scholarly journals Off-Line Camera-Based Calibration for Optical See-Through Head-Mounted Displays

2019 ◽  
Vol 10 (1) ◽  
pp. 193 ◽  
Author(s):  
Fabrizio Cutolo ◽  
Umberto Fontana ◽  
Nadia Cattari ◽  
Vincenzo Ferrari
Keyword(s):  
Real World ◽  
Calibration Procedure ◽  
Human Element ◽  
Spatial Alignment ◽  
Head Mounted Displays ◽  
Eye Motion ◽  
Generic Position ◽  
Planar Pattern ◽  
Camera Position ◽  
Planar Homography

In recent years, the entry into the market of self contained optical see-through headsets with integrated multi-sensor capabilities has led the way to innovative and technology driven augmented reality applications and has encouraged the adoption of these devices also across highly challenging medical and industrial settings. Despite this, the display calibration process of consumer level systems is still sub-optimal, particularly for those applications that require high accuracy in the spatial alignment between computer generated elements and a real-world scene. State-of-the-art manual and automated calibration procedures designed to estimate all the projection parameters are too complex for real application cases outside laboratory environments. This paper describes an off-line fast calibration procedure that only requires a camera to observe a planar pattern displayed on the see-through display. The camera that replaces the user’s eye must be placed within the eye-motion-box of the see-through display. The method exploits standard camera calibration and computer vision techniques to estimate the projection parameters of the display model for a generic position of the camera. At execution time, the projection parameters can then be refined through a planar homography that encapsulates the shift and scaling effect associated with the estimated relative translation from the old camera position to the current user’s eye position. Compared to classical SPAAM techniques that still rely on the human element and to other camera based calibration procedures, the proposed technique is flexible and easy to replicate in both laboratory environments and real-world settings.

scholarly journals Characterization of Visual Acuity and Contrast Sensitivity using Head-Mounted Displays in a Virtual Environment: A Pilot Study

2019 ◽  
Vol 63 (1) ◽  
pp. 547-551
Author(s):  
David Sproule ◽  
Rosemarie Figueroa Jacinto ◽  
Steve Rundell ◽  
Jacob Williams ◽  
Sam Perlmutter ◽  
...  
Keyword(s):  
Visual Acuity ◽  
Virtual Reality ◽  
Pilot Study ◽  
Contrast Sensitivity ◽  
Virtual Environment ◽  
Real World ◽  
Appropriate Use ◽  
Head Mounted Displays ◽  
Visualization Tools

Virtual reality (VR) and personal head-mounted displays (HMDs) can be a viable tool for the presentation of scientifically accurate and valid demonstrative data in the courtroom. However, the capabilities and limitations of the technology need to be fully characterized. The current pilot study evaluated visual acuity and contrast sensitivity using two commercially available HMDs (Oculus Rift and HTC Vive Pro). Preliminary findings indicated that visual acuity and contrast sensitivity experienced in VR may be less than what is experienced in real-world scenarios. The current pilot study provides a quantitative approach for characterizing the limitations of VR with respect to visual acuity and contrast sensitivity, and provides recommendations for the appropriate use of this technology when performing forensic investigations and developing visualization tools.

Using Virtual Reality to Study Subjective Time in Crowded Versus Uncrowded Environments

2019 ◽  
Vol 126 (5) ◽  
pp. 737-752 ◽  
Author(s):  
Kazuma Shimokawa ◽  
Eriko Sugimori
Keyword(s):  
Virtual Reality ◽  
Time Perception ◽  
Real World ◽  
Daily Life ◽  
Time Estimation ◽  
Subjective Time ◽  
Crowded Condition ◽  
Head Mounted Displays ◽  
Nature Park ◽  
Human Density

Human density in different locations influences time estimation. In this article, we report three experiments investigating whether research in virtual reality (VR) environments would replicate this earlier finding. In our first experiment, 35 participants wore head-mounted VR displays and watched two videos showing a cityscape and a countryside. While watching each video, participants were asked to provide their perceptions of 30 seconds of time passage. Perceived time in the cityscape condition was longer than in the countryside condition. In our second experiment, 43 participants wore head-mounted VR displays and watched two videos showing a crowded and uncrowded Ikebukuro station. While watching these videos, participants were asked to provide their perceptions of 60 seconds of time passage. Perceived time in the crowded condition was longer relative to the uncrowded condition. In our third experiment, 21 participants wore head-mounted displays and watched two videos showing a crowded and uncrowded nature park. While watching the videos, participants were asked to provide their perceptions of 60 seconds of time passage. These repeated findings in VR environments of longer time perception in crowded versus uncrowded conditions were similar to data reported by who examined how location and human density affected subjective time in the real world. We discussed the implications of the VR tool in subjective time research and how people perceive and use VR environments in daily life.

Helmet Mounted Display Layouts

2016 ◽  
Vol 60 (1) ◽  
pp. 1495-1498
Author(s):  
Victor S. Finomore ◽  
Christopher K. McClernon ◽  
Jantz V. Johnson ◽  
Jacob K. Snow ◽  
Jessica M. Steuber
Keyword(s):  
Real World ◽  
Visual Display ◽  
Relevant Information ◽  
Attention Allocation ◽  
Visual Displays ◽  
Information Displays ◽  
Head Mounted Displays ◽  
Alternative Means

Head mounted displays (HMDs) are being explored as an alternative means of displaying relevant information to dismounted operators. The goal of this project was to examine different visual display concepts and evaluate participant’s attention allocation to information presented on their HMD. Additionally, their ability to detect potential threats in the environment was also evaluated. This information will help revamp the design of information displays for HMDs. The task in this study required participants to monitor their HMD for critical alerts and respond accordingly while also making shoot/no shoot decisions to threats in their environment. We hypothesized that as information is presented in different layouts on the HMD, it will reduce the participants’ ability to detect real world events. Accuracy of the shoot/no shoot decisions was collected along with accuracy of detection of information on the HMD. We found that shooting performance was not affected between the three HMD layouts however information detected on the HMD was worst when all information was in the center of the HMD. The data from this study will be used to help develop intelligent visual displays used by Battlefield Airmen to accomplish their mission.

scholarly journals First-perspective spatial alignment effects from real-world exploration

2007 ◽  
Vol 35 (6) ◽  
pp. 1432-1444 ◽  
Author(s):  
Paul N. Wilson ◽  
Duncan A. Wilson ◽  
Laura Griffiths ◽  
Sarah Fox
Keyword(s):  
Real World ◽  
Spatial Alignment

Identifying the Pose Between a Head Mounted Display and a Head Pose Sensor

2000 ◽  
Author(s):  
Craig Reynolds ◽  
Louis J. Everett ◽  
Richard A. Volz
Keyword(s):  
Real World ◽  
Theoretical Basis ◽  
Virtual Reality Environment ◽  
Virtual Scene ◽  
The Real ◽  
Head Mounted Display ◽  
Real Scene ◽  
Head Mounted Displays ◽  
Virtual Display ◽  
Enhanced Reality

Abstract Head mounted displays (HMDs) are common hardware in a virtual reality environment. Sensors are commonly installed on the helmet to provide information about where the operator is looking. If the operator rotates the helmet, the virtual scene should rotate correspondingly. If the point of rotation (POR) of the operator’s head differs from the POR used to transform the image, the display may behave in bizarre ways. In “enhanced reality” and similar applications the virtual scene must also accurately correspond to the real world. When the virtual scene must accurately correspond to a real scene, it becomes necessary to accurately match the virtual display to the real world. A method for automatically collecting data to align these scenes is described and demonstrated in this paper. A theoretical basis for the method and experimental data are presented. Results indicate that the underlying assumptions of the theory are reasonable and that the errors in the method are reasonable.

World Authorship

2020 ◽  
Keyword(s):  
Real World ◽  
World Literature ◽  
World History ◽  
Literary Texts ◽  
Early Nineteenth Century ◽  
Human Element ◽  
The People ◽  
The World ◽  
Real Places ◽  
Different Parts

Booksellers, authors, and academics have been talking about world literature since Goethe made the term fashionable in the early nineteenth century. Yet amidst all the talk of books that ‘circulate’ and literature as a kind of ‘universal property’ that can function as a ‘window on the world’, how do we account for the people who live in real places, and who write, translate, market, and read the texts that travel on these global journeys? This handbook breaks new ground by showing how to bring together the real-world contexts of authorship with the literary worlds of fiction through the concept of the world author. ‘World authorship’ is a practical update on Michel Foucault’s ‘author function’ that significantly expands the network of people and practices involved with literature and is at the same time more grounded in the study of actual literary texts. The concept is set out in detail in a rigorous introduction followed by twenty-five keyword chapters that cover all core aspects of world authorship, from ‘Beginnings’ to ‘Voice’, and have been written by professionals who work right across the sector. In its entirety, the handbook illuminates how literature is made and shared in different parts of the world and at different times of world history. At the heart of all contributions, however, is one key question: where is the human element in world literature? Established authors, translators, publishers, prize judges, and festival coordinators as well as academics from a range of different disciplinary backgrounds collectively give us the answer.

scholarly journals Optical See-Through Head-Mounted Displays With Short Focal Distance: Conditions for Mitigating Parallax-Related Registration Error

2020 ◽  
Vol 7 ◽  
Author(s):  
Fabrizio Cutolo ◽  
Nadia Cattari ◽  
Umberto Fontana ◽  
Vincenzo Ferrari
Keyword(s):  
High Precision ◽  
Peripersonal Space ◽  
Calibration Procedure ◽  
Depth Range ◽  
Focal Distance ◽  
Registration Error ◽  
Head Mounted Displays ◽  
Beneficial Impact ◽  
Manual Tasks ◽  
Application Fields

Optical see-through (OST) augmented reality head-mounted displays are quickly emerging as a key asset in several application fields but their ability to profitably assist high precision activities in the peripersonal space is still sub-optimal due to the calibration procedure required to properly model the user's viewpoint through the see-through display. In this work, we demonstrate the beneficial impact, on the parallax-related AR misregistration, of the use of optical see-through displays whose optical engines collimate the computer-generated image at a depth close to the fixation point of the user in the peripersonal space. To estimate the projection parameters of the OST display for a generic viewpoint position, our strategy relies on a dedicated parameterization of the virtual rendering camera based on a calibration routine that exploits photogrammetry techniques. We model the registration error due to the viewpoint shift and we validate it on an OST display with short focal distance. The results of the tests demonstrate that with our strategy the parallax-related registration error is submillimetric provided that the scene under observation stays within a suitable view volume that falls in a ±10 cm depth range around the focal plane of the display. This finding will pave the way to the development of new multi-focal models of OST HMDs specifically conceived to aid high-precision manual tasks in the peripersonal space.

Seeing Colours: Addressing Colour Vision Deficiency with Vision Augmentations using Computational Glasses

2022 ◽  
Vol 29 (3) ◽  
pp. 1-53
Author(s):  
Jonathan Sutton ◽  
Tobias Langlotz ◽  
Alexander Plopski
Keyword(s):  
Literature Review ◽  
Visual Impairment ◽  
Real World ◽  
Colour Vision ◽  
State Of The Art ◽  
The State ◽  
Colour Vision Deficiency ◽  
Compensation Methods ◽  
Head Mounted Displays

Colour vision deficiency is a common visual impairment that cannot be compensated for using optical lenses in traditional glasses, and currently remains untreatable. In our work, we report on research on Computational Glasses for compensating colour vision deficiency. While existing research only showed corrected images within the periphery or as an indirect aid, Computational Glasses build on modified standard optical see-through head-mounted displays and directly modulate the user’s vision, consequently adapting their perception of colours. In this work, we present an exhaustive literature review of colour vision deficiency compensation and subsequent findings; several prototypes with varying advantages—from well-controlled bench prototypes to less controlled but higher application portable prototypes; and a series of studies evaluating our approach starting with proving its efficacy, comparing to the state-of-the-art, and extending beyond static lab prototypes looking at real world applicability. Finally, we evaluated directions for future compensation methods for computational glasses.

scholarly journals The (human) science of medical virtual learning environments

2011 ◽  
Vol 366 (1562) ◽  
pp. 276-285 ◽  
Author(s):  
Robert J. Stone
Keyword(s):  
Human Factors ◽  
Real World ◽  
Large Scale ◽  
Surgical Simulation ◽  
Interactive Systems ◽  
Graphics Hardware ◽  
Training Systems ◽  
Transfer Of Skills ◽  
Technological Advances ◽  
Head Mounted Displays

The uptake of virtual simulation technologies in both military and civilian surgical contexts has been both slow and patchy. The failure of the virtual reality community in the 1990s and early 2000s to deliver affordable and accessible training systems stems not only from an obsessive quest to develop the ‘ultimate’ in so-called ‘immersive’ hardware solutions, from head-mounted displays to large-scale projection theatres, but also from a comprehensive lack of attention to the needs of the end users. While many still perceive the science of simulation to be defined by technological advances, such as computing power, specialized graphics hardware, advanced interactive controllers, displays and so on, the true science underpinning simulation—the science that helps to guarantee the transfer of skills from the simulated to the real—is that of human factors, a well-established discipline that focuses on the abilities and limitations of the end user when designing interactive systems, as opposed to the more commercially explicit components of technology. Based on three surgical simulation case studies, the importance of a human factors approach to the design of appropriate simulation content and interactive hardware for medical simulation is illustrated. The studies demonstrate that it is unnecessary to pursue real-world fidelity in all instances in order to achieve psychological fidelity—the degree to which the simulated tasks reproduce and foster knowledge, skills and behaviours that can be reliably transferred to real-world training applications.

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