激光透射成像法测量石英管的外径与壁厚

为了同时同位测量石英管的外径和壁厚,建立了激光透射成像系统,对系统测量原理进行研究。基于几何光学和菲涅尔公式,分别导出平行光垂直照射石英管后的透射光线偏向角、相对光强与入射光线离轴距离之间的关系;通过数值计算,分析了偏向角、相对透射光强随入射光线离轴距离的变化特点;针对物方远心光路,分析了光阑对偏向角和相对光强的限制;基于CCD成像原理,通过引入标定系数和补偿因子,导出石英管外径与壁厚的计算公式。实验结果表明:外径绝对误差和相对误差的平均值分别为0.119mm和0.91%,壁厚绝对误差和相对误差的平均值分别为0.153mm和6%。     

多程放大器光束空间分布的优化设计

This paper focuses on measuring straightness of large-scale dimension by using laser diode fiber alignment, diffraction imaging technique and a CCD camera. In this method, we use a laser diode fiber alignment beam as the datum reference of straightness, deviation of the measured from this datum, can be detected by a CCD camera directly. Also a novel image processing algorithm is presented. The experiment result shows that the measurement range of L (m), the measurement accuracy of the system is 3+2.3×10-6L(\mm).     

Measurement of diameter of metal cylinders using a sinusoidally vibrating interference pattern

A method for measuring external diameters of metal cylinders is proposed in which a sinusoidally vibrating interference pattern (SVIP) of 100-μm period is used as an exact scale. Lights from the end-points of a metal cylinder are extracted with a spatial filtering in an imaging system to form a cross-sectional image of the metal cylinder. On the image a sinusoidally phase-modulated signal owing to the SVIP is detected with a CCD image sensor to measure the phases of the SVIP at the two end-points of the cylinder. The coordinates of the two end-points are obtained from the phases at the two end-points, the phase distribution of the SVIP, and the coordinates of the pixels of the CCD image sensor. Metal cylinder diameters of 7.99, 8.00, and 9.00 mm are measured along their length directions with an error less than 1 μm.     

体视显微镜与CCD成像系统在高阶贝塞尔光束光斑测量中的应用

主要对光学测量仪器体视显微镜与CCD成像系统在高阶贝塞尔光束光斑测量中的应用进行分析,通过以非相干LED绿光经过螺旋相位板和轴棱锥产生的高阶贝塞尔(Bessel)光束为例,模拟出沿轴向不同距离处的截面光强分布图,并与相应的实验参数(如:最大无衍射距离、中心暗斑直径等)进行比较。实验结果表明,体视显微镜与CCD成像系统的测量结果相吻合,但是体视显微镜测量误差较大会影响测量结果的准确度。     

利用激光三角测距法提高三维面型检测精度的方法

本文首先介绍了根据激光三角测距原理并采用片光照明、面阵ＣＣＤ接收的三维面形检测原理，其优点在于物面相对于测量头仅需一个方向移动即可完成二维扫描，使测量系统结构简单、便于控制。其次分析了影响其测量精度的几个主要因素，即散斑噪声、接收器件本身的分辨率、投影片光束的宽度与稳定性。散斑噪声造成了投影光斑的抖动，ＣＣＤ的分辨率限制了测量系统的分辨率，而片光束的质量影响着ＣＣＤ光敏面上像斑的准确定位。针对其各自的特点给出了相应的解决途径。     

基于全场干涉测量方法的透镜三维轮廓测量

为了满足高精度透镜加工工艺的要求,设计了一套基于全场干涉测量方法的透镜三维轮廓测量系统。已标定的透镜三维轮廓测量系统利用分布式反馈激光二极管对透镜进行波数扫描,对CCD相机采集到的干涉图像依次进行随机采样傅里叶变换和解卷绕算法,最终通过计算得出透镜的三维轮廓数据。实验结果表明:该系统横向和纵向的分辨率均为0.011 3 mm/pixels,深度方向的测量均方根误差为±19.8 nm。系统结构简单、稳定性高,对透镜没有任何接触,不会对透镜表面造成损伤,适用于透镜的高精度轮廓测量。     

全视角高精度三维测量仪光学系统误差分析研究

大视角、高分辨率、低畸变光学成像系统是全视角高精度三维测量仪中最为关键的核心器件。现有三维测量仪实际使用过程中不可避免会产生各种误差,因此科学合理地评估和降低全视角高精度三维测量仪的测量误差具有十分重要的科学及工程应用意义。通过多角度、全方面分析定量研究了相机内方位元素标定误差对几何定位误差的影响,以及相机光学系统MTF分析、点扩散函数分析、波像差分析和公差分析对匹配误差产生的影响。研究结果表明,在各种影响三维测量仪光学成像系统测量误差的因素当中,相机的传递函数是影响系统三维定位误差最主要的因素,当系统MTF_N值大于0.4 lp/mm、系统几何畸变小于1个像素,PSF能量集中在以3 μm为半径的圆环内(小于1个像素),且PSF峰值达到了0.9时,三维测量仪的定位误差可达到秒级精度。     

Enlarging lens design with f-Θ lens for real time laser lithography inspections

An enlarging lens, composed of a charge-coupled-device (CCD) lens and an f-Θ lens, has been designed for real time laser lithography visual inspection purposes. The object of this design is to enlarge the image of the working specimens in real time, which used to be done by an independent magnifying system after the lithography process. F-Θ lens has both roles in this design, being a laser lithography lens and a specimen imaging lens. A beam splitter has been inserted between the f-Θ lens and the CCD lens, which divides the UV laser beam and the visible beam to form a coaxial system. This design also reaches the image requirements in both wavelength bands, that the value of MTF is nearly diffraction-limit in UV wavelength and greater than 0.45 at 40 c/mm in visible wavelength.     

HLSⅡ干涉法测量储存环横向尺寸与发射度

为了满足合肥光源升级改造后测量小束流尺寸的需求,设计了干涉法测量束团尺寸与发射度系统。简要介绍了在可见光波段利用干涉法测量束团横向尺寸的原理,详细介绍了该系统的光路与软硬件系统和图像处理算法。为了消除CCD的本底噪声对测量的影响,建立了本底噪声图像与束流流强的查找表,最终得到了多束团模式下的在线实验结果。测量得到的水平尺寸为265μm,测量误差为5.78μm;垂直尺寸为114μm,测量误差为4.89μm。     

光纤干涉成像阵列全息相位校正研究

针对光纤传输和干涉成像阵列中的相位误差, 提出了一种基于特殊光子晶体的全息相位校正方法。首先分析了光纤干涉阵列成像的基本原理和相位信息的传输过程, 以一维线性阵列建立成像系统相位误差模型, 通过对参考光束和探测器前的快门交替打开和闭合, 来分别实现在晶体上写入由光纤阵列的出射光束与参考光束干涉形成的含有相位误差的光栅函数, 和光纤中出射光束被该光栅衍射和相位偏移以消除相位误差, 从理论上分析了上述基于光子晶体的全息法相位校正原理。最后采用所建立的含有相位误差的干涉阵列进行成像仿真, 对未加校正、采用本文方法和采用冗余基线校正的结果进行了对比分析。     

公共诊断搭载平台双CCD交汇瞄准系统

 CCD交汇测量作为一种非接触式坐标测量技术,在对空间目标进行坐标定位的应用中显示出其独特的优越性。建立公共诊断搭载平台双CCD交汇瞄准系统模型,设计了瞄准成像系统和瞄准调节系统,其中瞄准光学系统物高8 mm,物方分辨率8.3 μm,在61 lp/mm时MTF高于0.5,瞄准调节系统采用双脚万向节机构,完成系统二维指向的调节,通过对采集视频图像的处理,为搭载的诊断设备提供精确的指向。误差分析结果表明：该系统的瞄准精度可以达到16 μm,可安装在公共诊断搭载平台前端。     

基于线阵CCD的运动板材边缘检测方法

研究了一种利用线阵CCD的图像快速采集功能对运动板材边缘进行检测的方法。该方案用平行光投射系统来照明,采用一片AVR单片机驱动CCD工作并对测量结果进行处理,有效地简化了硬件结构。介绍了一种CCD输出信号的处理电路及其二值化原理,并给出了系统硬件、软件设计方案。实验证明:该方案的测量精度可达到0.03mm,响应时间少于2ms。     

光束指向稳定性高精度检测方法研究北大核心CSCD

光束指向稳定性是高能激光应用研究中的一项关键指标,光束指向稳定性的检测是高能激光系统性能实现的重要环节。以长焦距聚焦反射镜与高分辨率CCD(charge coupled device)为主要元件,构建高精度的光束指向检测装置。采用灰度重心法定位光斑中心,并以理想光斑与实测光斑为例进行验证,误差小于1个像元。利用CCD高频采样,统计单位时间内光斑中心位移,获得光束指向稳定性指标,检测实例精度可达1.25μrad。该方法简便易行,测量精度高,适用于各种波长的激光光束指向检测以及其他相关参数的测量。     

基于AOTF成像光谱精密测量技术的研究

声光可调滤波器(AOTF)作为光谱成像的一种新型分光元件,在运用其进行成像光谱时,一般选择入射光垂直于AOTF入射面时所对应的衍射中心波长为CCD的光谱测量波长。但在实际测量中,空间目标不同位置的光线总是以不同的角度进入到AOTF,这样就导致了CCD实际测量的光谱和以光垂直入射时所对应的光谱为测量光谱相比出现误差,影响了光谱的测量精度。采用的成像光谱系统的特点是目标光线经前置光学系统、AOTF和成像透镜后,聚焦成像于透镜的焦平面上,实现了目标光在整个系统的一次成像。此一次成像与传统的二次成像相比,能够有效的提高光能利用率和成像质量。由于AOTF的视场角为±3°,所以通过对AOTF视场角范围内衍射中心波长随入射角度变化的实际规律进行了分析研究,并对衍射波长随入射角度变化的实际测量值进行了拟合修正,得到了修正方程。实验结果表明用修正后的方程进行光谱测量,其相对误差值可以减小一个数量级。此方法可为今后提高AOTF成像光谱测量精度奠定基础。     

3D laser scanner system using high dynamic range imaging

Because of its high measuring speed, moderate accuracy, low cost and robustness in the industrial field, 3D laser scanning has been widely used in a variety of applications. However, the measurement of a 3D profile of a high dynamic range (HDR) brightness surface such as a partially highlighted object or a partial specular reflection remains one of the most challenging problems. This difficulty has limited the adoption of such scanner systems. In this paper, an optical imaging system based on a high-resolution liquid crystal on silicon (LCoS) device and an image sensor (CCD or CMOS) was built to adjust the image's brightness pixel by pixel as required. The radiance value of the image captured by the image sensor is constrained to lie within the dynamic range of the sensor after an adaptive algorithm of pixel mapping between the LCoS mask plane and image plane through the HDR imaging system is added. Thus, an HDR image was reconstructed by the LCoS mask and the CCD image on this system. The significant difference between the proposed system and a traditional 3D laser scanner system is that the HDR image was used to calibrate and calculate the 3D profile coordinate. Experimental results show that HDR imaging can enhance 3D laser scanner system environmental adaptability and improve the accuracy of 3D profile measurement.     

Straightness Measurement Using Laser Diode and CCD Camera

１ＩｎｔｒｏｄｕｃｔｉｏｎＩｎｍａｎｕｆａｃｔｕｒｅａｎｄａｓｅｍｂｌｅｏｆｍｏｄｅｒｎｍａｃｈｉｎｅｓａｎｄｉｎｓｔｒｕｍｅｎｔｓ，ａｎｉｎｄｉｓｐｅｎｓａｂｌｅｒｅｑｕｉｒｅｍｅｎｔｉｓｔｈｅｃｏｎｔｒｏｌｏｆｆｏｒｍａｎｄｐｏｓｉｔｉｏｎｅｒｏ...     

Full field deformation measurement of centimeter sized objects using optical phase retrieval

Most papers in the field of optical phase retrieval either consider only the intensity (or amplitude) profile of the object under inspection (or scatterer location in the X-ray version), or a uniform tilt/rotation of the object beam. However, phase retrieval is able to recover the phase profile of the object (beam) as well, which theoretically makes the observable interference of phase retrieved object waves possible. In this paper we demonstrate this principle experimentally on centimeter sized deformable reflective objects (as large as 40 mm by 40 mm) and corresponding simulations are also presented. When the CCD camera is moved along the optical axis in the Fresnel region, the interference fringes of the displacement field have low contrast. On the other hand, when an imaging setup is built, and the camera moves near the image plane, high fringe contrast can be obtained. These fringes however suffer from some phase error. In our work the iterative modulus projection algorithm was used as a simply implementable phase retrieval method.     

Measuring principle of vertical target density based on single linear array CCD camera

In consideration of the complexity and the high cost of the dual CCD intersection vertical target when it is used indoor. A novel measuring principle of one linear array CCD camera vertical target is presented. One low-power semiconductor sector-like laser with projection board is used to be the lamp-house of the CCD camera. The detection light screen of the CCD camera and the laser lamp-house are adjusted to same plane. When the projectile through the detection light screen, it blocks the part light of the laser and leaves a shadow of projectile on the board. The shadow and its coordinate are acquired and calculated by the CCD camera and computer, and the projectile coordinate of X and Y can be gotten through image processing and further calculation. The measuring principle and the formulas are given, and the measuring error is analyzed. The result indicates that the coordinate error of X and Y less than 1.5 and 2.2 mm, respectively, when the detection light screens is 1 m × 1 m, The principle presented has the advantages that measurement principle is simple, low cost and easy engineering.     

基于测量最小可分辨对比度的CCD相机成像质量的评价

针对评价CCD相机成像质量MTF方法的缺点,引入了最小可分辨对比度MRC这个评价指标,并研制了相应测量MRC的系统.在这个系统中采用两个重叠积分球分别对靶标的正反两面照明,通过改变这两个积分球的亮度就可以获得可变的对比度.实验结果表明：测量MRC系统测量亮度的误差可控制在±0.3cd/m2以内; CCD相机的MRC随着空间频率的增加而增加;测量CCD相机的MRC是评价CCD相机成像质量的一种快速有效的方法.     

单线阵CCD相机双激光器立靶测量系统误差分析

为提高单线阵CCD相机双激光器立靶测量系统的坐标测量精度,为系统设计提供理论和实验依据,对系统测量误差进行了理论分析,在建立系统数学模型的基础上,推导了系统测量误差公式,采用Matlab软件对测量误差进行了仿真,获得了各误差影响因素对着靶坐标测量误差影响的大小和趋势,以及1 m×1 m靶面内的误差分布,并通过模拟实弹实验对误差分析结果进行了实验验证,实验结果表明,x坐标测量误差的标准差σ_x为4.1 mm,y坐标测量误差的标准差σ_y为10.2 mm,模拟实弹实验坐标测量误差与理论分析结果一致。