【作者】 董巧英；

【导师】 高满屯；

【作者基本信息】 西北工业大学 ， 航空宇航制造工程， 2006， 硕士

【摘要】 视觉运动分析是计算机视觉领域中的一个主要课题,它研究从序列图像恢复刚体的运动参数和三维结构的理论和方法。视觉运动分析目前有基于特征和光流计算两种方法,该论文主要研究基于特征对应的刚体三维运动分析方法,利用序列图像之间的特征对应来恢复刚体的运动参数和三维结构。一旦估计出目标的三维运动和结构参数,就可以用这些信息结合目标模型的先验知识,识别出目标,估计出目标当前与未来位置和姿态,解决目标的识别与跟踪问题。因此视觉运动分析在军事、工业、商业、医学、气象等领域具有重要的应用前景。 从图像序列中检测运动目标并估计其三维运动和结构,首先需要对图像进行必要的预处理,从图像中提取出图像特征,根据特征的对应关系估计图像的二维运动特性,进行特征匹配;然后根据刚体运动方程和投影关系建立一组方程,求解物体的运动参数和结构。该论文对相关的特征提取与匹配方法进行了简要介绍,主要关注的问题是运动参数和结构的计算,即运动估计部分。 对于基于特征对应的刚体三维运动估计问题,前人多利用单纯的透视投影图像或正投影图像序列来进行研究,但是在实际应用中,常会有需要近景图像和远景图像相结合来恢复刚体三维运动参数和结构的情况。拍摄远景图像可用正投影模型来近似,而近景图像可以用常用的透视投影模型来近似。 该文充分考虑了应用实际中近景图像和远景图像的结合,使用透视和正投影两种线性投影模型的组合来代替单纯的透视投影模型,利用特征点(直线)对应来恢复刚体运动和结构。此方法既简化了极几何学,又不会影响欧几里得结构的恢复。文中首先介绍了三维运动估计问题的一些基础知识,然后重点研究了基于一幅正投影和一幅透视投影图像点特征、基于一幅正投影和两幅透视投影图像直线特征的刚体三维运动估计问题,给出了相应的极几何学关系、分析了中间参数矩阵、提出了简单有效的线性算法,进行了加噪声的数据模拟实验和仿真实验,实验显示其运动估计结果是有效而稳定的。更多还原

【Abstract】 This dissertation is the project supported by Aeronautical Foundation Science (No. 03I53062).Visual motion analysis has been a major topic of research in computer vision. It is the method of rigid-body 3-D motion and structure recovery from image sequences. Methods for it can be classifed as correspondence-based and optical flow-based. This dissertation discusses the former only, recovering the rigid-body 3-D motion and structure from features between the image sequences. Once the motion object is detected, computer vision system can recognize it and estimate the current and future object location and pose with the motion and three-dimensional structure information, so it can be used to resolve the problem of object recognition and object tracking. Visual motion analysis is widely used in military, commercial, industrial, medical, meteorological field and so on.The first step for extracting structure and motion information from image sequences is the necessary image pre-processing, image features (feature point and feature line) extracting and image features matching;then establishing a set of equations according to the rigid-body motion and projection equations, and getting the motion and structure parameters. The dissertation introduces the polular methods of feature extracting and matching briefly, while focuses on motion and structure parameters estimation.Previous work in rigid-body motion from feature correspondences focused either on two (or more) perspective images or on a set of orthographic (more generally, affine) images. In practice, a thorough study of structure from motion using combinations of close shot and distant shot is needed. Usually one can use the orthographic model for distant shot, and the perspective model for close shot.Taking the practical application into account, this dissertation presents a first investigation on the structure from motion problem from the combinations of perspective and orthographic images based on feature correspondences. The algorithmsimplified epipolar geometry without affectting the recovery of Euclidian structure. The dissertation introduces the foundational information about 3D motion estimation firstly, then focuses on two cases: 3D motion and structure between one perspective and one orthographic views from point correspondences, 3D motion, and structure between two perspective and one orthographic views from line correspondences. Its contribution includes: description of the epipolar geometry, analysis of the particular fundamental matrix, presentation of simple and effective linear algorithm. Computer simulation with data and artificial images show that the performance of the technique is effective and stable.更多还原