Nada Pavlovic

Smooth Rotation of 2-D and 3-D Representations of Terrain: An Investigation Into the Utility of Visual Momentum

Objective: The potential advantage of visual momentum in the form of smooth rotation between two-dimensional (2-D) and three-dimensional (3-D) displays of geographic terrain was examined. Background: The relative effectiveness of 2-D and 3-D displays is task dependent, leading to the need for multiple frames of reference as users switch tasks. The use of smooth rotation to provide visual momentum has received little scrutiny in the task-switching context. A cognitive model of the processes involved in switching viewpoints on a set of spatial elements is proposed. Methods: In three experiments, participants judged the properties of two points placed on terrain depicted as 2-D or 3-D displays. Participants indicated whether Point A was higher than Point B, or whether Point B could be seen from Point A. Participants performed the two tasks in pairs of trials, switching tasks and displays within the pair. In the continuous transition condition the display dynamically rotated in depth from one display format to the other. In the discrete condition there was an instantaneous viewpoint shift that varied across experiments (Experiment 1: immediate; Experiment 2: delay; Experiment 3: preview). Results: Performance after continuous transition was superior to that after discrete transition. Conclusion: The visual momentum provided by smooth rotation helped users switch tasks. Application: The use of dynamic transition is recommended when observers examine multiple views of terrain over time. The model may serve as a useful heuristic for designers. The results are pertinent to command and control, geological engineering, urban planning, and imagery analysis domains.

Advantage for Visual Momentum Not Based on Preview

Previous research has indicated that smooth rotation of geographic terrain between two- and three-dimensional (2D and 3D) views aids task switching. However, the time taken to show the smooth rotation may also provide a terrain preview for a post-rotation judgment. To test this possibility, we examined a situation where preview was provided but smooth transition violated. Twenty-four participants made judgments about the properties of two points placed on 2D or 3D displays of terrain. Participants performed the tasks in pairs of trials, switching tasks and displays between trials. In the continuous transition condition, the display rotated in depth and in azimuth from one display format to the other. In the discrete transition condition, the azimuth rotation was in the opposite direction, and then the terrain ”snapped” to the final orientation. The results showed that response time after transition was less for the continuous condition. We argue that smooth transition to the correct position provided improved visual momentum between displays.

Reference Frame Congruency in Search-and-Rescue Tasks

Objective: Our aim was to investigate how the congruency between visual displays and auditory cues affects performance on various spatial tasks. Background: Previous studies have demonstrated that spatial auditory cues, when combined with visual displays, can enhance performance and decrease workload. However, this facilitation was achieved only when auditory cues shared a common reference frame (RF) with the visual display. In complex and dynamic environments, such as airborne search and rescue (SAR), it is often difficult to ensure such congruency. Method: In a simulated SAR operation, participants performed three spatial tasks: target search, target localization, and target recall. The interface consisted of the camera view of the terrain from the aircraft-mounted sensor, a map of the area flown over, a joystick that controlled the sensor, and a mouse. Auditory cues were used to indicate target location. While flying in the scenario, participants searched for targets, identified their locations in one of two coordinate systems, and memorized their location relative to the terrain layout. Results: Congruent cues produced the fastest and most accurate performance. Performance advantages were observed even with incongruent cues relative to neutral cues, and egocentric cues were more effective than exocentric cues. Conclusion: Although the congruent cues are most effective, in cases in which the same cue is used across spatial tasks, egocentric cues are a better choice than exocentric cues. Application: Egocentric auditory cues should be used in display design for tasks that involve RF transformations, such as SAR, air traffic control, and unmanned aerial vehicle operations.

Effects of Resolution, Range, and Image Contrast on Target Acquisition Performance

Objective: We sought to determine the joint influence of resolution, target range, and image contrast on the detection and identification of targets in simulated naturalistic scenes. Background: Resolution requirements for target acquisition have been developed based on threshold values obtained using imaging systems, when target range was fixed, and image characteristics were determined by the system. Subsequent work has examined the influence of factors like target range and image contrast on target acquisition. Method: We varied the resolution and contrast of static images in two experiments. Participants (soldiers) decided whether a human target was located in the scene (detection task) or whether a target was friendly or hostile (identification task). Target range was also varied (50–400 m). In Experiment 1, 30 participants saw color images with a single target exemplar. In Experiment 2, another 30 participants saw monochrome images containing different target exemplars. Results: The effects of target range and image contrast were qualitatively different above and below 6 pixels per meter of target for both tasks in both experiments. Conclusion: Target detection and identification performance were a joint function of image resolution, range, and contrast for both color and monochrome images. Application: The beneficial effects of increasing resolution for target acquisition performance are greater for closer (larger) targets.

Crew Performance and Situation Awareness in Three UAS GCS Layouts

The aim of Canada’s Joint Unmanned Surveillance and Target Acquisition System program is to acquire an Unmanned Aircraft System (UAS) for Royal Canadian Air Force’s domestic and international operations. This UAS will be capable of complementing existing reconnaissance, surveillance, target acquisition, and engagement capabilities. Defence Research and Development Canada has developed a UAS ground control station simulator to investigate crew layouts, airworthiness certification, UAS crew training technologies and strategies, as well as novel human-machine interfaces. This paper investigates crew performance and situation awareness in three layouts of the ground control station: distributed, classroom, and boardroom. Preliminary results indicate that the boardroom layout outperforms the other layouts in terms of crew communication, teamwork and situation awareness.

Reducing False Alarms in Automated Target Recognition by Lowering the Level of Automation

Automated target recognition (ATR) technologies are designed to help operators detect and identify potential threats. However, ATRs can generate a high number of false alarms (FA), resulting in low operator trust and potential automation disuse. In this study, we examined whether lowering the level of automation (LOA) of ATR could reduce FAs and support automation compliance and reliance. Participants performed a visual search for a target with or without the help of ATR. The ATR operated at three LOAs and two levels of reliability. The results suggested that the lowest LOA resulted in greater automation compliance and reliance. Operators also performed better in one measure of diagnostic accuracy under the low automation condition. The findings suggest that operating ATR at lower LOAs provide an effective method for improving ATR use and for detecting potential threats.

Effects of Automated Scanning in a Search and Rescue Detection Task

Traditionally, search and rescue (SAR) technicians have conducted search by directly viewing the terrain below the aircraft. Defence R&D Canada is developing a multi-sensor imaging system for SAR that would replace this direct “out-the-window” inspection under low visibility conditions. The system could be designed to automate the sweep of the sensor across the terrain in order to minimize operator workload and to ensure that the sensor covers all of the area to be searched. In a previous prototype, the operator controlled the sweep of the sensor through the use of a joystick, adjusting the speed and direction of the sensor in real time. That interface permitted the operator to both cover the terrain and maximize the detection potential targets by moving the sensor more slowly over portions of the display that was more complex or contained cues to the potential presence of a target. The present study was designed to determine whether automation of the sweep function would compromise detection performance by preventing the operator from adjusting the motion of the sensor to make use of the visual information contained in the scene. The results demonstrate that detection is indeed superior when the sensor sweep is controlled by the operator, and that this effect is modulated by the detectability (contrast) of the target. Additionally, it was observed that the terrain could be more effectively covered under operator control, such that the operator was able to adjust the motion of the sensor to match changes in the visibility of the terrain.

Congruency between Visual and Auditory Displays on Spatial Tasks Using Different Reference Frames

This study investigated the effectiveness of spatial auditory cues for tasks using different reference frames, and examined how congruency between auditory and visual displays affected performance. Performance with three types of auditory cues (egocentric, exocentric and non-spatial) was compared on three spatial tasks: target search, target localization and target recall. There was a clear effect of reference frame congruency between auditory and visual displays on target search and target localization tasks. Interestingly, even incongruent auditory cues improved performance relative to non-spatial control conditions. In addition, egocentric auditory cues facilitated performance more than exocentric cues on incongruent trials. The findings have important implications for display design in work environments that involve diverse spatial tasks and displays that use different reference frames.