3D model retrieval using weighted bipartite graph matching

In this paper, we propose a view-based 3D model retrieval algorithm, where many-to-many matching method, weighted bipartite graph matching, is employed for comparison between two 3D models. In this work, each 3D model is represented by a set of 2D views. Representative views are first selected from the query model and the corresponding initial weights are provided. These initial weights are further updated based on the relationship among these representative views. The weighted bipartite graph is built with these selected 2D views, and the matching result is used to measure the similarity between two 3D models. Experimental results and comparison with existing methods show the effectiveness of the proposed algorithm.     

电镜重构病毒的三维显示与三维任意区域分割

利用冷冻电镜单颗粒三维重建方法获得分辨率1.5nm家蚕质多角体（BmCPV）;2.5nm,中蜂囊状幼虫病病毒（CSBV）;1.4nm,伊蚊C6/36细胞浓核病毒（C6/36DNV）的三维结构体数据,对三维结构数据进行了数据归并,并找到对显示细节较为敏感的向量维度,用表面显示方法对病毒体数据进行三维显示,用基于空间的方法完成了任意区域的交互分割。显示时间和信噪比与原有显示方法有了提高。病毒表面细节和轴上突起清晰可见。所分割的部分结构准确完整,并可以对所分割的部分进行量化分析。为冷冻电镜单颗粒重构提供了新的三维可视与分析方法。     

Fast 3D video stabilization using ROI-based warping

With the rapid development of portable digital video equipment, such as camcorders, digital cameras and smart phones, video stabilization techniques for camera de-shaking are strongly required. The cutting-edge video stabilization techniques provide outstanding visual quality by utilizing 3D motion, while early video stabilization is based on 2D motion only. Recently, a content-preserving warping algorithm has been acknowledged as state-of-the-art thanks to its superior stabilization performance. However, the huge computational cost of this technique is a serious burden in spite of its excellent performance. Thus, we propose a fast video stabilization algorithm that provides significantly reduced computational complexity over the state-of-the-art with the same stabilization performance. First, we estimate the 3D information of the feature points in each input frame and define the region of interest (ROI) based on the estimated 3D information. Next, if the number of feature points in the ROI is sufficient, we apply the proposed ROI-based pre-warping and content-preserving warping sequentially to the input frame. Otherwise, conventional full-frame warping is applied. From intensive simulation results, we find that the proposed algorithm reduces computational complexity to 14% of that of the state-of-the-art method, while keeping almost equivalent stabilization performance.     

基于3D-DWT及混沌映射的加密医用体数据鲁棒检索算法研究

随着医疗数据的共享日益频繁,数据安全问题变得日益突出.安全起见,把医学图像加密后存储到服务器或云端.如何实现对加密医学图像检索成为一个亟待解决的问题.提出一种基于混沌和三维小波变换的加密医用体数据鲁棒检索算法.其主要步骤为:首先,通过三维小波变换和混沌映射对医用体数据进行加密;然后,对加密体数据进行小波分解,得到子带图像,再对子带图像进行DCT变换,提取DCT变换能量聚集的低频系数作为加密体数据的特征向量,建立加密图像的特征向量数据库;最后,通过计算加密图像的特征向量的相似度来检索目标图像,将检索到的加密图像返回,并解密所检索到的医用体数据.实验结果表明,该检索算法对加密体数据的常规攻击和几何攻击具有较强的鲁棒性,并提高了图像检索的安全性和准确性.     

三维小波多分等级树视频压缩编码

提出了基于三维小波多发等级树视频压缩编码方法。通过将原始图象序列进行帧分组,并对每个图象帧组在时间、水平和垂直三维空间上进行小波变换。然后,对变换域的各个空间－时间频率了带按照其方向的不同。构成多个小波等级树,并对每个等级树分别进行ＳＰＩＨＴ编码算法。仿真实验表明了该方法的有效性。     

3D model retrieval by sample based alignment

In 3D model retrieval, preprocessing of 3D models is needed, in which alignment is a key factor that significantly affects retrieval performance. In particular, the anti-rotation image feature can obtain the alignment effect of 3D model views. In practice, the focus of many users of 3D models is not just on retrieval performance, but the use of aligned models for different purposes. In this paper, we propose a method, namely Sample Based Alignment (SBA) for better 3D model alignment and retrieval. In SBA, given a class, a sample model is used as the target for alignment, after which each 3D model in this class is then aligned one by one, i.e., the 3D model is actually rotated. Our experimental results, based on two 3D model datasets and performance comparisons with other methods, demonstrate the superiority of the SBA method over state-of-the-art methods in terms of 3D model retrieval and classification.     

3D Perception Algorithms:Towards Perceptually Driven Compression of 3D Video

In this paper, we summarize 3D perception-oriented algorithms for perceptually driven 3D video coding. Several perceptual effects have been exploited for 2D video viewing; however, this is not yet the case for 3D video viewing. 3D video requires depth perception, which implies binocular effects such as conflicts, fusion, and rivalry. A better understanding of these effects is necessary for 3D perceptual compression, which provides users with a more comfortable visual experience for video that is delivered over a channel with limited bandwidth. We present state-of-the-art of 3D visual attention models, 3D just-noticeable difference models, and 3D texture-synthesis models that address 3D human vision issues in 3D video coding and transmission.     

Dictionary-based color image retrieval using multiset theory

Dictionaries have recently attracted a great deal of interest as a new powerful representation scheme that can describe the visual content of an image. Most existing approaches nevertheless, neglect dictionary statistics. In this work, we explore the linguistic and statistical properties of dictionaries in an image retrieval task, representing the dictionary as a multiset. This is extracted by means of the LZW data compressor which encodes the visual patterns of an image. For this reason the image is first quantized and then transformed into a 1D string of characters. Based on the multiset notion we also introduce the Normalized Multiset Distance (NMD), as a new dictionary-based dissimilarity measure which enables the user to retrieve images with similar content to a given query. Experimental results demonstrate a significant improvement in retrieval performance compared to related dictionary-based techniques or to several other image indexing methods that utilize classical low-level image features.     

Flash Papervision3D中3D Web应用程序设计

为了能将日益应用广泛的Papervision3D、能在Flash Player中播放的目的,采用较为新颖的3D引擎方法,做了三维到二维的转换、Flint粒子系统实验,实现了平滑拉近物体从远处拉近及喷泉的效果.通用开源Flash 3D渲染引擎中Papervision3D是基于ActionScript的开源项目,而Flash在3D领域的应用相对贫乏,在Flash Player中播放,则具备体积小、与用户交互能力强、效果逼真的3D Web应用程序特点.     

Java3D在网络三维游戏设计中的应用探讨

随着网络技术、虚拟现实技术的迅猛发展、人们生活娱乐水平的提高,近几年三维网络游戏成为热门焦点.现介绍了三维网络游戏的发展现状,选择Java3D的优点并举例说明,也简要说明了它的一些不足之处.     

3D information extraction using Region-based Deformable Net for monocular robot navigation

This paper extends the Region-based Deformable Net (RbDN) technique described in [1] to extract the 3D information of all the objects in the scene from a single moving camera. The technique is used for segmenting real-time video sequences captured from a single moving camera. The deformation process tracks the changes in the location and the shape of the segments across the frames. These changes along with the camera displacement are used to estimate the 3D information. The algorithm is completely autonomous and does not require pre-knowledge, training, or assumption about the contents of the sequence. It can handle the difficult case where the motion of the camera is parallel to its optical axis. It can also estimate the distances to objects that are more than 100 m away as long as the camera displacement is over 10% of the expected distance to the objects.     

Direct reproduction of 3D microstructures using a hybrid approach; by creation of master-patterns and metallic molds for embossing

The fabrication of a three-dimensional (3D) metallic mold for multi-production of microstructures was studied to settle the problem of long processing time and efforts in 3D fabrication based on the accumulation of layer-by-layer. Even though two-photon induced polymerization (TPP) has been considered as a unique way for fabrication of precise real 3D microstructures such as 3D filters, 3D photonic crystals, microlens arrays, it required considerable effort and much processing time inevitably for these fabrications. Therefore, a simple and effective method was proposed using a metallic mold in this work. 3D micro-master patterns were prepared using TPP, and then counter-shaped Ni molds were created using an electroforming process. With this hybrid approach, 3D microstructures were much more easily and quickly reproduced by hot-forming compared to the TPP approach was used only. In this work, we report on the processing parameters used to fabricate a metallic mold and reproduce 3D microstructures using the mold.     

Design for manufacturing of 3D capacitors

3D capacitor design parameters have been evaluated in order to improve the capacitance per unit die area. The geometrical issues as well as the process manufacturing issues are both investigated. The main manufacturing issues have been experimentally tested: etching, deposition and warpage of the wafer. An improvement has been observed for the robustness of 3D structures and the density of the capacitor has been increased for several proposed 3D pattern. All capacitors tested in this paper are realised with PICS technology.     

二维图像转三维图像的立体成像系统的测试标准

本文具体介绍了一种将视频二维图像转换为兰维图像的立体成像系统的测试标准.     

三维激光扫描测量系统的三维图像数据压缩

三维彩色激光扫描测量系统是利用计算机视觉的原理对物体进行三维测量和重建,以获取物体的三维图像。三维图像的数据量很大,文中研究了三维图像的压缩策略和算法,采用三角形条带的网格压缩方法,以及顶点数据的编码方法,可以把三维图像的存贮空间减小到压缩前数据的１／６,从而有效地解决了测量系统在实际应用环境下的图像存贮和传输问题。     

基于多视图SIFT特征的三维模型检索

研究了一种基于多视图SIFT特征的三维模型检索算法。首先对三维模型进行多视图投影,得到其余方位的三维投影深度图,并在各投影深度图上提取SIFT特征。分别利用按模型特征数比例分次建立码本及建立模型库整体码本这两种方式建立了模型库的码本,继而将模型的SIFT特征聚类量化,并用一个多维向量将其表示出来。通过计算三维模型特征向...     

基于Java3D的三维模型交互设计系统的开发与应用

首先概括地介绍了Java3D技术在三维模型交互设计的应用.提出了采用Java3D用于虚拟三维模型的描述,通过远端客户机读取服务端客户上传的三维图形数据,实现与用户交互的虚拟三维交互建模方案,使用程序提供的绘图工具对图形进行编辑并将结果保存到服务端相应的文件,通过对服务器端文件的读写操作来实现用户之间的信息交互,共享数字化的设计信息,使Internet成为设计工作的主要协作平台.     

3D structuring of polymer parts using thermoforming processes

A new technique for the realization of complex three dimensional (3D) structures in polymer materials is presented. The described process can be applied for the fabrication of 3D structured foils as well as for 3D structured polymer parts using a replica molding process. In the first step, the foil is structured by Hot Embossing. This structured foil is then blown into a structured mold by pressure at high temperature, using a thermoforming process. The thermoforming process is realized in an especially designed tool, where different mold inserts can be applied. In the thermoforming process this tool, containing the mold insert and the structured foil is heated up and a pressure is applied which assures, that the foil covers the structured mold insert. Due to parameter optimization, high pattern fidelity can be achieved. As structures a porefield with a pore diameter of 500 nm and lines and spaces with a width of 1.6 μm were used. Besides a Moth Eye structure with a period of 280 nm and a blazed grating with a period of 1 μm and a blazed angle of 15° were imprinted and blown into the structured mold. The results show, that this process can be used to fabricate 3D structured foils with good structure fidelity. Besides the structured foils, additional poly(dimethylsiloxane) (PDMS) replications can be made out of this foils. These PDMS replications are used as stamps in a replica molding process. A micro fluidic system containing hydrophobic and hydrophilic channels was created using this process.     

用投影全息干涉条纹测量物体三维面形

在以往投影测量三维面形的装置中,其产生激光干涉投影条纹的装置较大,且干涉条纹较容易受外界的影响而漂移和抖动,影响测量结果精度的提高,本文提出用离轴全息干涉条纹替代投影法的激光干涉仪投影条纹,并将其用于实际测量中,实验结果表明：该方法产生干涉条纹的装置简单,且不受外界振动的影响,光能利用率高,易于移相和解调,这使得三维形貌检测精度高、速度快、实用性更强。     

助视3D显示技术概述

助视3D显示是指需要借助于3D眼镜等助视设备才能观看到3D图像的显示方式,它包括分色3D显示、偏振光3D显示和液晶快门3D显示。助视3D显示是目前最成熟的3D显示方式,近几年其相关技术及器件的性能得到了改进和提高。本文将介绍这三种助视3D显示技术。