高速科学CCD CAMERA系统设计

在实验结果的基础上,介绍了一种高速科学CCD相机系统设计。测试选用了柯达CCD芯片KAF-0401LE和KAF-1001E,用MAXII系列CPLD芯片实现了CCD驱动时序和数据采集时序控制;采用片内集成CDS的CCD信号A/D转换器AD9824进行相关双采样和高速模数转换;内置8051的CypressUSB2.0控制芯片CY7C68013A完成了高速同步数据传输及与上位机通讯,接收和发送上位机指令等;结合USB采集系统使用VisualC++编写了系统控制界面。实现了采集速率选择(最高10MHzPixelRate对应于20Mbyte/sUSB传输速度)、复合模式选择、单帧/连续采集、制冷温度采集和控制等,适用于同类型CCD相机的系统设计。

Application of CCD Cameras to Investigations of Mixing on Boundaries of a Thermal Plasma Jet

Mixing of a thermal plasma jet with the surrounding atmosphere was studied using two CCD cameras （PCO SensiCam） situated detecting simultaneously the radiation of argon and nitrogen. The evaluation of image differences between two records showed that the location of regions on plasma jet boundaries characterised by stronger nitrogen radiation changes with the plasma flow rate. Close-to-laminar flow results in a small mixing rate and consequently low nitrogen optical emission on plasma jet boundaries. The increase of the flow rate leads to the formation of a relatively thick and stable layer on the boundaries characterised by strong nitrogen radiation. Further enhancement of the flow rate results in the formation of unstable regions of excited nitrogen molecules moving along the jet.

Photographing of a Multi-Pellet Ablation Process in HL-1M Tokamak with CCD Camera

The 2D CCD camera has been used to take photos during hydrogen multi-pellet injection in HL-1M tokamak. The hydrogen multi-pellet (2 × 1.0 mm, 3× 1.2 mm, 3×1.2 ~ 1.3 mm) is horizontally injected into plasma. The observation is performed above the injection path at a sight angle 13.4°，As the shape of cloud ablation varies so quickly, the key points of the experiment have to be the high temporal resolution of CCD and the determination of pellet radial location in plasma. A series of improvements have been made with the experiment setup, including camera parameter, control (NA, ROI) and trigger mode, so as to satisfy the experiment requirements. Thus very nice photos along with the satisfying experimental results are obtained such as: (1) single exposure time reduced to 100 us (2) multi-frame in one discharge (FPS≥ 40) (3)multi-exposure for one pellet so that further observation of the temporal process of pellet ablation may be possible. Through the data analysis on the spatial distibution of pellet ablation clouds in photos taken, the pellet dimensions, trajectory of the cloud and pellet velocity are obtained, and the physical mechanism of pellet-plasma interactions also analyzed. In particular, it is possible to provide an effective means for measuring q-profile of HL-1M plasma.

Improved plasma position detection method in EAST Tokamak using fast CCD camera

To control the steady-state operation of Tokamak plasma, it is crucial to accurately obtain its shape and position. This paper presents a method for use in rapidly detecting plasma configuration during discharge of the Experimental Advanced Superconducting Tokamak device. First, a visible/infrared integrated endoscopy diagnostic system with a large field of view is introduced,and the PCO.edge5.5 camera in this system is used to acquire a plasma discharge image. Based on the analysis of various traditional edge detection algorithms, an improved wavelet edge detection algorithm is then introduced to identify the edge of the plasma. In this method, the local maximum of the modulus of wavelet transform is searched along four gradient directions, and the adaptive threshold is adopted. Finally, the detected boundary is fitted using the least square iterative method to accurately obtain the position of the plasma. Experimental results obtained using the EAST device show that the method presented in this paper can realize expected goals and produce ideal effects;this method thus has significant potential for application in further feedback control of plasma.

Preliminary Study of CAS-LIBB Single-Particle MicrobeamⅡEndstation:Ⅱ.Considerations for Choosing the Right CCD Camera

The proposed multi-dimensional quantitative fluorescence microscopy for the CASLIBB single-particle microbeam II endstation is a CCD-based imaging system. We systematically analyse the theoretical and the practical considerations pertinent to choosing the right CCD camera and unveiling the principles underlying multifarious parameters. Therefore, this analysis can be a valuable tool in scrutinizing each parameter and clarifying proper usage of a scientific CCD camera.

基于CCD的激光熔覆熔池平滑度在线监测系统研究

由于激光熔覆过程高温高亮,无法实时准确判断熔覆效果。使用CCD相机结合平滑度监测算法,对不同功率下的熔池形貌进行监测,验证算法性能,判断熔覆效果,同时尝试叶片修复。结果表明:激光功率过大或者扫描速度过慢,均会导致熔池边缘平滑度较差,进而认为熔覆参数不合适;为防止熔坏基材,可根据监测效果及时停机;发现激光功率与熔池边缘平滑度呈负相关。

CCD camera system design for the beam diagnostic by using OTR

In this paper, a new CCD camera system used in the OTR beam measurement is presented, the basic principle of OTR beam measurement and the application of CCD chips-ICX208CL and AD9929 in camera system design are introduced in detail.

A New Technique for CCD Camera Auto-Calibration

A novel feature-round-based coplanar drone for the CCD camera auto-calibration is designed. Based on the ellipse similarity, an ellipse recognition algorithm is proposed. The experiment indicates the calibration error is less than 0.4 pixel.

Studies of an X-ray imaging detector based on THGEM and CCD camera

Introduction The photons generated by the electron avalanche in gaseous detectors are known as the secondary scintillation light,of which the spectrum range is from ultraviolet to visible.So it is possible to collect directly the avalanche-induced photons in visible range by light sensors,such as charged-couple device(CCD).The optical readout is a new method for 2-D imaging of high spatial resolution based on the micro-pattern gaseous detectors(MPGDs).Purpose The traditional charge readout method for the MPGDs is complicated,expensive,and strongly depends on the technology of application-specific integrated circuit.In some cases,for example,low-frame-rate 2-D imaging,the optical readout has more advantages,such as simple,cheap and easy to use.Therefore,a gaseous detector was developed based on the thick gaseous electron multiplier(THGEM)and the ordinary scientific CCD camera as readout to realize the X-ray imaging instead of charge readout.Methods and materials The THGEMs with 60×60 mm^(2) sensitive area were developed to reach high gain,and the Ar+CF4 gas mixture was chosen for strong light emission.And so a general scientific CCD can be used for readout and replacing the intensified CCD,which is more expensive than general CCD.Results Some clear X-ray images were obtained by this optical readout THGEM detector,and the spatial resolution achieved is 275µm.It is indicated that this kind of detectors have promising imaging capability and great potential for practical application.

基于Camera Link总线的CCD高速图像采集技术

现代天文学研究越来越依赖于高质量的天文观测结果。针对天文实测的需要,对基于Camera Link总线的CCD高速图像采集技术进行了系统调研,分析对比了Camera Link总线技术及其优缺点,对基于Camera link接口的高速CCD采集技术进行了深入的研究,着重讨论了单缓存与双缓存高速采集技术和实现机制。经实际测试,所实现的技术稳定、可靠,CPU负载低,采集速度达到了厂家给出的CCD相机的最高采集速度,可以满足天文大数据量采集与准实时观测的需要。

Radiometric cross-calibration of the CBERS-02 CCD camera with the TERRA MODIS

For the application of the CCD camera, the most important payload on CBERS-02, the key is to provide long-term stable radiometric calibration coefficients. Although the vicarious calibration had been proved successful, it had its limitations such as test site requirement and unsuitable for historical data. Cross-calibration is one of the alternative methods, but it needs synchro surface spectrum to achieve spectral band matching factors. Our effort is to probe the influences on these factors. Simulations with a lot of surface spectrum showed that the factors changed with the viewing geometry, atmospheric condition and surface targets. However, simulating with the same viewing geometry and atmospheric condition, the spectral band matching factors of the same or similar surface targets’ spectrum acquired from different dates and different places would like to be consistent to each other within 1%―5%. Thus, the synchro measurement data can be substituted by the same or similar target from other source. Based on this method, using the MODIS as the reference, the cross-calibration was performed for CCD camera. The research demonstrated that the traditional method with single calibration site was inappropriate for CCD camera, since the offsets for its four spectral bands were not zeros. With four calibration sites, these offsets were obtained. And the camera was detected to degrade with dates based on four times of cross-calibrations.

基于Camera Link的线阵CCD外同步控制设计与实现

在纺织布匹疵点检测系统中,获取平稳清晰图像对后续布匹图像疵点的精确检测和类别正确识别至关重要。由于布匹疵点检测系统外部事件的不可预测性,如何控制线阵CCD以获取平稳清晰的图像。针对这一问题提出了一种线阵CCD相机外同步控制方法。该方法采用VHDL语言在Xilinx公司Virtex-II PRO FPGA架构上设计实现。重点介绍了相机自适应的外同步控制设计方案和实现方法,通过ModelSim仿真和布匹疵点检测系统的在线测试,验证了该方法的有效性和可行性。

Uncertainty analysis of cross-calibration for HJ-1 CCD camera

Radiometric calibration of sensor is the basis of quantitative remote sensing,and uncertainty analysis is critical to ensure the accuracy of cross-calibration.Therefore,firstly,cross-calibration formulas were improved by redefining calibration coefficient and spectral band matching factor.In these formulas,cci was redefined as the calibration coefficient of normalized apparent reflectance,and spectral band matching factor as the ratio of normalized apparent reflectance.Secondly,based on the contrast of ideal and actual conditions in cross-calibration,8 sources of cross-calibration uncertainty were proposed:calibration uncertainty of standard sensor;pixel matching uncertainty;spectral band matching factor uncertainty caused by site altitude setting error,atmospheric parameters setting error,surface spectrum source,surface bidirectional reflectance characteristic,and error of atmospheric radiative transfer model;and uncertainty caused by other factors which were not considered.Finally,the contribution of each uncertainty was further analyzed and discussed for the HJ-1 CCD camera.The results provide many valuable references for evaluating the feasibility of alternative cross-calibration measurements.

Numerical Simulations and Analyses of Temperature Control Loop Heat Pipe for Space CCD Camera

As one of the key units of space CCD camera,the temperature range and stability of CCD components affect the image's indexes.Reasonable thermal design and robust thermal control devices are needed.One kind of temperature control loop heat pipe(TCLHP) is designed,which highly meets the thermal control requirements of CCD components.In order to study the dynamic behaviors of heat and mass transfer of TCLHP,particularly in the orbital flight case,a transient numerical model is developed by using the well-established empirical correlations for flow models within three dimensional thermal modeling.The temperature control principle and details of mathematical model are presented.The model is used to study operating state,flow and heat characteristics based upon the analyses of variations of temperature,pressure and quality under different operating modes and external heat flux variations.The results indicate that TCLHP can satisfy the thermal control requirements of CCD components well,and always ensure good temperature stability and uniformity.By comparison between flight data and simulated results,it is found that the model is to be accurate to within 1℃.The model can be better used for predicting and understanding the transient performance of TCLHP.

Multi-digital Still Cameras with CCD

Digital still camera is a completely typical tool for capturing the digital images. With the development of IC technology and optimization-algorithm, the performance of digital still cameras(DSCs) will be more and more powerful in the world. But can we obtain the more and better info using the combined information from the multi-digital still camera? The answer is yes by some experiments. By using multi-DSC at different angles, the various 3-D informations of the object are obtained.

微小卫星高分辨率相机CCD焦面组件热控制

为了保证微小卫星高分辨率遥感器相机的成像品质,需控制焦面组件的温度水平及温度稳定性,特别是焦面CCD光学探测器件的温度控制。首先提出以相变储能与超低刚度柔性导热索相结合的焦面组件精密热控方法,对相变储能装置与石墨柔性导热索的设计及参数选取进行详细介绍;然后,建立焦面组件的热仿真模型并进行温度计算;最后,在真空环境下进行了热试验。计算与试验结果表明,焦面CCD器件长期温度为15~18.5℃,工作温升速率为0.33℃/min,具有良好的温度水平与温度稳定性;热控补偿功率≤4.8 W,约为焦面组件发热功率的1/10,可节省卫星能源消耗,验证了焦面组件热控制方法的正确性。

偏流角误差对TDI CCD相机成像的影响与仿真

本文分析了TDI CCD相机的偏流角调整过程和偏流角误差匹配的影响因素,依据偏流角误差导致的姿态稳定度偏差对相机成像质量的影响,建立推扫相机像点与物点一一对应的数学模型,根据TDI CCD成像时超出对应像素的横向与纵向偏移量的累加计算,仿真卫星姿态稳定度改变时相机的成像;同时,利用单轴气浮转台和面阵CCD进行成像实验,将实验条件的像移速度与仿真条件的像移速度匹配,并对面阵CCD成像进行偏移量的累加,模拟推扫CCD成像,最后利用图像对比度和互相关相似性测度分析仿真成像与实验成像质量。仿真成像与实验成像在对比度和互相关相似性测度上相差为0.03左右,能较好满足地面卫星相机连调试验的图像仿真。

环境一号卫星CCD相机应用于陆地气溶胶的监测

环境一号卫星CCD相机应用在陆地气溶胶的监测中,因缺少短波红外通道,使地表反射的去除变得异常困难.应用改进的暗目标法,利用辐射传输方程(6S)构建查找表,对CCD相机数据进行图像重采样和辐射定标处理,进而对查找表进行插值,获得气溶胶光学厚度(AOD)分布.通过AERONET地基数据的验证及与MODIS气溶胶产品的对比表明,环境一号卫星CCD相机对陆地气溶胶的监测结果在AOD较大(>0.2)时,精度与MODIS相近;在AOD较小(<0.2)时,结果欠理想.

大面阵彩色CCD航测相机的辐射定标

以大面阵彩色CCD航测相机为研究对象,分析其成像过程,提出了影响相机辐射响应特性的各个因素,并以此为基础,建立了辐射响应特性模型。分别在暗场和使用积分球的条件下进行了辐射响应标定实验,通过组合更改输入辐亮度、曝光时间和CCD增益等因素对相机的辐射响应特性进行测量和分析。结果表明,相机R、G、B颜色通道随输入辐亮度变化的辐射响应特性并不相同,但在工作谱段范围内均呈线性变化趋势。采用最小二乘法对辐射标定数据进行拟合,一次多项式拟合结果的决定系数R2值均可达到0.999以上。当输入辐亮度不变时,相机输出图像灰度值随曝光时间或CCD增益的变化呈线性变化趋势,从而为其它工作条件下辐射响应特性曲线的推演奠定了理论基础。将相机辐射响应标定结果应用于相机调光功能,成像结果表明,获得的图像亮度适中,图像平均灰度值满足调光要求。

空间高分辨率CCD相机次镜支架最佳结构设计

根据某空间高分辨率CCD相机的结构设计方案 ,利用结构设计软件Solidedge建立了次镜支架的结构分析模型 ,并利用有限元分析软件Vnastran对不同结构和尺寸的次镜支架进行了动力学分析计算 ,提出了次镜支架的鼓型偏置式四翼梁结构 该结构具有较高一阶谐振频率和良好的机械加工性能 。