Polarizationally Non-sensitive Pseudo-holographic Computer Reconstruction of Random Rough Surface

Abstract

The function, describing a profile of a random rough surface (RRS) is expanded in a Fourier series, i.e. the surface is considered as a composition of sinusoidal gratings. The total diffracted optical field from this RRS is a sum of the fields due to all harmonic gratings, since Kirchhoff's condition for ‘locally flat surface’ is realized for each harmonic grating at a given light wavelength and at an appropriate choice of the basic grating period. The registered s and p components of the diffracted (+1 diffraction orders of each harmonic gratings), incident and mixed optic fields are separated with an optical analyser. These fields are experimentally measured and from these values the phase and the amplitude of each grating are determined. The profile of the surface is reconstructed for s and p polarization of the light scattered field, when the electric vector of the incident light concludes an arbitrary angle with the incidence plane. The mean roughness is determined in both cases. It is shown, that both reconstructions of the profile and the determination of the mean roughness are not dependent on the polarization of the incident light. The separation of the s and p components is of great importance at the two-dimensional reconstruction, when independent of incident light polarization (s or p), the scattered optical field is always depolarized. In this case the profile of the two-dimensional surface can be easily reconstructed with s or p component of the mixing and diffracted fields.     

Computer Reconstruction of a Random Rough Surface in the Presence of Higher Diffraction Orders

Abstract

The profile of a random rough surface (RRS), whose mean roughness R_a is greater than the light wavelength, is visualized by computer processing. The surface is presented as a sum of sinusoidal gratings. The light diffracted from this surface field is registered by a photodiode array. The second and third diffraction orders from each grating are taken into account in computer processing of the diffracted field and the mixing field–the field obtained at the mixing of the reference and the diffraction fields. The criterion for taking into account higher diffraction orders is the asymmetry of the diffraction pattern to the left and to the right relative to the central peak (the field of zero diffraction orders obtained from each grating) The number of the diffraction orders higher than the first is defined from the average intensity distribution between the central peak and the diffraction orders to the left and to the right at arbitrary light wavelength. The surface profile is reconstructed by a computer program and the mean roughness R_a is calculated. The obtained value of R_a is in satisfactory agreement with that measured by the contact pin method.     

随机多相材料微观结构的三维统计重构

根据材料平面图像提供的局限的统计信息重构随机材料的三维微观结构是科学与工程中广泛研究的重要课题,而仅由样本提供的信息进行统计重构一直是一个公开的问题.综述了近年来多相材料三维微观结构的统计重构所使用的Gaussian随机场、JQA法、随机优化、信息论和模式识剐等主要方法的研究情况,在此基础上,提出了一些有待解决的问题,并展望了发展前景.     

粗糙表面散射基模高斯光束的散射特性实验研究

本文介绍良导体二维粗糙表面对红外激光束的散射分布;讨论不同偏振方式入射时散射光的分布特点,以及中等粗糙表面和弱粗糙表面散射能量在不同入射角下的变化趋势;分析表面参数对分布的影响。文章对观察到的弱粗糙表面散射在镜反射方向附近的边凸现象作了简述;这一现象由散射光的相干叠加而引起,有深入研究的价值。     

金属材料断口的计算机三维重构及分析

利用分层切片重构物体的原理,通过图像处理和三维数据场可视化的技术手段,自主开发出一套金属断裂面三维重构的软件-JHX_FSR.该软件自动处理由光学显微镜拍摄的一系列断口宏观侧面的切片照片,得到重构的三维断口形貌,经检验该软件可以较精确地重构断口.此外,通过空间几何的角度对断口的局部区域进行定量分析,结果证实,在断口三维数据场准确的情况下,从空间几何的角度对断口进行定量分析可以作为计算机分析断口的判据之一.     

复合评定法在三维粗糙表面评定中的应用

提出一种将双树复小波与分形理论相结合的复合评定方法。即利用双树复小波近似的平移不变性和方 向性好等优点,将信号分解成更为细腻的低频和高频信号,同时根据多尺度下信号分形维数的不变性,利用图像灰 度值自相关求得高低频信号的分形维数,通过计算高低频信号分形维数之间的差值（即分形维数距)来确定双树复 小波的分解尺度。仿真结果表明复合评定法可以较好地提取基准面,且分形维数距确定分解层数的准确性通过均 方根*Sq值得到了验证;两个实例均说明,复合评定法可以很好地提取具有分形特征的纳米级三维粗糙表面基准或 波纹度,为实际工程表面评定提供了可靠的理论基础。     

Imaging and Reconstruction for Rough Surface Scattering in the Kirchhoff Approximation by Confocal Microscopy

Abstract

Imaging of rough surfaces in confocal microscopy can be described using the concept of the three-dimensional (3D) coherent transfer function (CTF), which is developed on the basis of the Kirchhoff approximation. The 3D CTF is presented using a scalar but high-angle theory. Methods for reconstruction of surface profiles are considered.     

考虑腐蚀钢板表面形貌的三维逆向重建及力学性能退化分析

通过对Q235钢板进行中性盐雾加速腐蚀,得到了不同腐蚀率下的钢板试件;采用三维形貌仪测得腐蚀钢板表面特征,得到了腐蚀钢板表面三维形貌以及孔洞率等腐蚀损伤参量;分析了三维形貌随腐蚀时间的变化规律,建立了孔洞率与腐蚀率之间的关系;最后在试验基础上应用逆向工程软件Geomagic Studio和有限元软件ANSYS,来仿真模拟研究真实锈蚀表面下的单调拉伸力学性能。研究结果表明:腐蚀率及孔洞率较好地符合BidoseResp函数模型;采用逆向工程软件Geomagic Studio可以与ANSYS直接进行数据交流,从而能够运用计算机技术反映出腐蚀钢板的力学性能退化:随着腐蚀程度增加,钢板力学性能线性退化明显。     

粗糙表面的分形表征

最近的研究表明，随机粗糙表面是自仿射的多尺度的，因而表面轮廓的高度分布方差，叙率和曲率的方差不再是唯一的。本文基于分形几何理论提出了一种新的粗糙表面表征方法。使用Ｗｅｉｅｒｓｔｒａｓｓ－Ｍａｎｄｅｌｂｒｏｔ函数得到粗糙表面的分形参数－－“固有”参数，而这些参数可以提供任何长度尺度的粗糙度结构信息。     

随机结构粗糙表面的湿润性研究

依据荷叶表面具有的不规则自相似微纳双重结构,引入分形几何学构造类似荷叶的随机分形结构,建立相应的Cassie、Wenzel模型接触角方程,分析随机分形结构的分形维数和结构参数对其润湿性的影响。结果表明:分形结构表面的分形维数越大,结构越致密,接触角越大;分形结构中微/纳尺度参数之比越大,接触角也越大。然而,随机结构即使分形维数趋于最大的3.0,Wenzel模型表观接触角也不能达到超疏水的150°,Cassie模型最大表现接触角大于150°;更适合用于制备超疏水表面。     

基于随机模糊集的粗糙集模型

当知识库中的知识模块既是模糊的又是随机得到的,我们定义了基于随机模糊集的粗糙集模型。给出了随机模糊粗糙集的性质。讨论了利用模糊集的下近似和上近似定义的模糊测度和概率模糊测度的关系。     

粗糙表面的双相干谱分析

双谱分析是近年发展的一种随机信号的现代分析方法，它保留了信号的相位信息，可以定量描述信号之间的非线性相位耦合；同时具有很强的消噪能力，可以很好地反映信号的非对称特征．正常的加工条件下，表面轮廓符合高斯型分布，因此其双谱为零．但实际加工中，许多表面表现为非高斯型，其双谱不为零，此时可以用双谱分析定量地描述表面轮廓特征的非对称性．然而，用双谱表示灵敏度高、幅值大、不够直观，为了有效地反映表面轮廓的双谱特征，本文采用了双谱的归一化形式——双相干谱分析．最后还通过对几种典型试件的实验，证明了其有效性，并得出了一些有益的结论．     

计算机制作随机条形散斑体视图

提出一种新的显示立体图像方法,用计算机制作随机条形散斑体视对,利用其衍射和人眼的双目辐合来综合立体图。本方法为动态立体显示,彩色立体显示以及实际不存在物体的显示提供了可行的手段,也为研究人的视觉机理提供了一个有效的工具。     

Reconstruction of Charged Hydrogen Surface

The evolution of shape of the surface of equipotentially charged liquid hydrogen film condensed on lower or upper plate of a horizontally placed diode in external electric fields has been studied experimentally under the conditions of total compensation of the applied field by the surface charge. Reconstruction phenomenon — the formation of a solitary wave (soliton) — has been observed in an electric field higher than some critical value for the film covering the lower plate.     

纯位相随机相移器的计算机模拟

本文用计算机模拟了随机相移器对物谱的均化效果,显示了取各种量化值时谱的动态范围的改善及分布,并对此作了直方图分析及均方根计算;确定了在尽可能减化量化级的情况下,随机相移器的量化值取8较好。     

多晶体材料微观组织结构的计算机重构

介绍了用于多晶体材料微观组织结构重构的程序的算法.程序依据多晶体材料的电子背散射衍射(EBSD)分析所得数据,完成了多晶体材料微观组织结构的计算机重构,实现了多晶体材料微观组织的可视化,为采用数值化技术对多晶体材料微观组织结构进行定量分析创造了条件.     

粗糙表面轮廓的分形维数计算

本文介绍了粗糙表面轮廓盒维数的计算方法，并指出分形轮廓曲线的盒维数在１和２之间，而且其数值与取样长度、采样点数及测量仪器的分辨率均有关系．     

Multiple Scattering from Random Rough Surfaces Using the Kirchhoff Approximation

Abstract

Numerical results for scattering of electromagnetic waves from a rough surface are presented and compared with experimental results. The method uses the Kirchhoff or physical optics approximation to separate the single and double scatter terms in the total scatter pattern. It is shown that enhanced backscatter occurs in the double scatter term as predicted by a simple ray picture of the scattering process.     

高分子表面重构研究进展

综述了高分子表面重构研究手段的发展、表面重构的机理与高分子结构对重构的影响等,并对高分子表面重构研究的应用前景进行了展望。