共查询到19条相似文献,搜索用时 171 毫秒
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基于Kinect人体动态三维重建 总被引:1,自引:0,他引:1
从图像中恢复出三维物体表面模型的方法称为3D重构,是计算机图形学研究领域中一个重要的研究方向。准确可靠的三维动态几何重建在影视制作和游戏开发中具有重要作用。不同于静态物体表面三维重建,动态几何三维重建需要研究帧与帧之间准确的对应信息。本文提出的方法基于单个Kinect硬件系统,利用Kinect重建出人体的静态三维模型,结合Kinect识别出的骨架进行人物的动态三维模型重建。 相似文献
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针对普通单相机数字图像相关(DIC)系统仅能测量目标面内变形信息的问题,本文提出了一种采用单相机DIC系统实现三维全景测量的方法,即:根据多平面镜成像原理,被测目标的前后表面成像在一个共同的视场内,两个光路分别成像在两个平面镜中,将单相机扩展为4台虚拟相机,实现三维全景测量。为了更好地完成虚实像转换,实验之前对平面镜表面进行三维重建,分别采用动态、静态实验对该方法的可行性及精度进行验证。结果表明:在动态拉伸测试中,4个子区域有着相近的变化趋势,工程应变普遍分布在0.0125左右,且位移精度较高;在静态实验中,对决策币的前后表面进行三维重建,重建结果与决策币形貌相吻合。 相似文献
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激光冲击处理304不锈钢表面的形貌特征及其机理分析 总被引:4,自引:1,他引:3
为了研究激光冲击强化(LSP)过程中冲击波柔性加载条件下靶材的表面形貌与变形机理的联系,采用短脉冲强激光对304奥氏体不锈钢表面进行LSP处理,在没有对材料表面进行腐蚀的条件下,利用光学显微镜直接观察了LSP处理后材料的表面,并分析了其表面形貌特征与形成机理。研究发现,表面形貌呈现了多晶面心立方(FCC)金属的塑性变形特征,所浮现的形变组织能够直接反映材料在冲击波加载下的变形机制。实验结果表明,激光冲击后材料的表面形貌与塑性变形机制具有对应关系,这为LSP处理的变形机理的研究提供了一种新的实验方法。 相似文献
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基于FTP的动态相位展开方法的研究 总被引:3,自引:1,他引:3
在采用结构照明的光学三维传感方法中 ,相位展开是被测物体三维面形正确重建的关键步骤之一 ,也是一个难点。本文就动态傅里叶变换轮廓术中相位展开问题进行研究 ,对比分析了直接相位展开算法、基于相邻帧间相位差之间的相位展开算法和基于调制度排序的相位展开算法。解决了基于傅立叶变换轮廓术的动态三维测量中相位展开问题 ,特别是孤立区域的相位展开。为动态傅立叶变换轮廓术的在冲击和爆轰过程中应用 ,提供了理论基础。文中给出了详细的理论分析和计算机模拟 相似文献
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单次激光冲击下板料变形的理论分析 总被引:25,自引:14,他引:25
金属板料的激光冲击成形(LSF)技术是利用高能激光诱导的高幅冲击波的力效应,而非热效应。它是在激光冲击强化基础上拓展出的又一崭新的研究领域。根据爆轰波和爆炸气体动力学理论,建立了板料激光冲击成形中,激光-能量转换体-靶材系统的冲击波压力的物理模型和理论估算式。通过对激光冲击波载荷作用下板料变形过程的理论分析,建立激光冲击板料变形的数学模型,得到板料变形量与加工系统中各种参数之间的相互关系,为加工过程中各种参数的合理优化,板料变形过程的有效控制,实现大面积金属板料的激光冲击成形提供了理论依据。 相似文献
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结构光三维成像技术 总被引:2,自引:0,他引:2
近年来,结构光三维成像技术被深入研究和广泛应用,通常采用的技术方案是投影一个载频条纹到被测物体表面,利用成像设备从另一个角度记录受被测物体高度调制的变形条纹图像,再从获取的变形条纹图中数字解调重建出被测物体的三维数字像。与全息三维成像对应,结构光三维成像过程也是两步成像过程,先获取物体被结构光条纹调制的二维图像,再从包含变形条纹的二维像中通过数字重建方法得到物体的三维数字像。主要回顾了本课题组在基于结构光三维成像技术研究中的进展,讨论了基于傅里叶条纹分析、相移条纹分析和动态过程三维成像的方法,给出了相关应用的实验结果,分析了结构光三维成像的特点以及该领域今后的发展动向。 相似文献
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Optical 3D shape measurement for dynamic process 总被引:1,自引:0,他引:1
SU Xian-yu ZHANG Qi-can XIANG Li-qun 《光电子快报》2008,4(1):55-58
3D shape dynamic measurement is essential to the study of machine vision, hydromechanics, high-speed rotation, deformation of material, stress analysis, deformation in impact, explosion process and biomedicine, in recent years. In this paper, the results of our research, including the theoretical analysis, some feasible methods and relevant verifying experiment results, are compendiously reported. At present, these results have been used in our assembling instruments for 3D shape measurement of dynamic process. 相似文献
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Ghanei A. Soltanian-Zadeh H. 《IEEE transactions on information technology in biomedicine》2002,6(4):285-295
In this paper, we present a new curvature-based three-dimensional (3-D) deformable surface model. The model deforms under defined force terms. Internal forces are calculated from local model curvature, using a robust method by a least-squares error (LSE) approximation to the Dupin indicatrix. External forces are calculated by applying a step expansion and restoration filter (SEF) to the image data. A solution for one of the most common problems associated with deformable models, self-cutting, has been proposed in this work. We use a principal axis analysis and reslicing of the deformable model, followed by triangulation of the slices, to remedy self-cutting. We use vertex resampling, multiresolution deformation, and refinement of the mesh grid to improve the quality of the model deformation, which leads to better results. Examples of the model application to different cases (simulation, magnetic resonance imaging (MRI), computerized tomography (CT), and ultrasound images) are presented, showing diversity and flexibility of the model. 相似文献
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《IEEE transactions on medical imaging》1997,16(5):630-641
The recovery of a three-dimensional (3-D) model from a sequence of two-dimensional (2-D) images is very useful in medical image analysis. Image sequences obtained from the relative motion between the object and the camera or the scanner contain more 3-D information than a single image. Methods to visualize the computed tomograms can be divided into two approaches: the surface rendering approach and the volume rendering approach. In this paper, a new surface rendering method using optical flow is proposed. Optical flow is the apparent motion in the image plane produced by the projection of real 3-D motion onto the 2-D image. The 3-D motion of an object can be recovered from the optical-flow field using additional constraints. By extracting the surface information from 3-D motion, it is possible to obtain an accurate 3-D model of the object. Both synthetic and real image sequences have been used to illustrate the feasibility of the proposed method. The experimental results suggest that the proposed method is suitable for the reconstruction of 3-D models from ultrasound medical images as well as other computed tomograms 相似文献
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Intracranial deformation caused by brain tumors: assessment of 3-D surface by magnetic resonance imaging 总被引:1,自引:0,他引:1
Dai DY Condon B Hadley D Rampling R Teasdale G 《IEEE transactions on medical imaging》1993,12(4):693-702
A shape analysis technique has been developed to quantify intracranial deformation as a means of objectively assessing treatment for brain tumor. Conventional measurements of tumor volume are prone to ambiguity and error, so instead the authors are investigating the secondary space occupying effects of tumor, namely the deformation of structures within the brain. In order to avoid surface segmentation problems in MR images and to facilitate computation, the B-splines method has been introduced to approximate digital 3-D image surfaces. Using the mean curvature and the Gaussian curvature the authors classify a surface into 4 basic types: planar, parabolic, elliptic, and hyperbolic. The deformation of a surface can be described by measuring the geometric changes in these basic types. The method is independent of size, domain (translation), and viewpoint (rotation). These invariance properties are important as they overcome problems caused by wide variations in brain size within the normal population as well as small differences in patient orientation during acquisition. Experimental results show the potential of the technique in objectively monitoring patient response to treatment. 相似文献
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《Materials Science in Semiconductor Processing》2000,3(5-6):569-573
With the conventional micromachining technologies: isotropic and anisotropic dry and wet etching, a few shapes can be done. To overcome this limitation binary multi-masking technique, laser micro-stereolithography, or direct electron-beam-writing were used, but an inexpensive one-step UV-lithographic method, using the so-called “gray-tone lithography”, seems to be the best choice to produce local intensity modulation during exposure process. The paper reports on the study of arbitrary three-dimensional (3-D) shaping of negative and positive thick resists, using this method, and common technologies in standard ICs fabrication. Particular emphasis is placed on the design, manufacturing and use of half-tone transmission masks, required for UV-lithographic step in the fabrication process of mechanical, optical or electronics components. The original design and fabrication method, for the gray-tone reticles, were supported by experiments showing the main advantage of this new technology: the 3-D structuring of thick resists in a single exposure step, and also a high aspect ratio obtained over 9:1. Experimental results are presented in SEM micrographs, only for positive thick resists, showing different 3-D shapes in positive and negative polarity, and also the results obtained by using the wall-type test structure for aspect ratio evaluation. Finally, by optimization of the lithographic process, interesting applications are shown. 相似文献
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Surface wave electromagnetic acoustic transducers (EMATs) are becoming preferred sensors of automatic inspection systems for the detection of surface-layer defects in hostile environments. Aiming at establishing a 3-D model for meander-line-coil surface wave EMATs operating on the Lorentz principle, a novel modeling method is proposed by combining numerical calculations and analytical solutions with special attention to the influence of the dynamic magnetic field. Simulation and analysis find that the frequency of the surface waves due to the dynamic magnetic field is twice that due to the static magnetic field; the excitation of surface waves with two frequencies can effectively improve the sensitivity of EMATs to flaws; and the force due to the dynamic magnetic field generates surface waves more efficiently than that due to the static one when the excitation current exceeds 528.9 A. The accuracy of the established model is verified by experiment. 相似文献
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Heng Huang Li Shen Rong Zhang Fillia Makedon Andrew Saykin Justin Pearlman 《IEEE transactions on information technology in biomedicine》2007,11(4):474-482
In this paper, we propose a novel surface matching algorithm for arbitrarily shaped but simply connected 3-D objects. The spherical harmonic (SPHARM) method is used to describe these 3-D objects, and a novel surface registration approach is presented. The proposed technique is applied to various applications of medical image analysis. The results are compared with those using the traditional method, in which the first-order ellipsoid is used for establishing surface correspondence and aligning objects. In these applications, our surface alignment method is demonstrated to be more accurate and flexible than the traditional approach. This is due in large part to the fact that a new surface parameterization is generated by a shortcut that employs a useful rotational property of spherical harmonic basis functions for a fast implementation. In order to achieve a suitable computational speed for practical applications, we propose a fast alignment algorithm that improves computational complexity of the new surface registration method from O(n3) to O(n2). 相似文献