Assisting search and rescue through visual Attention

Abstract

With the ubiquity of visual data being recorded, we now have the ability to view vast amounts of visual imagery. However, searching through imagery for an indeterminate target in tasks such as security baggage inspection, medical scan screening and Wilderness Search and Rescue (WiSAR), remains problematic for most people and cannot be automated. If the imagery was presented to account for the way in which humans cognitively process such visuals, then the success of these tasks might be improved. This thesis proposes and evaluates a series of presentation methods to manipulate imagery to seek this improvement.

A series of user experience studies were conducted. Given the task of searching for inconspicuous 'lost' human beings in a WiSAR scenario, subjects observed multiple sequences of aerial photography embodied in six specially designed presentations. These presentations were designed following an analysis of existing visual attention literature.

The first study to evaluate these methods compared the standard live (i.e. scrolling) view of the terrain to a static representation. This static portrayal of aerial search yielded an improved success rate for target location. The second method adapted the static representation, by segmenting the image into smaller tiles that were displayed for correspondingly shorter durations, while the third method enlarged the segmented tiles to fill the display. With increased segmentation, the ability for subjects to locate targets was broadly unaffected. The fourth study investigated two methods that use eye-tracking equipment to dynamically enhance the display.

Contained within this thesis are the findings from these four studies, which include the analysis of each subject's performance, opinions and eye-movement behaviour. The inspiration for each presentation method was the development of a proposed model for visual search. Ultimately, the static method is revealed as the most effective for the chosen scenario of WiSAR.