广义光束法在普通数码影像中的应用

Application of generalized bundle adjustment to ordinary digital image

普通数码相机由于轻便、价廉等优点,目前已广泛应用于近景摄影测量领域.然而利用传统的直接线性变换解法(DLT)处理普通数码影像需在现场布设较多控制点.当控制点较少时,则计算结果精度低,难以满足工程精度要求.针对DLT算法缺点,现从空间影射变换理论出发,推导出广义的共线条件方程式;仿效自检校光束法,提出广义光束法并建立其平差模型;最后实验了普通数码影像广义光束法的有效性.结果表明,与DLT算法相比,普通数码影像的广义光束法能改善待定点物方坐标求解精度,且在控制点个数较少情况下,效果明显,同时最弱方向上精度提高最快.

Ordinary digital cameras are wildly used in the field of close range photogrammetry because of their priority in light-weight and low-price. When the method of direct liner transformation（DLT） is used to deal with digital imagines, many control points are needed. In the condition of fewer control points, the accuracy of calculated resuits is low, and cannot meet the requirement of engineering. From the theory of spatial projection, the generalized colinear equation was deduced, imitated self-calibrating bundle adjustment and based on the equation, the method of generalized bundle was proposed and its adjustment model was built. Based on the test, the effectiveness of ordinary digital imagine was studied. The results show that the generalized bundle adjustment can improve the accuracy of determining coordinate of ground point to be located, and its effect is obviously with fewer control points, and at the same time the accuracy improvement in the weakest direction is the fastest.