POS影像外方位元素相关性对模型上下视差理论精度的影响

Theoretical Accuracy Effect on Vertical Parallax of Relativities between Exterior Orientation Elements Obtained Via POS

推导了直接利用影像外方位元素重建立体模型时上下视差的理论精度公式,利用两组带POS数据的实际航摄影像进行了试验。结果表明,当顾及影像外方位元素间的相关性时,模型上下视差的理论精度可以正确反映影像外方位元素的真实精度;视外方位元素为独立参数时,所估算的模型上下视差的理论精度非常低,且存在明显系统误差,不能正确评价影像外方位元素的实际精度。因此,为了能在摄影测量中合理使用POS测定的影像外方位元素,在提供影像外方位元素值的同时应给出外方位元素参数间的协方差矩阵。

Based on the error propagation law, the theoretical accuracy model of exterior orientation elements to vertical parallax is proposed in this paper firstly. Then, two sets of actual data at different image scales were used for experiments. The empirical results show that when the relativities between the exterior orientation elements are considered, the theoretical accuracy of vertical parallax calculated can embody the actual accuracy of image exterior orientation elements exactly. But without considering the relativities, the results of theoretical accuracy are rather poor, existing obvious systematical error, which can not reflect the accuracy of exterior orientation elements obtained Via POS properly. Therefore, to use image exterior orientation elements obtained Via POS for photogrammetry properly, the covariance matrix of image exterior orientation elements should be provided together.