The Calibration Of Non-metric Digital Camera

As one of the main equipments about close-range photogrammetry to obtain images,non-metric digital camera with its own unique advantages, that has been widely used in close-range photogrammetry.An important factor of affect the accuracy of photogrammetric results is the camera parameters,because of unknowning of the machine inner orientation elements and distortion coefficient position about non-metric digital,and not stable enough, analytical calculation that can not be placed directly,so before useing the digital camera to obtain measurement data,need to camera calibration.So calibration of camera technical parameter is a key problem to guarantee result quality could meet precision request.For a large number of non-metric camera calibration methods,in this paper, the basis is the method of the direct linear transformation (DLT) model and based on the total line equation of the general type of the error equation about pixel coordinates that have been commonly used and the development of sophisticated,by analyzing the source of error in digital cameras,meanwhile considering the factor of main away from the camera,the principal point coordinates and the lens optical distortion,that cause the system error, mading successibe stereopairs relative orientation based on coplane condition,with the goal of target shooting to set up mathematical models of successive stereopairs,the use of taylor series to linearization the coplanarity equation model.The use of own procedures to solver that based the least-squares principle measurement data basis.With the absence of control points to achieve the self-calibration of parameters values, the proposed method of this paper does not do the high-precision control points at the scene, low cost,portable equipment,and avoid the risk of direct contact measurement environment,fit the request of site operations for complex requirements,through the geometric relationship between the photograph,volume calculation pixel coordinates,a new methods about implementation of calibration parameters,through the analysis and comparison to calibration results and precision for camera,and draw some conclusions.by analysis the experimental results the experimental result indicated that,calibration method based on the coplane condition is reliable and feasible.