The Importance of Providing Stereoscopic Vision in Training for Nap-of-the-Earth (NOE) Flight

Abstract

Nap-of-the-earth (NOE) flight in Army tactical helicopter operations necessitates high speed visual-motor coordinations in order to avoid obstacles in the flight path while making maximal use of the terrain for cover and concealment from enemy air defense weapon systems. The development of simulators for training pilots in NOE flight involves the design of visual display systems which provide all the important optical information available in actual flight. At the present time, however, there is insufficient information on the role of stereopsis in NOE flight to determine whether fully binocular displays must be designed into training simulators.

This paper describes results from two preliminary studies which examined the importance of binocular disparity for the perception of three-dimensional layout of the terrain in NOE flight. In the first experiment, it was determined that stereoscopic movies taken from the cockpit of a helicopter in NOE flight produce more compelling impressions of three-dimensionality than a non-disparate bioptic display. The results of the second experiment show that simple reaction times for detection of three-dimensionality in static binocular displays were substantially longer than for detection of fusibility of otherwise identical bioptic displays. Additionally, it was found that detection of fusibility required much more time than detection of a light flash.

These results are interpreted as inconclusive with respect to the desirability of stereoptic displays for NOE flight training simulators, and a program of further research needed to settle this issue is discussed.