Gaze-contingent multiresolutional displays (GCMRDs) center high-resolution information on the user's gaze position, matching the user's area of interest (AOI). Image resolution and details outside the AOI are reduced, lowering the requirements for processing resources and transmission bandwidth in demanding display and imaging applications. This review provides a general framework within which GCMRD research can be integrated, evaluated, and guided. GCMRDs (or "moving windows") are analyzed in terms of (a) the nature of their images (i.e., "multiresolution," "variable resolution," "space variant," or "level of detail"), and (b) the movement of the AOI (i.e., "gaze contingent," "foveated," or "eye slaved"). We also synthesize the known human factors research on GCMRDs and point out important questions for future research and development. Actual or potential applications of this research include flight, medical, and driving simulators; virtual reality; remote piloting and teleoperation; infrared and indirect vision; image transmission and retrieval; telemedicine; video teleconferencing; and artificial vision systems.

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Gaze-contingent multiresolutional displays: an integrative review.

Helmet-Mounted Displays: Design Issues for Rotary-Wing Aircraft

The objective of this study was to evaluate differences in driving performance, visual detection performance, and eye-scanning behavior between glaucoma patients and control participants without glaucoma. Glaucoma patients (n = 23) and control participants (n = 12) completed four 5-min driving sessions in a simulator. The participants were instructed to maintain the car in the right lane of a two-lane highway while their speed was automatically maintained at 100 km/h. Additional tasks per session were: Session 1: none, Session 2: verbalization of projected letters, Session 3: avoidance of static obstacles, and Session 4: combined letter verbalization and avoidance of static obstacles. Eye-scanning behavior was recorded with an eye-tracker. Results showed no statistically significant differences between patients and control participants for lane keeping, obstacle avoidance, and eye-scanning behavior. Steering activity, number of missed letters, and letter reaction time were significantly higher for glaucoma patients than for control participants. In conclusion, glaucoma patients were able to avoid objects and maintain a nominal lane keeping performance, but applied more steering input than control participants, and were more likely than control participants to miss peripherally projected stimuli. The eye-tracking results suggest that glaucoma patients did not use extra visual search to compensate for their visual field loss. Limitations of the study, such as small sample size, are discussed.

/pdf/obstacle-avoidance-visual-detection-performance-and-eye-3mqbgtg7e9.pdf

Obstacle avoidance, visual detection performance, and eye-scanning behavior of glaucoma patients in a driving simulator: A preliminary study

Head-mounted displays

: Since the l970s, the trend in Army aviation has been to rely on helmet-mounted displays (HMDs) to provide the aircrew with pilotage imagery, flight information, and fire control imagery and symbology. This paper is intended to serve as both a checklist and a guide for designers of future integrated helmet and display systems for rotary-wing aircraft. In this paper: 1) salient performance parameters of such systems are identified; 2) recommendations for values of these parameters are suggested, based on past research and the opinions of subject matter experts; 3) an analysis of potential health and safety hazards is provided; 4) a human factors engineering assessment (HFEA) is provided; and 5)lessons learned from previously fielded U.S. Army HMD systems are summarized. However, this paper is not a cookbook for building an integrated helmet and display system.

Design Issues for Helmet-Mounted Display Systems for Rotary-Wing Aviation.

The Aeroflightdynamics Directorate of the US Army's Aviation Research, Development and Engineering Center initiated a study to determine the effects of limiting a rotorcraft pilot's field-of-view (FOV) on performance and workload. Pilot FOV was restricted to simulate current and next generation helmet mounted display FOVs used in night vision systems. A helmet visor was constructed for this test to restrict the horizontal peripheral limits of the square shaped FOV to values of 100, 80, 60, 40, and 20 degrees. The vertical limits and overlap were held constant to 40 degrees (except for the 20 degree FOV). Six pilots executed a series of prescribed low altitude maneuvers with an instrumented NAH-IS (Cobra) rotorcraft at the Crows Landing Airfield located in California. The aircraft flight path was measured with a laser tracker. On board data was recorded, as well as pilot handling quality ratings and visual cue ratings. This test is not yet complete, but some preliminary observations and results are provided. It was observed that reducing FOV increased the difficulty of controlling the aircraft and altered head movement. Reducing FOV also diminished the pilots' situational awareness. The reduction in situational awareness affected the ability of the pilots to provide an accurate report of their own flying performance, and the ability to observe warning indicators inside the cockpit.

Effect of field-of-view restriction on rotocraft pilot workload and performance: preliminary results

The effect of night vision devices and degraded visual imagery on self-attitude perception is unknown. Thirteen Army aviators with normal vision flew five flights under various visual conditions in a modified AH-1 (Cobra) helicopter. Subjects estimated their altitude or flew to specified altitudes while flying a series of maneuvers. The results showed that subjects were better at detecting and controlling changes in altitude than they were at flying to or naming a specific altitude. In cruise flight and descent, the subjects tended to fly above the desired altitude, an error in the safe direction. While hovering, the direction of error was less predictable. In the low-level cruise flight scenario tested in this study, altitude perception was affected more by changes in image resolution than by changes in FOV or ocularity.

Helicopter pilot estimation of self-altitude in a degraded visual environment

The US Army Aviation RDEC's Aeroflightdynamics Directorate (AFDD) in cooperation with the Department of Defense Flight Symbology Working Group, the United Kingdom's Defense Research Agency (DRA), and The Technology Cooperative Program Helicopter Technical Panel 6 (HTP6), conducted a Helmet Mounted Display (HMD) symbology investigation using AFDD's Crew Station Research and Development Facility helicopter simulator located at the Ames Research Center, Moffett Field, California. The objectives of the experiment were to examine HMD symbology stabilization, pitch ladders, flight path presentations, and tasks and measures that capture objective and subjective performance differences. Symbology presentation techniques closely modeled specific presentations found in the US Army's AH- 64D Apache helicopter and proposed symbology techniques for the RAH-Comanche and Longbow Apache rotorcraft. Eight helicopter pilots from DOD and DRA participated in the study flying simulated low-altitude rotorcraft maneuvers. This paper describes the simulation flight tests, test results, implications of test findings and recommendations for future HMD investigations.© (1995) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Alan G. Lee

Papers

Effect of field-of-view restriction on rotocraft pilot workload and performance: preliminary results

Helicopter pilot estimation of self-altitude in a degraded visual environment

TRISTAR III: helmet-mounted display symbology