Calibration Method And System Realization Of The Non-metric Camera

Non-metric digital cameras are widely used in large scale UAV digital aerial photogrammetry.The inner orientation elements and lens distortion coefficients of non-metric digital cameras are important factors influencing the accuracy of the aerial photogrammetry.In order to determine the inner orientation elements and lens distortion coefficients accurately,this paper make some study and exploration in the following aspects.First,put forward the method of self-building calibration field based on extensive research and study on the theory of camera calibration method and cases of building a calibration field.It include relative merits of calibration methods of non-metric digital cameras,site selection of calibration field and the design,layout and measurement of control points.Second,automatic detection of control points position using Canny operator edge detection,morphological condition detection and fitting the center point of ellipse which greatly reduce the workload of finding points manually,improve accuracy of points position and avoid human error.Third,according to the collinear equation,deduce the direct linear transformation process and solve the inner orientation elements and lens distortion coefficients of non-metric digital camera.The method of direct linear transformation is given in this paper.Fourth,any error in lens distortion coefficients can be reflected in the control network adjustment.The lens distortion coefficients will be validated by Inpho project for if it is right and can be used for large scale UAV digital aerial photogrammetry projects.