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Objective: An evaluation study was conducted to answer the question of which system properties of night vision enhancement systems (NVESs) provide a benefit for drivers without increasing their workload. Background: Different infrared sensor, image processing, and display technologies can be integrated into an NVES to support nighttime driving. Because each of these components has its specific strengths and weaknesses, careful testing is required to determine their best combination. Method: Six prototypical systems were assessed in two steps. First, a heuristic evaluation with experts from ergonomics, perception, and traffic psychology was conducted. It produced a broad overview of possible effects of system properties on driving. Based on these results, an experimental field study with 15 experienced drivers was performed. Criteria used to evaluate the development potential of the six prototypes were the usability dimensions of effectiveness, efficiency, and user satisfaction (International Organization for Standardization, 1998). Results: Results showed that the intelligibility of information, the easiness with which obstacles could be located in the environment, and the position of the display presenting the output of the system were of crucial importance for the usability of the NVES and its acceptance. Conclusion: All relevant requirements are met best by NVESs that are positioned at an unobtrusive location and are equipped with functions for the automatic identification of objects and for event-based warnings. Application: These design recommendations and the presented approach to evaluate the systems can be directly incorporated into the development process of future NVESs.

Thirty-six pilots (31 men, 5 women) were tested in a flight simulator on their ability to intercept a pathway depicted on a highway-in-the-sky (HITS) display. While intercepting and flying the pathway, pilots were required to watch for traffic outside the cockpit. Additionally, pilots were tested on their awareness of speed, altitude, and heading during the flight. Results indicated that the presence of a flight guidance cue significantly improved flight path awareness while intercepting the pathway, but significant practice effects suggest that a guidance cue might be unnecessary if pilots are given proper training. The amount of time spent looking outside the cockpit while using the HITS display was significantly less than when using conventional aircraft instruments. Additionally, awareness of flight information present on the HITS display was poor. Actual or potential applications of this research include guidance for the development of perspective flight display standards and as a basis for flight training requirements.

In this study a multiple-view two-dimensional (2D) display was compared with a three-dimensional (3D) monocular display and a 3D stereoscopic display using a simulated telerobotic task. As visual aids, three new types of visual enhancement cues were provided and evaluated for each display type. The results showed that the multiple-view 2D display was superior to the 3D monocular and the 3D stereoscopic display in the absence of the visual enhancement depth cues. When participants were provided with the proposed visual enhancement cues, the stereoscopic and monocular displays became equivalent to the multiple-view 2D display. Actual or potential applications of this study include the design of visual displays for teleoperation systems.

This study tested whether selected visual display conditions can aid observers in prioritizing information from display elements that differ in reliability. The observer's task was to decide whether the information conveyed by an array of nine graphical elements represented a signal or noise input. The value displayed by each element was an independent sample from the signal or noise distribution. The reliability of a display element was manipulated by controlling the variance of these distributions (high reliability = low variance). Observers tended to weight high-reliability sources slightly more than low-reliability sources. The observers-detection performance and weighting efficiency were highest when the reliability of the source was cued by the luminance of the display element. Thus observers can prioritize visual information sources based on statistical properties such as variability if luminance cues are available during the presentation of the information.

A sequential or RAP COM (rapid communication) display was compared with a more conventional spatial display as participants monitored dynamically changing sets of three-digit numbers and responded to occasional target stimuli. In an effort to equate the stimulus-response compatibility of the two displays, we had participants respond to the targets with a chord keyboard in Experiment 1 and vocally in Experiment 2. We examined the influence of display duration on performance with the RAP COM and spatial formats by presenting stimuli at three different durations (400, 800, and 1200 ms). The influence of practice on performance with the RAP COM and spatial displays was also investigated. Participants responded to targets more quickly in the RAP COM than in the spatial displays at each of the three presentation durations and across more than 2000 trials of practice. Accuracy was influenced by the display presentation duration. Accuracy was higher for the RAP COM than for the spatial display at the 800-ms stimulus presentation duration in Experiment 1 and at the 800- and 1200-ms presentation durations in Experiment 2. The results are discussed in terms of the potential utility of RAP COM displays for complex, real-world systems.

Using perspective displays, observers judged whether two objects that approached each other in midair would collide. When objects were different sizes, observers often did not detect imminent collisions. Errors decreased with equal-sized objects or ground-intercept information. Results from these limited conditions suggest that judgments about collision in perspective displays (e.g., three-dimensional displays of aircraft) can be enhanced by minimizing ambiguities created by pictorial relative size cues. Results are consistent with studies of judgments about object-self collisions.

Polygon displays compress information that would otherwise be conveyed by separate indicators into a single display in which each reading is represented by the distance of a polygon vertex from its center. The effect on detection of fault states of varying the number of polygon vertices from 4 to 20 in a display presented peripherally around a dynamic, simulated flight display was studied. Presence of the dynamic task reduced both speed and accuracy of response to the polygon display but did not significantly affect the pattern of response to differing numbers of vertices. All measures of performance were better with larger numbers of vertices. If the vertices are processed serially, more vertices require more processing time. Therefore, the result argues for holistic processing and implies that such information integration is beneficial to human performance in fault detection.

In this study we contrast display-control movement relations defined in terms of stimulus-response (physical) compatibility with those defined by stimulus-cognitive compatibility, and we relate these findings to the issue of command versus status levels of decision aid support. A second issue addressed is the cost of inconsistency across multiple display-control mappings. Subjects performed a flight control task while responding to one to four analog indicators, formatted as either command or status displays. The results suggest that there is an advantage for the status format when subjects are required to verbally report the state of the indicator(s), but no advantage was found for either format when subjects were required to manually correct the indicated state. The data point to the importance of display-control consistency and suggest that it may even outweigh that of compatibility.

This paper presents a cognitive analysis of a pilot's navigation task and describes an experiment comparing a new map display that employs the principle of visual momentum with the two traditional approaches, track-up and north-up. The data show that the advantage of a track-up alignment is its congruence with the egocentered forward view; however, the inconsistency of the rotating display hinders development of a cognitive map. The stability of a north-up alignment aids the acquisition of a cognitive map, but there is a cost associated with the mental rotation of the display to a track-up alignment for tasks involving the ego-centered forward view. The data also show that the visual momentum design captures the benefits and reduces the costs associated with the two traditional approaches.

An auditory head-up display (AHUD) can provide a pilot with information about target azimuth and elevation. The AHUD presents headphone stimuli whose apparent position is fixed relative to the cockpit and invariant with respect to head movement. In normal (movement-linked) operation the AHUD samples the head position and then corrects the headphone stimuli so that they are perceived to be at fixed positions in physical space. This experiment tested the ability of observers to localize targets with an AHUD under different movement conditions. After listening to a sequence of three signals, the observer had to indicate the target's location. Three different conditions relating the observer's head movement to the target's spatial position were tested: (a) target fixed in physical space (normal AHUD mode), (b) no head movement allowed, and (c) target fixed in position relative to the observer's head. Azimuthal localization was much better when the position of the stimulus was veridically correlated with head movement, demonstrating the contribution of visual, kinesthetic, and vestibular cues to sound localization.

The work reported systematically examined four types of formatting (vertical, compact, chunk extended, and message extended), three levels of message load (two, four, and six units), four methods of sequencing (chunk, line, words, and unsequenced) and three presentation rates (0.25, 0.5, and 1. 00 sec/word). The first study was a repeated-measures design, in which 32 subjects were given all combinations of format and sequencing. From this initial study, one combination of format and sequence was selected for further study. The second study examined the compact chunk presentation for the three levels of message load and for three exposure rates. Recommendations are made for the optimal dynamic presentation of messages on computer-generated displays given limited viewing time. The examples considered here simulate the kinds of real-time messages flashed alongside highways to inform motorists of traffic situations ahead and to give directions for alternate routing.

A current trend in cockpit design is to incorporate synthesized speech to present secondary information. Multiple-resource theories of information processing support this, but theories of stimulus/central-processing/response compatibility suggest that spatial information presented visually may have some advantages over speech if the response is manual. Two experiments compare response performance over single and dual tasks when information was presented pictorially and by speech. Pictorial subjects responded more quickly than did speech subjects. The addition of the visual tracking task in the dual-task condition had a differential effect on performance, depending on the modality of the primary task and the rate at which information was presented. The dual task impeded performance more in the fast and medium presentation rates for the speech condition but had little differential effect across rates for the pictorial condition. Analysis of the error data indicated that subjects in the pictorial condition were better able to maintain the context of the emergency than those in the speech condition. Results are discussed in terms of current theories of information processing.

Ten men scanned cathode-ray-tube displays to search for designated target items. Search time increased with increasing display density, and was 50% faster when a 3-cps blink was imposed on items of the target class. The blinking of nontarget items was almost equally effective, indicating that blink can be used either as an inclusion or exclusion code. In comparison with steady, nonblinking displays, search time was not significantly different for displays in which all items blinked, or in which a random selection of items blinked. It is concluded that for visual search tasks of the kind reported here, there is no marked deleterious effect of blink coding on symbol legibility, and no marked interference attributable to irrelevant blink.