Method and system for calibrating camera for lane offset early warning

Abstract

The invention discloses a method and system for calibrating a camera for lane offset early warning. The method comprises the following steps that a calibration plate including calibration patterns is arranged at a first position in front of a vehicle, the central axis of the calibration plate and the central axis of the vehicle are made to be collinear, and the calibration plate is shot through a camera to be calibrated to obtain a first calibration image; the calibration plate is moved to a second position in front of the vehicle, the central axis of the calibration plate and the central axis of the vehicle are made to be collinear, and the calibration plate is shot through the camera to be calibrated to obtain a second calibration image; the coordinate values of a calibration point in the calibration patterns are obtained through calculation according to the first calibration image and the second calibration image, and the camera to be calibrated is calibrated according to the coordinate values of the calibration point. By means of the method and system for calibrating the camera for lane offset early warning, the operand of image processing and manual measurement parameters in an early stage are reduced, the site and the steps for calibration are simplified, the calibration time is shortened, so that the calibration precision and the calibration working efficiency of the camera are improved, and the method and system are suitable for large scale flow line production operation in large vehicle factories.

Description

technical field [0001] The invention relates to the technical field of lane departure warning, in particular to a camera calibration method and system for lane departure warning. Background technique [0002] Lane Departure Warning System (Lane Departure Warning System, LDW) is a camera that captures the road conditions in front of the vehicle, detects the relationship between the lane markings on the road surface and the vehicle's driving vector to determine whether the vehicle has drifted, and then An active safety driving system that reminds the driver to correct the driving direction when there is a deviation. The system parameters of the camera and the lane departure warning system need to be calibrated before the system is used. By establishing the relationship between the two-dimensional ground world coordinate system and the two-dimensional screen coordinate system, it is mainly to solve the perspective transformation matrix of the two coordinate systems, so as to de...

AI Technical Summary

Problems solved by technology

[0007] (1) This calibration method requires manual measurement of many parameters, including the installation height of the camera, the horizontal installation position of the camera, the distance between the camera and the wheel, and the distance between the camera and the front of the car. There are errors in the manual measurement of each parameter. The accumulated error of the parameters is even greater, so the accuracy is not high and the time cost is high;

[0008] (2) The manual operation of this calibration method is complicated, and a calibration board needs to be placed 2 meters in front of the vehicle, and the cursor on the LCD display interface is moved and displayed through the human-computer interaction unit, so that the center point of the camera is moved to the reference center of the calibration board Point contour position, so as to calculate the pitch angle, rotation angle and deflection angle of the camera, not only the efficiency is low, it is not conducive to the assembly line operation in the large-scale production of the car factory, but also the time cost and system cost are high

[0009] (3) There is no device on the calibration board to ensure that the board body is completely kept at 90 degrees to the ground. Due to the manufacturing process and long-term use, there will be a certain degree of deformation, which will cause the calibration board to not be completely perpendicular to the ground, thus affecting the calibration of the camera parameters. Spend;

[0010] (4) The central axis of the calibration plate and the central axis of the vehicle body must be collinear. This method only places the calibration plate roughly in front of the car, which cannot ensure that the two planes are coplanar, and will also affect the calibration accuracy of the camera parameters.

Images