大重叠度面阵航空数码影像的自动转点

Automatic Extraction of Image Tie Points for Aerial Digital Frame Imagery with Large Overlap

针对大重叠度航空数码影像提出了一种像方匹配-自由网平差-物方匹配的自动转点方法。首先,通过像方匹配和自由网平差获得影像外方位元素,为物方影像匹配提供初始值;然后,引入共线几何约束条件,使基于物方的多片最小二乘影像匹配可以顾及影像外方位元素的误差;最后,实现多张影像的整体匹配,以提高自动转点的可靠性和成功率。经对某地区一组大重叠面阵航空数码影像试验证实,该方法能够成功地匹配出大重叠度影像的航带连接点,可满足摄影测量区域网平差的自动转点要求,并显著提高加密点的高程精度。

For the aerial digital frame imagery with large overlap, we propose an automatic transferring point scheme composed of image matching in image-space-free network adjustment-image matching in object-space. Firstly, more accurately exterior orientation elements of images were obtained by image matching in image-space and free network a stment which provide approximate values for the image matching in object-space. Secondly, the col- linearity geometric constraints were introduced to image matching in object-space, which en- ables the multi-photo geometrically constrained least squares matching to consider the errors in the image exterior orientation elements flexibly. Finally, the multiple images were simul- taneously matched and the reliability and success rate of image are improved. Experimental results show that the proposed method can acquire the image tie points successfully for the images with large overlap, which can meet the demand for automatic point transferring in aerial triangulation, and improve the height accuracy of the photogrammetric points significantly.