Detecting the Corners of Light Shape of Automotive Low-beam Headlamp by Inverse Hough Transform

The corners are the key points of light shape of automotive low-beam headlamp. This paper explains, in detail, the principle of detecting the corners of light shape of automotive low-beam headlamp with inverse Hough transform. There are three major steps. Firstly, gradient method is used to obtain the dividing line between brightness and darkness in the light shape of low-beam headlight. Secondly, the straight lines are detected by Hough transform. Thirdly, the cross-points of straight lines are obtained by inverse Hough transform. Then according to the reasonability of cross-points, unreasonable cross-points are removed, thus the corners of light shape are obtained. Experiments are used to prove that this method can resist noise and work on real time. It realizes the transformation from manual detection to automatic detection in detecting optical axes of vehicle lamp.