Using depth information to improve display interpretation

Abstract

In previous studies it was shown that both pilots and non-pilots sometimes make roll reversal errors (RREs) when the aircraft bank angle is presented on a moving horizon type attitude indicator. This incorrect input has been shown to be caused by a misinterpretation of the horizon symbol on such an attitude indicator. The figure-ground relation of the aircraft symbol and horizon symbol on the attitude indicator has been cited as being a contributing factor to this misinterpretation. A Multi-Layer Display (MLD) is tested as a possible intervention tool for these interpretation errors. With this display type, the horizon symbol is presented on a physically deeper layer, making it possibly more easily interpreted as being in the background, and the aircraft symbol is presented on a second layer on the foreground. A group of 23 non-pilots and 18 pilots were tasked to perform a recovery task on a desktop-based simulator without outside visuals and only an Attitude indicator on both a MLD as well as a conventional Single Layer Display for repeated-measures. Although roll reversal errors were observed at a comparable level to previous research, no significant difference were observed on the error rate between the two display types. A possible explanation is that the stereoscopic depth of the MLD dissipates when the subject sits still and remains exactly in front of the display. This leaves open the possibility that other types of depth cues, such as monocular cues, can be added and used to enhance the figure-ground relation in displays.