对光学瓦斯检定器干涉条纹的探讨

本文从对光学瓦斯检定器干涉系统两相干光光程差产生原因的分析，探讨其干涉条纹的成因和干涉类型。     

基于数字化二次曝光干涉的光学元件波前畸变测量

将傅立叶变换条纹分析方法与二次曝光全息干涉计量相结合，提出了数字化二次曝光干涉术，用于测量光学元件引入的波前畸变。文中给出了理论分析，模拟与光学实验结果证实提出的方法具有高精度、快速的波前测量特点，可应用于激光系统中光学元件的波前畸变在线检测。     

Multi-Wavelength vs. Binary Code Pattern Unwrapping in Fringe Projection Method

Phase extraction, phase unwrapping and phase to height conversion are consecutive steps within the fringe projection method for reconstruction of 3D objects. The procedure of determining discontinuities on the wrapped phase, resolving them and achieving the unwrapped phase is called phase unwrapping. A software system was developed that provides the ability to create many kinds of patterns with a verity of desirable properties suitable for different demands in fringe projection systems. In our previous work, an experimental study was reported based on a multi-wavelength unwrapping approach. In the following work, we implemented a new method called binary code pattern unwrapping that is based on time analysis. A comparison of the two unwrapping approaches in terms of resolution, quality, noise, depth accuracy, and computational cost is provided.     

基于曲率和的主动声呐干涉条纹特征表征方法

干涉条纹特征是主动声呐目标识别所依据的重要特征之一。在浅水域环境中,声波能量传播特性较为复杂,信号会经过发射源到目标以及目标到接收器这2条不同的路径,目标的散射特性在声波的入射模式和散射模式之间相互作用,使得主动声呐干涉条纹呈现弯曲的结构。为对干涉条纹特征进行表征,提出一种基于曲率和的声呐特征提取方法。根据浅海声场主动声呐频率-距离干涉条纹图得到一段区间内的干涉条纹曲线散点曲率值,利用曲率求和的方法刻画条纹的弯曲程度,进而表征这一区间内的条纹特征。在理想波导环境下计算刚性球体目标在不同频率段下的曲率特征,通过统计平均值的方式得到平均曲率和为0.6左右,从特征表征结果可以看出,曲率和可通过统计离散点曲率强度描述干涉条纹特征,且在同一环境条件下,发射频率越大时曲率和强度越小。根据实测数据进行计算得到曲率和为0.512,实验与理论结果较为吻合,表明通过该方法可以获取主动声呐干涉条纹特征,进而实现目标识别和探测。     

基于MATLAB的PDV系统数据处理算法与实现

光子多普勒测振(Photonic Doppler Vibrometer,PDV)系统具有测量精度高、空间分辨力高、动态响应快等优点,适用于高温、高压、高速等特殊环境,应用范围广泛。数据处理是PDV系统的重要技术部分,旨在从含有大量噪声的测量数据中获得被测运动体的速度信息。本文在条纹法的基础上,针对原始信号的去噪、奇异点等问题,分别采用移动均值滤波以及小波变换法进行处理,最终得到被测物体的振动信息。利用激振台与经校准的激光测振仪进行振动测试对比实验,验证了该数据处理方法的可靠性和普适性。     

基于Sobel算子的图像边缘检测及其实现

Sobel算子是图像边缘检测中常用的方法之一,利用像素的左、右、上、下邻域的灰度加权算法,根据在边缘点处达到极值这一原理进行边缘检测。该方法不但产生较好的检测效果,而且对噪声具有平滑作用,可以提供较为精确的边缘方向信息。本文提供了利用Sobel算子实现灰度图像边缘检测的C 源程序。     

An interferometer for use with gauge blocks up to 1000 mm with laser and white-light sources

A displacement interferometer is described for measuring gauge blocks, in which a spatial filter is used to combine a laser beam with a white-light beam, and the length of the block is calculated from the phase differences of the laser signal corresponding to the centers of gravity of the achromatic fringes from the gauge and from the reference plate. __________ Translated from Izmeritel’naya Tekhnika, No. 9, pp. 3–5, September, 2006.     

杨氏双缝干涉实验条纹光强分布

分析了杨氏双缝干涉光强分布,对以前的研究成果进行了分析,并指出其不妥之处,并在此基础上定性地给出了在杨氏双缝干涉中明纹中心不等亮度的原因.     

基于分块技术的相位展开算法

对干涉相位图的相位展开是干涉合成孔径雷达处理过程中的重要步骤,也是干涉合成 孔径雷达理论与应用研究的难点所在.在充分利用干涉相位图中的干涉条纹信息的基础上,提出 了一种基于分块技术的相位展开算法.首先对干涉相位图做了分块处理,块是由干涉条纹线和图 像边界线组成的一个封闭的区域,在一个块内不存在相位跳跃,即在块内的相位展开已经完成. 在下一步对全图做相位展开时,再逐块进行.最后通过后处理技术进行错误校正.通过对真实数 据的实验和与传统方法的比较,证实了算法的有效性和稳定性．     

Alignment control of liquid crystals in a 1.0‐μm‐pitch spatial light modulator by lattice‐shaped dielectric wall structure

We achieved uniform liquid crystal (LC) alignment in lattice‐shaped dielectric walls 1 μm in pitch; this is a prerequisite when driving the individual pixels of spatial light modulators, facilitating the development of practical electronic holographic displays with a wide field of view. In lattice‐shaped dielectric walls, LC alignment becomes unstable, particularly on the bottom and the walls; the LC directors tend to align parallel to the walls. To overcome this problem, we created lattice‐shaped walls featuring partition plates that allow uniform LC alignment. When the plates confine LCs to small regions exhibiting spatial anisotropy, the LC elastic effect and wall anchoring forces align the LC directors parallel to the long anisotropic axis. We found that pixels 0.5 μm × 1.0 μm in pitch formed if the partition plates were sufficiently thick to allow shielding of electric field leakage.