Current military thermal driver vision systems consist of a single Long Wave Infrared (LWIR) sensor mounted on a manually operated gimbal, which is normally locked forward during driving. The sensor video imagery is presented on a large area flat panel display for direct view. The Night Vision and Electronics Sensors Directorate and Kaiser Electronics are cooperatively working to develop a driver's Head Tracked Vision System (HTVS) which directs dual waveband sensors in a more natural head-slewed imaging mode. The HTVS consists of LWIR and image intensified sensors, a high-speed gimbal, a head mounted display, and a head tracker. The first prototype systems have been delivered and have undergone preliminary field trials to characterize the operational benefits of a head tracked sensor system for tactical military ground applications. This investigation will address the advantages of head tracked vs. fixed sensor systems regarding peripheral sightings of threats, road hazards, and nearby vehicles. An additional thrust will investigate the degree to which additive (A+B) fusion of LWIR and image intensified sensors enhances overall driving performance. Typically, LWIR sensors are better for detecting threats, while image intensified sensors provide more natural scene cues, such as shadows and texture. This investigation will examine the degree to which the fusion of these two sensors enhances the driver's overall situational awareness.

The Rooivalk Attack Helicopter is designed and manufactured by Denel Aviation of South Africa, and in service with the South African Air Force. The Helmet Mounted Sight and Display (HMSD) hardware is manufactured by Sextant Avionique of France. The HMSD symbology is developed by Denel Aviation and is specific to the weapons and roles of the aircraft. The HMSD has visor projected NVG and PNVS images, and Flight and Weapon Symbology incorporating head slaved weapon aiming, helmet-to-helmet cueing, and helmet to main sight cueing. The NVG/PNVS image selection and main image controls are incorporated in the flight controls. The paper gives an overview of the aircraft visionic design and describes the integration process. The development of the displayed flight and weapon symbols is discussed. Aeronautical Design Standard 33E was chosen as a basis for the qualification process, and the development of the qualification criteria and the flight testing program are discussed.

A full-color Head Mounted Display (HMD) with both wide field of view and high resolution is very useful for aircraft flight simulation and training. This paper will describe the design evolution of the SIM EYE^TM from its inception as a monochrome, flight-worthy helmet-mounted display, through its changes to the current a wide field of view, full color, high-resolution HMD.

Vision Systems International_LLC has been tasked by several customers and users to develop a helmet mounted display system that can be used in day and night scenarios and accurate enough to be used as the primary display. To address this need, VSI has developed the Next Generation Helmet that is light weight for high G maneuvers, and has a wide field of view for night operations, with the accuracy required for a primary aircraft display.

Over the past 35-plus years that Honeywell has designed and built head-mounted display systems, there have been many changes in the requirements for displays with many attempts to use a "one size fits all" approach to meet those requirements. While there are overlaps in the requirements for many of the operating environments, any system optimized for use in one environment will not be ideal for use in any other environment. It may not even meet minimum functional needs for some of the environments. An extreme example is, ground soldiers prefer non-see-through displays and use them only when not moving. Pilots are always moving and need see-through displays to maintain situational awareness. This paper highlights the major display design differences imposed by the different use environments and shows examples ofthe designs. No attempt has been made to explore the non-military use of head-mounted display systems. Non-military applications range from game playing, to 3-D CAD, to fire rescue work, to maintenance work, to surgery applications, and NASCAR drivers. While the military usage of displays has been largely focused on enhancing situational awareness, the non-military applications have been either to provide a new viewing perspective or to provide data access. An example of a view not readily attainable in any other way is a surgeon viewing the inside of a patient's body. An application where large volumes of data must be viewed is a chemical plant maintenance worker that needs to know piping diagrams, fluid flows, temperatures and pressures for many processes. A second difference between military and non-military displays is the environmental requirements. For example, a foot soldier's display must work during exposure to rain and snow and an occasional submergence in dirty water. Even the most avid game player would not consider wearing his 3-D display in the shower. In the following pages, we will provide examples of displays designed for several different military environments and describe how their unique requirements/needs affect the design of the helmet mounted display (HMD). From the descriptions, it will be readily apparent that there is not, and probably never will be, a "one size fits all" solution to HMD needs.

DoD has established many simulation programs and it has been concluded that an integrated head-mounted display (HMD) system can enhance situational awareness and augment operational performance of military units in the aforementioned fields. This paper will highlight the accomplishments of the advanced research, development, operational experiments and demonstrations over the past decade and will report on the current status of HMD integration.

This paper reports the development of a complete eyeglass- mounted computer interface system including display, camera and audio subsystems. The display system provides an SVGA image with a 20 degree horizontal field of view. The camera system has been optimized for face recognition and provides a 19 degree horizontal field of view. A microphone and built-in pre-amp optimized for voice recognition and a speaker on an articulated arm are included for audio. An important feature of the system is a high degree of adjustability and reconfigurability. The system has been developed for testing by the Military Police, in a complete system comprising the eyeglass-mounted interface, a wearable computer, and an RF link. Details of the design, construction, and performance of the eyeglass-based system are discussed.

A Retinal Scanning Display (RSD) utilizes scanning mirrors and optics to produce a flying spot that forms a raster image directly on the retina of the eye. A high-frequency resonant horizontal scanner and a linear ramp vertical scanner function together to produce video typically at a 60Hz frame rate. Although the raster can be formed by Unidirectional Writing (using only the forward half-period of the horizontal scan function) and one flying spot, it is desirable to achieve Bidirectional Writing (utilizing the full period of the Horizontal scan function) with multiple scanned spots for the purpose of increased efficiency of the display with a limited horizontal scanner frequency. This paper will look at the limitations and requirements for the scanning functions to make this possible.

Head and helmet mounted displays (HMDs) can benefit greatly from new wide field-of-view, compact visor optics to project very high resolution (e.g., 5k X 4k) imagery. Physical Optics Corporation (POC) is developing novel, compact, lightweight wide field-of-view optics based on three-color multiplexed aberration-compensated holographic optical elements (MAC-HOEs). Taking advantage of the flexibility of holography, the HMD optics can be made compact using waveguide projection through the curved visor substrate, so that the see-through visor can have a wide field-of-view without large, bulky optical components. Using narrowband red-green-blue hologram multiplexing, MAC-HOEs can significantly reduce the chromatic and geometrical aberration introduced by conventional HOEs and refractive optics. In the initial phase of development, POC demonstrated the feasibility of the HMD optics through computer design and analysis, and by fabricating and demonstrating a MAC-HOE component.

A magnetic sensor system has been developed to measure the 3-D location and orientation of a rigid body relative to an array of magnetic dipole transmitters. A generalized solution to the measurement problem has been formulated, allowing the transmitter and receiver parameters (position, orientation, number, etc.) to be optimized for various applications. Additionally, the method of images has been used to mitigate the impact of metallic materials in close proximity to the sensor. The resulting system allows precise tracking of high-speed motion in confined metal environments. The sensor system was recently configured and tested as an abdomen displacement sensor for an automobile crash-test dummy. The test results indicate a positional accuracy of approximately 1 mm rms during 20 m/s motions. The dynamic test results also confirmed earlier covariance model predictions, which were used to optimize the sensor geometry. A covariance analysis was performed to evaluate the applicability of this magnetic position system for tracking a pilot's head motion inside an aircraft cockpit. Realistic design parameters indicate that a robust tracking system, consisting of lightweight pickup coils mounted on a pilot's helmet, and an array of transmitter coils distributed throughout a cockpit, is feasible. Recent test and covariance results are presented.

This paper presents a new application for optical correlation in the form of a head tracking system intended for use in a modern fighter aircraft, where knowing the direction of the pilot's field of view is very important. A video camera, mounted on the pilot's helmet is used to produce a sequence of views of the aircraft cockpit. This view will change from frame to frame as the pilot's head moves and we can use a joint transform optical correlator to track this motion from one frame to the next. In this system, a binary phase joint transform correlator is used to track the frame to frame motion, which can be converted into a change in angle of the pilot's view of the aircraft cockpit. Results from an experimental prototype optical correlation based head tracking system are presented.

In spite of an immense increase in interest in helmet- mounted displays (HMDs) over the past two decades, there have been few studies on head motion while using HMDs in operational flight. Rotary-wing flights conducted using a number of HMD configurations have resulted in a head position database that will be useful in filling this void. Various analysis techniques have been applied to investigate characteristics of head position distributions for a slalom flight maneuver for four visual environments: good visual environment (daytime, unaided), night vision goggles, HMD with thermal imagery, and HMD with thermal imagery and symbology.

There are several parameters that are used to characterize the quality of a night vision goggle (NVG) such as resolution, gain, field-of-view, visual acuity, etc. One of the primary parameters is visual acuity or resolution of the NVG. These two terms are often used interchangeably primarily because of the measurement methods employed. The objectives of this paper are to present: (1) an argument as to why NVG visual acuity and resolution should be considered as distinctly different parameters, (2) descriptions of different methods of measuring visual acuity and resolution, and (3) the results of a blind test by several agencies to measure the resolution of the same two NVGs (four oculars).

Technology is advancing to the point where night vision goggle designs being developed have wider fields of view to help achieve an increase in situational awareness. The appropriate diopter setting for the eyepiece of these goggles needed to be determined. Aircrew members were surveyed to determine the range of diopter settings they were using. In order to determine what fixed setting would work the best, two diopter settings were chosen (-1.0 and -0.5) to preset aircrew members' goggles. The aircrew flew with these presettings and then filled out a 14-question survey about the diopter settings.

Night vision goggles (NVGs) can enhance military and civilian operations at night. With this increased capability comes the requirement to provide suitable training. Results from field experience and accident analyses suggest that problems experienced by NVG users can be attributed to a limited understanding of NVG limitations and to perceptual problems. In addition, there is evidence that NVG skills are perishable and require frequent practice. Format training is available to help users obtain the required knowledge and skills. However, there often is insufficient opportunity to obtain and practice perceptual skills prior to using NVGs in the operational environment. NVG users need early and continued exposure to the night environment across a broad range of visual and operational conditions to develop and maintain the necessary knowledge and perceptual skills. NVG training has consisted of classroom instruction, hands-on training, and simulator training. Advances in computer-based training (CBT) and web-based training (WBT) have made these technologies very appealing as additions to the NVG training mix. This paper discusses our efforts to develop NVG training using multimedia, interactive CBT and WBT for NVG training. We discuss how NVG CBT and WBT can be extended to military and civilian ground, maritime, and aviation NVG training.

When properly employed, Night Vision Goggles (NVGs) improve a pilot's ability to see during periods of darkness. The resultant enhancement in situational awareness achieved when using NVGs, increases light safety during night VFR operations. FAA is constrained with a lack of requisite regulatory and guidance infrastructure to adequately facilitate the civil request for use in NVGs within the National Airspace System (NAS) Appliances and Equipment, is formed and tasked to develop: operational concept and operational requirements for NVG implementation into the NAS, minimum operational performance standards for NVGs, and training guidelines and considerations for NVG operations. This paper provides a historical perspective on use of NVGs within the NAS, the status of SC-196 work in progress, FAA integration of SC-196 committee products and the harmonization effort between EUROCAEs NVG committee and SC- 196.

The BAE SYSTEMS Knighthelm HMD is a unique two-part helmet design, using a form fitted inner helmet with an outer display module. It has been refined and enhanced, as part of an extensive development program, for the German Army Tiger helicopter, and is optimized for the attack helicopter application. The design optically mixes the output of an Image Intensifier Tube with Cathode Ray Tube imagery. This provides a flexible display of symbology overlaid on NVG imagery or symbology overlaid on FLIR video viewed as a collimated image in the see through combiner eyepiece in front of the users eyes.

The U.S. Army Aviation mission includes flying helicopters at low altitude, at night, and in adverse weather. Night Vision Devices (NVDs) are used to supplement the pilot's visual cues for night flying. As the military requirement to conduct night helicopter operations has increased, the impact of helicopter flight operations with NVD technology in the Degraded Visual Environment (DVE) became increasingly important to quantify. Aeronautical Design Standard-33 (ADS- 33) was introduced to update rotorcraft handling qualities requirements and to quantify the impact of the NVDs in the DVE. As reported in this paper, flight test methodology in ADS-33 has been used by the handling qualities community to measure the impact of NVDs on task performance in the DVE. This paper provides the background and rationale behind the development of ADS-33 flight test methodology for handling qualities in the DVE, as well as the test methodology developed for human factor assessment of NVDs in the DVE. Lessons learned, shortcomings and recommendations for NVD flight test methodology are provided in this paper.

Light scattered from helmet visors and aerospace transparencies is known to reduce visual performance. One popular measurement technique, maintained by the American Society for Testing and Materials, is ASTM D 1003. It is a standard procedure used to measure haze inherent in transparent materials, which is defined as the percent of the total transmitted light that is scattered. However, research has shown that visual acuity measured through several different types of helmet visors does not correlate well with visor haze. This is most likely due to the fact that the amount of light scattered from a transparent material depends heavily on the light illuminating the transparency and on the viewing geometry, behavior that ASTM D 1003 does not characterized. Scattered light causes transparent parts to appear luminescent and imparts a veiling luminance when superimposed over a target, reducing target contrast and inducing a visual performance loss. This paper describes an experiment in which threshold target background luminance, the luminance at which a target was barely visible, was measured for a number of observers viewing a Landolt C target through several levels of veiling luminance. Threshold luminance was examined for predictable behavior with respect to veiling luminance.

Although luminance contrast requirements for legibility of text are fairly well established, luminance contrast requirements for helmet-mounted display (HMD) color recognition are not. This is a significant issue for color HMDs, such as Helmet-Mounted Sight Plus (HMS+), because the symbol colors will sum with the outside scene, causing them to shift from their intended CIE chromaticity coordinates. Obviously, if the HMD luminance contrast is `sufficient', the colors will remain recognizable--but how much is sufficient? We generated representative outside scenes on a graphics system with superimposed Visually- Coupled Acquisition and Targeting System (VCATS) symbology, using the color code that can be generated by HMS+. For simplicity we used only the target designator box (TD box) from VCATS, and varied the luminance contrast in incremental steps from low to high until the observer could identify the color of the symbology. Further, to test luminance contrast color requirements against legibility requirements, observers then attempted to correctly identify the number at the top of the TD box (target degrees before break lock). If unsuccessful, the luminance contrast was raised until the observer could correctly identify the number. We discuss results in terms of luminance contrast requirements for color recognition as well as legibility.

Helmet-mounted displays (HMDs) provide essential pilotage and fire control imagery information for pilots. However, image quality testers for HMD validation do not currently exist in the field. This research employed techniques from imaging analysis and interpretation, and computer-aided design/computer-aided manufacturing (CAD/CAM) to demonstrate that a portable image quality tester can be developed for HMD validation in the field. For this study, a charge coupled device camera and lens were selected. Hardware characteristics such as viewing angles in horizontal and vertical positions, dynamic working range at day and night, pixel resolution, focal length, and aperture ratio were evaluated with respect to HMD functionality.

New HMD symbols, specifically designed for wide-field-of-view (WFOV) application, were dynamically prototyped using a WFOV helmet mounted display (HMD) in conjunction with the PRISMS helicopter flight simulator. Missions were flown through realistic terrain by an expert Apache pilot. The data indicate that: (1) Pilot performance, in almost all measures, is substantially improved with use of a WFOV (99), as compared to a narrow-field-of-view (NFOV) (40) display; (2) Earth-fixed navigational and tactical symbols improve navigation accuracy, enhance aircraft handling performance, improve target acquisition, and reduce pilot workload; (3) Best performances were typically exhibited using WFOV with the new symbols-- neither the WFOV nor the symbols alone could produce peak perform-ance; (4) A flight path marker symbol showing the aircraft velocity vector improves aircraft handling and reduces workload, especially when paired with a WFOV display; (5) The new symbols were valuable even in complete darkness, showing that the superiority of the WFOV is due not only to broader views of the terrain, but also to broader views of effectively designed symbology; and (6) The additional area of the WFOV display can be used to present useful ancillary data without cluttering the central zone.

The second and third in a series of evaluations of displays providing aircraft state information for processing by the pilot's ambient visual system are reported. The second experiment examined five drive laws relating longitudinal motion of the aircraft to the motion of objects in the ambient field. The third experiment examined four methods of displaying an artificial horizon.

This paper describes an evaluation of the Non-Distributed Flight Reference (NDFR) helmet-mounted display symbology for a simulated aircraft-maneuvering task. In this experiment, pilot performance concerning interpretability of three symbol sets (standard HUD, VCATS, and NDFR) during a simulated flying maneuver was assessed.

As part of risk reduction activities for the development of next-generation fighter cockpits, Lockheed-Martin Aeronautics Company is using the USAF Variable-stability In- flight Simulation Test Aircraft F-16 and its programmable display system for the demonstration and evaluation of a Virtual Head-Up Display (HUD) concept. The Virtual HUD concept promises a significant improvement in next- generation fighter cockpits by eliminating the HUD yet projecting the Primary Flight Reference symbology, formerly displayed in the HUD, on the pilot's Helmet-Mounted Display. The Virtual HUD is presented in an aircraft-stabilized position where the HUD combining glass would normally be located in today's fighters. This change provides a cost and weight reduction, and clears invaluable instrument panel space for larger displays with less clutter and discontinuity in displayed information. The Virtual HUD flight trials also studied the use of voice recognition in flight. Voice was used to control all aspects of the test and in-cockpit sound measurements were taken to understand the impact of cockpit noise on recognition performance.

An eye-safe Obstacle Warning System (OWS) based on a Laser-scanning Technology for helicopters was analysed during flight campaigns and by static measurements. This system of detection is composed of two parts; the Laser sensor and the Man Machine Interface (MMI), which are both described separately. Laser transmitter wavelength is 1.54 m for eye-safety. The Man Machine Interface, with stereoscopic information presented in a Helmet Mounted Display (HMD), is developed by Eurocopter Deutschland (ECD). The two and three dimensional helmet mounted displays of a Kaiser LCD-helmet and Sony LCD-glasses, shown during several presentations of the OWS subject, have impressed all viewers with their quality and realism. The landscape is clearly visible and recognisable by every viewer. The stereoscopic representation is very good due to the real 3D information contained in the sensor measurement, and this allows more than 20 stereoscopic plans with a 640 &#61620 480 HMD to be seen.

The Defence Evaluation Research Agency carried out an airborne demonstration and evaluation of a fast-jet Visually Coupled System (VCS) installed in ZD902, the Tornado Integrated Avionics Research Aircraft for the UK MOD. The installed VCS used a Head Steered Forward Looking Infra-Red (HSFLIR) sensor and a Head Tracking system to provide the pilot with an image of the outside world projected onto a Binocular Helmet Mounted Display. In addition to the sensor image, information such as aircraft altitude, attitude, and airspeed were also presented to the pilot through the HMD to eliminate the need to look inside the cockpit for critical flight data. The aim of the VIVIAN trial was to demonstrate by day and night the benefits of a fast-jet integrated HSFLIR and HMD as an aid to low level flight, navigation, target acquisition, take-off and landing. The outcome of this flight test program was very encouraging and, although testing has identified that improvements are necessary, in particular to HSFLIR image quality, Auto Gain Control performance, helmet fit and symbology design, test aircrew endorse the acceptability of a VCS.

Helmet Mounted Sights providing basic off boresight designation/cueing capability and they represent the `entry point' for head mounted displays. When coupled to a missile with high off-boresight designation capability, such a system offers major benefits in the `within visual range' air combat environment. Such a system can also be used to `point' other sensors such as the radar or a targeting pod so that despite the modest display capability, even this simple system greatly enhances the lethality of the aircraft.