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Head mounted display

Chen-Huei Lin, Ching-Kong Chao, Yi-Hsuan Tang, Jinn Lin
INTRODUCTION: Reports of driver slippage leading to difficult locking screw removals have increased since the adoption of titanium for screw fabrication; the use of titanium is known to cause cross-threading and cold welding. Such problems occur most frequently in screws with hex sockets, and may cause serious surgical complications. This study aimed to improve screw socket design to prevent slippage and difficult screw removal. MATERIALS AND METHODS: Three types of small sockets (hex, Torx, and cruciate) and six types of large sockets (hex, Torx, Octatorx, Torx+ I, Torx+ II, and Torx+ III) with screw head diameters of 5...
February 3, 2018: Injury
Wagner Souza Silva, Aravind Gayatri, Sangani Samir, Lamontagne Anouk
This study examines how three types of obstacles (cylinder, virtual human and virtual human with footstep sounds) affect circumvention strategies of healthy young adults. Sixteen participants aged 25.2 ± 2.5 years (mean ± 1SD) were tested while walking overground and viewing a virtual room through a helmet mounted display. As participants walked towards a stationary target in the far space, they avoided an obstacle (cylinder or virtual human) approaching either from the right (+40°), left (-40°) or head-on (0°)...
January 31, 2018: Gait & Posture
Takanori Chihara, Akihiko Seo
A head-mounted display (HMD) with inappropriate mass and center of mass (COM) increases the physical workload of HMD users. The aim of this study was to investigate the effects of mass and COM of HMD on physical workload. Twelve subjects participated in this study. The mass and posteroanterior COM position were 0.8, 1.2, or 1.6 kg and -7.0, 0.0, or 7.0 cm, respectively. The subjects gazed at the target objects in four test postures: the neutral, look-up, body-bending, and look-down postures. The normalized joint torques for the neck and the lumbar region were calculated based on the measured segment angles...
April 2018: Applied Ergonomics
Shoaib R Soomro, Hakan Urey
We propose an integrated 3D display and imaging system using a head-mounted device and a special dual-purpose passive screen that can simultaneously facilitate 3D display and imaging. The screen is mainly composed of two optical layers, the first layer is a projection surface, which are the finely patterned retro-reflective microspheres that provide high optical gain when illuminated with head-mounted projectors. The second layer is an imaging surface made up of an array of curved mirrors, which form the perspective views of the scene captured by a head-mounted camera...
January 22, 2018: Optics Express
Jin Su Lee, Yoo Kwang Kim, Yong Hyub Won
We report a liquid lens based optical see-through head mounted display that can simultaneously display both a maxwellian view and a hologram. Holograms are reconstructed by an angular spectrum layer based synthesis method. A hologram and Maxwellian view are simultaneously displayed by focusing the liquid lens from 0 D to 20 D with 60 Hz. The hologram is reconstructed at a position 1.5 m from the eye, and it is confirmed that the Maxwellian view is clear, even if the focus of the eye changes from 50 cm to 1...
January 22, 2018: Optics Express
Gabriel J Diaz, Melissa S Parade, Sean L Barton, Brett R Fajen
The present study investigated differences in the pickup of information about the size and location of an obstacle in the path of locomotion. The main hypothesis was that information about obstacle location is most useful when it is sampled at a specific time during the approach phase, whereas information about obstacle size can be sampled at any point during the last few steps. Subjects approached and stepped over obstacles in a virtual environment viewed through a head-mounted display. In Experiment 1, a horizontal line on the ground indicating obstacle location was visible throughout the trial while information about obstacle height and depth was available only while the subject was passing through a viewing window located at one of four locations along the subject's path...
2018: PloS One
Takeru Utsugi
Holographic scattering (HS) is a phenomenon that occurs when a scattered light wave is recorded on a holographic recording medium and is important for applications using volume holograms, such as holographic data storage, three-dimensional displays, and waveguides for head-mounted displays. We investigated the occurrence mechanism and characteristics of HS occurring in angular-multiplex recording of plane-wave holograms on a photopolymer. First, the reconstruction condition of the hologram formed by scattered light waves during multiplex recording is formulated...
January 20, 2018: Applied Optics
Sebastian Andress, Alex Johnson, Mathias Unberath, Alexander Felix Winkler, Kevin Yu, Javad Fotouhi, Simon Weidert, Greg Osgood, Nassir Navab
Fluoroscopic x-ray guidance is a cornerstone for percutaneous orthopedic surgical procedures. However, two-dimensional (2-D) observations of the three-dimensional (3-D) anatomy suffer from the effects of projective simplification. Consequently, many x-ray images from various orientations need to be acquired for the surgeon to accurately assess the spatial relations between the patient's anatomy and the surgical tools. We present an on-the-fly surgical support system that provides guidance using augmented reality and can be used in quasiunprepared operating rooms...
April 2018: Journal of Medical Imaging
Sharon L Farra, Sherrill J Smith, Deborah L Ulrich
With increasing use of virtual reality simulation (VRS) in nursing education and given the vast array of technologies available, a variety of levels of immersion and experiences can be provided to students. This study explored two different levels of immersive VRS capability. Study participants included baccalaureate nursing students from three universities across four campuses. Students were trained in the skill of decontamination using traditional methods or with VRS options of mouse and keyboard or head-mounted display technology...
December 28, 2017: Nursing Education Perspectives
Kazushige Kimura, James F Reichert, Ashley Olson, Omid Ranjbar Pouya, Xikui Wang, Zahra Moussavi, Debbie M Kelly
Adult participants learned to reorient to a specific corner inside either a real or virtual rectangular room containing a distinct featural object in each corner. Participants in the virtual-reality (VR) condition experienced an immersive virtual version of the physical room using a head-mounted display (HMD) and customized manual wheelchair to provide self-movement. Following a disorientation procedure, people could reorient by using either the geometry of the room and/or the distinct features in the corners...
December 22, 2017: Scientific Reports
Austin Wilson, Hong Hua
State-of-the-art optical see-through head-mounted displays for augmented reality (AR) applications lack mutual occlusion capability, which refers to the ability to render correct light blocking relationship when merging digital and physical objects, such that the virtual views appear to be ghost-like and lack realistic appearance. In this paper, using off-the-shelf optical components, we present the design and prototype of an AR display which is capable of rendering per-pixel mutual occlusion. Our prototype utilizes a miniature organic light emitting display coupled with a liquid crystal on silicon type spatial light modulator to achieve an occlusion capable AR display offering a 30° diagonal field of view and an angular resolution of 1...
November 27, 2017: Optics Express
Keisuke Suzuki, Warrick Roseboom, David J Schwartzman, Anil K Seth
Altered states of consciousness, such as psychotic or pharmacologically-induced hallucinations, provide a unique opportunity to examine the mechanisms underlying conscious perception. However, the phenomenological properties of these states are difficult to isolate experimentally from other, more general physiological and cognitive effects of psychoactive substances or psychopathological conditions. Thus, simulating phenomenological aspects of altered states in the absence of these other more general effects provides an important experimental tool for consciousness science and psychiatry...
November 22, 2017: Scientific Reports
Ruth Ruscheweyh, Antonia Fritz, Thomas Eggert, Shahnaz-Christina Azad, Andreas Straube
Objective: There is increasing evidence that the cerebellum has a role in pain processing. The present study investigates whether chronic pain patients, who are likely to have altered pain processing, exhibit signs of subtle cerebellar dysfunction. We used oculomotor tasks to assess dysfunction of the associated neuronal networks, including the cerebellum. Methods: Thirty patients with chronic nonspecific spinal pain and 30 age- and sex-matched controls were enrolled...
November 18, 2017: Pain Medicine: the Official Journal of the American Academy of Pain Medicine
Tobias Huber, Tom Wunderling, Markus Paschold, Hauke Lang, Werner Kneist, Christian Hansen
PURPOSE: Virtual reality (VR) applications with head-mounted displays (HMDs) have had an impact on information and multimedia technologies. The current work aimed to describe the process of developing a highly immersive VR simulation for laparoscopic surgery. METHODS: We combined a VR laparoscopy simulator (LapSim) and a VR-HMD to create a user-friendly VR simulation scenario. Continuous clinical feedback was an essential aspect of the development process. We created an artificial VR (AVR) scenario by integrating the simulator video output with VR game components of figures and equipment in an operating room...
November 18, 2017: International Journal of Computer Assisted Radiology and Surgery
Chuchuan Hong, Shane Colburn, Arka Majumdar
A near-eye visor is one of the most vital components in a head-mounted display. Currently, freeform optics and waveguides are used to design near-eye visors, but these structures are complex and their field of view is limited when the visor is placed near the eye. In this paper, we propose a flat, freeform near-eye visor that uses a subwavelength patterned metasurface reflector. The visor design imparts a spatial phase profile on a projected display pattern and can be implemented using a micron-scale-thick metasurface...
November 1, 2017: Applied Optics
Aram Kim, Zixuan Zhou, Kari S Kretch, James M Finley
The ability to successfully navigate obstacles in our environment requires integration of visual information about the environment with estimates of our body's state. Previous studies have used partial occlusion of the visual field to explore how information about the body and impending obstacles are integrated to mediate a successful clearance strategy. However, because these manipulations often remove information about both the body and obstacle, it remains to be seen how information about the lower extremities alone is utilized during obstacle crossing...
July 2017: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
Anatoly M Smolovich, Valery Chernov
Novel optical elements containing semitransparent wavelike films embedded into the bulk of transparent material, which form a reflection image without transmitted light distortion, are studied. The dynamic theory of light diffraction by a locally periodic multilayer semitransparent wavelike film is developed. A simple analytical formula for near Bragg diffraction order intensity is obtained for the case when only one diffraction order lies within the hologram angular selectivity. The phase modulation of light transmitted through the optical element containing wavelike films is estimated for single-layer and multilayer wavelike films with an arbitrary shape of surface...
August 1, 2017: Applied Optics
Miaomiao Xu, Hong Hua
The human visual system can perceive a much wider range of contrast than the addressable dynamic range afforded by the state-of-art head mounted displays (HMD). Increasing the dynamic range of HMDs becomes critical especially for augmented reality applications where the dynamic range of outdoor scenes can be as large as 14 orders of magnitude. In this paper, we present the integrated work of the design, implementation, calibration, and image-rendering algorithm of a high dynamic range HMD system. By using a pair of LCoS microdisplays as the spatial light modulators, accompanied with the relay optics to optically overlay the modulation layers, we demonstrate the reconstruction of high dynamic range images with high accuracy...
September 18, 2017: Optics Express
Stephan M Gerber, Marie-Madlen Jeitziner, Patric Wyss, Alvin Chesham, Prabitha Urwyler, René M Müri, Stephan M Jakob, Tobias Nef
After prolonged stay in an intensive care unit (ICU) patients often complain about cognitive impairments that affect health-related quality of life after discharge. The aim of this proof-of-concept study was to test the feasibility and effects of controlled visual and acoustic stimulation in a virtual reality (VR) setup in the ICU. The VR setup consisted of a head-mounted display in combination with an eye tracker and sensors to assess vital signs. The stimulation consisted of videos featuring natural scenes and was tested in 37 healthy participants in the ICU...
October 16, 2017: Scientific Reports
Hojong Choi, Jaemyung Ryu, Changhan Yoon
PURPOSE: A conventional see-through head mount display contains many optical lenses, which can be problematic in image-guided treatment applications due to its size, weight, structure, and focus limitation. Therefore, we have designed a new type of see-through head mount display with a reduced number of optical lenses and an adequate optical resolution that can be utilized for image-guided treatment applications. MATERIALS AND METHODS: A new type of adjustable focus head mount display with expanded virtual images and an external treatment space that can be provided to the eyes of a user by enlarging the images of a small display is designed and investigated in this study...
October 16, 2017: Computer Assisted Surgery (Abingdon, England)
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