TRIMMING AND ROAD ORTHO IMAGING FOR NIGHT IMAGES BY ONBOARD HIGH SENSITIVITY CONSUMER GRADE DIGITAL CAMERAS

Abstract. Various kinds of cameras have been utilizing as the onboard cameras in the construction of Intelligent Transport Systems. In recent years, utilization of the high sensitivity consumer grade digital cameras at night is attracting attention from the viewpoint of avoiding the effects of sunlight and congestion of people and cars. However, due to the image taken by the onboard cameras is a perspective projection image, the image is projected small at the far from car and the effect of the lens distortion will be greater at points far from the image center. In order to avoid these issues, the lower part of the projection image or a bird's-eye view image is used, but the imaging of the bonnet part caused by the car models and tilts of the cameras becomes a new issue. Furthermore, a bird's-eye view image at night has to be trimmed to coincide with the irradiation range because the irradiation distance and range of the headlights are limited. On the other hand, feature quantities such as vanishing points and feature points on the lane have been used for projective transformation from a perspective projection image to a bird's-eye view image, but the projective transformation based on feature quantities is an ill-posed problem.

Therefore, this paper discusses a quantitative trimming method based on projective transformation that does not depend on feature quantities and coincide with the irradiation range of the headlights.