Search Results (7)

The growing interest in augmented reality applications has led to an in-depth look at the performance of head-mounted displays and their testing in numerous domains. Other devices for augmenting the real world with virtual information are presented less frequently and usually focus on the description of the device rather than on its performance analysis. This is the case of projected augmented reality, which, compared to head-worn AR displays, offers the advantages of being simultaneously accessible by multiple users whilst preserving user awareness of the environment and feeling of immersion. This work provides a general evaluation of a custom-made head-mounted projector for the aid of precision manual tasks through an experimental protocol designed for investigating spatial and temporal registration and their combination. The results of the tests show that the accuracy ($0.6\pm 0.1$ mm of spatial registration error) and motion-to-photon latency ($113\pm 12$ ms) make the proposed solution suitable for guiding precision tasks. Full article

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. Full article

Virtual reality (VR)-based rehabilitation has been used in lower limb amputees; however, the extent to which VR is effective in reacquiring symmetrical gait in lower limb amputees is unclear. The purpose of this study was to confirm whether a VR intervention is effective in obtaining a simulated prosthetic gait. The participants were 24 healthy males who had never worn a simulated prosthesis. They were divided into three groups: VR, tablet, and control groups. The intervention consisted of 5 min of in situ stepping on parallel bars and watching a video of a simulated prosthetic leg walker on a head-mounted display or a tablet. Measurements included Gait Up parameters during a 10-m walk and immersion scores. After the intervention, there was a significant interaction between walking speed and leg swing speed in the VR group. The rate of improvement in walking speed and immersion scores was significantly higher in the VR group than in the other two groups, and there was a significant positive correlation between the rate of improvement and immersion scores. Compared to the tablet and control groups, the VR group showed the highest rate of immersion and improvement in walking speed. Full article

In this work, we propose a convenient method for evaluating levels of angular jerk in augmented reality (AR) and virtual reality (VR). Jerk is a rarely analyzed metric in usability studies, although it can be measured and calculated easily with most head-worn displays and can yield highly relevant information to designers. Here, we developed and implemented a system capable of calculating and analyzing jerk in real-time based on orientation data from an off-the-shelf head-worn display. An experiment was then carried out to determine whether the presence of AR user interface annotations results in changes to users’ angular head jerk when conducting a time-pressured visual search task. Analysis of the data indicates that a decrease in jerk is significantly associated with the use of AR augmentations. As noted in the limitations section, however, the conclusions drawn from this work should be limited, as this analysis method is novel in the VR/AR space and because of methodological limitations that limited the reliability of the jerk data. The work presented herein considerably facilitates the use of jerk as a quick component measure of usability and serves as an initial point off which future research involving jerk in VR and AR can be performed. Full article

Gait symmetry analysis plays an important role in the diagnosis and rehabilitation of pathological gait. Recently, wearable devices have also been developed for simple gait analysis solutions. However, measurement in clinical settings can differ from gait in daily life, and simple wearable devices are restricted to a few parameters, providing one-sided trajectories of one arm or leg. Therefore, head-worn devices with sensors (e.g., earbuds) should be considered to analyze gait symmetry because the head sways towards the left and right side depending on steps. This paper proposed new visualization methods using head-worn sensors, able to facilitate gait symmetry analysis outside as well as inside. Data were collected with an inertial measurement unit (IMU) based motion capture system when twelve participants walked on the 400-m running track. From head trajectories on the transverse and frontal plane, three types of diagrams were displayed, and five concepts of parameters were measured for gait symmetry analysis. The mean absolute percentage error (MAPE) of step counting was lower than 0.65%, representing the reliability of measured parameters. The methods enable also left-right step recognition (MAPE ≤ 2.13%). This study can support maintenance and relearning of a balanced healthy gait in various areas with simple and easy-to-use devices. Full article

Enabling the effective representation of an object’s position and depth in augmented reality (AR) is crucial not just for realism, but also to enable augmented reality’s wider utilization in real world applications. Domains such as architecture and building design cannot leverage AR’s advantages without the effective representation of position. Prior work has examined how the human visual system perceives and interprets such cues in AR. However, it has focused on application systems that only use a single AR modality, i.e., head-mounted display, tablet/handheld, or projection. However, given the respective limitations of each modality regarding shared experience, stereo display, field of view, etc., prior work has ignored the possible benefits of utilizing multiple AR modalities together. By using multiple AR systems together, we can attempt to address the deficiencies of one modality by leveraging the features of other modalities. This work examines methods for representing position in a multi-modal AR system consisting of a stereo head-mounted display and a ceiling mounted projection system. Given that the AR content is now rendered across two separate AR realities, how does the user know which projected object matches the object shown in their head-mounted display? We explore representations to correlate and fuse objects across modalities. In this paper, we review previous work on position and depth in AR, before then describing multiple representations for head-mounted and projector-based AR that can be paired together across modalities. To the authors’ knowledge, this work represents the first step towards utilizing multiple AR modalities in which the AR content is designed directly to compliment deficiencies in the other modality. Full article

Virtual reality using head-mounted displays (HMD) could provide enhanced physical load during active gaming (AG) compared to traditional displays. We aimed to compare the physical load elicited by conventional exercise and AG with an HMD. We measured energy expenditure (EE) and heart rate (HR) in nine healthy men (age: 27 ± 5 years) performing three testing components in a randomised order: walking at 6 km/h (W6), AG, and AG with an additional constraint (AG^W; wrist-worn weights). Although we found that HR was not significantly different between W6 and the two modes of AG, actual energy expenditure was consistently lower in AG and AG^W compared to W6. We observed that playing AG with wrist-worn weights could be used as a means of increasing energy expenditure only at maximum game level, but ineffective otherwise. Our findings indicate that AG in an HMD may not provide a sufficient stimulus to meet recommended physical activity levels despite increased psychophysiological load. The differential outcomes of measures of HR and EE indicates that HR should not be used as an indicator of EE in AG. Yet, adding a simple constraint (wrist-worn weights) proved to be a simple and effective measure to increase EE during AG. Full article