单应约束与核线约束对于影像匹配精度的对比

Comparison of Homography Constraint with Epipolar Geometry Constraint on Image Matching Accuracy

数字影像匹配是摄影测量作业的关键环节，其精度影响后续前方交会、生成DSM的质量。单应约束和核线约束作为两种基于先验同名点的约束准则，在提高匹配精度的同时也能提高匹配效率。本文首先对重叠的、有严重几何变形的两张影像进行特征匹配，得到可靠的高精度同名点；然后进行单应约束与核线约束实验，对比两种约束方法的精度。结果表明，在同等条件下，核线矩阵约束比单应矩阵约束精度高；同时，本文也为匹配约束中像素偏移阈值的选择提供了参考依据。

Digital image matching is critical in photogrammetry, whose accuracy directly influences the process of forward intersection and quality of DSM. As for homography constraint and epipolar line constraint are the constraint criteria based on the known matching pairs, they can improve matching accuracy as well as efficiency. First, this paper obtains reliable and precise matching pairs by establishing the feature matching on the two overlapping images with serious geometric distortion. Then it conducts homography constraint and epipolar line constraint experiments to compare the accuracy of the two constraints. The results show that epipolar geometry constraint can achieve higher accuracy compared with homography constraint under the equivalent conditions. Besides this paper also provides references for choose of pixel offset threshold in the image matching constraints.