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简化的三维体轮廓测量术 总被引:3,自引:0,他引:3
基于直接条纺位移分析的三维测量具有简单,快速,精确的特点,本给出了该方法的光学调制和计算机解调原理,以及用该方法进行简单三维测量的主要步骤。 相似文献
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利用空间坐标变换的三维测量系统 总被引:6,自引:0,他引:6
提出了一种新的三维面形测量合成方法,它可以用于大物体及具有复杂而形物体的多次测量,本文将空间坐标变换理论引入到三维面形测量中,并阐述了基于此物相转换方法及图像合成方法。测量结果表明,本方法可以基本消除传统方法中存在的问题,解决了三维测量中的一个瓶颈问题。 相似文献
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基于光学三维形貌数字重建的不规则表面的参数测量 总被引:1,自引:0,他引:1
针对不规则形状物体表面参数测量困难的问题,提出了一种利用光学三维形貌数字重建技术来获取待测物体表面三维数字信息的方法。首先利用傅里叶变换得到反映三维物体表面高度的相位数据,在计算机中重建三维待测物体,然后再利用Matlab软件编写面向用户的人机交互界面,通过计算机鼠标指定待测量的表面区域,最后运用Matlab软件对鼠标所指定区域的三维数字信息进行处理,根据几何关系计算出指定区域的表面积、两点间的曲线长度等参数,实现人机交互式的非接触测量。 相似文献
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用条纹图形接接法测量三维大物体面形 总被引:5,自引:3,他引:2
三维的同形的在各个领域中有着广泛的应用,用莫尔法、调制光场分析法测量具有非接触性、高精度、快速的特点,但对于大物体的测量的测量却存在着许多困难诸如阴影噪声难以消除、条纹对比度低。考虑到图形的相关性,本文提出了一种基于多孔径拼接原理三维万物体面形的方法;条纹图形拼接法,给出了数学模型,计算机模拟结果和实验结果。 相似文献
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针对大型物体三维形貌视觉测量,提出了一种新的视觉测量三维数据拼接方法。以一台高分辨率数码相机作为全局测量设备,在测量过程中固定不动,并以数码相机坐标系作为全局坐标系。视觉传感器流动到不同位置对物体各子区域进行测量,获得局部坐标系下的三维数据。以一平面靶标为中介将视觉传感器在各位置的局部坐标系统一到全局坐标系下,从而将三维数据统一到全局坐标系下,完成三维拼接。该方法无需在被测物上贴标记,因此适用于任何材质的被测物,且消除了拼接累积误差。实验结果表明,该方法相对拼接误差为0.076%。以Venus石膏像为被测对象,视觉传感器对其三个局部区域进行测量,给出了局部测量结果及拼接结果。 相似文献
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3-D profile measurement of a moving object using a novel phase-shifting technique is introduced. Digital gratings with two steps phase-shifting are projected periodically onto a measured object surface. The deformed fringe patterns are captured by a frame CCD camera within a short exposure time. By synchronizing the projector and the CCD camera accurately, there is an overlapping part which is the same part of the object among three neighbouring frames. The length of an overlapping part can be controlled as one third of a frame length. Hence the intensity values at the same surface point modulated by three neighbouring gratings can be obtained, and its phase value can be computed by an improved phase-extracting algorithm. The profile of a specimen is detected by the proposed method. Experimental results demonstrate that this method is effective for the profile measurement of a moving object. 相似文献
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本文提出一种测量半导体中非平衡载流子寿命的新方法。这方法是测量触针下分布电阻的光电导相位移,在不同的表面情况和不同的激发光光谱成分下,导得各种结果表达式,文中对通常所使用的测量条件即粗磨表面和长波激发条件给出数值计算的结果。同时,对这些结果进行较为详细的分析和讨论,这个方法具有一系列的优点。例如:1)可以在锭状晶体上测量;2)表面处理十分简单;3)在样品上不需制作固定电极;4)测量仪器简单,操作方便;5)有一定准确度。这个方法可以检验不均匀材料,可供科研机关作研究用,更适合于工厂检验单晶材料用。用这方法在锗和硅样品上进行测量,测得寿命值基本上与其它方法的结果一致。 相似文献
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A Fourier transform method of holographic fringe pattern analysis is applied to measure surface residual deformations generated by a pulsed ion implanter. The technique uses a fixture that makes it possible to remove the specimen and put it back into the same position after being implanted. The phase information from interferograms extracted by means of the Fourier transform method is unwrapped using an algorithm based on cellular automata. Results computed from the application of a numerical model are compared with those determined experimentally and a reasonable agreement is obtained. 相似文献
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A non-scanning,non-interferometric,three-dimensional(3D) optical profilometer based on geometric optics,critical angle principle,and the use of a charge-coupled device(CCD) camera is presented.The surface profile of the test specimen can be transferred into the reflectance profile.The reflectance profile,obtained from a CCD,is the ratio of the intensity at the critical angle to the intensity obtained at the total internal reflection angle.The optical profilometer provides a sub-micron measuring range with nanometer resolution and can be used to measure roughness or surface defects in real time. 相似文献
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We applied an image-based modeling and rendering technique to reduce the data size of a CG model to be obtained as a visualization
result. To date, this technique has been applied to the reconstruction of 3D graphical models from real objects; the size
of the models can be reduced effectively because both color information and geometric information can be reduced. We applied
a silhouette-and-voxel method that does not require design data for geometric simplification. Using our system, we simplified
two models, one of which, involving medical data, was reduced by about 85% in file size. An accompanying subjective quality
test showed that our approach maintains approximately the same visual quality as the geometric simplification method traditionally
used. 相似文献
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The non-delamination feature of 3D braided composites under transverse impact leads to their potential application in the field of ballistic impact protection. One of the effective ways to investigate the ballistic impact damage of the 3D braided composite is to simulate the penetration process by numerical method, such as finite element method. However the numerical simulations of ballistic impact damage are seldom conducted based on the microstructure level. This paper presents a microstructure model for simulating ballistic impact damage of 4-step 3D braided rectangular composite penetrated by a rigid steel projectile. The microstructure model is based on the same yarn spatial configuration with that of the braided composite and also on the assumptions of the braided yarns appear straight inside the braided preform, bending and then change to other directions only at the surface. The ballistic perforation of the braided composite specimen by a cylindrical-conically steel projectile has been simulated with finite element method. The comparisons between FEA and experimental results show the validity of the microstructure model, especially for the penetration resistance and impact damage of the composite. Compared with the other continuum models of the braided composite, the microstructure model can simulate impact damage more precisely. The velocity history and acceleration history of projectile, and impact damage development of the composite in FEM simulation indicate the different damage and energy absorption mechanisms of the braided composite compared with those of laminated composite. 相似文献
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基于三维重建理论的目标光谱散射特性研究 总被引:1,自引:0,他引:1
根据三维重建理论,基于目标的多角度视图,重建了目标表面的三维点云。利用德洛奈三角剖分法结合可见性原理,得到了目标的曲面和曲面面元的法线方向。根据粗糙面散射理论和目标表面的双向反射分布函数(BRDF),结合大气传输软件Modtran计算的某时间、地点的背景光谱辐射亮度,数值分析了目标光谱散射亮度分布特性。以覆盖车衣的汽车为例,重建的三维几何模型误差为4.11%,数值计算了目标在三个波段的光谱散射亮度分布。上述方法可以进一步用于卫星和其他空间目标的光谱辐射、散射特性研究。 相似文献
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A new specimen stage has been developed for the adjustment of specimens in reflection diffraction experiments. It permits small areas of the object surface to be investigated individually at different orientations, for all axes of rotation intersect in one point on which the electron beam is directed. To obtain a welldefined orientation of the specimen, its surface has first to be adjusted orthogonal to the azimuthal axis of rotation, so that the azimuth and, by inclining the azimuthal axis, the angle of incidence can be chosen independently. In order to bring other parts of the object surface to examination, the specimen can be displaced in two orthogonal directions lying within its surface, and in one direction perpendicular to it. During diffraction investigations, the object can be observed simultaneously with a light microscope, by which means the selection of the area to be examined is facilitated and some additional information relative to the geometry of the surface and the present orientation of the specimen may be obtained. 相似文献
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针对锂离子电池SOC(荷电状态)难以估算的问题,通过对电池建立等效的Thevenin电路模型,对不同时刻的SOC的模型参数进行拟合得到动态的模型参数,在Matlab中借助Simulink建立仿真模型,采用模块化结构,建立基于卡尔曼滤波算法的电池SOC估算系统;利用测得的电池电压电流,仿真系统可直接估算出实时的电池SOC,与实际的电池SOC对比,误差保持在2.5%以内,表明该方法可以有效的估计电池的SOC,对于锂离子电池在实际应用的容量估算有着重要意义。 相似文献