基于模糊判别的快速图切割立体匹配

针对图切割算法存在匹配时间过长的不足,提出了一种快速的图切割立体匹配方法.选用模糊逻辑提取少量的候选匹配点,然后用这些候选匹配点构造缩减的图,再进行图切割立体匹配.采用标准图像对文中方法进行测试,并与图切割立体算法和动态规划算法进行比较的结果表明,该方法较好地保留了图切割算法匹配的准确性,而运行时间仅为图切割算法的1/35.     

自适应窗口的时间规整立体匹配算法

针对立体视觉中图像对应点的误匹配问题,以时间规整算法(DTW)为基础,提出了自适应窗口的立体匹配算法．根据外极线的约束,在自适应窗口内采用灰度相关技术得到长度不相等的两个灰度段作为相容的匹配序列;利用动态规划法及连续性约束寻找一条最佳的匹配路径．根据回溯得到的匹配路径及其坐标值得到高密度视差图．实验结果表明,该算法具有较高的运行效率和良好的匹配效果．     

应用神经网络隐式视觉模型进行立体视觉的三维重建

针对传统的基于精确数学模型的立体视觉方法过程繁琐的不足,提出一种应用BP神经网络隐式视觉模型进行三维重建的算法。该算法将多个标定平面放置在有效视场内,用神经网络模拟立体视觉由两个二维图像重建三维几何的过程,经过网络训练建模后,无须摄像机标定即可进行三维重建。仿真实验结果证明,该算法比较简单,且能保持较高的精度。     

累进三维模型相似匹配算法

提出了一种构造三维模型特征二叉树的算法,并根据特征二叉树匹配来获得三维模型的相似程度,特征二叉树与二维模型坐标系统系旋转和平移无关,且适合于三维模型累进牵引匹配,实验结果表明,文中算法能较好地匹配三维模型的相似性。     

结合Harris算子和sift匹配方法的三维重建

该文针对三维重建过程中立体匹配问题进行研究和讨论,通过对目前检测性能较好的Harris角点提取方法和最近几年得到人们广泛关注的Sift特征匹配方法进行详细分析,总结出两者各自优缺点具有互补性,因此提出融合两者的优点,综合两者的匹配结果,以使用于重构的匹配点既能达到高的精确性,又能勾勒出重构物体的重要外貌。     

基于全局二值特征描述子的三维CBCT图像快速匹配算法

三维图像拼接是通过锥束CT(CBCT)获取大尺寸物体完整的高分辨率三维图像过程中的关键技术之一,成为目前三维图像处理的一个新的研究方向.针对基于特征点的三维CBCT图像拼接技术中相似特征匹配正确率低、匹配过程耗时长的问题,提出一种基于全局二值特征描述子的三维CBCT图像快速匹配算法.首先对二值特征描述子BRIEF进行三维拓展,以适应三维图像;在此基础上加入全局描述子,增强特征描述子的独特性;在特征点匹配时,根据上述特征描述子的特点设计由粗到精的匹配策略,提高特征匹配正确率和效率.实验结果表明,该算法简单有效,可以在大量相似特征条件下提高特征点匹配的正确率,同时也显著提升了匹配速度.     

三维曲面的特征描述和特征匹配

本文提出了一种新的三维曲面特征描述算法,将二维图像上的特征描述思想推广到三维网格。算法将三维网格表示成从顶点到高斯曲率的映射函数,从而获得可类比于二维图像的相似性。借助于法线和梯度建立局部球坐标系,通过二维统计直方图对特征点邻域的几何信息进行描述,使得特征描述具有平移、旋转和缩放不变性,最终生成128维的特征向量(特征描述符)。基于特征向量,我们实现了多分辨率和异拓扑网格下的特征匹配,展示并分析了实验结果。本文的研究动机来源于三维扫描建模以及多视点三维重建技术中对特征描述和特征匹配的需求,主要的应用方向包括:扫描配准、模型注册、动画跟踪、对称检测和模型检索。     

三维模型检索中的预处理技术

随着三维建模技术和数字化技术的发展,基于内容的三维模型检索技术应运而生.由于三维模型是一种自由度很高的信息,在特征提取之前对三维模型进行坐标系归一化预处理,从而保证所提取特征的平移不变性、比例不变性和旋转不变性,使得同样的三维模型在不同的坐标系下具有相同的相似度,这样可以提高基于内容的三维模型相似性比较算法的准确性.而预处理的效果对检索性能有着很大的影响,对PCA和各向异性变换这两种主要预处理技术进行了研究.     

3D model retrieval using principal plane analysis and dynamic programming

Three dimensional models play an important role in many applications; the problem is how to select the appropriate models from a 3D database rapidly and accurately. In recent years, a variety of shape representations, statistical methods, and geometric algorithms have been proposed for matching 3D shapes or models. In this paper, we propose a 3D shape representation scheme based on a combination of principal plane analysis and dynamic programming. The proposed 3D shape representation scheme consists of three steps. First, a 3D model is transformed into a 2D image by projecting the vertices of the model onto its principal plane. Second, the convex hall of the 2D shape of the model is further segmented into multiple disjoint triangles using dynamic programming. Finally, for each triangle, a projection score histogram and moments are extracted as the feature vectors for similarity searching. Experimental results showed the robustness of the proposed scheme, which resists translation, rotation, scaling, noise, and destructive attacks. The proposed 3D model retrieval method performs fairly well in retrieving models having similar characteristics from a database of 3D models.     

3D imaging application in the studies of micro air vehicles

3D techniques are increasingly used in aerospace industry to improve quality and performance of aircrafts. This paper presents a 3D imaging technique for studying the aerodynamic shape and flight performance of micro air vehicles. 3D stereoscopic vision, based upon stroboscopic imaging, was utilized to obtain the 3D information of the aircraft's flexible aerodynamic surface. The aircraft models with deformable aerodynamic shape were designed and tested in a purpose-built wind tunnel experimental environment. After calculation of SIFT feature points and subdivision of triangular meshes, deformable surface of the aircraft's aerodynamic shape was represented. The aircraft's 3D visualization was used for analyzing unsteady deformation in the aerodynamic shape under external airflow disturbances. The results, together with aerodynamic forces measured in the experiment, will be useful to improve the flight performance and disturbance resistance ability of micro air vehicles.     

三维无线传感器网络寿命和动态路由算法

无线传感器网络(WSNs)寿命受到电池能量的制约,利用无线能量传输技术对传感器节点进行充电,可以解决无线传感器网络的能量问题.以三维无线传感器网络为研究对象,证明三维最短Hamilton回路为无线充电设备遍历网络中节点的最优路径,提出了网络的连续时变模型,并简化复杂度为多项式的离散T+1阶段线性规划模型.仿真结果表明:通过运算离散T+1阶段线性规划模型能够使无线传感器网络持续运行.     

Piecewise‐Planar 3D Reconstruction with Edge and Corner Regularization

This paper presents a method for the 3D reconstruction of a piecewise‐planar surface from range images, typically laser scans with millions of points. The reconstructed surface is a watertight polygonal mesh that conforms to observations at a given scale in the visible planar parts of the scene, and that is plausible in hidden parts. We formulate surface reconstruction as a discrete optimization problem based on detected and hypothesized planes. One of our major contributions, besides a treatment of data anisotropy and novel surface hypotheses, is a regularization of the reconstructed surface w.r.t. the length of edges and the number of corners. Compared to classical area‐based regularization, it better captures surface complexity and is therefore better suited for man‐made environments, such as buildings. To handle the underlying higher‐order potentials, that are problematic for MRF optimizers, we formulate minimization as a sparse mixed‐integer linear programming problem and obtain an approximate solution using a simple relaxation. Experiments show that it is fast and reaches near‐optimal solutions.