Stanley N. Roscoe

Judgments of Size and Distance with Imaging Displays

The application of computer-animated imagery analogous to a contact view from an air-plane calls for a better understanding of the essential visual cues for spatial orientation. Such systems have application both as contact analog flight displays and as outside visual scenes for flight simulators. In either case, systematic errors in distance judgments are encountered that can be compensated for by magnifying objects in the animated scenes. Results of an experimental investigation of biased distance judgments with a projection periscope accounted for, but did not explain, a portion of the systematic error. The findings are discussed in relation to other unexplained experimental facts associated with size and distance judgments, including various optical illusions and the “projection” of afterimages.

Locus of the Stimulus to Visual Accommodation: Where in the World, or Where in the Eye?

Eight observers judged the apparent size of a moon simulated by projecting a collimated disk of light just above the horizon in real scenes and virtual images. In each of three viewing conditions, Back-lighted Screen (collimated), Back-projected Photograph (collimated), and Natural Campus Scene, masks inserted in the viewing aperture of the moon machine obscured various horizontal bands of the lower half of the visual field. With each experimental manipulation, both the perceived size of the moon and the observers visual accommodation distance (measured with a laser optometer) covaried systematically. From the combined results of two experiments, it appears that (1) viewing a collimated image of a natural vista does not have the same effects as viewing the actual scene, (2) the retinal locus of visible texture is the primary determinant of perceived size of objects of constant visual angle embedded in natural scenes, and it has a strong effect on accommodation to virtual images, and (3) the overall correlation between apparent, or perceived, size and accommodation shift from the individuals dark focus, averaged across observers, approaches unity (r = 0.97).

Bigness Is in the Eye of the Beholder

This report reviews an investigation of judgments of size and distance as required of pilots in flight. The experiments covered a broad spectrum of basic psychophysiological issues involving the measurement of visual accommodation and its correlation with various other dependent variables. Psychophysiological issues investigated included the size-distance invariance hypothesis, the projection of afterimages, the moon illusion, night and empty-field myopia, the dark focus and its so-called Mandelbaum effect, the nature and locus of the accommodative stimulus, the relation between accommodation, retinal size, and perceived size, and possible relationships among accommodative responses, autonomic balance, and personality variables.

Flight Display Dynamics Revisited

Good old ideas for pictorial flight displays that were once impractical warrant reconsideration in light of current microcomputing and display technology. Among the ideas are the contact analog, highway in the sky, and flight path predictor concepts. Basic pictorial display principles established in the 1950s and 1960s have been supported by additional experimental findings in the 1970s. These include pictorial realism, magnification, integration, compatible motion, frequency separation, pursuit presentation, quickening, and predicting. An extended analysis of dynamic display variables provides a broadened conceptual foundation for future multifactor experimental optimization of forward-looking pictorial flight displays.

When Day Is Done and Shadows Fall, We Miss the Airport Most of All:

Both the effectiveness of pilot training and the safety of flight can be influenced by the distribution of texture in the visual scene, the distance to which the eyes accommodate, and the associated shifts in the apparent size and distance of objects in central and peripheral vision. Studies reviewed and original results presented indicate that these factors are involved in various misjudgments and illusions experienced by pilots: (1) when searching for other airborne traffic or targets, (2) when making approaches to airports over water at night, (3) when breaking out of low clouds on a final approach to a landing by reference to head-up or head-down displays, and (4) when practicing simulated approaches and landings or air-to-surface weapon deliveries by reference to synthetically generated visual systems.

Computer-Animated Predictive Displays for Microwave Landing Approaches

The safe, orderly, and economical flow of air traffic at congested metropolitan airports can result from the advent of microwave radio guidance systems. By providing aircraft position in three dimensions, these terminal navigation aids potentially allow steeply curved landing approaches that will facilitate unprecedented noise abatement procedures, large fuel savings, and precisely timed arrivals at airport runways. To implement such complex flight procedures will require a combination of semiautomatic computer-assisted airplane guidance and control and radically different flight displays if pilots are to monitor such maneuvers confidently and execute them manually when necessary. Results of a simulator investigation, involving visual guidance and flight-path prediction embedded in computer-animated contact analog displays, show that pilots can reliably execute computer-programmed curved approaches to airport runways with the needed precision in the face of severe wind shears.

An integrated display for vertical and translational flight: eight factors affecting pilot performance

As part of an overall research program to optimize both forward-looking and downward-looking tactical situation displays for all-weather instrument flight in vertical takeoff and landing (VTOL) aircraft, an integrated horizontal situation display was developed for both vertical and translational flight. This paper covers the development and initial experimentation of the downward-looking portion of the overall display and control system. The effects of eight factors on pilot performance were tested, and a multiple regression model of VTOL pilot performance as a function of those eight factors was derived for each of three dependent performance measures. Factors having important effects were position error magnification, control order, prediction time, control gain, tracking mode, and several of their interactions.