密集光流法正射影像镶嵌线智能提取

Dense Optical Flow Method for Intelligently Extracting Seamline of Orthophotos

针对正射影像拼接时影像间存在复杂的几何错位问题,提出一种基于密集光流法正射影像镶嵌线智能搜索方法。利用影像密集光流、梯度信息和灰度信息构造代价影像并视其为带权无向图,以图割模型为基础,采用最大流最小割原理自诊断搜索镶嵌线。实验结果表明,采用所提方法得到的稀疏建筑区镶嵌线代价像素数大于100的仅占路径长度的0.7%,且相较于现有商业软件OrthoVista效率提升17%。对人工建筑物与正射影像间投影差较大的区域可实现自动规避,大大降低了几何错位的概率,可明显改善影像拼接的几何错位现象,实现正射影像镶嵌线搜索的智能化。

Objectives: Geometric misalignment is one of the key problems for orthophoto mosaicking. To solve this problem, this paper proposes a regional seamline detection algorithm based on dense optical flow.Methods: Firstly, the cost image is constructed with dense optical flow, gradient information and gray information. And the cost image is regarded as a weighted undirected graph. Secondly, the principle of maximum flow and minimum cut is used to search for seamline based on graph-cut model.Results: The experiment results show that the seamline cost of the sparse building area greater than 100 pixels obtained by the proposed method only accounts for 0.7% of the path length. And the search efficiency of the proposed method is increased by 17% compared with OrthoVista software.Conclusions: The proposed method can automatically avoid passing the building area and the areas with large projection in digital orthophoto map,greatly reduce the probability of geometric dislocation phenomenon of image mosaicking, and realize the intelligence of orthophoto seamline searching.