顾及影像拓扑的SfM算法改进及其在灾场三维重建中的应用

快速、准确的大场景影像三维重建技术可为灾害应急响应和灾情评估提供重要的决策依据。本文针对运动恢复结构(SfM)算法效率低的问题,提出了一种顾及影像拓扑关联关系的拓扑-运动恢复结构(TSfM)算法。TSfM算法利用低空无人机(UAV)自身的飞控记录构建影像拓扑关联关系,缩小了特征匹配时的影像搜索范围,与传统SfM算法相比,影像匹配的时间复杂度由O(n2)降低为O(n)。实验结果表明,TSfM算法实现了基于无人机影像序列的灾场快速三维重建,重建模型的相对精度与SfM算法的重建精度一致。将该方法用于四川芦山地震UAV影像三维重建,可检测出地震滑坡体及其形态信息。

Modification of SfM Algorithm Referring to Image Topology and Its Application in 3-Dimension Reconstruction of Disaster Area

The rapid and accurate large scene 3Dreconstruction technique from multi-view images canprovide important and reliable information for emergency response and disaster assessment.Againstthe low efficiency of Structure from Motion(SfM)algorithm,this paper develops an image Topologybased Structure from Motion(TSfM)algorithm referring to image topological conjunction.Genera-ting the image topological conjunction with the flight-control data acquired by unmanned aerial vehiclesystem(UAV),the searching range for matched images is reduced in the process of feature matching,and the time complexity of TSfM algorithm in the feature matching stage decreases from O(n2)toO(n)as compared with SfM algorithm.The experimental results show that TSfM algorithm makes itpossible for rapid large scene 3Dreconstruction with sequence images from UAV.Furthermore,it isreached that the relative error of the 3Dscene model reconstructed by TSfM algorithm is comparablewith that by SfM algorithm.The proposed TSfM algorithm is applied for Lushan earthquake disaster3Dreconstruction with UAV images,which can help to detect the seismic-induced landslides withmore information.