倾斜立体影像自动准稠密匹配与三维重建算法
an al gorithm of automatic quasi-dense matching and three-dimensionalreconstruction for oblique stereo images
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摘要: 倾斜影像之间因存在较大几何畸变已有算法尚难取得可靠准稠密匹配严重阻碍后续的三维重建本文提出一种基于仿射不变特征的自动准稠密匹配与三维重建算法 算法分三个阶段1种子匹配 先利用仿射不变特征获取初始匹配在此基础上进行最小二乘匹配least square matchinglsm 并自适应迭代求取lsm最大收敛区域maximum conver gence re gion mcr2准稠密匹配 对位于mcr内部的格网点采用透视变换模型的归一化互相关normalized cross correlation ncc测度进行匹配其余格网点则采用对极几何改正模型的加权差值平方和测度进行匹配对于匹配结果中可能存在的外点根据几何一致性关系剔除3三维表面重建 利用影像定向与共线方程对2步结果重建三维点云然后根据三维点云生成三维网格并贴上纹理得到最后的重建结果 实际的倾斜立体影像实验验证了算法的优越性Abstract: since there are severe geometric distortions between obli que imagesit is difficult for the available al gorithms to obtain satisfactor y quasi-dense matchingthus a serious obstacle to subsequentthree-dimensional reconstruction.this paper proposes an al gorithm of automatic quasi-dense matchingand three-dimensional reconstruction based on affine invariant features.the proposed method can bedivided into three sta ges seed re gion matching.the affine invariant features are first extractedand matchedbased on matched features least square matchinglsmis implemented.subse quentlythe maximum convergence re gion mcrof lsm can be calculated by adaptive iteration. quasidense matching.to detect correspondencesthe normalized cross correlation nccfor a pers pectivetransformation model was adopted to the grid points in mcrand the weighted sum of a squareddifference metric for a epipolar geometr y correction model was applied to the rest of grid points.afterwardsoutliers will be eliminated based on the geometrical consistenc y check. three-dimension-al surface reconstruction of the 3dpoint cloud commenced with the application of a image orientationand collinearit y equation.thena 3dsurface model was generated based on the 3dpoint cloud.experiments with obli que stereo images demonstrate the effectiveness of the proposed al gorithm