基于兴隆观测基地50cm望远镜的幸运成像系统

大气湍流会在很大程度上降低地基望远镜的空间分辨率,而幸运成像技术以较低的成本、简单的设备、易实现的算法可以有效修正大气湍流的影响,从而提高了地基望远镜开展天体成像和密集星场高精度测光观测的能力.基于兴隆观测基地50 cm望远镜研制了幸运成像系统,该系统包括滤光片、望远镜增焦子系统、数据采集子系统和数据处理子系统.在视宁度良好的晴夜对月球、大行星、球状星团和双星进行了观测,成功获取了月球表面的清晰图像,恒星星像的半高全宽(FWHM)达到0.6,好于2倍望远镜衍射极限.观测结果表明,该幸运成像系统能够有效提高地基望远镜的空间分辨本领,为下一步的高分辨天文观测研究奠定了基础.     

AOTF偏振光谱成像数据采集系统设计

偏振超光谱成像技术是一个新兴的交叉技术领域,探索该技术在航天、民用等领域的应用已经成为国内外的重点研究课题,特别是基于声光可调谐滤波器(AOTF)的光谱成像仪,与传统仪器相比,在工作机制和仪器设计上都有着众多的优点。通过研究AOTF的工作原理,分析实验中AOTF偏振光谱成像仪的工作过程,制定了相应的数据采集系统设计方案,并且详细论述了系统基于LabVIEW平台的设计流程,同时给出了各模块的LabVIEW程序设计框图。经过实测实验对系统的功能进行了验证,结果表明:系统能够高效可靠地完成对图像数据的采集与相应仪器的控制,具有一定的研究价值和实用价值。     

Development of neuronal signal mapping method for 2D encoding-based brain?computer interface system

A neuronal signal mapping method between the brain of a rat and a computer has been developed and applied to implement a 2D encoding-based real-time brain-computer interface system. The system transformed real-time neuronal activities from a prefrontal cortex, a non-motor area of a rat into control commands, which were used to drive a water disc in 2D space. The system was successfully implemented for a real-time operation based on the subject's motor intentions derived from a non-motor area, which showed a possibility of universal access to computers by removing withdraw restrictions on the motor-related region of the brain.     

Radar imaging from a distorted array: The radio camera algorithm and experiments

High angular resolution radar imaging may be achieved with a large-aperture antenna even if the aperture is distorted, provided that adaptive signal processing compensates for the distortion. The radio camera is an instrument designed for this purpose. Its algorithm for imaging ground-based targets is described and experimental results are given for a 3 cm wavelength demonstration system using a distorted 27-m random sparse array. The measured beamwidth of 1 mrad conformed to theory, confirming the validity of the technique. Extension of the algorithm to accommodate isolated targets such as aircraft and ships also is discussed.     

Measuring nonconstant flow in magnetic resonance imaging

An attempt is made to quantify rapid flow using magnetic resonance imaging techniques. An analysis is presented in which it is assumed that constant velocity gradients are present. A deconvolution scheme which can remove the blurring from motion with acceleration is developed. This allows improved resolution and velocity determination. Computer experiments were performed on simulated data, where the velocity drops from 100 cm/s to 50 cm/s over a distance of 5 cm. In noise-free data, velocities were recovered to within 2% of the lower velocity and, for data with 5% white noise, to within 6%     

激光云粒子成像探测仪研制

为了研究云粒子微观特性, 采用激光成像技术、高斯光束匀化处理技术、高分辨率阵列探测器以及图像抽帧还原算法, 研制出激光云粒子成像仪。通过地面模拟测量及实际飞行试验, 对仪器性能进行了测试。结果表明, 研制仪器可实现对25 μm~1550 μm云粒子的成像, 分辨率为25 μm, 粒径测量误差小于9.5%;实测的冰晶粒子形态符合云粒子自然分布规律, 粒子尺度谱符合指数分布, 决定系数在0.58~0.97之间。该研制仪器可为云降水微物理研究提供基础观测数据。     

无人机载激光线扫描浅滩三维成像研究

设计了一种基于三角法线扫描的无人机载激光雷达三维成像系统。系统以520 nm线激光为光源照射目标,利用无人机扫描获取目标的三维数据。文章设计了无人机载激光线扫描系统的硬件系统,构建了线激光水下折射三维坐标解算模型,提出了水上、水面与水下激光条纹提取的图像处理方法,并利用研制的雷达系统进行了近海浅水区域无人机扫描实验。实验结果表明,系统利用IMU及GPS能够有效提升三维图像的准确性,快速获取目标区域水上及水下目标的三维数据,平均距离分辨率达到3 cm,具有速度快、精度高、成本低的优势,在近岸浅海区域的大范围高速三维成像领域具有广阔的应用前景。     

检测半导体激光器性能的虚拟仪器

介绍一种检测半导体激光谱特性和Ｐ－Ｉ特性的仪器系统。系统采用虚拟仪器技术,提高了数据采集、处理能力及系统的拓展升级能力,增强了半导体激光器的驱动及其控制功能,达到简化系统结构、降低系统成本的目的,对几种半导体激光器进行了实际测试。证明本系统使用方便、效率高、结果可靠。     

Fluorescence lifetime imaging using a diode-pumped all-solid-statelaser system

A whole-field fluorescence lifetime imaging system is presented which is based, for the first time, on an all-solid-state diode-pumped oscillator/amplifier system. Fluorescence lifetime imaging of unstained biological tissue in vitro using this instrument demonstrated contrast between different tissue constituents     

利用太阳测量整层大气光谱透过率

简要介绍了利用太阳辐射测量整层大气光谱透过率的实验装置、测量原理和数据处理方法.为得到大气光学参数的实际变化规律,设计了由宽光谱范围的平场凹面光栅和高灵敏度的线阵CCD构成的硬件系统,利用太阳直接辐射测量其连续光谱,使用Langley拟合方法进行定标,通过运算得到了实际天气条件下的大气光谱透过率.将实测结果与现有其他设备的测量数据进行了对比,证明了测量结果的可靠性.     

基于线阵APD探测器的脉冲式一维非扫描激光雷达系统

介绍了非扫描激光雷达的原理,描述了研制的基于线阵APD雪崩光电二极管的一维非扫描激光雷达系统。该系统使用线阵APD作为探测器,红外脉冲式纳秒激光器作为探测光源,利用飞行时间法实现了目标的一维距离图像的非扫描测量。系统使用了APD多通道并行前置放大电路,并利用模拟开关控制高速继电器进行多通道轮询切换,实现了APD阵列的多通道驱动,并有效地降低了通道间的串扰。进行了多组6 ~18 m的一维距离成像实验,结果表明系统的距离分辨率优于10 cm,各通道的平均测距标准偏差约为8.6 cm。该系统的设计为将来的面阵APD二维非扫描激光雷达的研制奠定了基础。     

基于Labview的光声信号采集和成像系统

为了实现光声信号的快速采集和图像重建,采用基于Labview软件平台的光声信号采集和成像系统进行光声信号采集,并调用Matlab程序对采集到的数据进行处理,最后利用滤波反投影重建算法,实现了对模拟组织样品的光声层析成像。成像系统的分辨率为0.15mm,重建图像与实物十分吻合。实验表明,该系统具有快速、方便、直观等特点,有望发展成为一种低成本的实用的临床诊断仪器。     

基于DSP的继电保护测试仪信号采集装置硬件设计

继电保护测试仪检定技术是栓定继电保护测试设备性能指标是否满足要求的技术。详细介绍基于DSP的继电保护测试仪数据采集系统。该系统可以精确采集继电保护测试仪的各项参数指标,采集数据准确可靠,为继电保护测试仪检定装置的研究提供了良好的基础。重点描述该采集装置的硬件组成和电路设计,并简要分析各部分的功能及主要芯片的工作方式。     

基于GPRS和组态王的水文测报系统的设计

为了实现水文测报系统的高可靠性、低功耗性和较好的实时性,详细介绍了水文测报技术的基本原理和实现方法,主要包括GPRS无线通信技术的基本知识和水文信息采集系统的整体构成.在借鉴和分析了国内外水文测报技术的基础之上,设计出了基于GPRS的水文测报系统的软硬件系统,并利用组态王开发了水文测报系统的实时监控系统.整个系统以实用...     

Design of 8mm-band Aperture Synthetic Radiometer and Imaging Experiment

An aperture synthetic radiometer (ASR) based on interferometric technology is a new type of passive microwave imaging instrument, which has high spatial resolution. Restricted by devices performance and operating wavelength, however, the system design is difficult at MMW band. In this paper, an 8mm-band aperture synthetic radiometric imaging system based on minimum-redundancy linear array is described, the performance specification of the instrument is analyzed. The preliminary imaging experiment result shows that the system has good passive MMW imaging (PMMWI) performance, indicating a bright outlook for the development of this technique in the future.     

基于LabVIEW的飞机电气综合试验管理系统设计

利用虚拟仪器软件平台LabVIEW8．6开发一种飞机电气综合试验自动管理系统操作平台,用于测试飞机电气各项性能指标的重要试验环境。在详细介绍该系统各组成部分的基础上,重点分析了试验自动管理系统的组成与功能。试验自动管理系统通过高速以太网实现与各试验子设备之间的数据通信,以达到对各子系统远程控制和试验结果的上传。所设计的操作系统可针对不同的子系统来配置相应的控制操作命令,并实现对操作命令的保存、发送至各子系统;子系统接收操作系统的命令并执行和完成相应的动作。经实际运行测试,该系统运行稳定,人机交互界面良好,操作简便,自动化程度较高。     

Passive markers for tracking surgical instruments in real-time 3-D ultrasound imaging

A family of passive echogenic markers is presented by which the position and orientation of a surgical instrument can be determined in a 3-D ultrasound volume, using simple image processing. Markers are attached near the distal end of the instrument so that they appear in the ultrasound volume along with the instrument tip. They are detected and measured within the ultrasound image, thus requiring no external tracking device. This approach facilitates imaging instruments and tissue simultaneously in ultrasound-guided interventions. Marker-based estimates of instrument pose can be used in augmented reality displays or for image-based servoing. Design principles for marker shapes are presented that ensure imaging system and measurement uniqueness constraints are met. An error analysis is included that can be used to guide marker design and which also establishes a lower bound on measurement uncertainty. Finally, examples of marker measurement and tracking algorithms are presented along with experimental validation of the concepts.     

Multistatic Ground-Penetrating Radar Experiments

A multistatic ground-penetrating radar (GPR) system has been developed and used to measure the response of a number of targets to produce data for the investigation of multistatic inversion algorithms. The system consists of a linear array of resistive-vee antennas, microwave switches, a vector network analyzer, and a 3-D positioner, all under computer control. The array has two transmitters and four receivers which provide eight bistatic spacings from 12 to 96 cm in 12-cm increments. Buried targets are scanned with and without surface clutter, which is a layer of rocks whose spacing is empirically chosen to maximize the clutter effect. The measured responses are calibrated so that the direct coupling in the system is removed, and the signal reference point is located at the antenna drive point. Images are formed using a frequency-domain beamforming algorithm that compensates for the phase response of the antennas. Images of targets in air validate the system calibration and the imaging algorithm. Bistatic and multistatic images for the buried targets are very good, and they show the effectiveness of the system and processing.     

LabWindows/CVI在开发测试软件中的应用

LabWindows/CVI是基于ANSI C语言的集成开发工具,适用于虚拟仪器测试系统的开发,用于仪器控制、数据处理等,本文介绍了LabWindows/CVI的使用方法,包括通信方式,多线程技术等。采用LabWindows/CVI开发了ADS-B地面站测试系统的软件,该测试软件具有良好的人机界面,便于操作,同时提高了测试的效率。     

基于DSP和FPGA的MCI控制系统设计

给出了以EP2C35F484和TMS320F28335型32位浮点DSP为核心的,数字式地层微电阻率扫描成像系统的,信号采集及控制的基本原理及实现方案。由于传统芯片及附属数字芯片体积较大,导致井下电路过于复杂、庞大。结合仪器内径小、长度有限的具体实际,该系统设计由发送接收、信号采集、控制输出以及CAN通信4个模块构成,由DSP和FPGA联合实现采集控制功能。这里主要对DSP和FPGA模块进行设计,其数据传输速度、采集的信息量、数据处理精度以及系统可靠性等性能都有大幅提高。