A general framework for multiresolution image fusion: from pixels to regions

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.

/pdf/gaze-contingent-multiresolutional-displays-an-integrative-2kyq6tzjuf.pdf

Gaze-contingent multiresolutional displays: an integrative review.

A system for producing spatially modulated monochrome or color light having gray scale includes an active matrix liquid crystal spatial light modulator having light modulating means including (i) a layer of ferroelectric liquid crystal material which is designed to switch between ON and OFF states and (ii) active matrix means including VLSI circuitry for dividing the layer of liquid crystal material into an array of individual liquid crystal pixels and for causing each of the pixels of liquid crystal material to modulate light individually by switching between the ON and OFF states in a way that depends upon the data which the VLSI circuitry is written. The system also includes illumination means having a light source for directing light from the source into the pixel-divided layer of ferroelectric liquid crystal material in a specific way. And finally, the system includes means for writing the VLSI circuitry with preselected data in accordance with a particular data ordering scheme such that the circuitry, in response to the written data, causes the pixels of liquid crystal material to individually switch between their ON and OFF states and therefore modulate light from the source in a way which, depending upon the data, produces a specific overall pattern of gray scale light.

Active Matrix Liquid Crystal Image Generator

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

The work reported in this paper examines the effect of restricting visual field-of-view (FOV) on rotorcraft pilot head movement. To simulate the FOVs of current and future helmet mounted displays (HMDs) used for night vision pilotage, a FOV restrictor was attached to the helmets of the test subject pilots. The restrictor limited horizontal FOV to 100, 80, 60, 40, and 20 degrees. Ten test subject pilots executed a set of low altitude flight maneuvers in an instrumented NAH-1S helicopter at the NASA Crows' Landing Airfield Head movement was measured with an IR head tracker for those pilots who flew in the rear seat and by a video camera for those who flew in the front seat. Test data indicated that pilots responded to restriction sin horizontal FOV by changing their pattern of head movement, both in azimuth and elevation. These compensation strategies change as FOV decreases and vary from pilot to pilot. Test results reported in this paper, in conjunction with referenced data outlining FOV effects on flight performance, handling qualities, and visual cue ratings, give visionic system designers and users predictive information on pilot workload and performance.

Effects of in-flight field-of-view restriction on rotorcraft pilot head movement

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

Helmet- and Head-mounted Displays VII

Helmet- and Head-Mounted Displays and Symbology Design Requirements II

An experiment was conducted to compare performances on operational tasks with and without new earth-fixed symbology representing the positions of waypoints, battle positions, and engagement areas. Fourteen experienced AH-64 Apache pilots flew a representative attack mission in the Pilot/Rotorcraft Intelligent Symbology Management Simulator (PRISMS). Performances were significantly better in waypoint crossing accuracy, landing accuracy, engagement area recognition accuracy, and concealment from enemy positions when using the new symbols.

Loran A. Haworth

Papers

Effects of in-flight field-of-view restriction on rotorcraft pilot head movement

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

Helmet- and Head-mounted Displays VII

Helmet- and Head-Mounted Displays and Symbology Design Requirements II

Evaluation of earth-fixed HMD symbols using the PRISMS helicopter flight simulator