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.

scholarly journals Wearable Augmented Reality Platform for Aiding Complex 3D Trajectory Tracing

Sensors ◽  
2020 ◽  
Vol 20 (6) ◽  
pp. 1612 ◽  
Author(s):  
Sara Condino ◽  
Benish Fida ◽  
Marina Carbone ◽  
Laura Cercenelli ◽  
Giovanni Badiali ◽  
...  
Keyword(s):  
Augmented Reality ◽  
High Precision ◽  
Ad Hoc ◽  
User Study ◽  
Peripersonal Space ◽  
Planar Structures ◽  
3D Printed ◽  
Quantitative Results ◽  
Manual Tasks ◽  
Wearable Augmented Reality

Augmented reality (AR) Head-Mounted Displays (HMDs) are emerging as the most efficient output medium to support manual tasks performed under direct vision. Despite that, technological and human-factor limitations still hinder their routine use for aiding high-precision manual tasks in the peripersonal space. To overcome such limitations, in this work, we show the results of a user study aimed to validate qualitatively and quantitatively a recently developed AR platform specifically conceived for guiding complex 3D trajectory tracing tasks. The AR platform comprises a new-concept AR video see-through (VST) HMD and a dedicated software framework for the effective deployment of the AR application. In the experiments, the subjects were asked to perform 3D trajectory tracing tasks on 3D-printed replica of planar structures or more elaborated bony anatomies. The accuracy of the trajectories traced by the subjects was evaluated by using templates designed ad hoc to match the surface of the phantoms. The quantitative results suggest that the AR platform could be used to guide high-precision tasks: on average more than 94% of the traced trajectories stayed within an error margin lower than 1 mm. The results confirm that the proposed AR platform will boost the profitable adoption of AR HMDs to guide high precision manual tasks in the peripersonal space.

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.

High Precision Automatic Alignment and its Computer Vision Technology

1989 ◽  
Vol 1 (3) ◽  
pp. 220-226
Author(s):  
Tohru Tanigawa ◽  
◽  
Toshitsugu Sawai ◽  
Tadashi Nakao
Keyword(s):  
Computer Vision ◽  
High Precision ◽  
Flexible Manufacturing ◽  
High Speed ◽  
Manufacturing Systems ◽  
Ultraviolet Rays ◽  
Human Ability ◽  
Automatic Alignment ◽  
Computer Vision Technology ◽  
Application Fields

Recently, industrial robotics and computer vision technology has become very important in flexible manufacturing systems and automated factories. Especially high precision automatic alignment technology beyond human ability is essential to some manufactures, and its application fields are extending rapidly. This paper describes the high precision automatic alignment system of large-sized LCD panels. The features of the system are (1) high precision and high speed detection of position using the special alignment mark, (2) high contrast image obtained by the use of ultraviolet rays, (3) new image-processing algorithms for improvement of system reliability.

Design and Implementation of IEEE 1588 High Precision Clock Synchronization Based on GPS Time Service

2012 ◽  
Vol 532-533 ◽  
pp. 292-296 ◽  
Author(s):  
Kang Wang ◽  
Yong Hui Hu ◽  
Zai Min He ◽  
Hong Jiao Ma
Keyword(s):  
High Precision ◽  
Time Synchronization ◽  
Clock Synchronization ◽  
Time Service ◽  
Ieee 1588 ◽  
Design And Implementation ◽  
Nanosecond Range ◽  
Application Fields ◽  
Timing Requirement ◽  
Precision Clock

In view of PTP high precise timing requirement for many application fields, GPS time service is provided with the advantages of high precision and high stabilization. The principle and timescale of PTP based on GPS are analyzed and discussed. And then a PTP time synchronization platform with GPS-based UTC time is designed and implemented, the correlative key design flowchart is described as well. Finally, the paper gives the experiment results, which show the time synchronization accuracies can reach nanosecond range.

scholarly journals Visual Behavior Modeling of Hazard Identification Assessment From Eye-Tracking Data

2020 ◽  
Author(s):  
Abner Cardoso Da Silva ◽  
Alberto Barbosa Raposo ◽  
Cesar Augusto Sierra Franco
Keyword(s):  
Virtual Environments ◽  
Low Cost ◽  
Real Life ◽  
Hazard Identification ◽  
Behavior Modeling ◽  
Visual Behavior ◽  
Gaze Behavior ◽  
Hazard Detection ◽  
Head Mounted Displays ◽  
Application Fields

The easier access to virtual reality head-mounted displays have assisted the use of this technology on research. In parallel, the integration of those devices with eye-trackers enabled new perspectives of visual attention analysis in virtual environments. Different research and application fields found in such technologies a viable way to train and assess individuals by reproducing, with low cost, situations that are not so easily recreated in real life. In this context, our proposal aims to develop a model to measure characteristics of safety professional’s gaze behavior during the hazard detection process.

scholarly journals The Impact of Dynamic Convergence on the Human Visual System in Head Mounted Displays

2021 ◽  
Author(s):  
◽  
Ryan Sumner
Keyword(s):  
Visual System ◽  
Human Visual System ◽  
Statistical Significance ◽  
Depth Range ◽  
Binocular Fusion ◽  
Virtual Objects ◽  
Beneficial Effects ◽  
Mixed Response ◽  
Head Mounted Displays ◽  
The Impact

<p>The Accommodation-Vergence Conflict (AVC) is a phenomenon in the area of Head-Mounted Displays (HMDs) and one of the key issues hindering the popularity of HMDs largely due to it causing a large number of users to suffer from simulator sickness. There have been several proposed solutions developed by previous researchers, including the introduction of 'Dynamic Convergence' (DC) which, addresses the AVC problem in terms of the vergence depth cue. DC also helps in the performance of binocular fusion when viewing at a close vergence depth. As of yet however, DC has not undergone detailed testing for a number of important cases, which limits the amount of data that has been collected on DC's interaction with the human visual system. In addition, no DC research as of yet has dealt with the effect of a change in vergence depth, and how that change in the vergence angle of the focal plane would effect a user.  Thus, this thesis adds to the growing body of research and knowledge in this field by implementing DC with the addition of some transitions between a change in vergence depth. This is done within the Unity3D game engine in order to further investigate the impact of DC with regard to viewing close virtual objects on HMDs through a number of cases. The added transitions are also tested to see if they have any beneficial effects for users when the vergence angle changes. The investigation is centered around a perception based performance/appreciation-oriented visual study whereby participants were asked about their ability to perform binocular fusion on close virtual objects that were either stationary or moving and varying distances and speeds. Participants were also asked to report any symptoms of discomfort.  The research has adopted a mixed methodology experimental approach by conducting user experiments and surveys, before analysing the results through both in-depth quantitative statistical analysis and a variety of qualitative statistical techniques in order to measure and investigate the scale of the problem associated with the impact of DC on the human visual system in HMDs when viewing close virtual objects.  From the investigation it was confirmed that the approximate effective vergence depth range for DC was 0.3m or less, with statistical significance confirmed at the 0.15m distance. Participants reported having an easier time performing binocular fusion at these closer distances while DC was enabled. As a result of this, the majority of cases and scenarios did not report any significant negative responses in terms of discomfort symptoms. However attempts at improving DC with a transition between vergence depths were met with a mixed response from participants. While the need of a transition way be dependent on the user, there still exists some demand for one, thus it should still be available as an option.</p>

scholarly journals The Impact of Dynamic Convergence on the Human Visual System in Head Mounted Displays

2021 ◽  
Author(s):  
◽  
Ryan Sumner
Keyword(s):  
Visual System ◽  
Human Visual System ◽  
Statistical Significance ◽  
Depth Range ◽  
Binocular Fusion ◽  
Virtual Objects ◽  
Beneficial Effects ◽  
Mixed Response ◽  
Head Mounted Displays ◽  
The Impact

<p>The Accommodation-Vergence Conflict (AVC) is a phenomenon in the area of Head-Mounted Displays (HMDs) and one of the key issues hindering the popularity of HMDs largely due to it causing a large number of users to suffer from simulator sickness. There have been several proposed solutions developed by previous researchers, including the introduction of 'Dynamic Convergence' (DC) which, addresses the AVC problem in terms of the vergence depth cue. DC also helps in the performance of binocular fusion when viewing at a close vergence depth. As of yet however, DC has not undergone detailed testing for a number of important cases, which limits the amount of data that has been collected on DC's interaction with the human visual system. In addition, no DC research as of yet has dealt with the effect of a change in vergence depth, and how that change in the vergence angle of the focal plane would effect a user.  Thus, this thesis adds to the growing body of research and knowledge in this field by implementing DC with the addition of some transitions between a change in vergence depth. This is done within the Unity3D game engine in order to further investigate the impact of DC with regard to viewing close virtual objects on HMDs through a number of cases. The added transitions are also tested to see if they have any beneficial effects for users when the vergence angle changes. The investigation is centered around a perception based performance/appreciation-oriented visual study whereby participants were asked about their ability to perform binocular fusion on close virtual objects that were either stationary or moving and varying distances and speeds. Participants were also asked to report any symptoms of discomfort.  The research has adopted a mixed methodology experimental approach by conducting user experiments and surveys, before analysing the results through both in-depth quantitative statistical analysis and a variety of qualitative statistical techniques in order to measure and investigate the scale of the problem associated with the impact of DC on the human visual system in HMDs when viewing close virtual objects.  From the investigation it was confirmed that the approximate effective vergence depth range for DC was 0.3m or less, with statistical significance confirmed at the 0.15m distance. Participants reported having an easier time performing binocular fusion at these closer distances while DC was enabled. As a result of this, the majority of cases and scenarios did not report any significant negative responses in terms of discomfort symptoms. However attempts at improving DC with a transition between vergence depths were met with a mixed response from participants. While the need of a transition way be dependent on the user, there still exists some demand for one, thus it should still be available as an option.</p>

High-precision reflectivity measurements: improvements in the calibration procedure

2003 ◽  
Author(s):  
Marco Jupe ◽  
Florian Grossmann ◽  
Kai Starke ◽  
Detlev Ristau
Keyword(s):  
High Precision ◽  
Calibration Procedure

Optical System Design of High-Precision Static Star Simulator

2013 ◽  
Vol 552 ◽  
pp. 3-7
Author(s):  
Xue Tao ◽  
Guo Yu Zhang ◽  
Qiong Wu ◽  
Ming Jiao Sun
Keyword(s):  
High Precision ◽  
Optical System ◽  
Optical Design ◽  
Quality Analysis ◽  
Focal Distance ◽  
Imaging Quality ◽  
Technical Requirements ◽  
Effective Aperture ◽  
Design Requirements ◽  
Design Characteristics

In order to satisfy the high－precision technical requirements of static star simulator, according to the optical design characteristics of traditional star simulator, the paper designed a collimating objective optical system with little distortion, flat field apochromatism, made the simulated star chart by parallel light exit, on the entrance of star sensor produced star chart, and realized the static star simulator could simulate star accuracy static star simulator. This system is designed by four lenses, effective aperture is 20mm, and focal distance is 190.84mm. By imaging quality analysis it shows that in the angular field of view 6°×6°, the relative distortion of collimating objective optical system is less than 0.01%, MTF at 40lp/mm reached 0.6, and has higher imaging quality. It proves that the optical system meet the design requirements.

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