用低精度CCD获得高精度测量方法的研究

为了大幅提高线阵CCD的测量精度,提出了一种全新的CCD使用方法。该方法是将N个像元间距为H的线阵CCD器件许排组合住一起,并沿像元线性分布方向以距离为H/N依次均匀错开排列。多个线阵CCD的感光电信号经多通道模一数同步采集,保存到存储器中指定位置。然后,通过对所有CCD测量数据的分析计算来获得精确的测量值。分别采用单CCD和双CCD错排对长为30mm,直径为5．000mm、8．000mm、12．000mm的三个标准杆件的直径进行了测量。结果表明,蚁CCD错排可获得两倍于单CCD的测量精度。该方法可从理论上彻底打破CCD像元问距的限制,并使线阵CCD的测量精度大幅度地提高。     

用二次成像法测量透明玻璃板的折射率

介绍了用二次成像法测定透明玻璃板折射率的原理和方法.由于采用线阵光电耦合器件(CCD)测量,提高了测量精度.     

基于面阵CCD的瞬态光谱检测方法研究

针对瞬态光谱检测中对CCD线扫描速度要求高的特点,提出一种基于面阵CCD的瞬态光谱检测方法。该方法通过改变面阵CCD的电荷转移方式,以实现基于面阵CCD的高速线扫描。为了探究此方法的可行性,初步通过改变线阵CCD的电荷转移方式,建立了基于线阵CCD的单点超快探测系统。在发光二极管(light emitting diode,LED)光脉冲探测实验中,系统分别工作在单点超快探测模式和正常模式下。测试结果表明,基于线阵CCD的单点超快探测方法是可行的,单点探测速率可达20MHz。从而在理论上证明,通过改变CCD电荷转移方式以实现基于面阵CCD的瞬态光谱检测也是切实可行的。     

高分辨率光谱仪线阵CCD采集系统设计

为了满足高分辨率光谱仪高灵敏度、高分辨率、低噪声的技术要求,设计了用于微光成像系统的背照式CCD驱动电路及主控电路。线阵CCD采集系统采用Altera公司的MAX X系列FPGA作为核心控制器件,为线阵CCD提供多路驱动信号;线阵CCD探测器输出模拟信号经过信号预处理及AD采样,变换为数字信号后通过USB接口模块发送给光谱仪。通过将线阵CCD采集系统安装到高分辨率光谱仪,对汞灯谱线进行特征峰测试,光谱分辨率可以达到0.062 nm,满足高分辨率光谱仪的探测要求。     

线阵CCD的调制传递函数

线阵CD作为成像器件得到了日益广泛的应用,因而研究线阵CCD的调制传递函数MTF显得非常必要和重要。本文分析线阵CCD动态MTF及静态MTF,并对其影响因素进行讨论。     

一种低成本线阵CCD驱动与数据采集处理系统的研究

探索了一种在低成本下实现线阵CCD输出信号快速采集以及与PC通信的方法。讨论了线阵CCD系统的整体结构及工作流程。采用VHDL语言编写了驱动程序,实现了CCD的正确工作。利用DSP实现了对下位CCD的控制,在控制程序中利用"乒乓原理"实现了线阵CCD的数据采集,并同时给PC快速上传数据。基于Visual C++6.0平台编写了PC机控制软件,实现了对硬件电路的控制和对CCD输出信号的分析处理。     

透明管径及管厚的CCD成像在线测量方法

应用光线透过透明管径的折射规律,提出线阵CCD成像在线测量透明管状外径及壁厚的新方法。该方法用计算机进行模拟导出了数理模型。实验证明了这一方法的可行性,为透明管状产品的批量生产、高速、动态、非接触实时在线测量提供了一条新的技术途径。     

用正交线阵CCD实现高精度小圆孔自动测量

提出了一种使用线阵CCD自动测量小圆孔参数的方法。该方法充分利用了线阵CCD分辨率高的特点 ,适当的光学设计使两个线阵CCD正交 ,通过测量小圆孔的夫琅和费衍射条纹 ,实现了小圆孔半径的一维参数高精度自动测量和圆度误差的二维参数定性自动测量。该方法具有一定的实用价值及应用前景。     

双线阵CCD光学拼接与误差分析研究

基于线阵CCD的图像测量技术是当前工程应用中的一个重要领域,针对当前高精度大动态范围测量和标准线阵CCD测量范围及线阵CCD几何结构之间的矛盾,提出了一种高精度大范围的线阵CCD测量拼接方案。利用半反半透镜平面反射原理设计了双线阵CCD高精度拼接的光学拼接系统的光机结构原理,给出了重叠像元的标定原理,对其标定和拼接误差进行了分析。通过拼接系统的实验室长期实验结果表明:方案拼接简单,实用可靠,系统的整体拼接误差约为0.019mm,且拼接不存在漏缝现象,拼接精度满足高精度测量的要求。拼接方案对高精度、大动态范围CCD测量实际应用有一定的参考意义。     

线阵CCD在声光调制实验中的应用

用线阵CCD代替可移动的光电二极管,改进了声光调制实验。将声光调制的入射光和衍射光投射在线阵CCD上,线阵CCD的信号输出由数字示波器显示,利用数字示波器的＂光标＂功能测出光斑的距离。改进后,使测量变得简单快捷,提高了实验效率,并减小了实验测量误差。     

Double transmission-mediums based geometric phase analysis for determining the two surface profiles of transparent object

The accurate measurement for the surface profiles of transparent object is of significance for quality control in optical devices and precision instruments. Here, a double transmission-mediums based geometric phase analysis method has been developed to evaluate both the upper and lower surface profiles of transparent object. To do this, the tested transparent object is placed above a preprinted lattice pattern. When viewed from above with a CCD camera, any slope variations of the surfaces will lead to distortions of the transmission-lattice patterns. And when changing one side of object’s contact medium, the lattice virtual image with modulated phase is distorted once again. Combined with the derived relationship between phase variations of transmission-lattice patterns and out-of-plane heights of two surfaces, the double-sided surface profiles of transparent object can be reconstructed successfully. With this, the technique, which is verified experimentally, is demonstrated to be a feasible and reliable method. The advantage of this method is that it simplifies the setup and allows a fast estimation of the geometry of a transparent specimen. The double-sided profiles can be decoupled easily according to the big difference of refractive indexes between contact mediums. And the calculation accuracy can be guaranteed by the weighted average from four directions.     

杨氏模量的光学测量

以光的等厚干涉原理为基础(1),用读数显微镜和砝码测量透明介质的杨氏模量,并用CCD显像技术提高了读环精度。在用钠光灯作为光源的同时,探索了氦—氖激光用于实验操作时的现象(3)。     

基于数字图像相关的透明材料厚度测量

提出了一种测定透明材料厚度的新方法。该方法是基于透明材料对光的折射特点,利用光斑点面内位移与材料厚度的变化关系,将厚度的测量转化为对面内位移的测量。将此方法与数字图像相关法相结合,实现了单摄像机对厚度的测定。对轴向拉伸状态下的有机玻璃板的厚度变化进行了测定,将实验结果与理论值进行了对比,两者符合较好,证明了该实验方法的有效性和可行性。     

利用线阵CCD测定液体折射率

采用几何光学与波动光学相结合的方法,利用CCD图像测量技术实现了透明液体折射率的自动化测量.     

测量透明管壁厚的理论研究

透明管（如玻璃管）壁厚几何尺寸的公差大小是玻管生产中产品质量优劣的重要指标之一;因此透明管的壁厚测量的精度尤为重要。根据光矢量场的电磁场理论仔细分析了透明管在平面光波中的透射和反射的光学特性;并研究其能量分布。用ＣＣＤ作接收器件,进行非接触测量实验系统实验,将理论值与实验值相比较,提出了精确测量透明管壁厚的可行性方法     

Optical refractometry based on Fresnel diffraction from a phase wedge

A method that utilizes the Fresnel diffraction of light from the phase step formed by a transparent wedge is introduced for measuring the refractive indices of transparent solids, liquids, and solutions. It is shown that, as a transparent wedge of small apex angle is illuminated perpendicular to its surface by a monochromatic parallel beam of light, the Fresnel fringes, caused by abrupt change in refractive index at the wedge lateral boundary, are formed on a screen held perpendicular to the beam propagation direction. The visibility of the fringes varies periodically between zero and 1 in the direction normal to the wedge apex. For a known or measured apex angle, the wedge refractive index is obtained by measuring the period length by a CCD. To measure the refractive index of a transparent liquid or solution, the wedge is installed in a transparent rectangle cell containing the sample. Then, the cell is illuminated perpendicularly and the visibility period is measured. By using modest optics, one can measure the refractive index at a relative uncertainty level of 10(-5). There is no limitation on the refractive index range. The method can be applied easily with no mechanical manipulation. The measuring apparatus can be very compact with low mechanical and optical noises.     

Shadowgraphy and interferometry using a CW laser and a CCD of alaser-induced plasma in atmospheric air

We present a new application of a charged coupled device (CCD), where a continuous-wave (CW) laser is used as a probe beam in shadowgraphy and interferometric diagnosis of transparent media where the refractive index varies in time. The time resolution is obtained by gating the CCD. This configuration has the advantage that the temporal resolution of both techniques can be changed according to the evolution of the process under study and no stability setup is required, as usual, in CW interferometric techniques. We applied this method to the diagnosis of a laser induced plasma (LIP) in air measuring the evolution of plasma, shock wave, electron density, and hot core air expansion from the ns to the ms time scale     

Non-contact scanning measurement utilizing a space mapping method

In this study, a novel approach to a measuring methodology and calibration method for an optical non-contact scanning probe system is proposed and verified by experiments. The optical probe consists of a line laser diode and two charge-coupled device (CCD) cameras and is placed on a computer numerical control (CNC) machine to measure the workpiece profiles. A space mapping method using the least-squares algorithm is presented for the probe calibration and profile measurement. This method provides a simple and accurate calculation of the relationship between the real space plane and its related image space plane in a CCD camera. A transparent grid with regularly spaced nodal points is used to construct the space mapping function. The space coordinate of an object can be obtained from its image in the CCD camera via the mapping function. The measured profile data are smoothed by the B-spline blending function and can be transferred to a CAD/CAM package for industrial applications. Experimental results show that this technique can determine the 3-D profile of an object with an accuracy of 60 μm.