Monocular Head-mounted Display Research Articles

Effects of Head-Mounted Display (HMD) Position on Procedure Following Tasks and Usability

Background Head-mounted displays (HMDs) have found value in industrial applications as aids in performing long and/or complicated procedural tasks. Currently, there are gaps in understanding the impact of various design characteristics on the performance of tasks aided by HMDs. This study investigated how different positioning of head mounted displays affected the performance of workers during procedure following tasks. Methods Eight car maintenance tasks were performed by 20 participants with task guidance presented at four display conditions: above-eye, eye-centered, below-eye and via traditional paper manual. Task times, errors were measured and user experience measurements were collected. Results The results showed that none of the display conditions had significant effects on completion times. However, below-eye display outperformed the above-eye display condition for tasks requiring participants to perform assessments. User experience ratings showed that the eye-central condition was the most preferred display position among the three HMD conditions. Conclusions A non-transparent, monocular HMD that partially blocks a user’s FoV was not observed to significantly decrease overall task performance time. In support of previous findings, an HMD positioned below the eye outperformed the above-eye position for assess actions in this study. User overreliance on the instructions provided via HMD was also observed in this study. In a slightly different finding from previous studies, users indicated that the eye-central HMD position provided the best overall experience and was the most preferred by participants in this study.

The Role of Focus in Advanced Visual Interfaces

Developing more natural and intelligent interaction methods for head mounted displays (HMDs) has been an important goal in augmented reality for many years. Recently, small form factor eye tracking interfaces and wearable displays have become small enough to be used simultaneously and for extended periods of time. In this paper, we describe the combination of monocular HMDs and an eye tracking interface and show how they can be used to automatically reduce interaction requirements for displays with both single and multiple focal planes. We then present the results of preliminary and primary experiments which test the accuracy of eye tracking for a number of different displays such as Google Glass and Brother’s AiRScouter. Results show that our focal plane classification algorithm works with over 98 % accuracy for classifying the correct distance of virtual objects in our multi-focal plane display prototype and with over 90 % accuracy for classifying physical and virtual objects in commercial monocular displays. Additionally, we describe methodology for integrating our system into augmented reality applications and attentive interfaces.

18.5L: Late‐News Paper: OLED based Binocular Interactive See‐through HMD

AbstractThis paper describes the design and the setup of a novel interactive binocular see‐through head‐mounted display (HMD) based on OLED microdisplays. In contradistinction to previous reported bulky monocular eyetracking HMDs based on the OLED‐on‐CMOS technology, the presented system meets the requirements of lightweight eyeglasses with a high functionality.

Improved Visibility of Monocular Head-Mounted Displays Through the Bright Control of Backlighting

Monocular head-mounted displays (HMDs) will be a major tool for ubiquitous computing. However, monocular HMD visibility causes a decrease in the light received from the environment. Fluctuating light from the environment strongly affects the visibility of images presented on the monocular HMD. In the present study, we have studied a method for controlling HMD backlighting to improve visibility at the wearing a monocular HMD under variable lighting conditions. Three backlight control patterns were developed from Experiment I as psychophysical measurements, and their validities were subjectively evaluated in Experiment II. The results suggest increased visibilities at wearing a monocular HMD when controlling the backlight. Moreover, the rules for backlighting control are based on psychophysical theory.

A clinical evaluation of visual feedback-guided breath-hold reproducibility of tumor location

The purpose of this study was to evaluate the reproducibility of visual feedback-guided breath-hold using a machine vision system with a charge-coupled device camera and a monocular head-mounted display. Sixteen patients with lung tumors who were treated with stereotactic radiotherapy were enrolled. A machine vision system with a charge-coupled device camera was used for monitoring respiration. A monocular head-mounted display was used to provide the patient with visual feedback about the breathing trace. The patients could control their breathing so that the breathing waveform would fall between the upper and lower threshold lines. Planning and treatment were performed under visual feedback-guided expiratory breath-hold. Electronic portal images were obtained during treatment. The range of cranial–caudal motion of the tumor location during each single breath-hold was calculated as the intra-breath-hold (intra-BH) variability. The maximum displacement between the two to five averaged tumor locations of each single breath-hold was calculated as the inter-breath-hold (inter-BH) variability. All 16 patients tolerated the visual feedback-guided breath-hold maneuvers well. The intra- and inter-BH variability of all patients was 1.5 ± 0.6 mm and 1.2 ± 0.5 mm, respectively. A visual feedback-guided breath-hold technique using the machine vision system is feasible with good breath-hold reproducibility.

What Conditions are Required to Effectively Use Augmented Reality for Manuals in Actual Work

Augmented Reality (AR) is expected to be applied to manuals for assembling or inspecting tasks instead of traditional paper-based ones. Our previous study revealed that when an AR manual was experimentally used for a wiring task, efficiency became higher and human error decreased. However, in order to practically apply AR manuals in actual work situations, some human factor requirements should be clarified in advance. Thus, in this study, we attempt to make it clear what kinds of effects they have on performance by some conditions or restrictions. Particularly considering that a user wears a head-mounted display (HMD) and sees images presented by that superimposed on the real view, we examine the effects of those through some experiments. From the results, we found that a monocular HMD is better to be worn on nondominant eye, that information of an AR manual should be given part by part or one by one when the real view is complicated, and so on. We suggest conditions that do not affect their performance, or rather that enhance it in actual work situations, in this study.

Breath-hold monitoring and visual feedback for radiotherapy using a charge-coupled device camera and a head-mounted display: system development and feasibility

The aim of this study was to present the technical aspects of the breath-hold technique with respiratory monitoring and visual feedback and to evaluate the feasibility of this system in healthy volunteers. To monitor respiration, the vertical position of the fiducial marker placed on the patient's abdomen was tracked by a machine vision system with a charge-coupled device camera. A monocular head-mounted display was used to provide the patient with visual feedback about the breathing trace. Five healthy male volunteers were enrolled in this study. They held their breath at the end-inspiration and the end-expiration phases. They performed five repetitions of the same type of 15-s breath-holds with and without a head-mounted display, respectively. A standard deviation of five mean positions of the fiducial marker during a 15-s breath-hold in each breath-hold type was used as the reproducibility value of breath-hold. All five volunteers well tolerated the breath-hold maneuver. For the inspiration breath-hold, the standard deviations with and without visual feedback were 1.74 mm and 0.84 mm, respectively (P = 0.20). For the expiration breath-hold, the standard deviations with and without visual feedback were 0.63 mm and 0.96 mm, respectively (P = 0.025). Our newly developed system might help the patient achieve improved breath-hold reproducibility.

Depth of Focus and Visual Recognition of Imagery Presented on Simultaneously Viewed Displays: Implications for Head-Mounted Displays

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. 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. Depth of focus and visual recognition were measured with a staircase procedure, and visual discomfort was measured with a questionnaire. 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. Monocular HMDs can be integrated with multifaceted simulator displays without blurred imagery or visual discomfort, provided that the correct focal distance is adopted. For situations involving simultaneously viewed visual displays.

Reducing Binocular Rivalry in the Use of Monocular Head-Mounted Display

Monocular head-mounted displays (HMDs) can be used with wearable computers. However, such displays can cause binocular rivalry, a phenomenon in which the left and right images alternate, and is unstable. Binocular rivalry, when using HMD, causes the image of the environment to alternate with the HMD image, or even the total loss of perception of the image from the HMD. Binocular rivalry can occur with displays of any resolution. In this study, we used optokinetic nystagmus (OKN) to reduce binocular rivalry. A special stimulus synchronized to the occurrence of binocular rivalry was used to trigger OKN. The subject was asked to observe a visual stimulus and press a trigger button whenever binocular rivalry occurred. This initiated the presentation of a specific spatial frequency stimulus that broke up the rivalry. Electro-oculogram (EOG) electrodes recorded the observer's possible loss of perception of the HMD image, helping to confirm the occurrence of binocular rivalry. Sixteen subjects participated in the experiments. The results indicate that synchronizing special stimuli to the viewers' responses in order to induce OKN can reduce binocular rivalry

単眼ヘッドマウントディスプレイを用いた立体視法

We have developed a stereovision method that uses a monocular head-mounted display(mono-HMD). In the past, both images in stereovision have been set in either a virtual world or in the real world. In the former case, a person wearing special glasses can see 3D images, but other people can't even see 2D images. In the latter case, viewers can only see 3D images from a particular location. Our method solves both problems. In our method, one image is set in a virtual world displayed in a mono-HMD, and the other image is set in the real world. The viewer wears the mono-HMD and moves her body to align one retinal image with the other retinal image. The brain's vision center then perceives the two images as one stereoscopic image. Our experiments have shown that 3D images can be viewed stereoscopically using our method.

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.

The impact of non‐immersive head‐mounted displays (HMDs) on the visual field

Abstract— Binocular head‐mounted displays (HMDs) that could be used non‐immersively produced substantial interruption of the visual field. Monocular HMDs designed to be used non‐immersively created minimal interruption of the visual fields. The scotomata are small enough to allow the HMD to be worn in mobile situations, but inattention associated with use of the HMD may cause safety concerns for some mobile situations. A small opaque display can be positioned to provide a see‐through functionality.

Evaluation of Eye-Dominance Effects on Target-Acquisition Tasks Using a Head-Coupled Monocular Hmd

Monocular head-mounted displays (HMDs) require operators to place an eyepiece over only one of their eyes, raising the potential for eye-dominance performance differences. This issue is likely to be magnified when the task at hand requires frequent shifts of visual attention from head-coupled imagery to a fixed-CRT display. A study was conducted to determine the effects of eye dominance on a dual-display target-search task. Eight participants determined the presence/absence of a target amongst several decoys while using a head-coupled, see-through, monocular HMD in combination with a fixed-CRT display. Performance data did not reveal any significant eye-dominance effects. Additionally, there were no significant effects on participants' subjective preference between dominant and non-dominant eye for this task. Finally, it took significantly more time to determine that a target was not present than to identify a target that was present. However, there was a trend for female subjects to search longer before concluding that a target was absent.