Research On Calibration Method For Vehicle-mounted Camera Based On Highway Markings

At present, the intelligent vehicles vision navigation technology is accepted by the upscale automobile, which has broad physical demand and prospect. The main work of this research is a part of "Lane Recognition of highway". The contents include research on calibration method of vehicle-mounted camera, and providing the essential parameter for coordinate transformation of the highway image, which will provide the prerequisite for the further study of acquiring the distance between the two automobiles and auxiliary driving.The camera calibration is the premise and basic question in the computer vision realizing, which is a hot spot in computer vision research. This article works in the predecessor in the foundation, according to the characteristic of the highway marking, to find an analytical expression of the external parameters of a camera, vanishing point and imaging slopes can be established using the nature of vanishing point and vanishing line, and realizing to calibrate the exterior parameter. The main works are following:(1) More research is concentrated on the image processing methods and object recognition methods involved in vehicle-mounted camera calibration. Several representative kinds of camera calibration principle and methods in the computer vision are introduced.(2) A new camera calibration algorithm was presented. In the method, two vertical across lines were used as the calibration object. The intersect point of the two lines was set to be fixed, a set of linear equations could be set up using the property of perpendicular lines. Thus, a camera intrinsic matrix was obtained by solving these equations.(3) In accordance with this topic's application and the characteristic of highway markings, an analytical expression of the external parameters of a camera, vanishing point and imaging slopes can be established through mathematical derivation according to pinhole imaging model. The calibration of external parameters of a camera can be performed only needing to know the vehicles vertical spool thread's displacement quantity relative to three highway markings and the internal parameters of a camera, and determine the crossover points and slopes through manual or automatic schemes.This paper is concentrated on calibration method of vehicle-mounted camera. A new camera calibration algorithm was presented. In the method, two vertical across lines were used as the calibration object. The preliminary research has been made by using the characteristic of parallel highway line to calibrate external parameters fast accurately. This research will be a basis for the further investigations on calibration of vehicle-mounted camera.