Research On Camera Calibration Technology Based On Alternative Three-Dimensional Framework

Objective: Currently three-dimensional calibration in sports is mainly by the three-dimensional framework.However the three-dimensional framework has large volume,heavy weight,the installation is troublesome.This paper analyzes and summarizes the technology research of camera calibration in three-dimensional calibration system at home and aboard,according to the method for camera calibration using a three-dimensional framework,insufficient showing in the range calibration,error,portability and timeliness aspects,proposes the new method of three-dimensional calibration by using planar checkerboard.Methods: In 5 meters,10 meters and 30 meters distance,compare with meter board reconstruction results by using three-dimensional framework and planar checkerboard calibration plate.And when the calibrated meter board is located at the edge or within the control range of the outer plate plane calibration,spatial error distribution analysis.Result: 1.It is found that under the same shooting conditions,the precision range measured by planar checkerboard calibration is between 0mm to 2mm which is much better than the traditional three-dimensional framework calibration method(that the result is between 2mm to 4mm),and the data result is much more stable.Meanwhile the data shows that with the shooting distance increasing,the error of test result decrease.2.The spatial error distribution data shows that whether the calibrated object is located within the range of control point,the error is less than 2mm.Comparing with the calibrated point is out of three-dimensional framework space range,the error is decreasing.3.During the calibration operation,the checkerboard calibration method calibrating maker automatically by computer instead of manual calibration.Therefore reducing the errors caused by human factor.4.Finally,this paper implements the camera calibration based on checkerboard calibration board in sport,calibration board for large-range measurement and relevant calibration system are designed for sports application.Conclusion: Experimental results show that camera calibration method and system has significant advantages and comparing with the traditional three-dimensional framework calibration,planar checkerboard calibration has significant advantages,it overcame the shortcomings of the three-dimensional framework in use.It is suitable for large-range and high precision requirements of sports measurement.