数字全息在粗糙度检测中的应用

提出一种用数字全息测量物件表面粗糙度的新方法,基于离轴无透镜数字全息理论推导获得了表面粗糙度Ra值和用数字全息法获得的相位解包裹后相位分布之间的关系式,发现用此方法不需要用数字全息获得的真实的相位分布,而用相位解包裹后的相对相位分布即可.实验结果表明用此方法测量物件表面粗糙度是可行的并且变动度较小.     

超光滑表面三维微观轮廓检测的研究

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。     

数字全息技术在温度场检测中的应用

采用一种简单的无透镜傅里叶变换数字全息测量方法,实现了金属加热板附近区域的温度场测量。论述了测量原理,建立了实验装置,测量得到了金属加热板附近区域温度场一维分布,此结果与热电偶实际测量得到的温度误差在[-3．05K,0．47K]之内。     

激光全息技术在测量中的应用

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。     

在线检测超精细表面微观形貌的激光轮廓仪

介绍一种可用于在线和在位检测的高分辨力激光轮廓仪,此仪器具有很高的共模型抑制比和同类型仪器中最小的形状误差,分辨力优于0．2nm(Ra)。可以摆放在金刚石车床的刀架上测量超精密加工表面微观形貌。     

InSAR技术在矿区地面沉降监测的应用探讨

本文结合合成孔径雷达差分干涉测量技术监测地面沉降的原理、步骤进行研究,分析了InSAR技术在矿区沉降监测中的发展潜力和技术难点,并结合最新短基线集干涉处理技术,削弱大气延迟误差、DEM误差、相位解缠误差等,提高了监测精度。因此,对合成孔径雷达差分干涉测量监测地面沉降的理论与应用技术的研究,具有霞要的实用价值和社会意义。     

双光束激光散斑干涉技术在振动分析中的应用

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。     

计算机图像检测在干涉测量中的应用

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。     

全金属超表面在电磁波相位调控中的应用及进展

全金属超表面是由亚波长金属单元所组成的结构阵列,其在调控电磁波相位方面展现出了效率高、带宽大等特点,并且相较于金属-介质混合型超表面,全金属超表面具有优良的热学和机械性能,如耐高温、强度大、延展性好等,这使得其可以应用于高温高压等极端复杂环境中。本文对近年来全金属超表面取得的研究进展进行了简要的归纳总结,主要介绍了其在构建高效、多功能平面光学器件以及多频谱电磁隐身中的应用,并对其未来的发展方向进行了展望。

     

Measurement of Surface Shape and Position by Phase‐Shifting Digital Holography

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.     

叶片型面数控加工精度与测量误差分析

五坐标数控加工中心在航空发动机叶片生产现场的大量应用,使叶片型面误差得到有效控制,同时,也对叶片型面测量方法提出了更高要求,本文从分析、计算五坐标数控加工叶片型面误差入手,论述生产现场使用叶片样板和测具测量型面误差时存在的问题。     

Displacement Measurement Through Digital Image Correlation and Digital Speckle Pattern Interferometry Techniques in Cold‐Expanded Holes

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.     

表面测量中抗混叠数字滤波器的设计与实现

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．     

数字化网络在计量管理中的应用

数字化网络在计量管理中的应用主要解决了当前计量管理中面临的多要素集成管理的新需求,结合分析当前试飞计量管理,阐述了计量管理中的法规、技术、成本、行政、企业文化管理的多要素数字化模型建立及信息化、网络化运行,实现了数字化网络在计量管理中的应用。     

Study of the Mechanical Behaviour of a Clarinet Reed Under Forced and Auto-oscillations With Digital Fresnel Holography

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.     

Time Resolved Digital Holographic Interferometry for Investigations of Dynamical Events in Mechanical Components and Biological Tissues

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.     

Contouring of Diffused Objects by Using Lensless Fourier Transform Digital Holography and Dual‐Index Immersion Method

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.     

Identification of Specimen Position and Orientation Using Standard Deviation of Intensity in Phase‐Shifting Digital Holography1

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.