Proceedings Volume 8735

Head- and Helmet-Mounted Displays XVIII: Design and Applications

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Proceedings Volume 8735

Head- and Helmet-Mounted Displays XVIII: Design and Applications

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Volume Details

Date Published: 22 May 2013
Contents: 4 Sessions, 11 Papers, 0 Presentations
Conference: SPIE Defense, Security, and Sensing 2013
Volume Number: 8735

Table of Contents

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Table of Contents

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  • Front Matter: Volume 8735
  • HMD Components
  • Human Factors for HMDs
  • Systems Perspectives
Front Matter: Volume 8735
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Front Matter: Volume 8735
This PDF file contains the front matter associated with SPIE Proceedings Volume 8735, including the Title Page, Copyright information, Table of Contents, and the Conference Committee listing.
HMD Components
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Scorpion hybrid optical-based inertial tracker (HObIT)
Robert Atac, Eric Foxlin
Thales Visionix has developed a new helmet tracker based on a hybrid inertial optical approach. It uses the inside-out concept of the InterSense VisTracker technology, which has been acquired by Thales Visionix, upgraded with a tiny high-performance NavChip Inertial Measurement Unit (IMU). A unique feature of the tracker is that there is no aircraft mounted equipment. A group of small circular barcode-like fiducial stickers are placed on the interior surface of the cockpit. The tracker allows operation in both hybrid inertial/optical and inertial-only modes, which it seamlessly switches between as the pilot’s helmet goes in and out of the optical tracking zone. This paper describes the tracker, its features and performance.
Novel method for characterization and compensation for canopy distortion over a large head box
Robert Atac, Mark Fischler
Thales Visionix, a wholly owned subsidiary of Thales Communications, Inc., has developed a novel method for characterization of canopy distortion for a large head box. Canopy distortion occurs when the user is looking through any curved transparency. Any helmet mounted display system must either compensate for this distortion, or add canopy distortion error to its total error budget. To date, canopies have been characterized for only a few discrete locations in the cockpit. This results in a dilution of canopy distortion compensation as the pilot will rarely sit in one of the few defined locations. The method described herein allows for canopy distortion characterization and compensation for the entire HMD head-box.
Active matrix organic light emitting diode (AMOLED) performance and life test results
David A. Fellowes, Michael E. Botkin, Russell S. Draper, et al.
The U.S. Army and eMagin Corporation established a Cooperative Research and Development Agreement (CRADA) to characterize the ongoing improvements in the lifetime of OLED displays. This CRADA also called for the evaluation of OLED performance as the need arises, especially when new products are developed or when a previously untested parameter needs to be understood. In 2006, eMagin Corporation developed long-life OLED-XL devices for use in their AMOLED microdisplays for head-worn applications. Through Research and Development programs from 2007 to 2012 with the U.S. Government, eMagin made additional improvements in OLED life and developed the first SXGA (1280 X 1024 with triad pixels) and WUXGA (1920 X 1200 with triad pixels) OLED microdisplays. US Army RDECOM CERDEC NVESD conducted life and performance tests on these displays, publishing results at the 2012, 2011, 2010, 2009, 2008, and 2007 SPIE Defense, Security and Sensing Symposia. Life and performance tests have continued through 2013, and this data will be presented along with a comparison to previous data. This should result in a better understanding of the applicability of AMOLEDs in military and commercial head mounted systems, where good fits are made, and where further development might be desirable.
Dynamic sunlight filter (DSF) for HMD: controlling background illumination in a passive way
Ariela Donval, Noam Gross, Eran Partouche, et al.
In see-through HMD the background illumination is a crucial factor, which influences the ability of viewing the display. When using the HMD at a very bright day, the display image risks vanishing due to sun illumination. However, at a very cloudy day, one needs all the light to pass through the display to the user’s eye. The need for a better light control was our trigger for developing a Dynamic Sunlight Filter (DSF), which is a passive solution dedicated to regulate sunlight overpower events.
Sampled MTF of fused fiber optic components and bonded assemblies
Fused fiber optic devices are bundles of glass optical fibers that have been successively bundled and drawn to smaller and smaller sizes, effectively creating a “zero optical path window”. Due to the nature of fiber’s clad and core design, pixelization or sampling of the resulting image occurs; this sampling fundamentally degrades the image. Degradation of a resulting image caused by an optical system can be quantified by way of its Modulation Transfer Function. However, since fused fiber optic devices first sample then effectively project the original image, they do not meet the Fourier transform’s prerequisite conditions of being linear and isoplanatic. Current technologies at SCHOTT Lighting and Imaging have initiated a study to determine methodology for measuring the sampled modulation transfer function of bonded assemblies such as bonded Faceplate-to-OLED and Faceplate-tosensor assemblies. The use of randomly generated targets imaged through the bonded assemblies proved to be a useful tactic. This paper discusses the test methods developed and subsequent measurement of the sampled modulation transfer function of fused fiber optic bundles and bonded assemblies.
Human Factors for HMDs
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Insight into vergence/accommodation mismatch
Prolonged use of conventional stereo displays causes viewer discomfort and fatigue because of the vergenceaccommodation conflict. We used a novel volumetric display to examine how viewing distance, the sign of the vergenceaccommodation conflict, and the temporal properties of the conflict affect discomfort and fatigue. In the first experiment, we presented a fixed conflict at short, medium, and long viewing distances. We compared subjects’ symptoms in that condition and one in which there was no conflict. We observed more discomfort and fatigue with a given vergenceaccommodation conflict at the longer distances. The second experiment compared symptoms when the conflict had one sign compared to when it had the opposite sign at short, medium, and long distances. We observed greater symptoms with uncrossed disparities at long distances and with crossed disparities at short distances. The third experiment compared symptoms when the conflict changed rapidly as opposed to slowly. We observed more serious symptoms when the conflict changed rapidly. These findings help define comfortable viewing conditions for stereo displays.
Testing and evaluation of a wearable augmented reality system for natural outdoor environments
David Roberts, Alberico Menozzi, James Cook, et al.
This paper describes performance evaluation of a wearable augmented reality system for natural outdoor environments. Applied Research Associates (ARA), as prime integrator on the DARPA ULTRA-Vis (Urban Leader Tactical, Response, Awareness, and Visualization) program, is developing a soldier-worn system to provide intuitive ‘heads-up’ visualization of tactically-relevant geo-registered icons. Our system combines a novel pose estimation capability, a helmet-mounted see-through display, and a wearable processing unit to accurately overlay geo-registered iconography (e.g., navigation waypoints, sensor points of interest, blue forces, aircraft) on the soldier’s view of reality. We achieve accurate pose estimation through fusion of inertial, magnetic, GPS, terrain data, and computer-vision inputs. We leverage a helmet-mounted camera and custom computer vision algorithms to provide terrain-based measurements of absolute orientation (i.e., orientation of the helmet with respect to the earth). These orientation measurements, which leverage mountainous terrain horizon geometry and mission planning landmarks, enable our system to operate robustly in the presence of external and body-worn magnetic disturbances. Current field testing activities across a variety of mountainous environments indicate that we can achieve high icon geo-registration accuracy (<10mrad) using these vision-based methods.
Systems Perspectives
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Advancements in HMD technology: the DARPA-sponsored SCENICC program
Randall Sprague, Arthur Zhang, Scott Cookson, et al.
In this paper we report on the technical developments of the head worn display (HWD) for DARPA’s SCENICC program. The goal of the SCENICC program is to provide the warfighter with vision capabilities exceeding normal human vision. This is being achieved with an advanced imaging system that is able to capture the surrounding scene with superior visual acuity, contrast sensitivity, and wavelength sensitivity. With this increased visual information density, intelligent image processing provides imagery to the wearer’s eyes via an advanced HWD. The goal of this HWD is to provide digital visual information at the limits of human perception over a field of view near the human peripheral vision limits. This represents a tremendous amount of information requiring novel concepts in order to achieve such ambitious goals. One important concept is the use of imaging optics located directly on the eye, moving with the eye as it changes its gaze angle. A second concept is the use of demagnification optics to convert a large, low spatial resolution image into a smaller, high spatial resolution image. This is done in conjunction with image processing that is constantly modifying the image presented based on real-time pupil tracking. In addition to enabling a high performance optical system, integrating the imaging optical components into contact lenses eliminates much of the bulky imaging optics from the HWD itself creating a high performance wearable display in a standard protective eyewear form factor. The resulting quantum advance in HWD performance will enable HWDs to expand well beyond their current limited roles.
HMD digital night vision system for fixed wing fighters
Digital night sensor technology offers both advantages and disadvantages over standard analog systems. As the digital night sensor technology matures and disadvantages are overcome, the transition away from analog type sensors will increase with new programs. In response to this growing need RCEVS is actively investing in digital night vision systems that will provide the performance needed for the future. Rockwell Collins and Elbit Systems of America continue to invest in digital night technology and have completed laboratory, ground and preliminary flight testing to evaluate the important key factors for night vision. These evaluations have led to a summary of the maturity of the digital night capability and status of the key performance gap between analog and digital systems. Introduction of Digital Night Vision Systems can be found in the roadmap of future fixed wing and rotorcraft programs beginning in 2015. This will bring a new set of capabilities to the pilot that will enhance his abilities to perform night operations with no loss of performance.
Optical see-through head-mounted display with occlusion capability
Chunyu Gao, Yuxiang Lin, Hong Hua
Lack of mutual occlusion capability between computer-rendered and real objects is one of fundamental problems for most existing optical see-through head-mounted displays (OST-HMD). Without the proper occlusion management, the virtual view through an OST-HMD appears “ghost-like”, floating in the real world. To address this challenge, we have developed an innovative optical scheme that uniquely combines the eyepiece and see-through relay optics to achieve an occlusion-capable OST-HMD system with a very compelling form factor and high optical performances. The proposed display system was based on emerging freeform optical design technologies and was designed for highly efficient liquid crystal on silicon (LCoS) type spatial light modulator (SLM) and bright Organic LED (OLED) microdisplay. The proposed display technology was capable of working in both indoor and outdoor environments. Our current design offered a 1280x1024 color resolution based on 0.8" microdisplay and SLM. The MTF values for the majority of the fields at the cutoff frequency of 40lps/mm, which is determined by the pixel size of the microdisplay, are better than 15%. The design achieved a diagonal FOV of 40 degrees, 31.7 degrees horizontally and 25.6 degrees vertically, an exit pupil diameter of 8mm (non-vignetted), and an eye clearance of 18mm. The optics weights about 20 grams per eye. Our proposed occlusion capable OST-HMD system can easily find myriads of applications in various military and commercial sectors such as military training, gaming and entertainment.