多摄站数码影像光束法相机检校的研究

Study on the Calibration of Cameras with Multiple Camera Station Digital Image Bundle Method

普通数码相机在近景摄影测量中的使用越来越普遍,基于三维控制场的光束法作为相机检校的一种经典方法被广泛应用。为了研究影像数量和拍摄角度对光束法相机检校的影响,架设了多个摄站对三维控制场进行拍摄,通过依次增加摄站影像进行光束法相机检校,并对检校参数从稳定性和量测应用精度2个角度进行了比较分析。结果表明:在一定范围内,多摄站影像的光束法解算有利于提高检校参数的稳定性,并且量测应用精度较高,但并不是影像数量越多越好,随着拍摄时镜头距控制场中心距离的增加,以及镜头相对于正直拍摄方向偏转角度的增加,得到的影像并不利于检校,加入这些影像反而会导致检校效果变差。在实际的应用中,可以考虑在控制场的左前方、正前方和右前方等合适位置架设5个摄站,使用5张影像进行光束法相机检校以获得最佳的检校稳定性和量测应用精度。

The ordinary digital cameras are more and more common in close-range photogrammetry and measurement,and the bundle method based on 3D controlling field is widely used as a classical method of camera calibration.In order to study the influence of the number of images and shooting angles on the camera calibration with bundle method,a number of camera stations were set up to shoot the 3D controlling field,the camera calibration with bundle method was conducted by adding images to the camera stations in turn,and the calibration parameters were compared and analyzed from the perspectives of stability and measurement application accuracy.The results show that,within a certain scope,the solution of bundle method for multiple camera station images is beneficial to improve the stability of the calibration parameters,with high accuracy of measurement,but the number of images should be limited,and with the increase of the distance of cameras from the center of the controlling field during shooting,and the increase of the deflection angle of the lens from the direction of the straight shooting,the images obtained are not conducive to the calibration and adding these images will lead to poor calibration effect.In the actual application,we can consider setting up 5 camera stations in the suitable positions of the controlling filed,such as,left front,front and right front,and using 5 images for camera calibration with bundle method to obtain the best calibration stability and accuracy of measurement application.