Calibration method of a vehicle-mounted camera

Abstract

The invention discloses a calibration method of an on-board camera. The calibration method comprises the following steps of equipment installing, calibration site laying and image calibrating. The calibration method of the on-board camera is based on vanishing point detection. During distance measurement, coordinate transformation is conducted on the basis of a vertical coordinate YL of a vanishing point, it is avoided that re-calibration is conducted when the installation height and the pitch angle of a camera change, and operation is simple and convenient. In addition, a data calculation model is simplified, and reaction speed of an on-board computer is increased. The calibration method is unrelated to the pitch angle of an automobile, the corresponding relationship between a space coordinate and an image coordinate is rapidly calculated according to the vertical coordinate YL of the vanishing point on the road surface, distance measurement speed is high, and accuracy is high. The calibration method achieves automatic regulation of calibration data of the camera, and therefore resolves the problem that the measurement accuracy is insufficient when the camera is installed again or the pitch angle changes in a running process of the automobile.

Description

technical field [0001] The invention belongs to the early warning technology of safe vehicle distance in the field of modern traffic, and in particular relates to a calibration method of a vehicle-mounted camera. Background technique [0002] As people's requirements for car safety are getting higher and higher, safety distance warning devices are more and more used in ordinary cars. Using safety distance warning devices to remind or assist drivers to brake has become an important method to reduce traffic accidents. . Among them, the early warning device based on the vehicle camera is widely used in the monitoring and early warning of the existing vehicle safety distance due to its advantages of low cost and rich information. Then, the corresponding relationship between the image coordinate system and the vehicle body coordinate system is obtained based on the camera calibration technology, so as to calculate the actual distance between the target vehicle in the image and t...

AI Technical Summary

Problems solved by technology

[0003] Among the existing vehicle camera calibration methods, the camera calibration distance measurement method based on perspective transformation has the advantages of no restrictions on camera installation, no need to obtain camera internal parameters, and simple and feasible, but it must be calibrated on the ground after each installation Calibrate and correct, and there are the following two defects: (1) Once the vehicle-mounted camera is calibrated, its installation height and pitch angle cannot be changed, especially the change of pitch angle will cause serious ranging errors. To avoid this error, each time the vehicle distance warning device is installed on the vehicle, a new camera calibration is required, which cannot meet the user's demand for product simplicity; (2) When the vehicle pitches due to acceleration and deceleration or road undulations, etc. When the angle changes, the pitch angle of the vehicle camera will also change, thus affecting the ranging accuracy

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