【作者】 杨化超；

【导师】 张书毕；

【作者基本信息】 中国矿业大学 ， 大地测量学与测量工程， 2010， 博士

【摘要】 随着高分辨率CCD技术及计算机技术的快速发展,基于非量测数码相机的数字近景摄影测量技术已成为崭新的发展领域,成为非接触、灵活、快捷的三维空间信息获取主要方式之一。这也使得该领域成为近年来的研究热点。其中,相机标定、特征提取与匹配(尤其是宽基线摄影条件下的特征提取与匹配)是应用该技术时的关键问题,是后续影像定向和三维重建、数据分析的基础。本文对上述内容进行了研究。论文研究涉及数字图像处理、影像匹配、模式识别等多学科的理论与方法。主要包括:1.研究了基于平面格网的标志点识别与匹配方法及其相机标定应用。提出了一种基于物方几何约束的圆形标志点快速识别与匹配方法;结合平面场景的共线方程,论证和推导了分别基于灭点理论及二维直接线性变换的平面场景中相机外方位元素初值的计算方法;引入了一种基于逐次计算可靠性矩阵QVVP的自检校光束法平差中各类观测值权值的确定方法,提高计算的速度和稳健性。2.提出了基于SIFT特征的宽基线立体影像最小二乘匹配方法。算法首先基于特征点的空间分布和信息熵选取一定数量的最优SIFT特征点集,并采用基于奇异值分解的SIFT特征匹配、基于SIFT特征尺度和方位信息的自适应归一化互相关(NCC)匹配获得精度较高的初始匹配点对用于立体像对的基本矩阵和单应矩阵估计;然后在对极几何和单应映射的双重约束下,采用基于自适应NCC及距离加权的多尺度最小二乘匹配算法进行扩展匹配并同时保留匹配定位精度较高的原始SIFT同名特征点对;此外,算法还综合应用了基于积分影像的NCC快速计算、金字塔影像匹配等方法和策略,以提高匹配的速度和可靠性。3.提出了基于核线几何约束的尺度和旋转不变线特征描述符的提取与匹配方法。算法首先基于核线几何约束定义直线对的重叠距离、方位及线支持区,并据此构造了一种基于像素灰度及梯度分布统计信息的尺度和旋转不变线特征描述符;充分考虑了遮挡及视差断裂等因素的影响,采用双向多层次加权匹配策略完成直线段的匹配;采用核主成分分析对特征描述符进行降维处理,提高特征匹配的速度。4.在Windows平台上基于Visual C++6.0高级编程语言及OpenCV开放计算机视觉库编制了上述算法的相关应用程序;试验验证了上述理论和方法的正确性和有效性。论文的研究工作,丰富了数字近景摄影测量特征提取与匹配的相关理论和方法,并为后续的宽基线摄影测量三维重建打下了良好的基础。该论文有图71幅,表9个,参考文献108篇。更多还原

【Abstract】 With the fast development of high resolution Charged Coupled Device(CCD) and compute technology, digital close-range photogrammetry based on non-metric digital camera has become a very new research field, and at the same time, digital close-range photogrammetry has also become one of an important way to obtain the 3D spatial information with untouched, flexible and quick style . So, some problems related to this field have become hot topics around home and abroad recently. Among these, camera calibration, feature extraction and matching (especially feature extraction and matching for wide baseline stereo pairs) are the key problems when using this technology, because these problems are the basis for following photogrammetric processes, such as orientating the images, 3D reconstruction and data analysis, etc. The research work of this dissertation focus on previous problems and involved in multiple disciplinary theories and method, such as digital image process, image matching, and pattern recognition, etc, mainly include:1. Recognizing and matching methods of circular signalized points and its application of digital camera calibration were studied. The method of recognizing and matching the circular signalized points based on object geometric constraints was proposed; Two practical algorithms to obtain the initial values of the exterior orientation elements based on the vanishing points theory and the two dimensional direct linear transformation were demonstrated and deduced by combining the collinearity equations in planar scenes; Mathematical model of the bundle block adjustment with self calibration was given and the method of determining the weight of every class of observations based on repeat calculating the QVVP was introduced to improve the calculating speed and the stability.2. Least squares matching methods for wide base-line stereo images based on SIFT features were proposed. In this algorithm, the optimal SIFT features with good spatial distribution and large information content were first selected, then these SIFT features were matched by using the maching method based on singular value decompositon algorithm, adaptive NCC(Normalized Cross Correlation) matching method based on scale and orientation information of SIFT features, then the fundamental and homography matrix can be estimated by using these initial correspondences; Under the dual geometric constraints by using the fundamental and homography matrix, extended matching methods by using weighted least squares matching and multiple scale template windows were developed, further, by compared to the location error of the original correspondences of SIFT feature points, the least squares matching results were determined to adopted or not; In addition, some novel strategies such as NCC computing with high speed based on integral image, multi-level pyrmid image matching, etc, were adopted to improve the matching speed and reliability.3. Line feature description with scale and rotation invariant and matching methods based on epipolar geometry constraint were proposed. In this algorithm, the overlap distances, orientations and line support regions of line segments pair were defined based epiploar geometry constraint, and then a line descriptor with scale and rotation invariant based on the mean and standard deviation of the gray values and gradient vectors was constructed; By fully considering the occlude and disparity discontinuity of the line segment pair, the weighted similarity measure for line segment matching based on the two side line support regions were adopted; Dimensionality reduction method based on kernel principal component analysis was introduced to improve the matching speed.4. Application programms of the previous theories and methods were realized and established base on Windows platform with Visual C++6.0 high level programming languages and OpenCV(Open Compute Vision library), and relative experimental results indicate that the methods proposed in the dissertation is true and effective.Reseach work in this paper can enrich the relative theories and methods concerned on digital close-range photogrammetry, and good basis are provided for 3D reconstruction of wide baseline photogrammetry.更多还原