereopsis Improve Speed Perception?

Laboratory-based studies of perceived speed show that, under most circumstances, perceived speed is reduced as a function of contrast. However, a recent investigation of perceived vehicular speed while driving around a closed road circuit showed no such effect (Owens, Wood, & Carberry, 2010, Perception, 39: , 1199-1215). We sought to probe the source of this discrepancy, asking whether the presence or absence of stereoscopic motion information might account for the difference in results. In a two-alternative forced-choice psychophysical speed-discrimination task, observers compared the speed of high- and low-contrast driving clips filmed with a 3-D camera and presented either stereoscopically (3-D) or monoscopically (2-D). Although perceived speed was reduced at low contrast, the size of this misperception was equivalent for 2-D and 3-D presentations. However, the inclusion of stereoscopic cues to vehicular speed caused significant improvements in the precision of speed judgments. It is concluded that although stereopsis can provide access to valuable information on perceived speed, contrast-independent speed estimation as demonstrated by Owens et al. (2010) is more likely to reflect the use of the full visual field in a real driving situation (compared with limited field of view simulations), or the additional contributions of nonvisual cues rather than stereopsis.

Binocular Rivalry and Attention in Helmet-Mounted Display Applications

As monocular head-mounted displays (HMDs) are introduced into existing flight simulators for training and mission rehearsal it will be important to determine whether binocular rivalry affects the visibility of HMD presented symbology or the out-the-window (OTW) flight simulator display imagery. In the present study, we examined whether rivalry suppression could be objectively measured under conditions that simulated a monocular HMD and OTW display, and whether voluntary attention and moving imagery influenced the strength of rivalry suppression. The results indicated that strength of suppression under these conditions was less than that found under classic dichoptic viewing conditions, and that attention had little influence on performance.

Effects of Field-of-View Restrictions on Speed and Accuracy of Manoeuvring

Effects of field-of-view restrictions on the speed and accuracy of participants performing a real-world manoeuvring task through an obstacled environment were investigated. Although field-of-view restrictions are known to affect human behaviour and to degrade performance for a range of different tasks, the relationship between human manoeuvring performance and field-of-view size is not known. This knowledge is essential to evaluate a trade-off between human performance, cost, and ergonomic aspects of field-of-view limiting devises like head-mounted displays and night vision goggles which are frequently deployed for tasks involving human motion through environments with obstacles. In this study the speed and accuracy of movement were measured in 15 participants (8 men, 7 women, 22.9 ± 2.8 yr. of age) traversing a course formed by three wall segments for different field-of-view restrictions. Analysis showed speed decreased linearly with decreasing field-of-view extent, while accuracy was consistently reduced for all restricted field-of-view conditions. Present results may be used to evaluate cost and performance trade-offs for field-of-view restricting devices deployed to perform time-limited human-locomotion tasks in complex structured environments, such as night-vision goggles and head-mounted displays.

Visual Evoked Potential Using Head-Mounted Display Versus Cathode Ray Tube: A Pilot Study

Objective

To present a new stimulation method based on the use of a head-mounted display (HMD) during pattern reversal visual evoked potential (PR-VEP) testing and to compare variables of HMD to those of conventional cathode ray tube (CRT).

Methods

Twenty-three normal subjects without visual problems were recruited. PR-VEPs were generated using CRT or HMD stimuli. VEP outcome measures included latencies (N75, P100, and N145) and peak-to-peak amplitudes (N75–P100 and P100–N145). Subjective discomfort associated with HMD was determined using a self-administered questionnaire.

Results

PR-VEPs generated by HMD stimuli showed typical triphasic waveforms, the components of which were found to be correlated with those obtained using conventional CRT stimuli. Self-administered discomfort questionnaires revealed that HMD was more comfortable in some aspects. It allowed subjects to concentrate better than CRT.

Conclusion

The described HMD stimulation can be used as an alternative to the standard CRT stimulation for PR-VEPs. PR-VEP testing using HMD has potential applications in clinical practice and visual system research because HMD can be used on a wider range of subjects compared to CRT.

Taking Immersive VR Leap in Training of Landing Signal Officers

A major training device used to train all Landing Signal Officers (LSOs) for several decades has been the Landing Signal Officer Trainer, Device 2H111. This simulator, located in Oceana, VA, is contained within a two story tall room; it consists of several large screens and a physical rendition of the actual instruments used by LSOs in their operational environment. The young officers who serve in this specialty will typically encounter this system for only a short period of formal instruction (six one-hour long sessions), leaving multiple gaps in training. While experience with 2H111 is extremely valuable for all LSO officers, the amount of time they can spend using this training device is undeniably too short. The need to provide LSOs with an unlimited number of training opportunities unrestricted by location and time, married with recent advancements in commercial off the shelf (COTS) immersive technologies, provided an ideal platform to create a lightweight training solution that would fill those gaps and extend beyond the capabilities currently offered in the 2H111 simulator. This paper details our efforts on task analysis, surveying of user domain, mapping of 2H111 training capabilities to new prototype system to ensure its support of major training objectives of 2H111, design and development of prototype training system, and a feasibility study that included tests of technical system performance and informal testing with trainees at the LSO Schoolhouse. The results achieved in this effort indicate that the time for LSO training to make the leap to immersive VR has decidedly come.

In the eye of the beholder: A simulator study of the impact of Google Glass on driving performance

This study examined whether, and to what extent, driving is affected by reading text on Google Glass. Reading text requires a high level of visual resources and can interfere with safe driving. However, it is currently unclear if the impact of reading text on a head-mounted display, such as Google Glass (Glass), will differ from that found with more traditional head-down electronic devices, such as a dash-mounted smartphone. A total of 20 drivers (22-48 years) completed the Lane Change Test while driving undistracted and while reading text on Glass and on a smartphone. Measures of lateral vehicle control and event detection were examined along with subjective workload and secondary task performance. Results revealed that drivers' lane keeping ability was significantly impaired by reading text on both Glass and the smartphone. When using Glass, drivers also failed to detect a greater number of lane change signs compared to when using the phone or driving undistracted. In terms of subjective workload, drivers rated reading on Glass as subjectively easier than on the smartphone, which may possibly encourage greater use of this device while driving. Overall, the results suggest that, despite Glass allowing drivers to better maintain their visual attention on the forward scene, drivers are still not able to effectively divide their cognitive attention across the Glass display and the road environment, resulting in impaired driving performance.

Evaluating the Authenticity of Virtual Environments: Comparison of Three Devices

Immersive virtual environments (VEs) have the potential to provide novel cost effective ways for evaluating not only new environments and usability scenarios, but also potential user experiences. To achieve this, VEs must be adequately realistic. The level of perceived authenticity can be ascertained by measuring the levels of immersion people experience in their VE interactions. In this paper the degree of authenticity is measured via anauthenticity indexin relation to three different immersive virtual environment devices. These devices include (1) a headband, (2) 3D glasses, and (3) a head-mounted display (HMD). A quick scale for measuring immersion, feeling of control, and simulator sickness was developed and tested. The HMD proved to be the most immersive device, although the headband was demonstrated as being a more stable environment causing the least simulator sickness. The results have design implication as they provide insight into specific factors which make experience in a VE seem more authentic to users. The paper emphasizes that, in addition to the quality of the VE, focus needs to be placed on ergonomic factors such as the weight of the devices, as these may compromise the quality of results obtained when examining studying human-technology interaction in a VE.

Experimental identification of the behaviour of and lateral forces from freely-walking pedestrians on laterally oscillating structures in a virtual reality environment

Modelling pedestrian loading on lively structures such as bridges remains a challenge. This is because pedestrians have the capacity to interact with vibrating structures which can lead to amplification of the structural response. Current design guidelines are often inaccurate and limiting as they do not sufficiently acknowledge this effect. This originates in scarcity of data on pedestrian behaviour on vibrating ground and uncertainty as to the accuracy of results from previous experimental campaigns aiming to quantify pedestrian behaviour in this case. To this end, this paper presents a novel experimental setup developed to evaluate pedestrian actions on laterally oscillating ground in the laboratory environment while avoiding the implications of artificiality and allowing for unconstrained gait. A biologically-inspired approach was adopted in its development, relying on appreciation of operational complexities of biological systems, in particular their adaptability and control requirements. In determination of pedestrian forces to the structure consideration was given to signal processing issues which have been neglected in past studies. The results from tests conducted on the setup are related to results from previous experimental investigations and outputs of the inverted pendulum pedestrian model for walking on laterally oscillating ground, which is capable of generating self-excited forces.

Texting while driving using Google Glass™: Promising but not distraction-free

Texting while driving is risky but common. This study evaluated how texting using a Head-Mounted Display, Google Glass, impacts driving performance. Experienced drivers performed a classic car-following task while using three different interfaces to text: fully manual interaction with a head-down smartphone, vocal interaction with a smartphone, and vocal interaction with Google Glass. Fully manual interaction produced worse driving performance than either of the other interaction methods, leading to more lane excursions and variable vehicle control, and higher workload. Compared to texting vocally with a smartphone, texting using Google Glass produced fewer lane excursions, more braking responses, and lower workload. All forms of texting impaired driving performance compared to undistracted driving. These results imply that the use of Google Glass for texting impairs driving, but its Head-Mounted Display configuration and speech recognition technology may be safer than texting using a smartphone.

Internet addiction disorder and problematic use of Google Glass™ in patient treated at a residential substance abuse treatment program

INTRODUCTION

Internet addiction disorder (IAD) is characterized by the problematic use of online video games, computer use, and mobile handheld devices. While not officially a clinical diagnosis according to the most recent version of the Diagnostic and Statistical Manual of Mental Disorders (DSM), individuals with IAD manifest severe emotional, social, and mental dysfunction in multiple areas of daily activities due to their problematic use of technology and the internet.

METHOD

We report a 31year-old man who exhibited problematic use of Google Glass™. The patient has a history of a mood disorder most consistent with a substance induced hypomania overlaying a depressive disorder, anxiety disorder with characteristics of social phobia and obsessive compulsive disorder, and severe alcohol and tobacco use disorders.

RESULTS

During his residential treatment program at the Navy's Substance Abuse and Recovery Program (SARP) for alcohol use disorder, it was noted that the patient exhibited significant frustration and irritability related to not being able to use his Google Glass™. The patient exhibited a notable, nearly involuntary movement of the right hand up to his temple area and tapping it with his forefinger. He reported that if he had been prevented from wearing the device while at work, he would become extremely irritable and argumentative.

CONCLUSIONS

Over the course of his 35-day residential treatment, the patient noted a reduction in irritability, reduction in motor movements to his temple to turn on the device, and improvements in his short-term memory and clarity of thought processes. He continued to intermittently experience dreams as if looking through the device. To our knowledge, this is the first reported case of IAD involving problematic use of Google Glass™.

Visually induced motion sickness can be alleviated by pleasant odors

Visually induced motion sickness (VIMS) is a common side effect in virtual environments and simulators. Several countermeasures against VIMS exist, but a reliable method to prevent or ease VIMS is unfortunately still missing. In the present study, we tested whether olfactory cues can alleviate VIMS. Sixty-two participants were exposed to a 15-min-long video showing a first-person-view bicycle ride that had successfully induced VIMS in previous studies. Participants were randomly assigned to one of three groups; the first group was exposed to a pleasant odor (rose) while watching the video, the second group was exposed to an unpleasant odor (leather), and the third group was not exposed to any odor. VIMS was measured using a verbal rating scale (0-20) and the Simulator Sickness Questionnaire. Results showed that only half of the participants who were exposed to the odor did notice it (n = 21), whereas the other half failed to detect the odor. However, among those participants who did notice the odor, the rose scent significantly reduced the severity of VIMS compared to the group that did not notice the odor. A moderate positive correlation between odor sensitivity and VIMS showed that participants with higher odor sensitivity also reported stronger VIMS. Our results demonstrate that olfaction can modulate VIMS and that a pleasant odor can potentially reduce VIMS. The relationship between olfactory perception, olfactory sensibility, and VIMS is discussed.

Pleasant music as a countermeasure against visually induced motion sickness

Visually induced motion sickness (VIMS) is a well-known side-effect in virtual environments or simulators. However, effective behavioral countermeasures against VIMS are still sparse. In this study, we tested whether music can reduce the severity of VIMS. Ninety-three volunteers were immersed in an approximately 14-minute-long video taken during a bicycle ride. Participants were randomly assigned to one of four experimental groups, either including relaxing music, neutral music, stressful music, or no music. Sickness scores were collected using the Fast Motion Sickness Scale and the Simulator Sickness Questionnaire. Results showed an overall trend for relaxing music to reduce the severity of VIMS. When factoring in the subjective pleasantness of the music, a significant reduction of VIMS occurred only when the presented music was perceived as pleasant, regardless of the music type. In addition, we found a gender effect with women reporting more sickness than men. We assume that the presentation of pleasant music can be an effective, low-cost, and easy-to-administer method to reduce VIMS.

Differential effects of head-mounted displays on visual performance

Head-mounted displays (HMDs) virtually augment the visual world to aid visual task completion. Three types of HMDs were compared [look around (LA); optical see-through with organic light emitting diodes and virtual retinal display] to determine whether LA, leaving the observer functionally monocular, is inferior. Response times and error rates were determined for a combined visual search and Go-NoGo task. The costs of switching between displays were assessed separately. Finally, HMD effects on basic visual functions were quantified. Effects of HMDs on visual search and Go-NoGo task were small, but for LA display-switching costs for the Go-NoGo-task the effects were pronounced. Basic visual functions were most affected for LA (reduced visual acuity and visual field sensitivity, inaccurate vergence movements and absent stereo-vision). LA involved comparatively high switching costs for the Go-NoGo task, which might indicate reduced processing of external control cues. Reduced basic visual functions are a likely cause of this effect.

Substitutional reality system: a novel experimental platform for experiencing alternative reality

We have developed a novel experimental platform, referred to as a substitutional reality (SR) system, for studying the conviction of the perception of live reality and related metacognitive functions. The SR system was designed to manipulate people's reality by allowing them to experience live scenes (in which they were physically present) and recorded scenes (which were recorded and edited in advance) in an alternating manner without noticing a reality gap. All of the naïve participants (n = 21) successfully believed that they had experienced live scenes when recorded scenes had been presented. Additional psychophysical experiments suggest the depth of visual objects does not affect the perceptual discriminability between scenes, and the scene switch during head movement enhance substitutional performance. The SR system, with its reality manipulation, is a novel and affordable method for studying metacognitive functions and psychiatric disorders.

Sensor and display human factors based design constraints for head mounted and tele-operation systems

For mobile imaging systems in head mounted displays and tele-operation systems it is important to maximize the amount of visual information transmitted to the human visual system without exceeding its input capacity. This paper aims to describe the design constraints on the imager and display systems of head mounted devices and tele-operated systems based upon the capabilities of the human visual system. We also present the experimental results of methods to improve the amount of visual information conveyed to a user when trying to display a high dynamic range image on a low dynamic range display.

Patient monitoring with head-mounted displays

PURPOSE OF REVIEW

Head-mounted displays (HMDs) are head-worn display devices that project an information display over the wearer's field of view. This article reviews a recent program of research that investigates the advantages and disadvantages of monitoring with HMDs, and discusses the design considerations and implementation issues that must be addressed before HMDs can be clinically adopted.

RECENT FINDINGS

HMDs let anesthesiologists spend a larger proportion of their time in the operating room looking towards the patient and surgical field, and a correspondingly smaller proportion of time looking at the standard monitors. Anesthesiologists can detect patient events faster with an HMD when they are busy performing procedures, but not during normal monitoring. There was no evidence of anesthesiologists' performance or monitoring behavior being affected by perceptual issues with the HMD, and no evidence that more events were missed with the HMD due to inattentional blindness.

SUMMARY

Anesthesiologists may be able to monitor their patients more effectively when an HMD is used in conjunction with existing monitors, but several engineering and implementation issues need to be resolved before HMDs can be adopted in practice. Further research is needed on the design of information displays for HMDs.

Locomotion through a Complex Environment with Limited Field-of-View

Restrictions of field-of-view are known to impair human performance for a range of different tasks. However, such effects on human locomotion through a complex environment are still not clear. Effects of both horizontal (30°, 75°, 112°, 120°, 140°, 160°, and 180°) and vertical (18° and 48°) field-of-view restrictions on the walking speed and head movements of participants maneuvering through an obstacle course were investigated. All field-of-view restrictions tested significantly increased time to complete the entire course, compared to the unrestricted condition. The time to traverse the course was significantly longer for a vertical field-of-view of 18° than for a vertical field-of-view of 48°. For a fixed vertical field-of-view size, the traversal time was constant for horizontal field-of-view sizes ranging between 75° and 180° and increased significantly for the 30° horizontal field-of-view condition. In the restricted viewing conditions, the angular velocity of head movements made while stepping over an obstacle increased significantly over that for the unrestricted field-of-view condition, but no difference was found between the different field-of-view sizes. Implications of the current findings for the development of devices with field-of-view restrictions are discussed.

Motion sickness and postural sway in console video games

OBJECTIVE

We tested the hypotheses that (a) participants might develop motion sickness while playing "off-the-shelf" console video games and (b) postural motion would differ between sick and well participants, prior to the onset of motion sickness.

BACKGROUND

There have been many anecdotal reports of motion sickness among people who play console video games (e.g., Xbox, PlayStation).

METHOD

Participants (40 undergraduate students) played a game continuously for up to 50 min while standing or sitting. We varied the distance to the display screen (and, consequently, the visual angle of the display).

RESULTS

Across conditions, the incidence of motion sickness ranged from 42% to 56%; incidence did not differ across conditions. During game play, head and torso motion differed between sick and well participants prior to the onset of subjective symptoms of motion sickness.

CONCLUSION

The results indicate that console video games carry a significant risk of motion sickness.

APPLICATION

Potential applications of this research include changes in the design of console video games and recommendations for how such systems should be used.

Effects of field-of-view restriction on manoeuvring in a 3-D environment

Field-of-view (FOV) restrictions are known to affect human behaviour and to degrade performance for a range of different tasks. However, the relationship between human locomotion performance in complex environments and FOV size is currently not fully known. This paper examined the effects of FOV restrictions on the performance of participants manoeuvring through an obstacle course with horizontal and vertical barriers. All FOV restrictions tested (the horizontal FOV was either 30 degrees , 75 degrees or 120 degrees , while the vertical FOV was always 48 degrees ) significantly reduced performance compared to the unrestricted condition. Both the time and the number of footsteps needed to traverse the entire obstacle course increased with a decreasing FOV size. The relationship between FOV restriction and manoeuvring performance that was determined can be used to formulate requirements for FOV restricting devices that are deployed to perform time-limited human locomotion tasks in complex structured environments, such as night-vision goggles and head-mounted displays used in training and entertainment systems.

Binocular rivalry and head-worn displays

OBJECTIVE

We provide a review and analysis of much of the published literature on binocular rivalry that is relevant to the design and use of head-worn displays (HWDs).

BACKGROUND

This review draws heavily from both the basic vision literature and applied HWD literature in order to help provide insight for minimizing the effects of binocular rivalry when HWDs are worn.

METHOD

Included in this review are articles and books found cited in other works as well as articles and books obtained from an Internet search.

RESULTS

Issues discussed and summarized are (a) characteristics of binocular rivalry, (b) stimulus factors affecting rivalry, (c) cognitive variables affecting rivalry, and (d) tasks affected by rivalry.

CONCLUSION

This paper offers a set of recommendations for minimizing the effects of binocular rivalry when HWDs are used as well as recommendations for future research.

APPLICATION

Considerations of the basic vision literature on binocular rivalry will provide insight for future design solutions for HWDs.

Depth of focus and visual recognition of imagery presented on simultaneously viewed displays: implications for head-mounted displays

OBJECTIVE

We sought to determine the optimal focal distance for a semitransparent monocular head-mounted display (HMD) integrated with a flight simulator display and to investigate whether observers experienced visual discomfort or impaired target recognition when using an HMD set at the optimal distance.

BACKGROUND

When an observer wears a monocular HMD and views a simulator display, focal distances of both displays must be within the observers' depth of focus to prevent blurred imagery. Because focal distance can vary by as much as 0.5 m in U.S. Air Force multifaceted simulator displays, we determined whether a monocular HMD could be integrated with a simulator display without blurred imagery or discomfort.

METHOD

Depth of focus and visual recognition were measured with a staircase procedure, and visual discomfort was measured with a questionnaire.

RESULTS

Depth of focus was 0.64 diopters in one condition tested, but it was affected by luminance level and display resolution. It was recommended that HMD focal distance equal the optical midpoint of the range of viewing distances encountered in the simulator. Moreover, wearing an HMD produced a decline in recognition performance for targets presented on the simulator display despite both displays being within observers' depth of focus and producing no visual discomfort.

CONCLUSION

Monocular HMDs can be integrated with multifaceted simulator displays without blurred imagery or visual discomfort, provided that the correct focal distance is adopted.

APPLICATION

For situations involving simultaneously viewed visual displays.

Motion sickness, console video games, and head-mounted displays

OBJECTIVE

We evaluated the nauseogenic properties of commercial console video games (i.e., games that are sold to the public) when presented through a head-mounted display.

BACKGROUND

Anecdotal reports suggest that motion sickness may occur among players of contemporary commercial console video games.

METHODS

Participants played standard console video games using an Xbox game system. We varied the participants' posture (standing vs. sitting) and the game (two Xbox games). Participants played for up to 50 min and were asked to discontinue if they experienced any symptoms of motion sickness.

RESULTS

Sickness occurred in all conditions, but it was more common during standing. During seated play there were significant differences in head motion between sick and well participants before the onset of motion sickness.

CONCLUSION

The results indicate that commercial console video game systems can induce motion sickness when presented via a head-mounted display and support the hypothesis that motion sickness is preceded by instability in the control of seated posture.

APPLICATION

Potential applications of this research include changes in the design of console video games and recommendations for how such systems should be used.