光学成像系统光学波前的高精度测试

基于扩展奈波尔-泽尼克理论,分析了不同出瞳振幅分布情况对光学系统焦面处光强分布的影响.针对光学成像系统出瞳振幅实际分布状态,提出了一种新的测试光学波前的方法,解决了相位恢复算法中出瞳振幅分布不均匀和快速傅里叶变换引入计算误差的问题.通过测评实验,对一光学系统进行了测试,获得的光学系统出瞳波前(PV)值为0.196 5λ...     

A test procedure for artificial finger joints

This paper highlights the lack of an agreed testing standard for artificial finger joints. It reviews the anatomy, pathology and biomechanics of finger joints as well as the various designs of finger prostheses and the machines used to test them. While pre-implantation testing should be fundamental, increasing regulation of the biomedical engineering industry will further demand testing of prostheses to pre-agreed standards. Standards relating to the testing of other artificial joints are reviewed before possible parameters for testing finger prostheses are offered.     

Digital-signal-processor-based dynamic imaging system for optical tomography

In this article, we introduce a dynamic optical tomography system that is, unlike currently available analog instrumentation, based on digital data acquisition and filtering techniques. At the core of this continuous wave instrument is a digital signal processor (DSP) that collects, collates, processes, and filters the digitized data set. The processor is also responsible for managing system timing and the imaging routines which can acquire real-time data at rates as high as 150 Hz. Many of the synchronously timed processes are controlled by a complex programmable logic device that is also used in conjunction with the DSP to orchestrate data flow. The operation of the system is implemented through a comprehensive graphical user interface designed with LABVIEW software which integrates automated calibration, data acquisition, data organization, and signal postprocessing. Performance analysis demonstrates very low system noise (approximately 1 pW rms noise equivalent power), excellent signal precision (<0.04%-0.2%) and long term system stability (<1% over 40 min). A large dynamic range (approximately 190 dB) accommodates a wide scope of measurement geometries and tissue types. First experiments on tissue phantoms show that dynamic behavior is accurately captured and spatial location can be correctly tracked using this system.     

Quasianamorphic optical imaging system with tomographic reconstruction for electron beam imaging

We have developed a quasianamorphic optical tomography system coupled to a streak camera to provide continuous recording of the electron beam profile of an intense, long-pulse induction accelerator. A tomographic reconstruction method based on a maximum-entropy algorithm is used to reconstruct the images. The system has simplified the calculation of beam moments, eliminated ambiguity due to beam motion, and contributed to accelerator tuning.     

立体成像眼底相机光学系统设计

为了实现从不同角度同时拍摄同一眼底视网膜区域的图像,使采用双目立体视觉法进行眼底三维重建成为可能,设计了一种免散瞳立体成像眼底相机光学系统。该光学系统由成像系统和照明系统两部分组成,在成像系统中,使用Gullstrand-Le Grand眼模型来模拟正常人眼,运用体视显微镜成像原理进行分光设计;在照明系统中,通过设置黑点板的方式消除网膜物镜产生的杂散光,并加入环形光阑以避免角膜反射光的产生。设计结果表明,本立体成像眼底相机光学系统截止频率在95lp/mm处各视场的MTF值均大于0.2,成像系统畸变小于-3%,场曲值小于0.1mm,色差矫正良好,并且具有较强的调焦能力,能对-10~+5m~(-1)的人眼清晰成像。     

空间成像与激光通信共口径光学系统设计

针对空间成像系统与激光通信天线同时需要大口径光学系统而使卫星载荷质量增大的问题,提出了一种成像光学系统与收发合一激光通信天线共口径工作的新型光学系统。从像差理论出发,给出了以主次反射镜为共用部分、成像和通信工作在不同视场的共口径光学系统初始结构设计方法。实际设计了共口径光学系统,该系统口径为600mm,次镜遮拦比为0.225,成像系统的传递函数在50lp/mm时大于0.47,接近衍射极限;发射分系统波像差远小于λ/20,发射激光的最小束散角可达4μrad,出射光斑质量良好;接收系统达到衍射极限,光斑远小于探测端面,满足探测要求。最后,进行了公差分析,给出了光学系统的装调方法。该设计通过共用主次镜减少了系统总质量和总体积,同时满足空间成像和激光通信系统的性能要求。     

The wear of artificial finger joints using different lubricants in a new finger wear simulator

A new design of finger wear simulator has been manufactured. The simulator is a dual cycle machine, interspersing dynamic flexion–extension motion, where the loads were 10–15 N, with periods of a static 100 N ‘pinch’ load. Also, a two-piece finger prosthesis has been designed and manufactured from silane cross-linked polyethylene. Using the simulator, a comparison of the wear of the cross-linked polyethylene prosthesis was undertaken, with Ringer solution, distilled water and dilute bovine serum as the lubricants. Each test was run at 37°C and included a control prosthesis to account for lubricant uptake. All prostheses came from the same batch, having a gel content of 87%. In total, testing exceeded 27 million cycles. With bovine serum, the total wear factor for the prosthesis was 0.07×10⁻⁶ mm³/N m. With Ringer solution it was 0.98×10⁻⁶ mm³/N m and with distilled water the wear factor was 0.60×10⁻⁶ mm³/N m. This order of results matched that found with pin on plate wear tests using these same three lubricants. The lower wear found with bovine serum may have been due to the positive boundary lubricating effects of the proteins within the serum. Lubricant uptake was greater and more significant in the bovine serum test.     

空间合成孔径成像光学系统的光瞳对称性

从对称性的角度分析比较了几种常见光学系统结构对非相干成像的影响.首先,采用了二维点扩散函数和二维空间调制传递函数分析评价复杂光瞳光学系统,通过理论分析得出复杂光瞳分布的对称性影响着点扩散函数和调制传递函数的对称性的结论.最后,利用二维评价手段,针对几种常见的合成孔径光学系统结构,Golay3、Golay4、JWST和G...     

Diffractive elements for imaging optical systems

The problems and prospects of using diffractive elements with a sawtooth relief-phase microstructure in imaging optical systems are analyzed. Particular attention is paid to minimizing the adverse side effect of diffraction orders on the quality of the image formed by an optical system with a diffractive element due to the change-over from single-layer microstructures to structures containing several layers and reliefs. Requirements are formulated for the design parameters of the microstructure and operating conditions of diffractive elements in optical systems that ensure no visible halo caused by adverse diffraction orders. It is shown by a number of examples that the use of a diffractive element in a plastic-lens imaging optical system corrects chromatic aberrations and provides high resolution in the generated image.     

位相复原技术在光学成像质量测评中的应用

对于大口径或特殊波段成像的光学系统,采用常规测试手段难以实现对光学系统成像质量的评估。而光学系统波像差是表征光学系统成像质量的重要指标之一。本文基于信息光学基础理论采用傅立叶变换和迭代算法通过对光学成像系统星点图像（光强点扩散函数PSF）计算分析,从而实现对光学成像系统位相的复原获得波像差信息。本文论述了有关的理论依据和分析计算公式;并研制了位相复原分析计算软件。通过计算机仿真与误差分析论证了研制的位相复原计算方法的正确性,复原误差小于5%。提出了在实际应用中采用此方法时减少复原误差的一种途径。通过实际采集的光学系统星点图像的位相复原实验验证了位相复原分析软件的适用性。此方法为非常规光学成像系统波相差的评估工作提供了新途径。     

利用激光全息技术校正大口径光学成像系统像差

基于光学全息原理,分析了激光全息技术校正光学成像系统像差的机理和方法,建立了全息记录实验系统,用于校正口径500 mm、低质量球面反射镜光学系统对有限远物体成像时的像差。采用原光路再现的方法,通过比较像差校正前后的干涉图样和成像结果,验证了该校正方法的可行性。实验结果表明,校正后该系统剩余波像差约为λ/8。     

制冷器件晶粒相邻面准共焦成像检测的光学装置

提出了一种半导体制冷器件晶粒相邻面同时准共焦成像检测的光学装置。选择晶粒天面成像光路中直角反射转像棱镜到玻璃载物转盘之间的距离调节来实现双面准共焦成像。设计了晶粒相邻面缺陷同时准共焦成像检测的光学系统,完成了晶粒相邻面缺陷同时准共焦成像检测的实验验证。结果表明,该检测装置可以实现晶粒相邻面缺陷同时成像检测的功能,满足晶粒相邻面缺陷成像检测的性能要求。具有提高检测速度、简化结构且提高系统可靠性等优点,可在晶粒缺陷智能检测筛选系统中获得应用。     

基于平面对称光学系统像差理论的折反射全景成像系统优化设计

全景成像技术在机器人、计算机视觉和虚拟现实领域有着重要的应用,与此同时也对其成像质量提出更高的要求。然而,对于此类大视场系统的设计较多地停留在光线追迹的方法,没有出现能对大视场像差进行参量化设计的方法。现将平面对称光学系统像差理论应用于此系统,得到关于光学参数的像质评价函数,采用差分进化算法解决多变量评价函数的优化问题,实现了一种折反射全景成像系统的优化设计,并用Zemax光线追迹软件证实了理论的正确性。结果表明,此类系统可以采用平面对称光学系统像差理论来优化设计,该思路是正确有效的。     

Balanced homodyning for apertureless near-field optical imaging

A quadrature optical detection technique, based on polarized balanced-homodyne interferometry, has been developed for specific application to apertureless near-field scanning optical microscopy (ANSOM). With such technique, multiplicative background interference, inficiating quantitative optical imaging in standard homodyne-based ANSOM, can be suppressed. Periodic modulation of interferometric optical phase, typically employed in heterodyne-based ANSOMs even to such purpose, is not needed in the present configuration. Homodyne detection also facilitates detection of harmonic components of the ANSOM optical signal at the probe/sample distance modulation frequency, necessary for near-field discrimination and suppression of artifacts. Furthermore, since amplitude signal is not affected by phase fluctuations generated in the optical path of the interferometer, an optical fiber could be included in one interferometer arm, to couple the ANSOM head to the detection system, obtaining improved versatility of the instrument. A demonstration of the interferometer performance is given by a test confocal optical scan of a mirror surface. This technique, as applied to near-field microscopy, is anticipated to provide absolute values of optical contrast not depending on background interference and topography artifacts.     

大视场主动光学成像系统的成像研究

从主动光学成像系统的照明模型出发,研究了大视场情况下目标和景物的成像性质,分析了传输介质对照明和成像光束的衰减作用,得出了光学成像系统像面照度的计算公式,并对其衬比传递特性和视场大小对成像的影响进行了详细的分析,得出了小视场近似的条件,其结果可用于主动光学成像系统的设计、图像分析和目标识别.     

激光为光源的液晶自适应眼底成像系统

摘要：本文介绍了基于液晶波前校正器的模拟人眼眼底自适应成像系统,该系统采用Shark-Hartman波前探测器进行波面探测,将探测所得波前畸变经过计算处理转化为灰度图通过电脑施加到LCOS上进行波面校正,通过校正人眼像差的方式来提高系统成像质量。经过校正后系统波前误差从1.92m降低到0.048m系统分辨率接近70lp/mm已经到达该光学系统衍射极限分辨。     

Harmonic optical microscopy and fluorescence lifetime imaging platform for multimodal imaging

In this work, we proposed and built a multimodal optical setup that extends a commercially available confocal microscope (Olympus VF300) to include nonlinear second harmonic generation (SHG) and third harmonic generation (THG) optical (NLO) microscopy and fluorescence lifetime imaging microscopy (FLIM). We explored all the flexibility offered by this commercial confocal microscope to include the nonlinear microscopy capabilities. The setup allows image acquisition with confocal, brightfield, NLO/multiphoton and FLIM imaging. Simultaneously, two‐photon excited fluorescence (TPEF) and SHG are well established in the biomedical imaging area, because one can use the same ultrafast laser and detectors set to acquire both signals simultaneously. Because the integration with FLIM requires a separated modulus, there are fewer reports of TPEF+SHG+FLIM in the literature. The lack of reports of a TPEF+SHG+THG+FLIM system is mainly due to difficulties with THG because the present NLO laser sources generate THG in an UV wavelength range incompatible with microscope optics. In this article, we report the development of an easy‐to‐operate platform capable to perform two‐photon fluorescence (TPFE), SHG, THG, and FLIM using a single 80 MHz femtosecond Ti:sapphire laser source. We described the modifications over the confocal system necessary to implement this integration and verified the presence of SHG and THG signals by several physical evidences. Finally, we demonstrated the use of this integrated system by acquiring images of vegetables and epithelial cancer biological samples. Microsc. Res. Tech. 2012. © 2012 Wiley Periodicals, Inc.     

气动手爪伺服系统设计

机械手爪是机械手执行机构中的重要部件,其性能的优劣将直接影响到整个系统的作用和效率。为了分析机械手爪抓取易碎物体时的运行机理．以SMC公司MHZ系列气动手爪为例,阐述了气动手爪的结构及工作原理,分析了气动手爪的运动方程,推算了系统的传递函数,建立了系统的AMESim仿真模型,并对系统进行了仿真分析及校正,结果表明设计是正确合理的。     

Development of a hand exoskeleton system for index finger rehabilitation

In order to overcome the drawbacks of traditional rehabilitation method,the robot-aided rehabilitation has been widely investigated for the recent years.And the hand rehabilitation robot,as one of the ...