Title
On the relationship between human search strategies, conspicuity and search performance
Author
TNO Defensie en Veiligheid
Hogervorst, M.A.
Toet, A.
Bijl, P.
Contributor
Holst, G.C. (editor)
Publication year
2005
Abstract
We determined the relationship between search performance with a limited field of view (FOV) and several scanning- and scene parameters in human observer experiments. The observers (38 trained army scouts) searched through a large search sector for a target (a camouflaged person) on a heath. From trial to trial the target appeared at a different location. With a joystick the observers scanned through a panoramic image (displayed on a PC-monitor) while the scan path was registered. Four conditions were run differing in sensor type (visual or thermal infrared) and window size (large or small). In conditions with a small window size the zoom option could be used. Detection performance was highly dependent on zoom factor and deteriorated when scan speed increased beyond a threshold value. Moreover, the distribution of scan speeds scales with the threshold speed. This indicates that the observers are aware of their limitations and choose a (near) optimal search strategy. We found no correlation between the fraction of detected targets and overall search time for the individual observers, indicating that both are independent measures of individual search performance. Search performance (fraction detected, total search time, time in view for detection) was found to be strongly related to target conspicuity. Moreover, we found the same relationship between search performance and conspicuity for visual and thermal targets. This indicates that search performance can be predicted directly by conspicuity regardless of the sensor type. Keywords: Search performance, Field of Regard, Field of View, Modelling, Conspicuity, Scan path, Zooming, Detection time, Detection probability, Search strategy
Subject
Visual search
Field of view
Target detection
Conspicuity
Detection probability
Detection time
Field of Regard
Field of View
Modelling
Scan path
Search performance
Search strategy
Zooming
Computer simulation
Computer vision
Demodulation
Image sensors
Mathematical models
Target drones
Tracking (position)
Conspicuity
Detection probability
Detection time
Field of regard
Field of views
Scan path
Search performance
Search strategy
Zooming
Imaging systems
To reference this document use:
http://resolver.tudelft.nl/uuid:b7ba159c-d01e-4cd3-9c01-542c9acd5a6e
TNO identifier
15994
Source
Infrared Imaging Systems: Design, Analysis, Modeling, and Testing XVI, 240-251
Series
Proceedings of SPIE - The International Society for Optical Engineering
Document type
conference paper