Abstract
A field study with eight participants negotiating a road course in a military vehicle measured the driving performance for natural and indirect vision. The indirect vision system was driven with fixed panoramic flat panel, liquid crystal displays (LCD) in the cab and a forward viewing monocular camera array mounted on the front roof of the vehicle and tilted slightly downward. The results are that for benign driving conditions (a well-marked course, good visibility, and essentially flat terrain), the participants successfully drove the vehicle with indirect vision for the different fields of view (FOV) of the cameras: near unity, wide, and extended. However, they drove the course faster and made fewer lane marker strikes with natural vision than they did with the indirect vision systems. Further, the course speed significantly decreased with increased camera FOV, while the number of lane marker strikes increased slightly. Workload ratings show a significant increase in perceived workload with indirect vision, while a test of situational awareness shows an increase in demand component. While the heart rate increased significantly with course speed because of the increased exertion, the predicted metabolic work output was least for the natural vision and increased with the indirect FOV because of the longer course times. Most participants reported a discomfort associated with motion sickness while in the moving vehicle with the displays, The subjective stress rating of the drivers was least for natural vision and increased with indirect FOV. In comparing the camera's FOV, the driving performance was fastest with the near unity FOV. However, cognitive processing tests show a trend for improved spatial rotation and map planning with the wide FOV, a design which was selected by the researchers to provide a balance of the resolution needed for obstacle avoidance and scene perspective for course following.
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