Non-Metric Camera Lens Calibration Based On Calibration Fields

Complete a three-dimensional reconstruction process,the need for three steps:camera lens calibration,image matching technology,three-dimensional modeling process.As the first step,the calibration precision and speed directly affect the follow-up work.Because the traditional camera calibration algorithm has the problems of low accuracy,complex structure,difficult programming,limited calibration and other problems,this paper mainly improves the traditional DLT algorithm,which is realized by MATLAB programming,and a new calibration method is fast and accurate in the 3D and 2D fields.Specific work is as follows:(1)To improve the traditional DLT 3D algorithm,the improved algorithm does not need to set the initial value.The iterative linearization method is used to calibrate the non metric digital camera(Canon eos60D digital camera),and the calibration coefficients obtained from the TASI nonlinear algorithm are compared with the same conditions.In this paper,the improved DLT 3D algorithm in the program running speed,can reach one percent seconds of the order of magnitude,compared with the nonlinear TSAJ algorithm to calculate the rate is about 30 times faster than the solution.In the solution,the improved DLT 3D algorithm can control the residual value of 2 pixels,and the nonlinear TSAI algorithm is less than the improved DLT 3D algorithm.(2)When Z takes a constant,the modified DLT 3D algorithm to transform,proposed a new 2D plane calibration algorithm,this improved DLT 2D algorithm is also using iterative linearization of the equation program implementation,the establishment of simple calibration site,the non measurement digital camera(this paper choose the Nikon D3100 digital camera)calibration,and the same conditions of the Zhang Zhengyou plane method for comparison.The DLT 2D algorithm proposed in this paper is faster than the Zhang Zhengyou plane method,which is about 30 times faster than the test speed.The improved DLT 2D algorithm in the calculation results accuracy,after the return generation of the coordinates of the pixels are less than 2,the accuracy is higher than the same set of data under the Zhang Zhengyou plane calibration method.In summary,the algorithm of a non measuring digital camera can rapidly and accurately realize the camera calibration,calibration is digital camera either used in close range photogrammetry or large angle without man-machine oblique photography has certain reference significance.