Objective: We examined the effects of several display characteristics of head-mounted displays (HMDs) on simulator sickness (SS).Background: Technological limitations, such as display delay and reduced field of view (FOV), affect perception when using an HMD and are often thought to be related to SS. Few studies have examined the relationship between FOV and geometric FOV (image scale factor) or how HMD characteristics may interact.Method: Participants made active head movements to locate objects when viewing a live video via an HMD.Results: Compared with no added delay, an additional 200 ms of display delay did not result in increased SS, as measured by the Simulator Sickness Questionnaire. Furthermore, an effect of image scale factor on SS was not revealed. However, SS was greater when peripheral vision was occluded than when it was not. Peripheral vision moderated the effects of image scale factor and delay on head movement velocity.Conclusion: Occluding peripheral vision may subject HMD users to the p...

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Characteristics of Head-Mounted Displays and Their Effects on Simulator Sickness

Virtual reality training systems are commonly used in a variety of domains, and it is important to understand how the realism of a training simulation influences training effectiveness. We conducted a controlled experiment to test the effects of display and scenario properties on training effectiveness for a visual scanning task in a simulated urban environment. The experiment varied the levels of field of view and visual complexity during a training phase and then evaluated scanning performance with the simulator's highest levels of fidelity and scene complexity. To assess scanning performance, we measured target detection and adherence to a prescribed strategy. The results show that both field of view and visual complexity significantly affected target detection during training; higher field of view led to better performance and higher visual complexity worsened performance. Additionally, adherence to the prescribed visual scanning strategy during assessment was best when the level of visual complexity during training matched that of the assessment conditions, providing evidence that similar visual complexity was important for learning the technique. The results also demonstrate that task performance during training was not always a sufficient measure of mastery of an instructed technique. That is, if learning a prescribed strategy or skill is the goal of a training exercise, performance in a simulation may not be an appropriate indicator of effectiveness outside of training—evaluation in a more realistic setting may be necessary.

Effects of Field of View and Visual Complexity on Virtual Reality Training Effectiveness for a Visual Scanning Task

The term immersion continues to be applied inconsistently within and across different fields of research connected with the study of virtual reality and interactive media. Moreover, immersion is oftentimes used interchangeably with the terms presence and engagement. This article details a review of existing definitions of immersion originating within the study of video games, virtual environments, and literary works of fiction. Based on this review, a three-dimensional taxonomy of the various conceptualizations of immersion is proposed. That is, the existing definitions of immersion may be broadly divided into three categories, each representing a dimension of the taxonomy: immersion as a property of a system, a subjective response to narrative contents, or a subjective response to challenges within the virtual environment. Finally, four distinct theories of presence are introduced and, based on the established taxonomy, we discuss how the individual theories relate to existing definitions of immersion.

https://vbn.aau.dk/files/244598779/Nilsson_Nordahl_Serafin.pdf

Immersion revisited: A review of existing definitions of immersion and their relation to different theories of presence

As wearable computing goes mainstream, we must improve the state of interface design to keep users productive with natural-feeling interactions. We present the Personal Cockpit, a solution for mobile multitasking on head-worn displays. We appropriate empty space around the user to situate virtual windows for use with direct input. Through a design-space exploration, we run a series of user studies to fine-tune our layout of the Personal Cockpit. In our final evaluation, we compare our design against two baseline interfaces for switching between everyday mobile applications. This comparison highlights the deficiencies of current view-fixed displays, as the Personal Cockpit provides a 40% improvement in application switching time. We demonstrate of several useful implementations and a discussion of important problems for future implementation of our design on current and near-future wearable devices.

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The personal cockpit: a spatial interface for effective task switching on head-worn displays

http://people.rennes.inria.fr/Julien.Pettre/pdf/GP2013.pdf

Collision avoidance between two walkers: Role-dependent strategies

We investigated the effects of anxiety on the execution of police officers' arrest and self-defense skills Police officers (n=13) performed three tasks in which they kicked, blocked, or restrained an opponent who attacked them with a rubber knife (low anxiety, LA) or a shock knife (high anxiety, HA) in a within-subject design We analyzed performance (on a 5-point Likert scale), movement times, posture, and movement velocity and acceleration Results revealed that performance was worse in the HA compared to the LA condition Furthermore, analysis of full-body movement showed that under increased anxiety, police officers' performance contained characteristics of avoidance behavior, such as faster reactions (to reduce the time being exposed to the threat), leaning further backward (kick), and ducking down (block) In line with recent theoretical developments, it appears that under increased anxiety, police officers were less able to inhibit stimulus-driven processing (fear of getting hit) and enforce goal-directed processing (perform the skill as well as possible) leading to avoidance behavior and a decrease in performance

Effects of anxiety on the execution of police arrest and self-defense skills.

This study investigated how human locomotion through an obstacle environment is influenced by visual field limitation. Participants were asked to walk at a comfortable pace to a target location while avoiding multiple vertical objects. During this task, they wore goggles restricting their visual field to small (S: 40° × 25°), medium (M: 80° × 60°), large (L: 115° × 90°), or unlimited (U) visual field sizes. Full-body motion capture was used to extract for each trial the mean speed, pathlength, mean step width, magnitude of head rotation and head mean angular speed. The results show that compared with the U condition, the M and L conditions caused participants to select a wider path around the obstacles without slowing down or altering step width. However, the S condition did slow down the participants, and increased both their step width and path length. We conclude that only for the S condition, balancing problems were substantial enough to spend more energy associated with increased step width. In all cases, participants choose to optimize safety (collision avoidance) at the cost of spending more energy.

https://link.springer.com/content/pdf/10.1007%2Fs00221-011-2757-1.pdf

Human locomotion through a multiple obstacle environment: strategy changes as a result of visual field limitation.

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 befween 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 accutacy 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 testricdons. 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 resricting devices deployed to perform timelimited human-locomotion tasks in complex structured environments, such as night-vision goggles and head-mounted displays.

Effects of field-of-view restrictions on speed and accuracy of manoeuvring

Realistic simulation of interacting virtual characters is essential in computer games, training and simulation applications. The problem is very challenging since people are accustomed to real-world situations and thus, they can easily detect inconsistencies and artifacts in the simulations. Over the past twenty years several models have been proposed for simulating individuals, groups and crowds of characters. However, little effort has been made to actually understand how humans solve interactions and avoid inter-collisions in real-life. In this paper, we exploit motion capture data to gain more insights into human-human interactions. We propose four measures to describe the collision-avoidance behavior. Based on these measures, we extract simple rules that can be applied on top of existing agent and force based approaches, increasing the realism of the resulting simulations.

Exploiting Motion Capture to Enhance Avoidance Behaviour in Games

Haptic exploratory procedures (EPs) are prototypical hand movements that are linked to the acquisition of specific object properties. In studies of haptic perception, hand movements are often classified into these EPs. Here, we aim to investigate several EPs in a quantitative manner to understand how hand dynamics and contact forces differ between them. These dissimilarities are then used to construct an EP identification model capable of discriminating between EPs based on the index finger position and contact force. The extent to which the instructed EPs were distinct, repeatable, and similar across subjects was confirmed by showing that more than 95 percent of the analyzed trials were classified correctly. Finally, the method is employed to investigate haptic exploratory behavior during similarity judgments based on several object properties. It seems that discrimination based on material properties (hardness, roughness, and temperature) yields more consistent classification results compared to discrimination based on the acquisition of shape information.

/pdf/identifying-haptic-exploratory-procedures-by-analyzing-hand-2fyaodf0ig.pdf

Sander E. M. Jansen

Papers

Effects of anxiety on the execution of police arrest and self-defense skills.

Human locomotion through a multiple obstacle environment: strategy changes as a result of visual field limitation.

Effects of field-of-view restrictions on speed and accuracy of manoeuvring

Exploiting Motion Capture to Enhance Avoidance Behaviour in Games

Identifying Haptic Exploratory Procedures by Analyzing Hand Dynamics and Contact Force