The classic tradeoff in the development of virtual environments applications is between the quality of the graphic image and the speed at which the application runs, as reflected in the update rate of the graphics and the response time of the system to user inputs. On a personal computer platform, with limited computational resources, this tradeoff is more pronounced. To optimize performance, the content and quality of the image should be simplified as much as possible without losing important visual information and perceptual cues. In driving simulation, the quality and content of the visual information is critical; drivers extract most of the information they need from visual input. Speed is also critical; Wierda stresses the importance of the response time in creating an effective driving simulator.
This thesis investigates the effects of the display device and two graphic image factors on driver performance and perception in a virtual environments based driving simulator. Two studies of driver performance compare two different display devices (head-mounted display and monitor), two rendering algorithms (flat shaded and wireframe) and three levels of road side delineation poles, which provide different amounts of peripheral visual cues. Subjects were tested in a simple road-tracking task and in a test of speed estimation in constant-speed travel. The subjects in the tracking study also answered questionnaires designed to evaluate their subjective perception of the realism of the simulation and their sense of immersion in the virtual environment.
The results of the study confirm previous work on the beneficial effects of road side delineation poles on driving performance. The results also point to the importance of lag in the perception of task performance and immersion in the virtual driving environment, and the importance of shaded images in actual driving task performance. The results of the speed estimation study confirm previous studies of speed estimation and demonstrate the capability of the graphic content in the simulator to provide useful perceptual cues.