共查询到18条相似文献,搜索用时 140 毫秒
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从等厚子干涉的解释出发,推导出了二维空间的相干方程。基于空间相干方程,利用SLM产生了一个新的空间非相干光源。同时提出了新的相移方案,并结合这个新的相移方案,实现了轴向空间距离的探测和干涉条纹的相移。分析了空间方向角度相干方程的影响,并给出了实验验证。通过对非相干光源的参数和特定的空间距离以及空间方向角的匹配,重建了一个具有标准段差的实际物体的表现形状。为光学表面形状测量提供了新的思路。 相似文献
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本文研究了云纹干涉法的现场测量技术.该方法在现场测量过程中复制变形的试件栅.试件栅上保留了载荷引起的变形信息,通过云纹干涉法可以得到这些变形信息.该方法不但具有云纹干涉法的所有优点,并且使云纹干涉法可以在光学实验室以外场合中应用. 相似文献
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电子散斑干涉和Video全息干涉 总被引:7,自引:2,他引:7
本文综述了有关电子散斑干涉法(ESPI)和Vidco全息干涉技术的一些近期成果.主要包括:有机玻璃模型中主应力和的测量,二维气体温度场和轴对称气体温度场的测量,三维物体表面形状和三维位移场的测量.条纹图均用数字图象处理系统处理.文中介绍了各种测量光路和操作技术,分析了可能出现的误差,提供了部分实验结果. 相似文献
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激光反射全息干涉法现场测量残余应力的实验研究 总被引:1,自引:0,他引:1
本文根据激光反射干涉法的基本原理,采用钻盲孔释放残余应变的手段,提出一种新颖的残余应力激光全息现场测量的方法,推导出该光学测量方法3种计算公式.解决了激光全息干涉法不能进行现场实测的难题. 相似文献
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本文根据激光反射干涉法的基本原理,采用钻盲孔释放残余应变的手段,提出一种新颖的残余应力激光全息现场测量的方法,推导出该光学测量方法3种计算公式.解决了激光全息干涉法不能进行现场实测的难题. 相似文献
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Based on geometric moire method, moire interferometry and microscopic moire interferometry, a high spatial resolution and
high sensitivity geometric microscopic moire method is presented. Geometric micron-moire patterns are produced by the superposition
of two high frequency gratings through a microscope system. Compared with other grating-based photo-mechanics methods, microscopic
moire method could provide whole-field moire patterns of both high spatial resolution and high sensitivity. The frequency
of specimen and reference gratings used in this method can be from 1 line/mm to 10000 lines/mm. Additionally, a 4F optical filter system is used to enhance the contrast of microscopic moire patterns effectively.
The project supported by the National Natural Science Foundation of China 相似文献
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三维位移场(U,V,W)实时观测的云纹干涉法 总被引:1,自引:0,他引:1
本文将一特殊布置的云纹干涉系统和一垂直入射试件栅的麦克尔逊干涉系统组和起来,利用云纹干涉系统测量两个面内位移分量U、V,垂直入射的麦克尔逊干涉系统测量离面位移分量 W。调节云纹干涉系统中入射光的入射角,使正、负一级衍涉波的传播方向偏离开试件栅法向一微小角度,从而使一级衍涉波的频谱点与麦克尔逊干涉系统中的零级衍涉波的频谱点在频谱面上分开。利用小反射镜的反射来改变一级衍射波的传播方向,从而使我们在三个彼此分开的成像面上同步实时观测到三维位移场的条纹图。文中给出了严格的理论推导和实验验证。 相似文献
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本文将云纹干涉法与载波法、倍增技术相结合,提出一种位移场和应变场云纹干涉条纹倍增方法,该方法使得云纹干涉法测量灵敏度提高四倍以上。文中对该方法给出了严格的理论推导和实验验证。 相似文献
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An analysis of the spatial frequency ranges for the nonlinear Schrödinger equation (NLS), subject to initial conditions with Gaussian and band-limited spatial frequency spectra, is presented in this paper. The analysis is based on a Volterra series representation of the NLS equation. This study reveals the relationship between the spatial frequency ranges of the solution, along with the evolution of the system, and the spatial frequency ranges of the initial conditions, and extends previous results in linear and nonlinear finite dimensional systems. The analysis also reveals a variety of nonlinear phenomena including self-phase modulation, cross-phase modulation and Raman effects modelled using the NLS equation. 相似文献
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Depth-resolved Imaging and Displacement Measurement Techniques Viewed as Linear Filtering Operations
The last 5 years have seen the emergence of a family of optical interferometric techniques that provide deformation measurements
throughout three-dimensional (3-D) weakly scattering materials. They include wavelength scanning interferometry (WSI), tilt
scanning interferometry (TSI), phase contrast spectral optical coherence tomography (PC SOCT) and hyperspectral interferometry
(HSI) and can be thought of as a marriage between the phase sensing capabilities of Phase Shifting Interferometry and the
depth-sensing capabilities of Optical Coherence Tomography. It was recently shown that some closely related 3-D optical imaging
techniques can be treated as shift-invariant linear filtering operations. In this paper, we extend that work to include WSI,
TSI, PC SOCT and HSI as spatial filtering operations and also relate the properties of their transfer functions in the spatial
frequency domain to their spatial resolution and phase sensitivity, for depth-resolved displacement measurements. 相似文献
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An alternative technique for crack detection in a Timoshenko beam based on the first anti-resonant frequency is presented in this paper.Unlike the natural frequency,the anti-resonant frequency is a local parameter rather than a global parameter of structures,thus the proposed technique can be used to locate the structural defects.An impedance analysis of a cracked beam stimulated by a harmonic force based on the Timoshenko beam formulation is investigated.In order to characterize the local discontinuity due to cracks,a rotational spring model based on fracture mechanics is proposed to model the crack.Subsequently,the proposed method is verified by a numerical example of a simply-supported beam with a crack.The effect of the crack size on the anti-resonant frequency is investigated.The position of the crack of the simply-supported beam is also determined by the anti-resonance technique.The proposed technique is further applied to the"contaminated"anti-resonant frequency to detect crack damage,which is obtained by adding 1-3% noise to the calculated data.It is found that the proposed technique is effective and free from the environment noise.Finally,an experimental study is performed,which further verifies the validity of the proposed crack identification technique. 相似文献
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Optical techniques are now broadly used in the field of experimental mechanics. The main advantages are they are non intrusive and no contact. Moreover optical techniques lead to full spatial resolution displacement maps enabling the computing of mechanical value also in high spatial resolution. For mesoscopic measurements, digital image correlation can be used. Digital holographic interferometry is well suited for quantitative measurement of very small displacement maps on the microscopic scale. This paper presents a detailed analysis so as to compare digital Fresnel holography and digital image-plane holography. The analysis is based on both theoretical and experimental analysis. Particularly, a theoretical analysis of the influence of the aperture and lens in the case of image-plane holography is proposed. Optimal filtering and image recovering conditions are thus established. Experimental results show the appropriateness of the theoretical analysis. 相似文献