光学3D坐标测量技术研究

研究了光学坐标测量系统三维精密视觉测量方法,对其核心技术:数字成像器件模型及标定方法、辅助靶标技术以及高精度亚象素图像处理算法进行了深入的讨论,并提出了详细的解决方法.经实验证明,这些方法切实可行,达到了所要求的精度,从而为光学坐标测量系统的设计提供了可靠依据.     

高转速标准装置研究与建立

研究建立了高转速标准装置,在转速范围30000～100000r/min内,实现了基于直流无刷空心杯微电机和FPGA转速控制的高精度转速的发生,分辨力1r/min,装置校准不确定度1×10-5,k=3。介绍了装置的结构组成和解决的关键技术问题,描述了双闭环控制的策略,给出了校准的实验数据。高转速标准装置是光电转速测量仪和高精度转速表在30000r/min以上量程有效溯源的重要计量标准装置。     

Optical imaging of dose distributions in Fricke gels

Ferrous-sulphate infused gels, or 'Fricke gels', encounter great interest in the field of radiation dosimetry, due to their potential for 3D radiation dose mapping. Typically, magnetic resonance (MR) relaxation rates are determined in these systems in order to derive the absorbed dose. However, when large concentration gradients are present, diffusion effects before and during the MR imaging may not be negligible. In these cases, optical techniques may represent a viable alternative. This paper describes research aimed at measuring 3D dose distributions in a Fricke-xylenol orange gel by measuring optical density with a CCD camera. This method is inexpensive and fast. A series of early experiments is described, in which optical density profiles were measured with a commercial microdensitometer for film dosimetry. The light box of the device was modified to work at 567 nm, close to the maximum absorbance of the ferric ion-xylenol orange complex. Under these conditions, the gel shows linearity with dose and high sensitivity.     

Adaptive systems in speckle-pattern interferometry

The concept of adaptivity in television holography is discussed, and various realizations of adaptivity are presented. In one possible variation, functions of the components of the optical arrangement may be changed to adapt them to measurement conditions. An additional peculiarity of the technique is that reference waves are produced by holographically reconstructed virtual images. A method, believed to be new, is introduced for synthesizing the phase front of the master object beam that is produced by a simple holographic optical element and is used as a smooth or a speckled reference beam in the electronic speckle-pattern interferometer. An adaptive interferometer is presented as a measuring device for various measuring tasks. Selected applications are shown, demonstrating different aspects of adaptivity.     

基于静力称重法的微小容量光学检测系统标定

实验室常用静力称重法对微量液体容量进行检测,该方法在1μL容量的精确度达到2.18%,重复性为1.85%,但该方法无法在实验室外进行。现有的光学测量微量液体容量法的在1μL的精度为6.09%,重复性为1.31%。该法可实现在线检测,但其精度不如静力称重法。对光学测量微量液体容量的方法进行研究分析,提出了一种新的标定容量参照标准的方法,该标定方法将静力称重法与光学测量法两者结合,以静力称重法容量测量结果为参照标准,代替光学法原先的标准液。新的标定方法在原理上将参照标准由点扩展到线,可将光学测量法在10μL点的精度提高到2.014%,重复性1.30%。     

激光干涉仪在纳米测量中的典型应用

激光干涉仪具有测量分辨力高、测量结果可溯源等优点,在纳米测量中的应用日益广泛。介绍纳米测量机和低膨胀材料线膨胀系数测量装置中应用的迈克尔逊型激光干涉仪以及在高准确度位移测量装置中应用的法布里-珀罗型激光干涉仪,并结合这些实例对激光干涉仪光学系统设计、测量环境控制、迈克尔逊干涉仪非线性误差补偿以及法布里-珀罗干涉仪量程扩展等方面的关键问题进行分析和总结。所述原则和方法对实现纳米级测量准确度具有重要意义,可为高准确度激光干涉仪的研制及其在纳米测量中的更广泛应用提供技术参考。     

平衡式干涉仪的光学系统设计

介绍了两种平衡式干涉仪的光学系统设计方法,分别给出了用于单端测量和双端测量的具体设计方案.由于采用的平衡式光学系统中测量光束和参考光束具有近似相等的光程长度和相似的路径,其光程差仅由被测件的长度或被测表面与测量参考镜之间的距离而引起,因此干涉仪具有很高的稳定性.用双端测量双光程平衡式干涉仪对准零长度试样进行测量,在185 h测量中所得数据的标准偏差为2.1 nm.     

Asphere testing with a Fizeau interferometer based on a combined computer-generated hologram

Fizeau interferometers with an additional diffractive optical element are frequently used for measuring spherical and aspherical surfaces. We present a new (to our knowledge) optical test method, in which the Fizeau principle is now perfectly fulfilled by generating reference and measuring wavefront on the last optical surface, which carries a diffractive optical element. This method has been examined experimentally by testing a reference f/0.68 spherical mirror and can be applied identically for testing aspheres. Several advantages of this method are discussed and proved experimentally.     

标准测氡仪的量值溯源方法研究

研究了利用氡活度绝对测量装置制备高准确度标准氡源的方法,得到了活度扩展不确定度为0.8%(k=2)的量传用氡源。依据计算标准氡体积活度的基本原理,对用于氡源活度量传所配套的小氡室的有效体积进行了校准,其有效体积的扩展不确定度为0.46%(k=2),对一般氡标准装置(标准氡室)所用的参考仪器(AlphaGUARD型标准测氡仪)进行校准,得到其平均体积活度响应为1.01,体积活度响应的扩展不确定度为3.2%(k=2)。     

Determination of the linear equations of position-sensing detectors for small motion measurement systems

Small motion measurement systems are widely used in industry measurement fields to measure small positional/angular motions. These systems usually consist of two parts: a measuring assembly and a reference assembly. The position-sensing detectors (PSDs) are embedded in either measuring assembly or reference assembly to sense the variations of laser light incidence points when there are any small positional/angular motions. To use these systems, it is necessary to determine the linear equations of PSD readings, which relate the six-degrees-of-freedom small positional/angular motions and PSD readings. The purpose of this paper is to derive these equations based on the paraxial raytracing method. Two measurement systems are used as illustrative examples to validate the proposed methodology. The methodology of this study will be useful for system design of PSD-based measurement systems and their applications.     

Optical resonant ultrasound spectroscopy for fluid properties measurement

The properties of fluids are studied using unusually small containment spherical resonators. Proper identification of resonant fluid signatures allows determination of pressure and density of the internal gas with great accuracy using an appropriate equation of state (EOS). Low noise and high sensitivity detection of vibration are critical parameters to characterizing the contained gas when its pressure approaches 1 atm. or less. The benefits of using spherical resonators to determine fluid properties are discussed, and some example calculations of sound speed are presented. In addition to measuring fluids, a comparative experimental approach is taken to explore and, eventually, to optimize vibration detection. In the experiments, two detection methods, a contact piezoelectric transducer (PZT) device and a non-contact optical device, are compared simultaneously and quantitatively. This is done in a unique manner without change in vibration coupling to the sample between tests. A commercially available resonant ultrasound spectroscopy system is used as the contact system, while another commercial device (used as the non-contact vibration detector) combined with the same excitation source (used in the contact system) comprises the other system. The non-contact detector is an optical interferometric receiver that provides adaptation to optically rough surfaces and high sensitivity to acoustic displacements through optical interference in photorefractive GaAs. Both vibration detection systems are compared with particular emphasis on displacement sensitivity, frequency response, and noise level. Furthermore, the results from comparing detection modalities are presented, and their effects on fluid properties measurement are discussed     

使用位敏探测器PSD的焦面检测方法

本文介绍一种新的焦面检测方法,以位置敏感探测器PSD作为检焦器件对光学系统的实际焦面进行检测。该方法原理简单、处理快速方便、检测精度较高,特别适用于对透镜截距的测量和胶片摄影系统的精密调焦。还讨论了使用PSD测量先学系统其它参数的方法以及影响PSD测量精度的主要因素。文中还将PSD与CCD等器件做了一些比较,充分肯定了PSD驱动电路简单、处理速度快和分辨率高等优点。     

Device for measuring the angle of turn of an object with respect to a reference direction

The described device is protected by an Author's Certificate. A distinctive feature of this device is the possibility of measuring two angles of turn in planes containing the reference direction specified by a laser beam. Expressions are given for estimating the measurement accuracy. The device is quite universal and can find applications in various information measuring systems, and after certain refinements also in automatic control systems.Translated from Izmeritel'naya Tekhnika, No. 9, pp. 33–34, September, 1994.     

滚动轴承滚针直径测量结果的不确定度评定

在立式光学计上测量滚动轴承滚针直径,利用量块尺寸作为标准,将测量装置调整为零位,然后测出滚针与量块标准尺寸的差值,求出被测滚针的直径尺寸。分析了温度误差、测量力误差、示值误差、标准量块极限误差、测量重复性和测量装置定位误差等对测量装置不确定度的影响,并给出了相应的不确定度的计算公式。     

一种用于线膨胀系数测量的高稳定性激光干涉系统

介绍了一种可以对材料长度变化进行测量的高稳定性双光程激光干涉系统,由于该干涉系统的测量光路和参考光路具有相似的传播路径,光程差仅由被测试样的长度引起,干涉系统具有较强的抵抗环境温度变化和振动等外界干扰的能力。通过平晶反射膜测量试验,对干涉系统的稳定性进行了验证,结果表明在6. 5 h内测量数据的标准偏差为4. 2 nm。该激光干涉系统可用于材料尺寸变化(如线膨胀系数)的高准确度测量。     

反射式灰阶测试卡测量装置及方法研究

为解决评价摄影图像质量用反射式灰阶测试卡的量值溯源问题,利用实验室现有测试仪器搭建了光学测试平台,并提出了一种简单、可行的测试方案。在卤素灯光路侧加装平行光管作为光源,采用双轴步进电机和基于PCI接口的微机内置式PCI试验卡,实现45°/0°转角系统自动控制。选用光谱分光辐射度计作为接收单元,用已知标准值的标准白板做标准,采用相对测量法,实现反射式光密度无接触测量。实验数据分析表明:用该装置测量TE-108型反射式灰阶测试卡的测量结果与出厂值之间的光密度值最大示值误差仅为0.02,装置的可靠性和测量方法的可行性均较高,同时证明了被测反射式灰阶测试卡的印刷质量较好,可为后续的研究工作提供有价值的参考。     

Electrically controllable in-line-type polarizer using polymer-dispersed liquid-crystal spliced optical fibers

The polarization-dependent transmission of light through an electrically controllable in-line-type polarizer that is made from polymer-dispersed liquid-crystal spliced optical fibers is discussed experimentally and theoretically. This in-line-type optical splicing method has the advantage of low transmission loss when it is applied in optical fiber communication systems. An anomalous diffraction approach is used to compute the scattering cross section of polymer-dispersed liquid-crystal droplets. The experimental results are supported by a theoretical analysis. This device can be employed in electrically controllable in-line-type polarizers and has the potential to yield electrically controllable polarization-dependent loss compensators.     

眼科光学相干层析成像设备分辨率关键参数的小型化检测装置研制

通过分析眼科光学相干层析设备的成像分辨率理论计算模型,设计并研制了一套用于测量其光源光谱和系统数值孔径的小型化检测装置。针对一台商业化的临床在用眼科光学相干层析设备,通过对其关键参数的测量,得到该设备的纵向分辨率为6.9μm,横向分辨率为42.3μm。该检测装置未来可作为眼科光学相干层析设备的质控与计量器具。