A new shape preserving parallel thinning algorithm for 3D digital images

This paper is concerned with a new parallel thinning algorithm for three-dimensional digital images that preserves the topology and maintains their shape. We introduce an approach of selecting shape points and outer-layer used for erosion during each iteration. The approach produces good skeleton for different types of corners. The concept of using two image versions in thinning is introduced and its necessity in parallel thinning is justified. The robustness of the algorithm under pseudo-random noise as well as rotation with respect to shape properties is studied and the results are found to be satisfactory.     

鲁棒的二值图像并行细化算法

通过分析两种典型的并行细化算法,提出一种新的增强并行细化算法（Enhanced Parallel Thinning Algorithm,EPTA）．经过大量对比实验表明,新算法能很好解决斜线信息丢失、冗余像素和多余枝杈问题,且效率高、鲁棒性强．     

一种实用并行细化算法及其实现

介绍一种实用并行细化算尘,对细化模板和细化条件作了分析,实验结果表明,该细化算法获得取的图象骨架不仅避免了过度腐蚀,还具有良好的连通性。     

基于OpenMP的三维并行Delaunay网格生成算法及实现

针对大多数并行Delaunay网格生成算法无法充分利用多核共享内存结构的问题,在原有面向共享内存的二维并行算法基础上,根据三维问题的特点提出基于OpenMP的三维并行Delaunay网格生成算法。算法采用划分求解区域为方格的方法实现候选点集的划分和并行插点。使用OpenMP对算法进行实现,并利用多种实现技术避免线程间的同步等待,提升算法效率。实验结果表明,本文算法及所采用的实现技术可以在三维条件下快速生成大量网格单元,具有较高的并行效率,同时能够保证良好的网格质量。     

Voxel-based three-view hybrid parallel network for 3D object classification

Three-dimensional models are widely used in the fields of multimedia, computer graphics, virtual reality, entertainment, design, and manufacturing because of the rich information that preserves the surface, color and texture of real objects. Therefore, effective 3D object classification technology has become an urgent need. Previous methods usually directly convert classic 2D convolution into 3D form and apply it to objects with binary voxel representation, which may lose internal information that is essential for recognition. In this paper, we propose a novel voxel-based three-view hybrid parallel network for 3D shape classification. This method first obtains the depth projection views of the three-dimensional model from the front view, the top view and the side view, so as to preserve the spatial information of the three-dimensional model to the greatest extent, and output its predicted probability value for the category of the three-dimensional model, and then combining the three-view parallel network with voxel sub-network performs weight fusion, and then uses Softmax for classification. We conducted a series of experiments to verify the design of the network and achieved competitive performance in the 3D object classification tasks of ModelNet10 and ModelNet40.     

基于三维胞元空间的MA双向并行路由算法

针对传统移动代理(MA)在监测无线传感器网络(WSNs)的感兴趣信息时产生的延迟较大和能耗较多问题,提出了基于三维胞元空间的MA双向并行(3D-BPMA)路由算法.3D-BPMA将MA与传统的客户/服务器(c/S)模式相结合,在胞元内利用C/S模式搜集信息,在单层胞元系统和路由器与路由器之间采用MA双向并行的策略进行传输.仿真结果表明:3D-BPMA与LCF,DSG-MIP算法相比减少了平均响应时间和网络平均能耗,提高了MA发送率.     

基于Cart3D的全机数值模拟及并行计算

利用CFD商用软件Cart3D对亚声速飞行飞机的三维绕流流场进行了数值模拟以及并行计算,得到了飞机附近的流场,实现了此软件在高性能并行计算机上的并行;通过对比不同商用软件的计算结果,验证了用Cart3D软件进行数值模拟的有效性,为大规模科学工程计算提供了技术参照。     

一种基于正弦变换的三维泊松方程并行求解算法

泊松方程的数值解法在许多物理或者工程问题上得到广泛应用,但是由于大部分三维泊松方程的离散化格式不具有明显的并行性,实际中使用整体迭代的思想,这使得计算效率和稳定性受到了限制。摒弃了传统数值解法中整体迭代的思想,结合离散正弦变换理论(DST),基于27点四阶差分格式,将三维泊松方程求解算法在算法级进行修改和并行优化,把整个求解问题转化成多个独立的问题进行求解,稳定性和并行性能得到大幅提升。对于确定的离散化形式,可以使用同一套参数解决不同的泊松方程,大大提高了编程效率。基于共享存储并行模型实现了该算法,实验结果显示,对于给出的实例,新算法具有较好的加速效果,计算结果精度误差约为10e-5,在可接受范围内,并且计算精度随着维数的升高具有一定提升。     

A study of 3D Network-on-Chip design for data parallel H.264 coding

In this paper, we implement, analyze and compare different Network-on-Chip (NoC) architectures aiming at higher efficiencies for MPEG-4/H.264 coding. Two-dimensional (2D) and three-dimensional (3D) NoCs based on Non-Uniform Cache Access (NUCA) are analyzed. We present results using a full system simulator with realistic workloads. Experiments show the average network latencies in two 3D NoCs are reduced by 28% and 34% respectively, comparing with 2D design. It is also shown that heat dissipation is a trade-off in improving performance of 3D chips. Our analysis and experiment results provide a guideline to design efficient 3D NoCs for data parallel H.264 coding applications.     

沿三维直线的非单位体素遍历的多步整数算法

提出一种只用整数运算的沿三维直线的体素遍历算法,适用的体素空间可以分割成非单位的和非正方体的.首先研究了二维平面中的体素直线遍历算法,然后提出一种以二维平面中的遍历算法为基础的沿三维直线的体素遍历算法.该算法是一个多步整数遍历算法,每一步可以遍历最多3个体素,且所用的判断公式非常精炼,不仅计算量很小而且没有累计误差.与现有的体素遍历算法进行比较的结果表明,该算法不仅没有累计误差,而且执行速度也是最快的.     

大场景三维重建中多核并行捆集调整算法

将三维重建中捆集调整算法用于优化重建结果,是非常关键的步骤,然而传统单核串行算法耗时量大不太适合大场景重建。对此,首先对捆集调整算法本身进行了改进;然后在此基础上提出了多核并行捆集调整算法并采用图像处理器(GPU)实现该算法。实验表明,所提出的多核并行捆集调整算法提高了算法优化参数的精度和处理速度。     

3D自由曲线的绘制及智能修改算法

目前有关曲线及曲面的生成，大量的研究致力于从控点和节点的设置到曲率、切线矢量进一步精确的调整．然而其繁琐的几何参数计算、复杂的数学概念局限了设计者的使用，尤其他们更不适合早期的概念设计。此研究描述了基于笔输入的自由3D曲线的绘制．识别及直观的修改算法，此算法支持任意3D自由曲线的绘制，通过优化的采样机制自动识别产生适应性的B样条逼近曲线，它扩展了基于约束的曲线的生成方法，进而提出的简单的局部修改技术，引入了比例因子及区域间距的控制，有效的解决了曲线的光滑性，并通过实践检验了它们的高效性。     

Space–time tradeoffs for parallel 3D reconstruction algorithms for virus‐structure determination

The 3D electron‐density determination of viruses, from experimental data provided by electron microscopy, is a data‐intensive computation that requires the use of clusters of PCs or parallel computers. In this paper we report on three parallel algorithms used for 3D reconstruction of asymmetric objects from their 2D projections. We discuss their computational, communication, I/O, and space requirements and present some performance data. The algorithms are general and can be used for 3D reconstruction of asymmetric objects for applications other than structural biology. Copyright © 2001 John Wiley & Sons, Ltd.     

融合形状特征的MRG骨架树三维检索方法

提出一种基于MRG骨架树的三维模型检索方法。根据多分辨率Reeb图(MRG)的原理,提取反映模型拓扑特征的Reeb图骨架并且映射成树形结构,分析了节点的拓扑属性。针对拓扑属性在形状特征上的表达能力不足,在节点相应区域提取离散曲率和面积比例描绘局部的形状特征。有效地结合了模型的拓扑特征和形状特征计算模型的相似度。该方法突出了模型的整体拓扑特征和形状特征,实验结果表明了该方法的高效性和鲁棒性。     

一种改进的八元树三维目标表示方法

利用八元树表示三维物体是一种十分有效的方法。传统指针表示的八元树结构具有占据内存容量大、节点间关系少等缺点。在分析了物体的空间布局和八元树结构的基础上,文章提出了一种改进的八元树三维表示方法。从医学图像三维重建的实验结果看,提出的方法可行并且在内存存储结构和访问方式等方面优于传统的表示方法。     

三维图像重建算法的并行化设计和分析

利用类体素法进行三维图像重建，速度快，精度高，本文主要从片间并行着手讨论了它的并行化设计技术，分析了在不同的数据存储情况下的计算时间和通信开锁。并在曙光一号并行上实现了基于片间并行的多线程化算法，对算法的性能进行了测试分析。     

A language for representing and extracting 3D geometry semantics from paper-based sketches

Every product that exists, ranging from a toothbrush to a car, has first been conceived as a mental concept. Due to its efficacy in rapidly externalizing concepts, paper-based sketching is still extensively used by practising designers to gradually develop the three-dimensional (3D) geometric form of a concept. It is a common practice that form concepts are sketched on paper prior to generating 3D virtual models in commercial Computer-Aided Design (CAD) systems. However, the user-interface of such systems does not support automatic generation of 3D models from sketches. Furthermore, the inherent characteristics of form sketching (e.g. idiosyncrasy) pose a challenge to computer-based understanding of the form concept semantics expressed on paper. To address these issues, this paper is therefore concerned with the development of a visual language that is prescribed and to be used by product designers to annotate paper-based sketches such that the form geometry semantics can be formally represented; parsing the annotated sketch allows for the automatic generation of 3D virtual models in CAD. Inspired by re-usable 3D CAD modelling functions and the related environmental constraints and requirements, a prescribed sketching language, PSL, has been developed to annotate paper-based form sketches. The framework architecture which parses the annotated sketch and subsequently extracts the form concept semantics is described. Based on this framework, a prototype computer tool has been implemented and evaluated. Evaluation results provide a degree of evidence, first on the suitability of PSL in representing the semantics of a range of forms, and secondly on the designers׳ acceptance of taking up this annotated sketching approach in practice.     

基于骨架的三维网格局部编辑

复杂网格的编辑是三维动画设计的关键技术,已经出现了多种比较成功的方案和算法。在研究了三维网格的骨架生成及其优化方法的基础上,提出了一种基于骨架的局部网格编辑算法。先由用户确定编辑区域,绘出与变形后的骨架相对应的编辑曲线,再根据网格顶点与骨架曲线及编辑曲线之间的对应关系,实现网格结点的平移和旋转等编辑操作。实验证明,该算法的实现具有编辑直观、易于控制等特点,能够很好地应用于网格的局部特征编辑。