Driver assistance systems using forward facing cameras are becoming mainstream. These cameras are typically rigidly mounted inside the driver cabin near the rearview mirror. This puts the cameras at a fixed position, significantly above the vehicle headlights. In this configuration the shadows produced by the headlights, when driving on dark roads, are visible in the camera image. This paper describes how to use these shadows to enhance obstacle detection. In particular it describes how the shadows can be used for detecting speed-bumps and negative obstacles at night from a moving vehicle. This information can be used to warn the driver or to prepare the vehicle for the anticipated change in road surface. This paper has analyzed the image motion of the shadows formed by the host vehicle headlights due to negative obstacles. The results show the validity of the mathematical model and the usefulness in dark road situations. In nights scenes where there are streetlights (illuminated night) only about half the light hitting the road surface comes from the vehicle headlights. In this case candidate shadows cannot be detected simply by thresholding but rather, one must look for patches that are darker than the surroundings. The dark patches over time and the method described in this paper will determine if they are shadows due to the host vehicle headlights and negative obstacles. Shadows formed by the stationary streetlights will behave like patches on the road. Some vehicle LED headlights oscillate on and off. If the camera is synchronized to the headlight frequency image subtraction may be used to further enhance enhance the shadows.
The shadow knows: Detecting speed bumps and negative obstacles at night
2012
6 Seiten, 10 Bilder, 6 Quellen
(nicht paginiert)
Conference paper
Storage medium
English
British Library Online Contents | 1996