反射光学式位移检测系统

系统由半导体激光器、聚焦镜头、反射式标尺光栅、四裂相指示光栅和光电接收元件组成。该系统具有光学两倍频作用和大光栅副间隙下使用及间隙对莫尔条纹信号调制度不敏感等特点,并且整体结构分离式、小型化和轻型化,在各类精密测量装置和精密加工仪器中将得到越来越广泛的应用。本文介绍这种反射光学式位移检测系统的结构原理,系统特点和应用。     

光电测量系统中衍射及滤波对系统测量精度的影响

分析了以CCD为接收器的光电测量系统在测量过程中光学图象及电子图象信号的形成及传输过程,导出了表达这些过程的数学模型,用简单的矩形波作输入函数,对系统输出的电子图象进行了计算,阐明了图象测量中衍射及滤波的影响,得出图象边缘点处应取的采样电平值,系统各参数对测量精度的影响。     

位相型自聚焦微分滤波器

介绍一种用二元光学方法制作的光学图象微分滤波器，它是由两个频率相近的位相型Ｒｏｎｃｈｉ光栅和离轴型位相菲涅耳波带片的组合而成的。称之为位相型自聚焦滤波器。它具有衍射效率高，光路简单，使用方便等特点。     

自扫描光电二极管阵列光电信号测量系统及其测试实例的研究

本文介绍了一种利用自扫描光电二极管阵列(SSPDA)图象传感器作为光电转换器件,可用于大面积显示器件图象质量评价和测微领域的测量系统。该系统由光学成象、SSPDA图象传感器、数据采集、接口电路和微型计算机等部分组成,能对各种被测量参数进行处理,并打印出数据和曲线。通过对彩色显象管(CPT)的线宽、三束间距以及光学狭缝等的测试,该系统显示了足够的测量精度。     

光电混合MESH互连网络的研究

提出了一种自由空间空分复用的光学MESH互连网络系统。该系统由N×4位相型计算全息付里叶光栅分束器、高速多量子阱空间先调制器SEED器件和高速间接耦合光电探测器列阵组成，具有互连数大、数据通道同步性好、光学硬件少、系统简单等特性。     

重叠体光栅相干组束的耦合波分析

目前基于重叠体光栅的相干组束系统还没有完整的理论模型和参数分析,针对这个问题,本文采用耦合波理论,建立了比较完整的基于重叠体光栅的双光束组束模型,给出了各光束在重叠体光栅内传播的解析解.模型表明,基于重叠体光栅的双光束组束系统其输出光强受两入射光的振幅和位相、体光栅间的相移和折射率调制振幅、光栅厚度,失谐量等多个光学参数的影响.通过数值计算,详细分析了各光学参数对组束结果的影响.最后总结了设计高效重叠体光栅相干组束系统时必须遵循的条件,如必须对光栅厚度进行优化、各光栅的折射率调制振幅必须相同,保证失谐量足够小等.     

光电晶体钽酸锂

光电子学是新兴的技术部门。从光源、光调制、倍频、偏转到接受、信息处理等都需要晶体元件及制造元件的晶体材料。钽酸锂光电晶体是一种铁电材料,具有较好的光电性能。做为调制材料,由于其光学均匀性好,抗光性好,用改变长度比调制电压可得到一百伏以下,是目前已达实用阶段的最好的调制晶体。用其做成的调制器可用于光电通讯,激光大屏幕彩色电视及电开关等。作为压电材料,由于它具有较高的机电耦合系数,在一定方位上频率常数的温度系数为     

分步重复投影光刻机同轴对准系统

对投影光刻机同轴对准系统进行了理论分析，阐述了系统的成象机理和工作过程，并在整机上检测了同轴对准系统的重复精度。该系统在掩模和硅片均刻有对准光栅标记，对光栅衍射后形成干涉信号，使对准信噪比大大提高，并实现了掩模和硅片之间的直接对准，同时利用光弹性调制器组件对光学信号进行了光学调制，由电路实施解调，提供了一种保持高信噪比，又使弱信号探测不降低精度的对准方案。该系统可适用于各种硅片衬底，工艺适应能力强     

SU3型扇型超声显像仪

本文描述的ＳＵ３型扇形扫描超声显像仪为机械探头扇形扫描超声显像仪。仪器 的高速摆动机械探头结构为光电伺服系统，并利用光电信号经过函数变换电路，形 成供扇扫用的正余弦调制信号，得到均匀扇形扫描光栅；仪器采用ＰＮＢ高阻尼压电 陶瓷新材料，改善了近场分辨率。实验纵向分辨率≤１ｍｍ；横向分辨率≤２．５ｍｍ。 仪器经过二个医院的临床使用，对２００多例各种心脏疾病进行检查，均取得满意的结 果。     

高分辨率显示管屏空间特性分析系统设计

介绍高分辨率显示管屏空间特性分析系统。该系统采用ＣＣＤ作为光电转换器，借助于一个结构简单，制作方便，所需驱动率极小的四维移动与定位机构，并利用ＰＣ机进行自动控制和数据处理，光学系统实现自动聚集，对被测管任意位置上的屏空间特性进行测量。本系统可测量线宽，线间距，调制深度，对被测管任意位置上的屏空间特性进行测量。本系统可测量线宽，线间距，调制深度，调制传递函数，空间谐波，光点的亮度分布，光栅畸变等参量     

Adjustable active optical low-pass filter

This paper presents an active optical low-pass filter (AOLPF) capable of changing the resolution of an imaging system on demand in order to remove aliasing noise from a sampling image. This is advantageous over conventional optical low-pass filters, which are fixed image-blurring optical components that are built into the imaging system, in order to remove aliasing in the image. Furthermore, conventional filters smear images regardless of the presence or lack of high spatial frequency, which can exceed the Nyquist limit of the sensor. On the contrary, the proposed AOLPF can dynamically adjust the modulation transfer function of an imaging system to eliminate aliasing artifacts. In addition, this filter can be turned off in the absence of high spatial frequency to maximize resolution and prevent unnecessary blurring of the sampling image.     

Area modulation grating for sinusoidal structure illumination on phase-measuring profilometry

Sinusoidal structured illumination is used widely in three-dimensional (3-D) sensing and machine vision. Phase algorithms, for example, in phase-measuring profilometry, are inherently free of errors only with perfect sinusoidal fringe projection. But it is difficult to produce a perfect sinusoidal grating. We propose a new concept, area modulation, to improve the sinusoidality of structured illumination. A binary-coded picture is made up of many micrometer units. An aperture is open in every micrometer unit, and its area is determined by the value of the sinusoidal function. When such a grating is projected onto an object surface, the image of the grating becomes sinusoidal because of the convolution function of an optical system. We have designed and manufactured an area modulation grating for sinusoidal structure illumination using a large-scale integration technique. The area modulation grating has been used in the high-precision phase-measuring profilometry system, and the phase errors caused by the area modulation grating are reduced to 0.1%. The grating guaranteed the entire measuring accuracy to a 1% equivalent wavelength. The experimental results proved that area modulation grating would be of significant help in improving the phase-measurement accuracy of the 3-D sensing system.     

成像式光栅自准直测角方法研究

针对目前光电自准直仪难以做到既有高分辨力同时又有大的测量范围的不足,提出一种成像式光栅自准直测角方法。该方法将成像式光栅方法、自准直测角技术相结合,利用标尺光栅像和指示光栅形成的光栅副反映被测物体的角度变化。试验结果表明,该系统接收到的光栅信号稳定,满足光栅计数的要求,成像式光栅自准直测角方法原理可行。该方法避免了光栅副间隙带来的误差,具有大量程及较高的分辨力。     

近贴X射线成像系统调制传递特性联合检测方法

利用光学调制传递函数评价原理,在建立了各个成像子系统信号传递关系的基础上,提出了一种近贴式X射线成像光学调制传递特性检测方法。从像增强器约束、射线源约束和噪声约束这3个角度对近贴式X射线成像系统光学调制传递函数进行理论定标。将近贴式X射线成像系统后端的CCD望远系统换成CCD显微系统并对不同空间分辨率的铅栅进行成像与对比度拟合。实验结果表明:时域均衡可以有效提高拟合精度。其拟合结果表明空间分辨率为10线对/mm时其调制传递函数仍有10%,与理论定标结果基本一致。故传统近贴式X射线成像系统的望远光学镜头分辨率才是真正的成像瓶颈。     

基于X射线像增强器成像的相衬滤波模型

对铝、黄铜、不锈钢3种金属材料制作的光栅在不同射线剂量和厚度差异的条件下进行图像采集,结合系统级的联合调制评价模型研究不同材料对X射线的调制作用,结果表明:在相同的射线剂量下,无论哪种材料的光栅,厚度差异越大成像反差越大;在厚度差异相同的情况下,随着射线剂量变化,不同材料对射线的调制能力变化趋势相差甚远。对光学调制传递函数、射线剂量和光栅厚度差异值进行三维曲线拟合,建立物质对X射线的调制模型和采集模型。在像增强器成像模型的基础上提出X射线相衬增强滤波模型,通过对薄膜基准目标源进行图像采集,在噪声环境下对其进行积分滤波处理和相衬增强处理,结果压低了图像噪声的同时也强化了目标轮廓信息,并大幅地增强X射线的成像反差。     

Polarized differential-phase laser scanning microscope

A polarized differential-phase laser scanning microscope, which combines a polarized optical heterodyne Mach-Zehnder interferometer and a differential amplifier to scan the topographic image of a surface, is proposed. In the experiment the differential amplifier, which acts as a PM-AM converter in the experiment, converting phase modulation (PM) into amplitude modulation (AM). Then a novel, to our knowledge, phase demodulator was proposed and implemented for the differential-phase laser scanning microscope. An optical grating (1800 lp/mm) was imaged. The lateral and the depth resolutions of the imaging system were 0.5 mum and 1 nm, respectively. The detection accuracy, which was limited by the reflectivity variation of the test surface, is discussed.     

Optimal implementation of a microspectrometer based on a single flat diffraction grating

An analytical model has been developed and applied to explore the limits in the design of a highly miniaturized planar optical microspectrometer based on an imaging diffraction grating. This design tool has been validated as providing the smallest possible dimensions while maintaining acceptable spectral resolution. The resulting planar spectrometer is composed of two parallel glass plates, which contain all components of the device, including a reflective slit and an imaging diffraction grating. Fabrication is based on microelectromechanical system technology and starts with a single glass wafer; IC-compatible deposition and lithography are applied to realize the parts in aluminum, which makes the microspectrometer highly tolerant for component mismatch. The fabricated spectrometer was mounted directly on top of an image sensor and takes up a volume of only 50 mm(3). The measured spectral resolution of 6 nm (FWHM) in the 100 nm operating wavelength range (600-700 nm) is in agreement with a model calculation.     

光电跟踪测量系统的动态成像分辨率分析及优化设计

光电跟踪测量系统的测量精度与成像质量受成像系统动态分辨率的影响.成像系统动态分辨率受光电跟踪测量系统跟踪精度的影响.分析与试验表明,光电跟踪测量系统的动态成像分辨率主要取决于静态分辨率和跟踪精度;工作过程中的光电跟踪测量系统的动态成像分辨率比光电跟踪测量系统的静态成像分辨率低;与传感器的积分时间相比,高频目标与低频目标对动态成像分辨率的影响模型不同;在传感器积分时间、目标的运动状态及对动态分辨率要求确定的条件下,可对静态成像分辨与控制系统进行优化设计.     

畸变测量中应用窗口傅里叶变换载频条纹分析

为了测量光学成像系统的径向畸变,提出了基于伸缩窗口傅里叶变换空间载频条纹相位分析的测量新方法.畸变分布测量转化为调制相位测量.首先,将纵向朗奇基准光栅作为模板,通过成像系统成为变形光栅即畸变像.接着采用伸缩窗口傅里叶变换提取畸变载频光栅条纹中心无畸变点的基频和相位信息,获得理想无畸变像的基频成分,然后对变形载频光栅条纹进行频谱分析,滤波提取基频信息、逆傅里叶变换、相位解包,提取径向调制相位分布,计算畸变图像的径向位置畸变分布.最后利用该径向位置畸变分布规律和双线性插值灰度重建对畸变图像进行校正.详细的理论分析和实验结果证明,该方法是可行的.     

Agile dual-channel spectral imaging with spectral zooming

A dual-channel spectral imaging system with agile spectral band access and spectral bandwidth tuning capability is presented. A diffractive grating and an acousto-optic tunable filter (AOTF) are respectively used as spectral dispersion and spectral filtering elements for the two channels. A 4f spectral filtering channel using an adjustable slit is set up at the first diffraction order of the grating to realize coarse spectral band selection. The AOTF selectively filters the spectrum of the nondispersed zero order to realize fine spectral imaging. The spectral zooming function is achieved without increasing spectral frame number facilitating real-time spectral imaging operation. Feasibility of the spectral imaging has been demonstrated through preliminary experiments. Minimum 6 nm spectral resolution and 1.2 degrees field of view have been achieved. The real-time spectral imaging capable of wide spectral band operation without loosing desired fine spectral capability is particularly useful for a variety of defense, medical, and environmental monitoring applications.