长波红外广角地平仪镜头的光学设计

介绍适用于非致冷凝视式焦平面阵列的长波红外(LWIR)广角地平仪镜头的光学设计.其工作波长范围10～16μm,全视场角为135°.采用"负-正-正"型式的反远距像方远心光路镜头结构,仅有三块非球面锗透镜构成.能够很好地解决广角镜头轴外像差校正和像面照度均匀性问题.此镜头结构简单、体积很小、后工作距离大,成像质量接近于衍射极限,在20lp/mm空间频率处的调制传递函数值超过0.6,像高与视场角关系偏离线性的相对误差不超过15%.文中还分析了此镜头的加工和装调公差.     

星载多光谱CCD相机研究

研制的星载多光谱 CCD相机采用线阵 CCD推扫方式成像 ,具有蓝、绿、红、近红外、全色五个成像谱段 ,在轨工作时地面像元分辨率为 2 0米 ,覆盖宽度 113公里。相机光学系统采用单镜头焦面分色结构实现多光谱成像 ,每个谱段的探测器阵列由 3片 2 0 4 8元 CCD光学拼接而成 ,以实现地面宽覆盖成像。多片 CCD信号采用串行读出方式 ,使焦面 15片 CCD形成两路视频信号输出给数据传输系统。测试结果显示 ,相机各谱段 MTF典型值为 0 .2 5 ,满足使用要求。     

Characterisation of a standard CCD video camera devoted to the design of an efficient particle image velocimetry instrument

A particle image velocimetry (PIV) instrument using a video frame grabbing system and two unsynchronised CCD video arrays was constructed. In the optical device, the two CCD are positioned at two perpendicular axes, with an image splitter located at their intersection and a single imaging lens in front of it. An optical characterisation of each CCD array and the imaging lens is needed to ensure that the field of view is similar for each vision system. Firstly, the experimental method of Cornu was used to deduce the basic optical parameters of the imaging lens. A simple video model was then performed to extract the unknown optical parameters of the device such as the angular field of view, the efficient dimensions of each CCD array and the transfer function from the CCD to the TV screen. An identification method based on global magnification measurements allowed the resolution of the micrometric stages needed for the spatial calibration step of the final instrument, to be deduced. Experimental tests have shown that the aberration in image formation was minimum with this configuration.     

Estimation of the Alignment Parameters of a Scanning Device with a Multirow Focal Plane Array

Scanning devices based on multirow focal plane arrays providing increased resolution impose much more stringent requirements on alignment than single-row arrays. This paper presents a new method for measuring and estimating the scanning speed and the angle of orientation of a multirow focal plane array relative to the scanning direction — the parameters that determine the quality of the discrete image formed. The method is based on an analysis of the image of a simple test object — an optical slit. An algorithm for estimating these parameters is proposed which provides high-accuracy estimates under fairly weak requirements for the image quality of the test object. The estimation accuracy was calculated analytically and confirmed by simulation modeling.     

极紫外太阳望远镜分辨率检测

在完成极紫外太阳望远镜（EUT）的装调工作之后,需要对其成像质量进行检测。将分辨率板置于平行光管的焦点处,由可见光照明该分辨率板,透射光经平行光管后成为平行光束并充满待测EUT入瞳,再经EUT成像在CCD相机上,根据所得的像可判断待测望远镜分辨率。实验结果表明EUT在可见光波段(λ=570nm)的分辨率为1.22″,接近此波段的衍射极限(1.20″)。根据可见光检测结果估算出EUT工作波段的分辨率可以达到0.32″,满足设计要求。     

星敏感器星象模拟软件的研究

星敏感器是高精度姿态测量部件,广泛应用于各种航天器中,作用对象是空间恒星,成像过程涉及光学系统、CCD探测器及前端信号处理系统,最后输出惯性坐标系或地心坐标系下的姿态角.本文完成了对星敏感器成像过程的模拟,研制了星敏感器星像模拟软件,为星敏感器及其他类似航天器的性能评价提供了有效手段.     

Experimental ultra fast X-ray computed tomography with a linearly scanned electron beam source

We devised and tested a computed tomography approach that utilises a scanned electron beam X-ray source to produce fast tomographic image sequences of transient density distributions. Potential application areas for this technique are the visualisation and measurement of two-phase and particle flows in thermofluid dynamics research, chemical processes, or transport systems for fluids and bulk solids. In our setup we used a linear deflection pattern for the electron beam and a non-annular detector arc to record transmission data of an object from different projection angles. This approach gives the highest achievable axial resolution and is comparatively moderate in effort and costs. For the inverse problem we applied iterative image reconstruction techniques to reconstruct the density distribution from a limited data set. The method has been experimentally tested on static and dynamic phantoms with a frame rate of 1000 images per second and a spatial resolution of approximately 1 mm in plane and axial.     

中波红外两档变焦光学系统

报道了一种用于320×240制冷型探测器的中波红外两档变焦光学系统。该系统采用二次成像、前组透镜轴向移动变焦的光学结构形式。根据探测器类型和实际的使用要求给出了系统的光学参数,并利用光学设计软件对系统的像质进行了的分析。结果表明,该系统可以实现焦距为180/60两档变焦,工作波段为3～5μm,F数为1.96,满足100％冷光阑效率,截止频率16lp/mm处的MTF值大于0.6,结构简单,使用方便,像质好。     

星载多谱段双视场紫外大气探测仪

针对天底和临边综合紫外大气探测的需求,分析了天底和临边双视场观测原理和技术指标,设计和研制了多谱段双视场紫外大气探测仪原理样机。该样机光学系统由前透镜组、环形透镜、中继透镜组和窄带滤光片组成,3个工作谱段的中心波长分别为265nm、295nm和360nm,带宽均小于20nm,天底视场为10°,临边视场为360°(141.8°~146.6°),焦距为5mm,F数为3.3,通过切换窄带滤光片完成3个谱段的探测。多谱段双视场紫外大气探测仪整机质量约为3kg,体积为Φ90mm×300mm。对样机的静态传递函数和像面照度均匀性进行了测试。测试结果表明,在特征频率38.5lp/mm处,天底视场的静态传递函数为0.24,临边视场的静态传递函数为0.22,像面照度均匀性为94%,均优于设计指标要求。该原理样机体积小、重量轻,满足空间光学遥感仪器小型化和轻量化的要求。     

Polarized light field microscopy: an analytical method using a microlens array to simultaneously capture both conoscopic and orthoscopic views of birefringent objects

For the comprehensive analysis of anisotropic materials, a new approach, called 'polarized light field microscopy' is introduced. It uses an LC-PolScope to which a microlens array was added at the image plane of the objective lens. The system is patterned after the 'light field microscope' that achieves both lateral and axial resolution in thick specimens in a single camera exposure. In polarized light field microscopy, the microlens array generates a hybrid image consisting of an array of small conoscopic images, each sampling a different object area. Analysis of the conoscopic images reveals the birefringence of each object area as a function of the propagation direction of transmitted light rays. The principles and utility of the instrument that we are calling 'light field LC-PolScope' are demonstrated with images of a thin, polycrystalline calcite film, revealing the azimuth and inclination angle of the optic axis for many crystals simultaneously, including crystals with diameters as small as 2 microm. Compared to traditional conoscopy and related methods, the vastly improved throughput and quantitative analysis afforded by the light field LC-PolScope make it the instrument of choice for measuring 3D birefringence parameters of complex structures.     

焦平面阵列红外光谱图象系统——FT-IR光谱学的革命性进展

显微红外光谱学已成为现代FT-IR光谱学的一重要分支,利用红外显微镜进行的红外图象分析有两种方式:(1)传统的“画地图”—Mapping方式,利用自动显微镜载物台逐点移动样品,逐点测定其红外光谱;(2)最新的焦平面阵列(Focal Plane Array),红外图象系统,焦平面阵列式红外检测器含有128×128或64×64个阵列检测单元,它可以高空间分辨率快速完成较大面积的红外图象采集,该技术代表着FT-IR的最新发展,现已应用于生物学、医学、地质学、聚合物分析等领域。     

共孔径消热差红外双波段光学系统

设计了适用于制冷型320×256中波红外凝视焦平面阵列探测器和320×256长波红外凝视焦平面阵列探测器的共孔径消热差折反射式红外双波段光学系统。该系统在中波3.7~4.8μm,长波7.7~11.7μm,环境温度10~40℃下工作,其焦距为292mm,视场角为1.56°×1.875°,F/#为1.93,满足100%冷光阑效率。设计的系统共用主镜、次镜和准直镜组,利用分光镜实现中波红外、长波红外光谱分光,后接各自的校正镜组校正剩余像差。给出了设计原理、设计过程和工程设计时需考虑的一些因素,通过选择合适的光学材料、机械材料和分配光焦度,实现了两路系统在10~40℃环境温度下具有良好的成像性能。该系统成像质量良好、可加工性好、装配难度小、工程可实施性强。     

A spectral system with the spatial resolution for plasma motion detection in the GOL-3 multi-mirror trap

A spectral system with the spatial resolution intended for diagnosing rotation of the plasma in the GOL-3 facility is described. The system is capable of measuring the radial dependences of the Doppler shift and broadening of spectral lines emitted by the plasma from various points in it. A DFS-24 double focusing spectrometer with a reciprocal linear dispersion of 0.45 nm/mm is the basis for the spectral system. If a radiation source is axially symmetric and extended, it is possible to obtain the intensity of spectral lines on the surface of the photosensitive area of a CCD array with the spatial resolution across the plasma by forming an image of the plasma in the sagittal focal plane of the entrance collimation lens, though the spectrometer astigmatism is strong. As a result, a spatial resolution of 0.8 mm has been attained in the developed system at a 55-mm field of view.     

Integration of a high‐NA light microscope in a scanning electron microscope

We present an integrated light‐electron microscope in which an inverted high‐NA objective lens is positioned inside a scanning electron microscope (SEM). The SEM objective lens and the light objective lens have a common axis and focal plane, allowing high‐resolution optical microscopy and scanning electron microscopy on the same area of a sample simultaneously. Components for light illumination and detection can be mounted outside the vacuum, enabling flexibility in the construction of the light microscope. The light objective lens can be positioned underneath the SEM objective lens during operation for sub‐10 μm alignment of the fields of view of the light and electron microscopes. We demonstrate in situ epifluorescence microscopy in the SEM with a numerical aperture of 1.4 using vacuum‐compatible immersion oil. For a 40‐nm‐diameter fluorescent polymer nanoparticle, an intensity profile with a FWHM of 380 nm is measured whereas the SEM performance is uncompromised. The integrated instrument may offer new possibilities for correlative light and electron microscopy in the life sciences as well as in physics and chemistry.     

基于图像处理的自动变焦人眼跟踪系统

在视觉人机交互中,为实现光学系统成像放大率不变,采用电动变焦镜头,基于图像处理跟踪人眼特征信息,自动变焦实现图像大小不变。系统以PC机为上位机对眼部图像处理,采用单片机为下位机对变焦镜头驱动控制,两者之间以串口通信。实验结果表明系统能根据人眼图像大小对变焦物镜作实时闭环控制,系统在400mm～1000mm距离内实现了连续变焦,距离分辨力为120mm。     

A compact STED microscope providing 3D nanoscale resolution

The advent of supercontinuum laser sources has enabled the implementation of compact and tunable stimulated emission depletion fluorescence microscopes for imaging far below the diffraction barrier. Here we report on an enhanced version of this approach displaying an all-physics based resolution down to (19 ± 3) nm in the focal plane. Alternatively, this single objective lens system can be configured for 3D imaging with resolution down to 45 × 45 × 108 nm in a cell. The obtained results can be further improved by mathematical restoration algorithms. The far-field optical nanoscale resolution is attained in a variety of biological samples featuring strong variations in the local density of features.     

红外变焦光学系统设计

对于320×256非制冷焦平面阵列探测器(像元尺寸25μm×25μm),设计了工作在8～12μm波段折射式红外连续变焦光学系统。该系统在变焦过程中相对孔径不变,F/#为1,系统变倍比为3∶1,焦距50～150mm,光学筒长209.5mm。该系统由5片透镜构成,并且仅使用锗一种材料。该系统采用机械补偿的方法,通过引入非球面和衍射面,使系统结构简化,并且提高了成像质量。系统在空间频率为20lp/mm处,各个视场的MTF均在0.5以上。     

数码单反相机焦平面光电转换函数的测量及分析

为了在光学实验中合理应用数字成像设备，需要获取并处理其物理输入量与数字输出量之间的关系。基于ISO 14524:2009标准，对数码单反相机Canon EOS 500D的焦平面光电转换函数进行了实验测量及数据分析。通过比较不同尺寸像素区域及不同图片格式对测量结果的影响，发现焦平面光电转换函数的测量偏差随像素区域尺寸的减小而增大，而RAW和JPEG两种文件格式的数字输出值与焦平面曝光量的关系分别为线性和非线性。当单反相机用作光分布记录测量的仪器时，采用直接反应传感器接收的辐照度信息的RAW格式作为输出数据，可以获得较大的动态范围，理论上可以避免相机非线性变换等后续处理带来的影响，经过必要的校正可以更精确地表示场景信息。     

360°高阶非球面反射式全景镜头设计

为了简化系统配置、提高图像采集及处理效率,实现单一光学系统环视高清全景成像,依据折反射式光学系统的工作原理,设计了高阶非球面反射式360°全景镜头,并对光学结构和系统像质进行优化设计。该相机采用高阶非球面反射镜压缩视场角,将垂直光轴方向俯仰角从-55°到20°的环视目标光引入到系统,接着,在后续光路中利用玻璃透镜组对目标光进行接收,并使其聚焦于相机靶面,获得物体的环形全景图像。通过对系统像质的优化,得到高清的360°环视全景图像,并对光学系统的主要性能指标进行了分析。所设计的360°全景镜头采用1片高阶非球面反射镜和10片玻璃球面镜组成,系统的焦距为0.4mm,光圈数为2.2,俯仰角达到75°,像方全视场在150lp/mm处的光学传递函数值均大于0.3。该360°全景镜头采用单一光学系统成像,解决了传统拼接式全景镜头图像采集与图像处理效率低的问题,同时通过简化系统结构,使该产品符合成本低、可量产的要求。     

Computer-aided two-coordinate autocollimator for measuring small angular deviations

A computer-aided autocollimator for measuring small angular deviations is described. Small angular displacements are determined by the displacement of the laser beam image on a CCD array in the focal plane of a lens. Automatic control of the displacement systems allows one to test many times the systems of precision remote displacement of optical components with a minimum detectable angular deviations of about 0.2″. Original Russian Text ? A.V. Kirsanov, T.V. Barmashova, V.V. Zelenogorskii, A.K. Potemkin, 2009, published in Pribory i Tekhnika Eksperimenta, 2009, No. 1, pp. 155–157.