共查询到20条相似文献,搜索用时 62 毫秒
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超光滑表面三维微观轮廓检测的研究 总被引:1,自引:1,他引:0
利用干涉共模抑制和光电信号共模抑制技术,辅以二维扫描平台及计算机控制与数据处理技术,可以高精度地无损测量超光滑表面三维微观轮廓。本论述了上述测量系统的原理,结构和误差分析,并了关于三维微观轮廓的定义问题。 相似文献
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李献波 《中国新技术新产品》2011,(20):149-149
本文介绍了激光全息发展的状况,阐述了激光全息的原理以及数字全息的特点,对激光全息应用于测量方面的研究进行了总结,以期启迪人们研究测量的新方法。 相似文献
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本文分析了散斑干涉的原理,采用双光束激光散斑干涉法,设计了一种数字散斑干涉的振动测量系统给出了实验结果并对实验结果进行了讨论。 相似文献
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计算机图像检测在干涉测量中的应用 总被引:4,自引:0,他引:4
介绍了利用CCD固体摄像传感器和奔腾微机测量干涉条纹的方法,介绍了干涉条纹数字图像检测的原理和软件设计思想。根据此原理,提出了一种微小位移的高精度测量方法,测量精度可达到λ/100的数量级以上。 相似文献
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Abstract: Phase‐shifting digital holography is applied to measure the shapes and positions of rough surfaces from the averaged conjugate product of the reconstructed complex amplitudes, named complex coherence factor, corresponding to dual wavelengths. The phase of the averaged product at the object plane provides the shape of the surface, whereas the peak position of the modulus with respect to reconstruction distance provides the position of the surface. The phase is almost free from speckle noise and easy to be unwrapped. The resultant resolution of surface shape amounts to a few tens of micrometres. The sensitivity of the position measurement that requires no marking on the object is several per cent of object distance from a charge‐coupled device (CCD). The method corresponds to the detection of the position of maximum contrast of the fringes to be observed in conventional holographic interferometry. It makes use of fringe phase for shape measurement and fringe contrast for position measurement. Both the theory explaining the principle and experimental results are presented. 相似文献
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Abstract: In this paper, the displacement field induced by the split‐sleeve cold expansion of holes was measured using both digital image correlation (DIC) and digital speckle pattern interferometry (DSPI) techniques. Thus, the experimental results, which were evaluated on the inlet surface of a 6082‐T6 aluminium plate, were compared with those from theoretical prediction. DIC provided accurate measurements up to the elastic–plastic boundary, whereas the DSPI technique highlighted the changes of displacement in the elastic domain. Prediction of the displacement based on the existing analytical model agreed with the experimental results achieved with both techniques. Possible explanations for the differences are discussed. 相似文献
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在表面测量数据采集系统中,针对抗混叠滤波器设计问题,提出了“模拟滤波器+数字滤波器”的设计方法.设计了具有线性相位的有限脉冲响应(FIR)型抗混叠数字滤波器,得出了幅频特性和相频特性,满足了表面测量信号处理的要求.与传统的单纯模拟抗混叠滤波器相比,该方法有效降低了对模拟滤波器的设计要求,使其易于实现,滤波效果好.把该方法应用于表面测量系统中,通过对实测数据的应用试验,验证了滤波器的性能. 相似文献
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Abstract: This paper presents methods for vibration analysis using digital Fresnel holography. Methods are based on time averaging for forced oscillations and pulsed recording devoted to auto-oscillations. The two methods are applied to a clarinet reed. In the forced oscillation regime, the reed is excited by an acoustic wave with controlled frequency and amplitude such that the reconstructed holograms exhibit resolvable Bessel fringes. In the case of the auto-oscillation regime, the reed is placed in an artificial mouth. Deformation of the clarinet reed can be extracted with the recording of 3150 pulsed digital holograms. Experimental results show the vibration behaviour of the clarinet reed under forced and auto-oscillation regimes, exhibiting the modal structures and high amplitude shocks. 相似文献
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Abstract: In the first part (section 2) of the paper, a system based on digital holographic interferometry for the measurement of vibrations is presented. A high-power continuous laser (10 W) and a high-speed charge coupled device camera are used. Hundreds of holograms of an object that was subjected to dynamic deformation are recorded. The phase of the wave front is calculated from the recorded holograms by use of a two-dimensional digital Fourier-transform method. The deformation of the object is obtained from the phase. By combination of the deformations recorded at different time it is possible to reconstruct the vibration of the object. In the second part (section 3) of our paper, the holographic method is used for the measurements of the elastic properties of the bone. Samples of bone were loaded and deformed and a large number of interferograms (digital holograms) were recorded over a short period of time. In the third part (section 4) of the paper, we show how the holographic systems are adapted for performing measurements in hidden cavities. 相似文献
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Abstract: A simple method for contouring of diffused objects by using lensless Fourier transform digital holography and dual‐index immersion method is presented. It is noticed that to get more accurate results speckle noise should be eliminated/reduced from the reconstructed phase map from digital holograms. Speckle noise is handled by 5 × 5 median filtering. Depth contour interval up to a maximum of 0.12 mm could be achieved without making the interference phase fringes overcrowded. 相似文献
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Abstract: Phase‐shifting digital holography is a useful method to measure the displacement distribution and the strain distribution of an object surface. The complex amplitude distribution of an object surface is obtained as the complex amplitude distribution at a reconstruction distance. It is, however, difficult to measure the reconstruction distance by actual measurement. We discovered that the standard deviation of the intensity on the reconstructed image becomes the maximum value when the reconstruction distance is the same as the actual optical path length. The displacement distributions are obtained for the x‐, y‐ and z‐directions. When the normal direction of an object surface inclines from the z‐direction, the displacements defined on the xyz‐coordinate system should be transformed into the object coordinate system. It is, therefore, required to develop a measurement method of the orientation of the object to obtain the parameters for transforming from the xyz‐coordinate system into the object coordinate system. In this paper, the method to identify the position and the orientation of a specimen using the standard deviation of the intensity distribution is proposed. 相似文献