This PDF file contains the front matter associated with SPIE Proceedings Volume 7326, including the Title Page, Copyright information, Table of Contents, and the Conference Committee listing.

A collaborative occupational health study has been undertaken by Headquarters Army Aviation, Middle Wallop, UK, and the U.S. Army Aeromedical Research Laboratory, Fort Rucker, Alabama, to determine if the use of the Integrated Helmet and Display Sighting System (IHADSS) monocular helmet-mounted display (HMD) in the Apache AH Mk 1 attack helicopter has any long-term (10-year) effect on visual performance. The test methodology consists primarily of a detailed questionnaire and an annual battery of vision tests selected to capture changes in visual performance of Apache aviators over their flight career (with an emphasis on binocular visual function). Pilots using binocular night vision goggles serve as controls and undergo the same methodology. Currently, at the midpoint of the study, with the exception of a possible colour discrimination effect, there are no data indicating that the long-term use of the IHADSS monocular HMD results in negative effects on vision.

This study investigated the impact on near to eye displays on both operational and visual performance employing a human-in-the-loop simulation of straight-in ILS approaches while using a near to eye (NTE) display. The approaches were flown in simulated visual and instrument conditions while using either a binocular NTE or a monocular NTE display on either the dominant or non dominant eye. The pilot's flight performance, visual acuity, and ability to detect unsafe conditions on the runway were tested.

A flight study was conducted to assess the impact of hyperstereopsis on helicopter handling proficiency, workload and pilot acceptance. Three pilots with varying levels of night vision goggle and hyperstereo helmet-mounted display experience participated in the test. The pilots carried out a series of flights consisting of low-level maneuvers over a period of two weeks. Four of the test maneuvers, The turn around the tail, the hard surface landing, the hover height estimation and the tree-line following were analysed in detail. At the end of the testing period, no significant difference was observed in the performance data, between maneuvers performed with the TopOwl helmet and maneuvers performed with the standard night vision goggle. This study addressed only the image intensification display aspects of the TopOwl helmet system. The tests did not assess the added benefits of overlaid symbology or head slaved infrared camera imagery. These capabilities need to be taken into account when assessing the overall usefulness of the TopOwl system. Even so, this test showed that pilots can utilize the image intensification imagery displayed on the TopOwl to perform benign night flying tasks to an equivalent level as pilots using ANVIS. The study should be extended to investigate more dynamic and aggressive low level flying, slope landings and ship deck landings. While there may be concerns regarding the effect of hyperstereopsis on piloting, this initial study suggests that pilots can either adapt or compensate for hyperstereo effects with sufficient exposure and training. Further analysis and testing is required to determine the extent of training required.

Helmet-mounted display (HMD) designs have faced persistent head-supported mass and center of mass (CM) problems, especially HMD designs like night vision goggles (NVG) that utilize image intensification (I2) sensors mounted forward in front of the user's eyes. Relocating I2 sensors from the front to the sides of the helmet, at or below the transverse plane through the user's head CM, can resolve most of the CM problems. However, the resulting increase in the separation between the two I2 channels effectively increases the user's interpupillary distance (IPD). This HMD design is referred to as a hyperstero design and introduces the phenomenon of hyperstereopsis, a type of visual distortion where stereoscopic depth perception is exaggerated, particularly at distances under 200 feet (~60 meters). The presence of hyperstereopsis has been a concern regarding implementation of hyperstereo HMDs for rotary-wing aircraft. To address this concern, a flight study was conducted to assess the impact of hyperstereopsis on aircraft handling proficiency and pilot acceptance. Three rated aviators with differing levels of I2 and hyperstereo HMD experience conducted a series of flights that concentrated on low-level maneuvers over a two-week period. Initial and final flights were flown with a standard issue I2 device and a production hyperstereo design HMD. Interim flights were flown only with the hyperstereo HMD. Two aviators accumulated 8 hours of flight time with the hyperstereo HMD, while the third accumulated 6.9 hours. This paper presents data collected via written questionnaires completed by the aviators during the post-flight debriefings. These data are compared to questionnaire data from a previous flight investigation in which aviators in a copilot capacity, hands not on the flight controls, accumulated 8 flight hours of flight time using a hyperstereo HMD.

Modern helmet-mounted night vision devices, such as the Thales TopOwl^TM helmet, project imagery from intensifiers mounted on the sides of the helmet onto the helmet visor. This increased effective inter-ocular separation distorts several cues to depth and distance that are grouped under the term "hyperstereopsis". Stereoscopic depth perception, at near to moderate distances (several hundred metres), is subject to magnification of binocular disparities. Absolute distance perception at near distances (a few metres) is affected by increased "differential perspective" as well as an increased requirement for convergence of the eyes to achieve binocular fixation. These distortions result in visual illusions such as the "bowl effect" where the ground appears to rise up near the observer. Previous reports have indicated that pilots can adapt to these distortions after several hours of exposure. The present study was concerned with both the time course and the mechanisms involved in this adaptation. Three test pilots flew five sorties with a hyperstereo night vision device. Initially, pilots reported that they were compensating for the effects of hyperstereopsis, but on the third and subsequent sorties all reported perceptual adaptation, that is, a reduction in illusory perception. Given that this adaptation was the result of intermittent exposure, and did not produce visual aftereffects, it was not due to the recalibration of the relationship between binocular cues and depth/distance. A more likely explanation of the observed visual adaptation is that it results from a discounting of distorted binocular cues in favour of veridical monocular cues, such as familiar size, motion parallax and linear perspective.

JAXA (Japan Aerospace Exploration Agency), together with Shimadzu Corporation and NEC, has initiated a research project named SAVERH (Situation Awareness and Visual Enhancer for Rescue Helicopter) that aims at inventing method of presenting suitable pilot information to support helicopter search and rescue missions. As the initial stage of this research, a series of flight experiments was conducted to investigate the feasibility of operations enhanced by an E/SVS (Enhanced / Synthetic Vision System) and to clarify system issues. An integrated system comprising an HMD (Helmet Mounted Display) and a FLIR (Forward Looking Infrared) sensor were installed in a JAXA research helicopter, and Tunnel-in-the-Sky symbology and a Synthetic Terrain image combined with the FLIR image were presented on the HMD and/or on a Head Down Display (HDD). Through a total of 17 flights including night flights, the potential capability of the system was demonstrated while many issues for further investigation were identified.

Pilots identified an off-boresight cueing capability as one of the most urgently needed upgrades to the A-10C Weapon System. The currently fielded JHMCS appeared cost prohibitive, driving the need for a new solution that could provide day/night cueing capabilities. Gentex Visionix and Lockheed Martin Systems Integration initiated an accelerated development program that delivered an affordable system (Scorpion HMCS) to the Air Force for flight test, within a twelve month period. In addition to providing the required cueing capabilities, this new system displays color symbology and sensor video. Operational Utility Evaluation flight tests were performed on an A-10C aircraft by the ANG and AFRC Test Center.

Next generation night displays are expected to have higher resolution, larger field of view and lower costs. These displays will be expected to provide real world images at starlight overcast with minimal scintillation, improved dynamic range and symbology. VSI is developing a series of displays that will meet this demand and will provide an overview of the capabilities in this paper. We will address the requirements and design conflicts associated with the development of an all digital system. Finally, we will provide insight into the capability of an "all" digital system and its potential future.

We hypothesize that human-aware helmet display systems can drastically improve situation awareness (SA), reduce workload, and become the cognitive gateway to two-way human-systems information. We designed a ruggedized prototype helmet liner that was fitted with active electroencephalogram (EEG) electrodes and pulse oxymetry sensor. This liner was integrated into a helmet that was fitted with a binocular SR-100A helmet mounted display. We modified the SR-100A to include dual-eye tracking capability. The resulting system is able to pick up physiological signals from the wearer in real-time for cognitive state characterization by the Cognitive Avionics Tool Set (CATS). We conducted a preliminary test of the cognitive state estimation system in a simulated close-air-support task in the laboratory and found that workload throughout the mission could be gauged using physiological parameters. Cognitively-linked helmet systems can increase situation awareness by metering the amount of information based on available cognitive bandwidth and eventually, we feel that they will be able to provide anticipatory information to the user by means of cognitive intent recognition. Considerable design challenges lie ahead to create robust models of cognitive state characterization and intent recognition. However, the rewards of such efforts could be systems that allow a dramatic increase in human decision making ability and productivity in dynamical complex situations such as air combat or surface warfare.

Helmet-Mounted Display (HMD) technologies have been developing for over 3 decades and have been studied for multiple applications ranging from military aircraft, to virtual reality, augmented reality, entertainment and a host of other ideas. It would not be unreasonable to assume that after this much time they would be employed in our daily lives as ubiquitously as the common desktop monitor. However, this is simply not the case. How can this be when they can be used in so many ways for so many tasks? Throughout this work we will look at some of the reasons why as well of some of the ways they can be used.

Scientists and Engineers in the Air Force Research Laboratory (AFRL) are constantly asked what are the new technologies and concepts that are being developed to significantly increase the warfighters capabilities. The warfighting communities have different opinions and priorities based on their platform capabilities and operational requirements that the Laboratory has to make trade-offs to maximize the payoff on investment for the Air Force operator community in this tighter budget era. This paper will discuss the current state of helmet mounted displays in rotorcraft and fast jets as well as the future technology advancements needed to increase warfighter productive and/or reduce life cycle costs.

Virtual reality (VR) systems provide exciting new ways to interact with information and with the world. The visual VR environment can be synthetic (computer generated) or be an indirect view of the real world using sensors and displays. With the potential opportunities of a VR system, the question arises about what benefits or detriments a military pilot might incur by operating in such an environment. Immersive and compelling VR displays could be accomplished with an HMD (e.g., imagery on the visor), large area collimated displays, or by putting the imagery on an opaque canopy. But what issues arise when, instead of viewing the world directly, a pilot views a "virtual" image of the world? Is 20/20 visual acuity in a VR system good enough? To deliver this acuity over the entire visual field would require over 43 megapixels (MP) of display surface for an HMD or about 150 MP for an immersive CAVE system, either of which presents a serious challenge with current technology. Additionally, the same number of sensor pixels would be required to drive the displays to this resolution (and formidable network architectures required to relay this information), or massive computer clusters are necessary to create an entirely computer-generated virtual reality with this resolution. Can we presently implement such a system? What other visual requirements or engineering issues should be considered? With the evolving technology, there are many technological issues and human factors considerations that need to be addressed before a pilot is placed within a virtual cockpit.

This paper presents the design and first evaluation of a full-color 1280×3×1024 pixel, active matrix organic light emitting diode (AMOLED) microdisplay that operates at a low power of 200mW under typical operating conditions of 35fL, and offers a precision 30-bit RGB digital interface in a compact size (0.78-inch diagonal active area). The new system architecture developed by eMagin for the SXGA microdisplay, based on a separate FPGA driver and AMOLED display chip, offers several benefits, including better power efficiency, cost-effectiveness, more features for improved performance, and increased system flexibility.

The US 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. RDECOM CERDEC NVESD conducted life tests on these displays, finding over 200% lifetime improvement for the OLED-XL devices over the standard OLED displays, publishing results at the 2007 and 2008 SPIE Defense and Security Symposia^1,2. In 2008, eMagin Corporation made additional improvements on the lifetime of their displays and developed the first SXGA (1280 × 1024 triad pixels) OLED microdisplay. A summary of the life and performance tests run at CERDEC NVESD will be presented along with a recap of 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.

We report the progress in full-color 0.97-inch-diagonal SXGA and 0.57"-inch-diagonal XGA active matrix liquid crystal displays. The circuits for these displays are fabricated on 8-inch silicon-on-insulator (SOI) wafers, which are then transferred to glass wafers to produce transmissive liquid crystal displays. Significant power savings and display performance improvements have been made with innovations in display architectures and the use of indium tin oxid (ITO) pixels. The new thin efficient backlight with improved color spectrum also contributes to lower power consumption and better color gamut. The Mantech program for the SXGA display has enabled the processing of many wafers to resolve various production issues, which will result in substantially higher yield for the SXGA microdisplays.

Traditionally head up displays and helmet mounted displays use a conventional arrangement of complex lenses to generate a display for the pilot from an image source such as a Cathode Ray Tube (CRT) or Liquid Crystal Display (LCD). These systems tend to be complex, comprising many components and they also add mass and adversely modify the centre of the gravity of the helmet. This has resulted in the development of the Holographic Optical Waveguide, a revolutionary new optical technology which dramatically reduces size and mass whilst liberating the designer from many of the constraints inherent in conventional optical solutions. This technology is basically a way of moving light without the need for a complex arrangement of conventional lenses. This is made possible by embedding within the substrate a specially designed hologram which has carefully tailored set of optical properties. The image (or light waves) is constrained to follow a path through the substrate. As these waves pass through the substrate the hologram is programmed to allow some energy to escape in a carefully controlled manner reforming the image that was injected into the substrate. At the same time the hologram design modifies the image geometry such that the user views it as a full size conformal image precisely overlaid on his outside world view. Furthermore this image is maintained over a very large exit-pupil giving the user great flexibility in the installation of the display onto a helmet. The image is formed conventionally from a reflective LCD illuminated with a high brightness LED. The Q-Sight^TM Helmet Mounted Display (HMD) which exploits this concept is part of a modular-family of Helmet Mounted Displays; allowing the addition of capability as required in a flexible, low-cost way. The basic monocular QSightTM architecture offers plug-and-play solutions into any cockpit with either Analog (stroke) or Digital Video Interface (DVI) connections. This offers a significant upgrade opportunity to those users currently struggling with cumbersome legacy CRT using conventional glass optical lenses. Q-Sight^TM is configured to fit onto any aircrew helmet in service today, the large eye motion box permitting flexible installation onto loose fitting helmets. The Q-Sight^TM approach results in design solutions which are fully compatible with all in-service Night Vision Googles (NVGs) and does not require any adaptation to the NVG or its mounting bracket. This approach has distinct advantages that at night the user gets unimpaired Night Vision performance with very high quality symbology.

This paper presents a comparative analysis of pixel resolution of standard digital imaging formats to the imaging output of a Generation III image intensifier. The comparative analysis will focus on the application of recognition of a man size target at a specified distance in nighttime (starlight conditions) utilizing a 1X night vision system with 40° field of view (FOV). Simple geometric theory will be applied to determine image intensified pixel format, digital imaging formats, and man size target pixel coverage for respective imaging pixel format. Daylight and night time experiments are described in detail using the several digital CCD formats (640×480, 1280×1024, and 2615×1471) through a standard Generation III image intensifier (64 lp/mm) in a night vision monocular system (AN/PVS-14). Detailed image analysis is conducted and presented on experimental data. Paper has been cleared by DOD/OSR for Public Release under Ref: 05-S-0347 on December 13, 2004.

This paper presents a revisit of the traditional measurement of limiting resolution using tri-bar patterns of various digital imaging and image intensifier (I²) systems. Utilizing digital recording of target tri-bar images combined with modern image processing based "line scan" analysis, this reexamination will explore the utility and validity of measuring spatial limiting resolution of various digital electro-optical systems from high light to low light conditions. Also, this paper will provide a detailed line shape analysis of the tri-peak profiles derived from the limiting resolution measurements for low light level ranges provided by these electro-optical systems. Finally, this paper will examine an alternate method for determining limiting resolution using other modern off the shelf digital imaging algorithms/methods and compare this alternate method to the "line scan" method using the traditional tri-bar pattern system. Paper has been cleared by DOD/OSR for Public Release under OSR Ref: 08-S-2710 on November 17, 2008.

There is a need for variable transmission technology for Goggles, Spectacles, and visors for Helmet-Mounted Displays (HMDs). At present, most HMDs do not allow the pilot to control the transmission level of a flight visor while transitioning from high to low light levels throughout flight. Sunglasses are often used for non-HMD conditions but become impractical for HMD use. For individuals moving from high to low brightness levels, momentary blindness is an issue in both recreational sports and military applications. A user-controlled or automatically controllable variabletransmittance lens is a possible solution. The Eclipse Visible Electrochromic Device (EclipseECD^TM) is well suited for these light modulation applications. The EclipseECD^TM modulates light intensity by changing the absorption level under an applied electric field. The optical density may be continuously changed by varying voltage allowing for analog instead of digital (on/off) light levels. EclipseECD^TM is comprised of vacuum deposited layers of a transparent bottom electrode, an active element, and a transparent top electrode, incorporating an all, solid-state electrolyte. The solid-state electrolyte eliminates possible complications associated with gel-based or liquid crystal based technologies including lamination, and precludes the need for additional visor modifications. This all solid-state ECD system can be deposited on flexible substrates, eg. PET, PC, etc. The low-temperature deposition process enables direct application to polymer lenses and HMD flight visors. Additionally, the coating is easily manufactured; can be trimmed, has near spectral neutrality and fails in the clear (bleached) condition.

We have presented a new approach for Optical HMT (Head Motion Tracker) last year (Proc. SPIE 6955, 69550A1-11, 2008) [1]. In existing Magnetic HMT, it is inevitable to conduct pre-mapping in order to obtain sufficient accuracy because of magnetic field's distortion caused by metallic material around HMT, such as cockpit and helmet. Optical HMT is commonly known as mapping-free tracker; however, it has some disadvantages on accuracy, stability against sunlight conditions, in terms of comparison with Magnetic HMT. We have succeeded to develop new Optical HMT, which can overcome particular disadvantages by integration with two area cameras, LED markers, image processing techniques and inertial sensors with simple algorithm in laboratory level environment. We have also reported some experimental results conducted in laboratory, which proves good accuracy even in the sunlight condition. This time, we show actual performance of the Optical HMT in flight condition, including evaluation of stability against sunlight. Shimadzu Corp. and JAXA (Japan Aerospace Exploration Agency) is conducting joint research named SAVERH (Situation Awareness and Visual Enhancer for Rescue Helicopter) [2] that aims at inventing method of presenting suitable information to the pilot to support search and rescue missions by helicopters. The Optical HMT has been evaluated through a series of flight evaluation in SAVERH and demonstrated the operation concept.

Mixed reality training systems using Head Mounted Displays (HMDs) require very high precision knowledge of the 3D location and 3D orientation of the user's head. This is required by the system to know where to insert the synthetic actors and objects in the HMD. The inserted objects must appear stable and not jitter or drift. Moreover latency of less than 5 milliseconds for pose estimation is required for lag-free see-through HMD operation. We describe how to achieve this performance using a multi-camera based visual navigation system mounted on the HMD. A Kalman filter is used to integrate high rate estimates from an IMU with a visual odometry system and to predict head motion. Landmark matching and GPS when available are used to correct any drifts.

Rubber boots used on optical eye-pieces to control stray illumination from optics and displays used in the battlefield environment also creates a micro-environment where tear evaporation can induce condensation on eye-piece optics that obscures object or target recognition. The author presents condensation models to show the condition occurs under a broader range of conditions than previously recognized. Techniques are explained to control the problem.

This paper outlines an approach to simulate and validate the attenuation performance of Integrated Helmet Display designs within BAE Systems. The validation studies are performed at material coupon, sub-system and system levels of Display and Helmet designs to facilitate integrated Display Helmet model development and allow a rigorous assessment of model accuracy. Simulation results are presented which show close agreement with the shape of the acceleration history and peak acceleration values obtained in laboratory scale qualification tests conducted at the British Standards Institute (BSI). The final system level model provides a detailed insight into the key characteristics which effect attenuation performance in Integrated Display Helmet designs. The overall aim of this work is to develop and validate models which can be used to assess the influence of design modifications on current and future Display Helmet products within BAE Systems. The application of simulation for product development is regarded as a key driver within BAE Systems to reducing the development cost of Helmet Mounted Display (HMD) products and improving product performance.