Transmission measurement of three-dimension profile based on infrared-light interference technology with wafer compensation

A new method of three-dimension profile measurement is proposed based on infrared-light interference technology, which is extended from visible-light region to infrared-light region for white-light scanning interferometry. Microstructure with two steps of different heights is used to be demonstrative sample to prove the property of designed system based on linnik-type interferometric microscope with phase-stepping algorithm. Three-dimension profile and step height can be obtained accurately with GaAs wafer transmission compensation and are highly consistent with the results that obtained from the famous commercial instrument MSA 400. The novel method has widely potential applications in the field of MEMS, such as reconstructing the internal profile of encapsulation devices and analyzing the quality evaluation of bonding interface based on semiconductor materials.     

Profile measurement system based on linnik-type interferometric microscope for visible-light region and infrared-light region

A profile measurement system consisting of linnik-type interferometric microscope, light source and cameras is developed based on white-light scanning interferometry extending from the visible-light region to the infrared-light region. Three-dimensional profiles of microstructures are obtained via a phase-stepping algorithm using a CMOS array camera for the visible-light region and an InGaAs CCD array camera for the infrared-light region. Errors of the measurement system along with extensive applications in MEMS device profile reconstruction of top surface, sidewall and internal structures are discussed in detail.     

基于白光数字莫尔的三维数字成像系统

提出一种基于数字莫尔的三维光学数字成像系统,此系统采用了非相干光投影和空间相移算法以及混合模板相位复原技术来重构连续位相分布图。给出一种光学几何灵敏度的确定方法并由此区得空间自由表面的三维数字图像。文中还给出由该光学数字化系统得以的真实人体面部的三维数字图像的实验结果。     

3D surface topography from the specular lobe of scattered light

Scattered light from a surface contains a huge amount of information including surface slope, roughness, pattern, texture, etc. In this paper, the relationship between the intensity distribution of scattered light from a surface and the 3D surface topography will be investigated. From the geometrical point of view the intensity distribution of scattered light from a surface may be modelled with three components, the specular spike, specular lobe and diffuse lobe. In the situation when light is scattered from a relatively smooth surface whose roughness is much larger than the wavelength of the incident light, the scattered light intensity distribution will consist of only a diffuse lobe and a specular lobe, which are well described by a combination of the Lambertian and Torrance–Sparrow geometrical models. Based on the light scattering phenomenon, in this paper a scanning method capable of measuring the 3D surface topography with 500 mm scanning width, high scanning speed, and micron resolution is presented. The 3D topography measurement is implemented by using a linear photodiode array to measure scattered light intensity distribution at different angles against the surface normal. Then the specular lobe of the scattered light will be extracted at each scanning point to calculate the surface normal distribution. Sequentially, the 3D surface topography is obtained by using gradient integration techniques.     

用数值模式匹配算法高效仿真轴对称型散射体海洋可控源电磁响应

圆盘、球体以及球冠状体是地球物理研究中非常重要的一类散射类型.在海洋环境中,圆盘可以用于描述玄武岩基岩以及油气圈闭构造等电阻率异常体,而球冠可以近似描述某些基岩隆起或起伏地形等.这类散射体的一个重要特征是其电阻率空间分布具有轴对称性.如果能够针对这类形状的散射体研究建立一套有效的海洋可控源电磁数值模拟方法,对于认识复杂地层条件下海洋电磁响应的变化特征、研究建立相关的资料处理和解释方法具有非常重要的意义.本文根据电导率轴对称分布特征,设法用一个或多个不同半径、不同厚度的水平同心圆盘逼近这类轴对称电导率散射体,并将这些同心圆盘与海洋环境中的空气、海水、沉积层和基岩等背景介质结合,形成一个在水平方向电导率具有轴对称分布、在垂直方向又具有分层特征的水平层状非均质模型.在此基础上,应用数值模式匹配法研究水平电偶极子天线电磁场的数值模拟方法,给出位于对称轴上的水平发射天线电磁场在层状非均质地层中的半解析解,建立海洋可控源电磁响应高效算法.最后通过数值模拟结果对该算法进行检验并考察海洋可控源三维电磁响应特征.     

Measurement of transparence topography based on principal component analysis

An algorithm based on the principal component analysis (PCA) is proposed to measure transparent surface topography. First, many frames of random phase shifted fringe patterns are captured. Second, the first and second principal components are extracted from the phase shifted fringe patterns by PCA. Then, the phase is calculated from principal components. Finally, the correct global phase sign is determined by the clustering method considering local fringe phase monotonicity. The experimental results show that the proposed method can directly extract the three-dimensional (3D) shape, which does not need to determine the amount of phase shift, without precise phase shifter. It reduces the experimental hardware requirements and improves its adaptability in profilometry.     

一种液面微形貌测量技术及在微浮力和表面张力研究中的应用

应用改进的云纹法测量微小物体漂浮在水面上所产生的水面凹陷曲面的三维形貌,并根据此三维形貌来定量测量微小物体受到的微浮力和表面张力,分析其与水面的相互作用.通过对不同大小的硬币浮在水面上所形成的液面三维形貌的测量以及进一步的分析表明:硬币浮在水面上是表面张力和浮力共同作用的结果,其中浮力起主要作用.该实验验证了所提出的技...     

Angle-resolved three-dimensional analysis of surface films by coherence scanning interferometry

The Fourier components of interference signals generated by scanning a high-numerical-aperture objective orthogonal to an object surface correspond to different angles of incidence on the surface. The phase and amplitude of these Fourier components relate to the structure of the object, including in particular the 3D topography and thickness profiles of thin-film layers.     

Dynamic properties of three-dimensional piezoelectric Kagome grids

Piezoelectric Kagome grids can be considered as a kind of functional material because they have vibration isolation performance and can transform mechanical energy to electric energy. In this study, the dynamic properties of three-dimensional (3D) piezoelectric Kagome grids without and with material defects are studied based on the frequency-domain responses. The spectral element method (SEM) is adopted to solve a 3D piezoelectric beam which contains bending components in two planes, tensional components, and torsional components. The dynamic stiffness matrix of a spectral piezoelectric beam is derived. Highly accurate solutions in the frequency-domain are obtained by solving the equation of motion of the whole structure. Compared with the results from the FEM and those in the existing literature, it can be seen that the SEM can be effectively used to study the 3D piezoelectric Kagome grids. The band-gap properties of Kagome grid and defect state properties of Kagome grid with material defects are analyzed. The effect of the piezoelectric parameter on the band-gap property is investigated further.     

Differential confocal measurement method of linear scanning based on dual linear array camera北大核心CSCD

针对目前微观三维表面形貌测量技术中存在检测效率和测量范围较小的问题,提出一种基于双线阵相机的线扫描差动共聚焦三维形貌测量方法。采用线扫描光源,利用线扫描拼接算法,分别合成焦前和焦后图像;再利用差动算法获得样本位于测量区域的差动图像,结合预先刻度的轴向响应曲线,完成样本的三维形貌还原,实现大范围高效测量。实验结果证明:基于双线阵相机的线扫描差动共聚焦三维形貌测量方法在相同时间内测量范围和测量效率分别是白光干涉仪的16.48倍和6.59倍,并且该方法在测量过程中不需要停顿,只需实现一次对焦,就可以对样品进行连续不间断的扫描检测。研究成果为满足智能制造中在线在位、实时高效、大范围测量的检测需求提供依据。     

3D color reconstruction based on underwater RGB laser line scanning system

Laser line scanning (LLS) as an optical 3D survey method is recently used for underwater 3D imaging. This paper presents an approach for both 3D reconstruction and color restoration based on the LLS system. The system is set up with RGB laser scanning components for acquiring 3D data and color data at the same time. Direct calibration algorithms and RGB additive color model are involved for processing 3D color data. The experiment result shows that underwater targets can be feasibly 3D reconstructed with color texture simultaneously, at millimeter scales.     

Study on tribological behavior and cutting performance of CVD diamond and DLC films on Co-cemented tungsten carbide substrates

The tribological behaviors of diamond and diamond-like carbon (DLC) films play a major role on their machining and mechanical applications. In this study, diamond and diamond-like carbon (DLC) films are deposited on the cobalt cemented tungsten carbide (WC-Co) substrate respectively adopting the hot filament chemical vapor deposition (HFCVD) technique and the vacuum arc discharge with a graphite cathode, and their friction properties are evaluated on a reciprocating ball-on-plate tribometer with counterfaces of silicon nitride (Si₃N₄) ceramic, cemented tungsten carbide (WC) and ball-bearing steel materials, under the ambient air without lubricating condition. Moreover, to evaluate their cutting performance, comparative turning tests are conducted using the uncoated WC-Co and as-fabricated CVD diamond and DLC coated inserts, with glass fiber reinforced plastics (GFRP) composite materials as the workpiece. The as-deposited HFCVD diamond and DLC films are characterized with energy-dispersive X-ray spectroscopy (EDX), scanning electron microscope (SEM), X-ray diffraction spectroscopy (XRD), Raman spectroscopy and 3D surface topography based on white-light interferometry. Furthermore, Rocwell C indentation tests are conducted to evaluate the adhesion of HFCVD diamond and DLC films grown onto WC-Co substrates. SEM and 3D surface topography based on white-light interferometry are also used to investigate the worn region on the surfaces of diamond and DLC films. The friction tests suggest that the obtained friction coefficient curves that of various contacts exhibit similar evolution tendency. For a given counterface, DLC films present lower stable friction coefficients than HFCVD diamond films under the same sliding conditions. The cutting tests results indicate that flank wear of the HFCVD diamond coated insert is lower than that of DLC coated insert before diamond films peeling off.     

Software support of the technology of substrates for multilayer interference structures

A computer-aided machining (CAM) system for nanoscale polishing of cylindrical optical elements with a flat, parabolic, elliptic, or table-defined generatrix we developed is described. This system is one of the key components of the fabrication of templates for producing substrates of 2D optical systems based on multilayer interference structures. The field of application of this software can be easily extended to production of various 3D surfaces.     

基于单摄像机的三维位移测试方法

基于三维位移测量手段在工程技术领域的必要性和重要性,开展了基于单摄像机和数字图像相关的三维位移测试方法研究.基于图像位移场矢量中心和斜率与面内和离面位移的分别对应关系,采用Savitzky-Golay(SG)微分滤波器分离图像位移子区内的常数项与一次项,可实现物体三维位移分量的有效分离.以针孔摄像机成像模型为基础,开展了相应的数值模拟实验及悬臂梁端部受载的实验,发展了与三维线性变形对应的散斑图模拟方法,验证了基于二阶位移模式的牛顿-拉夫森迭代法的精度和适用性.数值模拟与实验结果均验证了三维位移测试方法用于实现物体三维位移重构的可行性和优越性.     

三维复杂温度场高精度声学测量方法

声学温度场检测技术通过多路径声波传播时间数据,反演被测区域的温度分布。提供了一种高精度的三维复杂温度场的声学测量方法。首先从射线声学角度给出了三维非均匀温度场中声波传播路径的数学模型。在此基础上,将三维温度场的重建问题转化为声波传播路径的求解和温度场的反演问题,建立了基于多项式修正径向基函数(RBF-PR)和改进的Tikhonov正则化三维温度场重建算法。采用两种典型的炉膛三维温度场模型,在信噪比SNR=35 dB下进行了数值模拟,分析了声波传播路径在非均匀温度场中的弯曲特性、算法的重建质量和抗噪性,同时进行了实际炉膛内二维温度场的重建。结果表明了提出的考虑声线弯曲的温度场重建算法具有精度高,抗噪性强、适用性好的特点,为实现高精度的复杂温度场的声学测量提供了有效方法。      

Performance evaluation of an optical flow technique applied to particle image velocimetry using the VSJ Standard Images

A Dynamic Programming based Optical Flow technique has been applied to the Particle Image Velocimetry (PIV) problem. It has been used for the extraction of dense velocity fields in a planar section of a fluid flow illuminated by a thin laser light sheet. Two (in-plane) components of the velocity vectors can be recovered using a single camera and all three components can be recovered using two or three cameras. Quantitative performance tests have been carried out on calibrated synthetic image sequences from the PIV Standard Project of the Visualization Society of Japan (VSJ). Results are presented for the 2D flow based sequences (STD01 to STD08 Standard Images) and the 3D flow based sequences (STD301, STD302, STD331 and STD337 Standard Images). The RMS error is within the 2–3% range and within the 4–8% range for recovery of the two-component and the three-component velocity vectors respectively.     

Dynamic propagation study of phase-controlled infrared-light pulses in low-dimensional semiconductor heterostructures

We study the propagation effects of the phase-controlled infrared-light pulses in semiconductor quantum-well (QW) heterostructures under realistic experimental conditions. By numerically solving the coupled Bloch–Maxwell equations for electrons and fields simultaneously on numerical grids in time and space, we show that the propagation dynamics can be dramatically modified by varying the relative phase of the applied fields. This opens up the possibility to study optimal control of light propagation in the QW solid materials.     

基于双目视觉的三维重建中特征点提取及匹配算法的研究

三维重建是计算机视觉技术的主要内容之一。基于双目视觉的二维图像特征点的提取及特征点的匹配是三维重建技术的核心。通过以双目立体视觉理论为基础,提取立体图像的Harris角点作为特征点,经过基于小波变换的子线段匹配方法,较好地的解决了匹配精度与匹配速度之间的平衡问题。采用该方法对水泥冷却机内熟料的高度进行了测量,实现了熟料的三维重建。实验表明,该方法可提高图像匹配的速度和精度,能够较精确地对物体实现三维重建。     

Generating 3D and 3D-like animations of strongly uneven surface microareas of bloodstains from small series of partially out-of-focus digital SEM micrographs

When dealing with microscopic still images of some kinds of samples, the out-of-focus problem represents a particularly serious limiting factor for the subsequent generation of fully sharp 3D animations. In order to produce fully-focused 3D animations of strongly uneven surface microareas, a vertical stack of six digital secondary-electron SEM micrographs of a human bloodstain microarea was acquired. Afterwards, single combined images were generated using a macrophotography and light microscope image post-processing software. Subsequently, 3D animations of texture and topography were obtained in different formats using a combination of software tools. Finally, a 3D-like animation of a texture–topography composite was obtained in different formats using another combination of software tools. By one hand, results indicate that the use of image post-processing software not concerned primarily with electron micrographs allows to obtain, in an easy way, fully-focused images of strongly uneven surface microareas of bloodstains from small series of partially out-of-focus digital SEM micrographs. On the other hand, results also indicate that such small series of electron micrographs can be utilized for generating 3D and 3D-like animations that can subsequently be converted into different formats, by using certain user-friendly software facilities not originally designed for use in SEM, that are easily available from Internet. Although the focus of this study was on bloodstains, the methods used in it well probably are also of relevance for studying the surface microstructures of other organic or inorganic materials whose sharp displaying is difficult of obtaining from a single SEM micrograph.     

A novel color fringe projection based Fourier transform 3D shape measurement method

A novel Fourier transform 3D shape measurement method based on color fringe projection is proposed in order to solve the spectrum overlapping and phase unwrapping problems existed in Fourier transform profilometry (FTP). The R and G components of the color fringe are set to two sinusoidal patterns with different frequencies and the B component is set to the average value of R or G component. Then this pattern is projected to the object and the deformed fringe image is captured. Three gray patterns are separated from the color fringe, the background and high frequency noise can be eliminated using our method and the accurate unwrapped phase can be got. Only one shot color pattern is projected to get the 3D information of the object. Experiment results show that the 3D information of an object can be obtained rapidly and accurately.