三维重建的统一方法——模拟退火法

针对给定平行截面线重建物体表面的三维重建问题，本文利用重建表面的图论表示和模拟退火法，提出了一种能统一处理多种目标函数的三维重建算法。     

基于ToF相机的三维重建技术

针对利用ToF相机实现物体的重建提出一种新的三维重建算法,通过分析物体重建过程的特点,对KinectFusion的重建算法进行改进。点云匹配过程包括粗匹配和精匹配两个过程,最后进行全局优化,提高相机位姿估计的精度,从而得到更精确的三维重建结果。利用泊松重建算法重建物体表面,相比于TSDF算法,能够实现完整表面的重建。提出结合强度图对深度图进行多边滤波的算法以及一种新的补空洞法则,增强深度图像。多边滤波算法在PSNR和SSIM的评估中都优于双边滤波结果,提出的三维重建算法与KinectFusion三维重建结果对比,表面更完整,重建结果更优。     

一种辅助轮廓线的断层医学图像三维重建算法

针对轮廓线重建过程中的轮廓分叉问题,提出了一种改进的多轮廓线三维重建算法,通过构造辅助轮廓线将多轮廓线的连接转换为单轮廓线的连接,改进了利用多轮廓线进行三维重建的不足,利用可接受表面实现特征点的三角化,并根据曲率的变化拟合重建过程中的不光滑表面,进而实现断层医学图像的三维重建。实验结果证明,运用本算法在保证重建物体正确的同时,缩短了体数据的构造时间,加快了整个表面的重建速度。     

三维表面平滑约束断层图象形状插值

断层图象序列的层间插值是三维重建的关键技术之一。已有的断层插值方法主要使用灰度，灰度梯度，距离，方向等约束，重建的三维表面往往不平滑，本文引入有向距离概念，增加表面平滑约束，提出一种重建三维平滑表面的断层图象间形状插值方法。     

基于激光扫描辅助立体摄影的无规则物体的三维重建

提出一种形状不规则物体表面数据的测量和重建方法,利用立体摄影的非接触和高分辨率以及线式激光源良好的方向性和精确的图像匹配等优点实现表面数据的获取,再利用简单几何模型的自适应变形法进行表面的三维重建,并对重建模型的精度进行实验分析,结果显示该方法具有设备简单、测量和重建速度快、结果精度高等优点,适用于一般图像的三维重建。     

像素的移动体素面绘制算法

移动立方体算法是最具影响力的等值面构造算法。本文以移动立方体算法为基础,提出了像素点移动体素面绘制算法。根据物体表面的显示特性和体素特点,利用像素点组成的边界体素绘制物体的等值面,实现物体表面的三维重建。在实验中,对一组CT图像中的骨骼组织进行三维表面重建和显示,并与用Matlab绘制函数重建的三维结果进行比较。实验分析表明,该算法能对物体进行三维重建,避免了二义性问题,但重建表面不光滑,重建花费的时间较长。     

利用多尺度小波变换的光度立体快速三维表面重建算法

光度立体三维测量中,需要通过三维重建算法从二维梯度场重建三维表面深度.针对传统的三维重建算法如全局迭代优化算法,在高分辨率情况下耗时较长的问题,提出利用多尺度小波变换的光度立体快速三维表面重建算法.首先利用梯度场代替传统小波通道,实现多尺度Haar小波变换,得到一种改进的多尺度小波变换算法;然后将该算法应用于光度立体三维表面重建中,提高了三维重建的速度.实验结果表明:与传统算法时间复杂度均高于线性阶相比,文中算法的时间复杂度与梯度场分辨率成线性阶关系;该算法适用于从高分辨率梯度场重建三维表面,并具有误差较小、鲁棒性好的优点.     

采用CT切片的三角片曲面重构算法

采用二维平行轮廓线三维重建表面是三维建模研究领域的一项重要研究课题，具有非常广泛的应用领域。重建过程中计算量非常庞大，有效地化简重建的数据可以大大提高重建效率。文中提出了一种基于分析轮廓骨架点的表曲面重构算法。首先对CT切片进行预处理及图像分割，然后对轮廓线提取骨架，再进行骨架剪裁，最后采用模拟退火法进行三维重建。该算法使三维重构的数据大大化简，同时克服了局部优化算法中需交互指定初始连接边的缺点。     

采用去抖动模糊算法的稠密三维重建

针对无人机在航拍大场景对象进行三维重建时因抖动产生的图像模糊现象,以及二维图像序列经运动恢复结构SFM后得到的点云较为稀疏,可视化差等不足,采用去抖动模糊算法恢复模糊图像的原始图像信息,然后在运动恢复结构的基础上进行基于点云的稠密三维重建,最后对稠密重建后的点云进行泊松表面重建以得到表面致密、均匀的三维模型。实验结果表明,去抖动模糊算法可以有效地提高图像的质量,大场景对象经过基于点云的稠密三维重建后得到的重建效果逼真,可视化强。     

基于MC算法的MEMS光刻仿真的三维重建方法研究

以MC(Marching Cubes)算法为基础,提出了一种补全重建后生成的三维形体表面出现空洞的方法,使用该方法进行三维重建生成的三维形体具有完整的外表面和良好的可视化效果.提出了一种三维重建时对多个形体进行布尔运算的新方法,该方法以MC算法为基础,将三维重建和布尔运算相结合,可以简单、方便、高效地进行三维重建时的布尔运算.     

A graph model for mutual information based clustering

We propose a graph model for mutual information based clustering problem. This problem was originally formulated as a constrained optimization problem with respect to the conditional probability distribution of clusters. Based on the stationary distribution induced from the problem setting, we propose a function which measures the relevance among data objects under the problem setting. This function is utilized to capture the relation among data objects, and the entire objects are represented as an edge-weighted graph where pairs of objects are connected with edges with their relevance. We show that, in hard assignment, the clustering problem can be approximated as a combinatorial problem over the proposed graph model when data is uniformly distributed. By representing the data objects as a graph based on our graph model, various graph based algorithms can be utilized to solve the clustering problem over the graph. The proposed approach is evaluated on the text clustering problem over 20 Newsgroup and TREC datasets. The results are encouraging and indicate the effectiveness of our approach.     

Object association with belief functions, an application with vehicles

The problem tackled in this article consists in associating perceived objects detected at a certain time with known objects previously detected, knowing uncertain and imprecise information regarding the association of each perceived objects with each known objects. For instance, this problem can occur during the association step of an obstacle tracking process, especially in the context of vehicle driving aid. A contribution in the modeling of this association problem in the belief function framework is introduced. By interpreting belief functions as weighted opinions according to the Transferable Belief Model semantics, pieces of information regarding the association of known objects and perceived objects can be expressed in a common global space of association to be combined by the conjunctive rule of combination, and a decision making process using the pignistic transformation can be made. This approach is validated on real data.     

Simultaneous stabilization: Universal controller synthesis

We consider the simultaneous stabilization problem for linear time-invariant stationary objects of arbitrary order. For such objects, we formulate numerically verifiable necessary and sufficient simultaneous stabilization conditions and show a constructive algorithm for the construction of a stabilizing controller with minimal restrictions on the structure and parameters of the stabilized objects. We give a general scheme of studying simultaneous stabilizability of a family of objects and analyze in detail a numerical algorithm for finding a stabilizing controller with applied interval analysis. To solve the problem, we use an approach based on the study of affine transformations of controller parameter spaces into the spaces of coefficients of denominators of closed-loop objects.     

三维形体的形态学运算及应用

本文首先讨论了边界表示的物体的形态学运算问题。文中讨论了任意形状的物体，包括凸物体和非凸物体；引入了负形体的概念；并提出了２Ｄ和３Ｄ连续物体的Ｍｉｎｋｏｗｓｋｉ运算的统一算法。利用这一算法，提出了３Ｄ任意形体间的变形新算法，把边界表示的物体的形态学运算的概念扩展到任意曲线和任意曲面上，并且介绍了３Ｄ物空间中曲线的概念和３Ｄ物空间双参数曲面的概念。文中任意形体的３Ｄ变形算法能很好地解决具有不同拓扑结构的３Ｄ边界表示的物体之间的变形问题。     

电子学习语义网

语义网上的一个重要问题是存储在远程或本地数据库中的学习对象的重用和方便二次开发;另一个司题是本体的架构;第3个问题是使学习对象更具智慧,以便在语义网上充当更有意义的角色.讨论的这些问题及提出的基于语义网的学习模型将影响语义网上学习对象的开发.     

Efficient Path-Space Differentiable Volume Rendering With Respect To Shapes

Differentiable rendering of translucent objects with respect to their shapes has been a long-standing problem. State-of-the-art methods require detecting object silhouettes or specifying change rates inside translucent objects—both of which can be expensive for translucent objects with complex shapes. In this paper, we address this problem for translucent objects with no refractive or reflective boundaries. By reparameterizing interior components of differential path integrals, our new formulation does not require change rates to be specified in the interior of objects. Further, we introduce new Monte Carlo estimators based on this formulation that do not require explicit detection of object silhouettes.     

On the recognition of curved objects

The problem of determining the identity and pose of occluded objects from noisy data is examined. Previous work has shown that local measurements of the position and surface orientation of small patches of an object's surface may be used in a constrained search process to solve this problem, for the case of rigid polygonal objects using 2-D sensory data, or rigid polyhedral objects using 3-D data. The recognition system is extended to recognize and locate curved objects. The extension is done in two dimensions, and applies to the recognition of 2-D objects from 2-D data, or to the recognition of the 3-D objects in stable positions from 2-D data     

Computation of interferences between three-dimensional objects and the optimal packing problem

The related problems of computing the separation/interference distance between two three-dimensional objects and clearance/protrusion distance between an object and a container wall occur frequently in industry. A method for computing these distances by solving appropriate optimization problems is presented. The method can treat three-dimensional objects with curved sides. The problem of optimally packing objects into a container is also discussed. The packing problem is also solved as an optimization problem The separation/interference and clearance/protrusion problems become subproblems to the packing problem. Examples are presented in the paper.     

Solving a maximin location problem on the plane with given accuracy

We consider the optimal placement problem in a bounded region on a plane with fixed objects. We specify minimal admissible distances between placed and fixed objects. The optimization criterion is to maximize the minimal weighted distances from placed objects to fixed ones. We propose a quasipolynomial combinatorial algorithm to solve this problem with a given accuracy. We show the results of a computational experiment with the integer programming model and the IBM ILOG CPLEX suite.     

Ada's derived types and units of measure

Types in programming languages cannot model many properties of real world objects and quantities. Consequently, many errors resulting from the inconsistent usage of program objects representing real world objects and quantities cannot be detected automatically. For example, the real variables PRICE and WEIGHT, representing the price of diesel fuel and the weight of a person, may be inadvertently added, giving a non-sensical value; such an error cannot be detected by a compiler. The programming language Ada introduces the concept of derived types to tackle this problem. An alternative solution to this problem is the incorporation of units of measure as a new data attribute. Derived types only partially solve the problem of detecting the inconsistent usage of objects; some valid usages of objects are also not allowed. Moreover, the solution is inelegant and inconvenient to use. On the other hand, specification of units of measure solves the problem elegantly and conveniently. The two solutions are compared and analysed. Several ways to implement units of measure in Ada are examined.