Effects of Displays on Visually Controlled Task Performance in Three‐Dimensional Virtual Reality Environment

This study aims to evaluate three commercial virtual reality (VR) display devices on the market via a 3D Fitts's task. In addition, a symptom questionnaire was used to assess the severity of cybersickness symptoms induced by these displays. Ten participants performed repetitive pointing tasks over different conditions of varying display devices, movement directions, and indices of difficulty. On the basis of the results, the projection display obtained the best task performance with the lowest movement time and the highest throughput. It had the least symptoms among the three display devices. The HMD gave the worst results in all criteria. The 3D TV could be considered as good as the projection display in task performance but induced slight level of discomfort, fatigue, and eyestrain. These findings not only provided an initial understanding of differences between the 3D TV and the other two familiar display devices in human performance when interacting within a 3D VE but also pointed a direction to effectively improve future VR display technique.     

Self-reported discomfort when using commercially targeted virtual reality equipment in discomfort distraction

Commercially targeted virtual reality (VR) equipment is gaining popularity and might be a viable tool for pain distraction. This experimental research aimed to discover whether active distraction techniques (such as commercially targeted VR and video games) result in reduced subjective discomfort relative to passive distraction techniques. The study examined a healthy adult population who experienced an experimentally induced discomfort task. Participants were 27 adults, 14 females and 13 males. Participants completed four tasks, a baseline measure of physical discomfort, video clip distraction (passive distraction), video game distraction (active distraction) and exploring a VR world using an Oculus Rift head-mounted display (active distraction). In all four test conditions, participants were asked to sit on a chair holding their non-dominant leg at a height of approximately 30 cm from the floor, up to a maximum of 5 min. Counterbalancing of task order was conducted to reduce effects of participant fatigue. The participants indicated significantly reduced self-reported discomfort in the active distraction tasks when compared to the passive distraction tasks. While the findings demonstrate the effectiveness of a commercially targeted VR technology in increasing pain tolerance, the relative benefits of this technology over non-immersive video games are not apparent.     

The effect of stereoscopic viewing in a word‐search task with a layered background

Abstract— The benefits of stereoscopic viewing were explored in searching in words superimposed over a background. In the first experiment, eight participants searched for text in a normal 2‐D display, a 3‐D display using a parallax barrier, and a darkened 2‐D display of equivalent brightness to the 3‐D display. Word‐search performance was significantly faster for the bright 2‐D display vs. the 3‐D display, but when brightness was controlled, performance on the 3‐D display was better relative to the 2‐D (dim) display. In a second experiment, the effect of floating text vs. sinking background disparity was assessed across four background conditions. Twenty participants saw only the floating‐text (FT) condition and 20 participants saw only the sinking‐background (SB) condition. Performance of the SB group was significantly better than that of FT group, and the advantage of SB disparity was greater with the more‐complex backgrounds. Thus, when a parallax‐barrier 3‐D display is used to view text or other figural information overlaid on a background, it is proposed that the layer of primary interest (foreground) should be displayed with zero disparity (on the physical display surface) with the secondary layer (background) appearing to be sunk beneath that surface.     

Multiple two-dimensional displays as an alternative to three-dimensional displays in telerobotic tasks

In this study a multiple-view two-dimensional (2D) display was compared with a three-dimensional (3D) monocular display and a 3D stereoscopic display using a simulated telerobotic task. As visual aids, three new types of visual enhancement cues were provided and evaluated for each display type. The results showed that the multiple-view 2D display was superior to the 3D monocular and the 3D stereoscopic display in the absence of the visual enhancement depth cues. When participants were provided with the proposed visual enhancement cues, the stereoscopic and monocular displays became equivalent to the multiple-view 2D display. Actual or potential applications of this study include the design of visual displays for teleoperation systems.     

A comparison of adaptive and adaptable automation under different levels of environmental stress

The effectiveness of different forms of adaptive and adaptable automation was examined under low- and high-stress conditions, in the form of different levels of noise. Thirty-six participants were assigned to one of the three types of variable automation (adaptive event-based, adaptive performance-based and adaptable serving as a control condition). Participants received 3 h of training on a simulation of a highly automated process control task and were subsequently tested during a 4-h session under noise exposure and quiet conditions. The results for performance suggested no clear benefits of one automation control mode over the other two. However, it emerged that participants under adaptable automation adopted a more active system management strategy and reported higher levels of self-confidence than in the two adaptive control modes. Furthermore, the results showed higher levels of perceived workload, fatigue and anxiety for performance-based adaptive automation control than the other two modes. PRACTITIONER SUMMARY: This study compared two forms of adaptive automation (where the automated system flexibly allocates tasks between human and machine) with adaptable automation (where the human allocates the tasks). The adaptable mode showed marginal advantages. This is of relevance, given that this automation mode may also be easier to design.     

Eye movement measures for predicting eye gaze accuracy and symptoms in 2D and 3D displays

The current study applied Structural Equation Modeling (SEM) to analyze the interrelationship among index of difficulty (ID), environment, saccade duration (SD), revisited fixation duration (RFD), number of fixation (NF), pupil size (PS), eye gaze accuracy (AC), and symptoms simultaneously. SD, RFD, NF, PS, and AC were measured by utilizing the Tobii eye tracker system. Twelve participants were recruited to perform multi-directional tapping task using within-subject design with two different environments (2D screen display and 3D stereoscopic display) and six different levels of ID. SEM showed that ID had significant direct effects on SD and RFD while environment was found had significant direct effects on SD, RFD, PS, AC, and symptoms. Among selected eye movement measures, NF was found to be the best predictor of AC and PS was found to be the best predictor of symptoms. In addition, RFD was also found to be a good predictor of symptoms. Our results found that higher AC was achieved by projecting the image in the 2D screen display with higher ID and it resulted in higher SD and higher NF. Regarding the symptoms, our results found that lower symptoms were achieved by projecting the image in the 2D screen display with lower ID and it resulted in lower PS, and lower RFD.Practitioner Summary: The SEM could provide valuable theoretical foundations to identify the interrelationship among eye movement measures, AC, and symptoms particularly for VR researchers and interface developers.     

Performance Comparison of a SSVEP BCI Task by Individual Stereoscopic 3D Susceptibility

This study aimed at investigating the differences in brain–computer interface (BCI) task performance between 2D and 3D displays depending on their individual susceptibility to stereoscopic 3D. Eleven female and 10 male participants attempted a steady-state visually evoked potential BCI navigation task in a virtual home environment with and without 3D views. Participants were categorized into fatigued and unfatigued groups, depending on their individual susceptibility to 3D, which was characterized using a subjective evaluation method for 3D visual fatigue. The task completion time for the fatigued group under the 3D conditions was significantly delayed relative to the 2D mode. In contrast, a significantly decreased completion time was observed in the 3D view relative to the 2D view for the unfatigued group. The averaged positive predictive value significantly increased in the 3D mode relative to the 2D one for the unfatigued group only. These results are expected to provide a practical implication for enhancing BCI task performance in light of individual vulnerability to 3D.     

Comparison of changes in visual fatigue and ocular surface after 3D and 2D viewing with augmented reality glasses

The extensive use of electronic devices commonly results in visual discomfort, particularly in stereoscopic display. Augmented Reality (AR) is a mixed technology that superimposes three-dimensional (3D) digital data onto an image of reality. Even though the visual health evaluation of 3D contents has been widely concerned, the difference between 3D and two-dimensional (2D) viewing using AR display was rarely studied. We aimed to compare the changes in visual fatigue and ocular surface parameters after 3D and 2D viewing with optical waveguide AR glasses for one hour (1hr). In the experiment, thirty young healthy participants watched the same film in 2D and 3D mode separately using AR glasses with one week interval. Subjective visual fatigue questionnaire and ocular examinations were evaluated at 3 time points: pre-watching, post-2D and post-3D visual task for 1hr. Lipid layer thickness (LLT) and total blink (TB) were evaluated with the LipiView interferometer. Tear meniscus height (TMH) and noninvasive tear breakup time (NIBUT) were measured using Keratograph 5M. The effect of viewing 2D and 3D videos for 1hr with AR glasses suggested slight visual discomfort except the symptom of pain and dullness. The lipid layer thickness and total blink showed increasing trends in both post-visual task but more obvious after 2D viewing. Blinking patterns and tear film stability are meaningful for video display terminal users in visual health education. Ocular parameters are needed to be considered in the design and usage of future AR applications.     

Dual-Finger 3D Interaction Techniques for mobile devices

Three-dimensional capabilities on mobile devices are increasing, and the interactivity is becoming a key feature of these tools. It is expected that users will actively engage with the 3D content, instead of being passive consumers. Because touch-screens provide a direct means of interaction with 3D content by directly touching and manipulating 3D graphical elements, touch-based interaction is a natural and appealing style of input for 3D applications. However, developing 3D interaction techniques for handheld devices using touch-screens is not a straightforward task. One issue is that when interacting with 3D objects, users occlude the object with their fingers. Furthermore, because the user’s finger covers a large area of the screen, the smallest size of the object users can touch is limited. In this paper, we first inspect existing 3D interaction techniques based on their performance with handheld devices. Then, we present a set of precise Dual-Finger 3D Interaction Techniques for a small display. Finally, we present the results of an experimental study, where we evaluate the usability, performance, and error rate of the proposed and existing 3D interaction techniques.     

3D Display Using Passive Optical Scatterers

A new class of 3D displays uses a digital projector and a cloud of passive optical scatterers etched in a glass cube with laser-induced damage.These inexpensive devices can be used to display simple 3D objects, extend videogames to three dimensions, and create 3D avatars. Over the past century, researchers have worked vigorously to create a device that can display realistic high-resolution 3D content. As an offshoot of that, we are developing an inexpensive class of volumetric displays that can present certain types of 3D content, including simple 3D objects, extruded objects, and 3D surfaces that appear dynamic when projected with time-varying images, at relatively low resolution. Our displays use a simple light engine and a cloud of passive optical scatterers. The basic idea is to trade off the light engine's 2D spatial resolution to gain resolution in the third dimension. One way to achieve such a tradeoff is to use a stack of planar grids of scatterers where no two stacks overlap each other with respect to the light engine's projection rays.     

The influence of information presentation formats on complex task decision-making performance

Understanding the influence of information presentation formats on decision-making effectiveness is an important component of human–computer interaction user interface design. The pervasive nature and ease of use associated with information display formats in widely used personal productivity software suggests that decision-makers are likely to create and/or use documents with both text-based and more visually oriented information displays. Past research has investigated the role of these displays on simple decision tasks; however, empirical research has not extended to more complex tasks, more comparable to the types of tasks decision-makers face every day. Results from the empirical analysis suggest that the relationship between information presentation format and decision performance is moderated by the complexity of the task. More specifically, spatial formats result in superior decision accuracy for simple- and complex-spatial tasks and faster decision time for all tasks except the complex-symbolic task where graphs and tables result in equivalent decision time.     

Effects of display technologies on operation performances and visual fatigue

The use of 3D stereoscopic display technology in all aspects of life has attracted considerable research attention. However, only few studies have simultaneously considered the effects of stereoscopic display technologies on visual fatigue and operating performances. This study with 36 participants (50% females; mean age = 23.17 years, SD = 3.3) analyzed the effects of display technologies, task complexity, and use time on operation performances, subjective and objective visual fatigue. Results indicated that display technology did not significantly affect the operation performances, whereas task complexity did. However, no interaction took place between them. Display technology had no significant effects on subjective visual fatigue and near-point accommodation (NPA) but affected critical fusion frequency (CFF) significantly. Use time had significant effects on both subjective and objective visual fatigue.     

Virtual realia: maneuverable computer 3D models and their use in learning assembly skills

Two experiments compared real and virtual models as aids for learning assembly skills. In Experiment 1, ten participants individually studied either a fully assembled model, or a computer-generated one, in exploded view, that could be spatially manipulated in any direction. Participants then assembled the object in front of a video camera. ANOVA indicated virtual model are studied significantly longer but yield faster assembly than a real model. Experiment 2 used the same treatments plus a fully assembled virtual mode, randomly assigned to 28 participants who studied the aid, assembled the model, and then repeated the task from memory 3 days later. ANOVA indicated no differences between the three groups in assembly speed or accuracy. However, participants studied the exploded virtual model significantly longer than the two intact views of the model suggesting the former may impose a greater cognitive load due to the additional visual information it provides.     

Effects of display design on performance in a simulated ship navigation environment

Although automation is playing an increasing role on the ship's bridge, empirical research on the effectiveness of alternative bridge designs is limited. In this paper, we describe an experimental study of the benefits of integrated information display, using a computerized simulation of a highly automated ship's bridge. The study compared three types of interface design, which presented radar and electronic chart information to the operator in different ways: (a) integrated display, (b) functionally-separate display, and (c) spatially-separate display. Effects were examined in relation to time on watch and scenario complexity. Following extensive training on the task, 39 participants were tested over a 4-h experimental session, during which they encountered a sequence of collision scenarios of varying complexity. Using a dual-task methodology, a range of measures of primary and secondary task performance were taken, together with assessment of information sampling behaviour and subjective operator state (workload, fatigue, anxiety and situation awareness). The results indicated slight navigational advantages of the integrated display over the two alternative display types, although it also incurred higher levels of operator cost, particularly fatigue. There were no marked effects of time on watch, but more complex scenarios were associated with impaired performance, increased workload and reduced situation awareness. Overall, the findings have suggested some benefits of integrating primary information sources in a ship's bridge environment. The study further confirms the value of experimental simulations as tools for investigating design issues for ship's bridge automation.     

Adaptive interaction in a 3D product structure browsing system for maintenance training

The traditional maintenance training method with a physical model of the product is costly and inconvenient. Computer‐aided instruction (CAI) technology along with multimedia can provide much help in the training but provides limited interaction between the user and the system. In this article, a 3D model‐based product structure browsing system for maintenance training, CAMT, is developed for complex products adopting desktop virtual reality technology. To improve training performance, the interaction between the trainee and the CAMT system is enhanced by adaptive change of the zoom level, mouse sensitivity, and rotation origin. Details about the implementation of adaptive interaction are discussed. Experiments were conducted to test the effectiveness of this adaptive interaction. Seventy participants were arranged randomly into two groups assigned to perform product structure learning tasks using software with or without adaptive interaction functions. Statistical analysis showed that there were significant differences between the groups in task time, operation convenience, and learning satisfaction. Most participants preferred to use the system with adaptive interaction. It may be concluded that using adaptive interaction with maintenance training systems can significantly improve the usability of the systems and the efficiency of interactive learning. Although adaptive interaction has obvious advantages, our experiment also suggested that it is not a good idea to provide only the adaptive interaction mode. It is better to set adaptive interaction as the default mode but also to provide the possibility for a user to switch to a mode without adaptive interaction because a static view scope is also helpful to learn the 3D structure of a complex product. © 2007 Wiley Periodicals, Inc.     

Robo-Erectus: a low-cost autonomous humanoid soccer robot

An exoskeleton robot can replace the wearer's motion function by operating the human's body. The purpose of this study is to propose a power assist method of walking, standing up and going up stairs based on autonomous motion of the exoskeleton robot suit, HAL (Hybrid assistive Limb), and verify the effectiveness of this method by experiment. In order to realize power assist of tasks (walking, standing up and going up stairs) autonomically, we used the Phase Sequence control which generates a task by transiting some simple basic motions called Phases. A task was divided into some Phases on the basis of the task performed by a normal person. The joint moving modes were categorized into active, passive and free modes according to the characteristic of the muscle force conditions. The autonomous motions which HAL generates in each Phase were designed corresponding to one of the categorized modes. The power assist experiments were performed by using the autonomous motion with a focus on the active mode. The experimental results showed that the wearer's muscle activation levels in each Phase were significantly reduced. With this, we confirmed the effectiveness of the proposed assist method.     

Advances in the Dynallax solid-state dynamic parallax barrier autostereoscopic visualization display system

A solid-state dynamic parallax barrier autostereoscopic display mitigates some of the restrictions present in static barrier systems, such as fixed view-distance range, slow response to head movements, and fixed stereo operating mode. By dynamically varying barrier parameters in real time, viewers may move closer to the display and move faster laterally than with a static barrier system, and the display can switch between 3D and 2D modes by disabling the barrier on a per-pixel basis. Moreover, Dynallax can output four independent eye channels when two viewers are present, and both head-tracked viewers receive an independent pair of left-eye and right-eye perspective views based on their position in 3D space. The display device is constructed by using a dual-stacked LCD monitor where a dynamic barrier is rendered on the front display and a modulated virtual environment composed of two or four channels is rendered on the rear display. Dynallax was recently demonstrated in a small-scale head-tracked prototype system. This paper summarizes the concepts presented earlier, extends the discussion of various topics, and presents recent improvements to the system.     

Putting the User in the Loop for Image-Based Modeling

We refer to the task of recovering the 3D structure of an object or a scene using 2D images as image-based modeling. In this paper, we formulate the task of recovering the 3D structure as a discrete optimization problem solved via energy minimization. In this standard framework of a Markov random field (MRF) defined over the image we present algorithms that allow the user to intuitively interact with the algorithm. We introduce an algorithm where the user guides the process of image-based modeling to find and model the object of interest by manually interacting with the nodes of the graph. We develop end user applications using this algorithm that allow object of interest 3D modeling on a mobile device and 3D printing of the object of interest. We also propose an alternate active learning algorithm that guides the user input. An initial attempt is made at reconstructing the scene without supervision. Given the reconstruction, an active learning algorithm uses intuitive cues to quantify the uncertainty of the algorithm and suggest regions, querying the user to provide support for the uncertain regions via simple scribbles. These constraints are used to update the unary and the pairwise energies that, when solved, lead to better reconstructions. We show through machine experiments and a user study that the proposed approach intelligently queries the users for constraints, and users achieve better reconstructions of the scene faster, especially for scenes with textureless surfaces lacking strong textural or structural cues that algorithms typically require.     

The development of a panorama manifestation virtual reality system for navigation and a usability comparison with a desktop system

The virtual reality (VR) system has become popular in the last two decades and is being applied increasingly to navigation studies. This study developed a panorama manifestation (PM) VR system, with six monitors forming a circular display and an interactive chair equipped with rotation sensors and operating knobs. The advantages of the PM system include a large circular display, a body-centred design, body engagement and a low set-up cost. Based on navigation experimental tasks, this system's usability was compared with that of a typical desktop (DT) system. The results showed that participants using the PM system had a significantly higher success rate and required less completion time than participants using the DT system, indicating that the PM system outperforms the DT system in terms of effectiveness and efficiency in some navigation tasks, and also suggesting that the PM system may require lower spatial cognition workload in the navigation tasks. However, the participants’ subjective evaluations of task difficulty (TD) failed to reach significance although the PM group did report a lower mean value for TD. Additionally, in the PM system, the participants’ spatial ability was more predictive to their navigation performance than that in the DT system, indicating that the PM system offered greater usability for some spatial experiments and could provide more support for participants’ navigation tasks.     

Audio channel constraints in video-mediated communication

This study investigated the effects of two types of audio channels upon the effectiveness of task-based interactions in a video-mediated context (VMC). Forty undergraduates completed a collaborative task (The Map Task) using either a full or half-duplex audio channel. Their performance was compared to face-to-face interactions, taken from the Human Communication Research Centre corpus of Map Task Dialogues. Effects of varying the audio channel were explored by comparing task performance, patterns of speech, and establishment of mutual understanding. Users of the full-duplex VMC made insufficient allowance for the VMC context; they completed the task less accurately than face-to-face participants, and interrupted each other more frequently than other participants. Participants in the half-duplex VMC however performed as well as face-to-face participants. They made sensible adaptations to the constraints imposed by the half-duplex VMC context, producing longer dialogues, with more explicit turn-taking management, and taking greater care in establishing mutual knowledge.