Enhancement of the SAAM Driving Simulator Graphics Pipeline for Speed Perception Studies

This paper presents a speed perception study focusing on the impact of a visual scale factor. This factor corresponds to the ratio between the geometric field of view (of the camera) and the driver’s field of view covered by the screen. 20 participants have reproduced 2 speeds (50 and 90 km/h) without knowing the numerical values of these consigns, and with 5 different visual scale factors: 0.70, 0.85, 1.00, 1.15 and 1.30. We show that this visual factor has a significant impact on the speed reached by the subjects and that the variation of perceived speed can be deducted from the used visual scale factor. To be able to conduct this experiment, we had first to solve an image correction issue. As the visual display is projected on a cylindrical screen, a distortion correction must be performed. This correction is dependent on the viewer’s position and so is also dependent on the visual scale factor. We had then to improve our image warping approach to be able to take into account in real time the observer’s position (which was not the case until now). This paper presents a concise state of the art about image correction and some details about the implementation of the chosen algorithm.