论文部分内容阅读
直接线性变换方法 (DLT),以无需内、外方位元素的初始近似值的优点,广泛应用于非量测相机的近景摄影测量数据处理中。然而,直DLT系数Li的求解的主要依据是控制点,当控制点的精度较低、布设少或者不合理时,会导致解算结果精度较低甚至无法应用。而光束法平差中泰勒级数展开在构建误差方程中有着高精度的特点,但它对初始值有很强的依赖性,在近景摄影测量中整体广义逆求解比较慢。在此基础上,本文提出了一种附加约束条件DLT和光束法平差协同解算方法,用DLT算法确定光束法平差的初始值,保证了结果的收敛,弥补了光束法平差中泰勒级数展开法的不足。扬长避短,既继承了泰勒级数展开算法的精确性和顽健性,又具备最速下降法迭代前期收敛速率快、计算量小的优点。通过基坑变形监测试验加以验证,取得了较好的效果。
Direct Linear Transformation (DLT) is widely used in near-field photogrammetry data processing of non-metric cameras without the need of initial approximations of internal and external orientation elements. However, the main basis for the solution of the straight DLT coefficient Li is the control point. When the control point has low accuracy, small or unreasonable layout, the resolution of the solution can not be accurately applied or even applied. However, the Taylor series expansion in beam-law adjustment has the characteristics of high accuracy in constructing error equation, but it has strong dependence on the initial value. In the near-field photogrammetry, the overall generalized inverse solution is relatively slow. On this basis, this paper presents a collaborative solution method of DLT and beam method with additional constraints, using DLT algorithm to determine the initial value of beam method adjustment, to ensure the convergence of the results, to make up for the beam method adjustment Taylor Lack of series expansion method. It not only inherits the accuracy and robustness of the Taylor series expansion algorithm, but also has the advantage of the steepest descent method with fast convergence rate and small computation amount in the pre-iteration. Deformation monitoring test to verify the foundation, and achieved good results.