Noise analysis and measurement of time delay and integration charge coupled device

Time delay and integration （TDI） charge coupled device （CCD） noise sets a fundamental limit on image sensor performance, especially under low illumination in remote sensing applications. After introducing the complete sources of CCD noise, we study the effects of TDI operation mode on noise, and the relationship between different types of noise and number of the TDI stage. Then we propose a new technique to identify and measure sources of TDI CCD noise employing mathematical statistics theory, where theoretical analysis shows that noise estimated formulation converges well. Finally, we establish a testing platform to carry out experiments, and a standard TDI CCD is calibrated by using the proposed method. The experimental results show that the noise analysis and measurement methods presented in this paper are useful for modeling TDI CCDs.

Investigating the Thermal Stress of Millisecond Pulsed Laser Irradiation on Charge-Coupled Devices

In this study, a two-dimensional model describing thermal stress on a charge-coupled device (CCD) induced by ms laser pulses was examined. Considering the nonlinearity of the CCD’s material parameters and the melting phase transition process of aluminum electrode materials was considered by using equivalent specific heat capacity method, the physical process where a laser pulse irradiating a CCD pixel array was simulated using COMSOL Multiphysics software. The temperature field and thermal stress field were calculated and analyzed. In order to clarify the mechanism producing damage on the CCD detector, Raman spectra from silicon were measured with a micro-Raman spectrometer to determine stress change in the CCD chip. The procedure presented herein illustrates a method for evaluating strain in a CCD after laser irradiation.

Surface contamination of the charge-coupled device

An experimental method to study the influence of surface contamination of a thinned, backside illuminated charge-coupled device(CCD) upon its quantum efficiency in soft X-ray region is suggested. A transmission grating spectrometer(TGS), in which the transmission grating is coupled to a thinned, backside illuminated charge coupled device, is used to measure the continuum X-ray emission from the end of cylindrical target irradiated by laser. In the measured spectra, only the carbon K absorption edge at wavelength of 4.4 um due to condensation of the vacuum oil oil the CCD surface is clearly seen. The surface contamination is considered as an effective "carbon filter" and the filter absorption to correct the quantum efficiency of the CCD camera is taken into account. The effective thickness of the carbon filter is determined by comparing the jump height of the measured spectra at 4.4um with those of the carbon absorption coefficient curves obtained from various carbon thickness. The accuracy of this method is tested by comparing the X-ray spectrum measured by the TGS with that obtained by a soft X-ray spectrometer.

Charge Couple Device-Based Systemfor3-di mensional Real Ti me Positioning on the Assessment of Segmental Range of Motion of Lumbar Spine

Objective： To observe the tested results of the segmental range of motion （ROM） of lumbar spine by charge couple device （CCD）-based system for 3-dimensional real-time positioning （CCD system）, and to analyze its clinical significance. Methods： Seven patients with lumbar joint dysfunction and 8 healthy subjects were tested twice by the CCD-based system with an interval of 10 min. Results： The ROM of the patients was obviously lesser than that of the healthy subjects. The measuring data of segmental ROM of lumbar spine by CCD system is correlated significantly to the same data checked later on the same subjects in every direction of the movements. The differences between two checks are usually less than 1 degree. Conclusion： Specially designed CCD based system for 3-dimensional real-time positioning could objectively reflect the segmental ROM of lumbar spine. The system would be of great clinical significance in the assessment of the biomechanical dysfunction of lumbar spine and the effect of the treatment applied.

Measurement of cathode surface temperature using the method of CCD imaging in arc discharge

A two-wavelength pyrometry device using ordinary array CCD (charge coupled device) to collect the ra- diation data in the horizontal and vertical directions has been developed for measuring the cathode surface temperature during the arc discharge. Analyses of experimental results show that the device can make the measurement of the cathode surface temperature feasible. The cathode surface temperatures measured are lower than the melting point of tungsten (3653 K), and the arc current, cathode diameter, and the cathode length are the main influencing factors of the cathode surface temperature.

Calibration and Monte Carlo simulation of a single-photon counting charge-coupled device for single-shot X-ray spectrum measurements

A Princeton Instruments PI-LCX 1300 charge-coupled device （CCD） camera used for X-ray spectrum measurements in laser-plasma experiments is calibrated using three radioactive sources and investigated with the Monte Carlo code Geant4. The exposure level is controlled to make the CCD work in single photon counting mode. A summation algorithm for obtaining accurate X-ray spectra is developed to reconstruct the X-ray spectra, and the results show that the developed algorithm effectively reduces the low-energy tail caused by split pixel events. The obtained CCD energy response shows good linearity. The detection efficiency curves from both Monte Carlo simulations and the manufacturer agree well with the experimental results. This consistency demonstrates that event losses in charge collection processes are negligible when the developed summation algorithm of sDlit Dixel events is emDloved.

Surface diffuse discharge mechanism of well-aligned atmospheric pressure microplasma arrays

A stable and homogeneous well-aligned air microplasma device for application at atmospheric pressure is designed and its electrical and optical characteristics are investigated. Current-voltage measurements and intensified charge coupled device （ICCD） images show that the well-aligned air microplasma device is able to generate a large-area and homogeneous discharge at the applied voltages ranging from 12 kV to 14 kV, with a repetition frequency of 5 kHz, which is attributed to the diffusion effect of plasma on dielectric surface. Moreover, this well-aligned microplasma device may result in the uniform and large-area surface modification of heat-sensitive PET polymers without damage, such as optimization in hydrophobicity and biocompatibility. In the biomedical field, the utility of this well-aligned microplasma device is further testified. It proves to be very efficient for the large-area and uniform inactivation of E. coli cells with a density of 103/cm2 on LB agar plate culture medium, and inactivation efficiency can reach up to 99% for 2-min treatment.

The nonlinearity measurement of charge-coupled device array spectrometer using colorful LED

A nonlinearity measurement of the charge-coupled device(CCD) array spectrometer using flux addition and comparison method is described. The light with various colors from the colorful light emitting diode(LED) light source is applied to measure the nonlinearity of the spectrometer at different wavelengths, respectively. An high-end CCD array spectrometer is tested. For colorful LED light sources, the nonlinearity factors of the CCD array spectrometer(absolute value) are as follows: k<0.8% for white light, k <1.1% for red light, k <2.2% for green light and k<4.7% for blue light. By using those quasi-monochromatic light sources, it is shown that the nonlinearity depends on the wavelength. It is important to be wariness about the spectral nonlinearity and related uncertainty evaluation when the narrow-band light source is tested.

基于线阵CCD的实验教学平台设计

在光电类课程的实验教学中,电荷耦合器件(CCD)是一个重要内容,传统的相关实验教学一般以演示性实验为主,导致学生对该器件的了解不够深入。该文提出一种适合各种线阵CCD的综合实验平台,采用该平台学生可以自主进行CCD驱动电路的设计实验、积分时间调节实验、角度测量实验和长度测量实验等。通过使用该平台,有助于提高学生的线阵CCD使用能力、单片机调试能力、基于LabVIEW的软件编程能力、电路板焊接能力和光路搭建能力。

多光谱TDICCD航天相机快视一体化地面检测系统设计与实现

针对多光谱时间延迟积分电荷耦合器件(Time Delay Integration Charge Coupled Devices,TDICCD)航天相机的产品研发,提出快视一体化地面检测系统的设计方案,并依托项目实现该设计方案。设计包括主机系统搭建、CXP(CoaXPress)高带宽数传采集卡、测控采集卡、图采测控上位机、光电参数测试、非均匀性校正以及刷新芯片重注等实现。采用一体化设计,所有软硬件全部集成于地检主机系统,方便携带和使用。采用模块化设计方法,使用通用的主机接口,实现多种采集卡在不同主机系统之间交叉使用;使用通用的数据传输接口、RS-422传输接口,使得采集卡不仅适用于本相机的接口协议,也能在修改现场可编程逻辑门阵列(Field Programmable Gate Array,FPGA)代码后适用于其他相机。经验证,该地面检测系统能有效完成多光谱TDICCD航天相机的功能测试、光电参数性能测试的要求,为项目顺利进行提供有力保障。

亚像元的CCD几何超分辨方法

为了在现有CCD像元尺寸的基础上提高CCD像元分辨力,对CCD几何超分辨问题进行了研究。从研究现状入手,给出了现有算法及其不足,建立了亚像元超分辨成像数学模型,提出了亚像元的CCD几何超分辨方法。该方法将两片线阵CCD集成在同一器件中,在线阵方向上错开半个像元,同时读出时间减半,最终交织重组图像数据,以合成高分辨率图像。利用MATLAB7.0.1软件对双线性插值方法及亚像元成像方法进行了仿真,并定性定量地分析了两种方法的效果。结果显示:亚像元方法合成图像分辨率约为低分辨率图像的2倍,且两组仿真图像中的PSNR比双线性插值图像分别高出1.4864dB和2.2070dB。该方法可以显著地减轻欠采样引起的图像模糊,且实时性优于双线性插值方法。

一种新型CCD驱动电路设计方法

在结合直接数字电路驱动法与单片机口驱动法的基础上,设计了一种新型的CCD驱动电路,保留了原有两种方法各自的优点。仿真与实验结果表明该方法能提供多路驱动时序,驱动频率高,硬件电路简单,编程方便,具有较好的性价比及应用推广价值,已用于CCD图像采集系统的研制。

基于CCD的智能车导航系统研究

目前智能车导航大多采用摄像机来获取路面信息,针对这一特点研究开发了基于CCD的导航模块.详细介绍了CCD视频信号的采集及处理方法.考虑到环境光线的变化会影响导航效果,提出了一种自适应动态阈值图像处理算法;该算法运算量小,能跟踪环境光线的变化.同时给出了系统抗干扰的处理方法,从而有效解决了因外界光线和赛道变化引起的智能车跑偏问题.通过系统实验和竞赛,证明了该导航系统具有良好的智能性和抗干扰能力,即此方案是有效的.

基于HJ卫星CCD数据的冬小麦病虫害面积监测

遥感在农作物病虫害监测中广泛采用的简单植被指数阈值法难以判别冬小麦的健康状况。该研究选择二值逻辑回归法,分别建立实测光谱得到的植被指数与其健康状况之间的关系模型。结果表明,重归一化植被指数RDVI模型和三角植被指数TVI模型可信度较好。考虑到遥感监测冬小麦病虫害时,涉及的地域范围广,冬小麦生长状况存在明显的局域差异,采用了3×3邻域像元的一致性假设消除局部环境差异。将模型应用到中国新近发射的环境与灾害监测预报小卫星星座HJ-CCD传感器数据,得到提取的冬小麦受病虫害胁迫范围与枣阳市植保站普查结果相符,也与地面实测结果相一致,其中,TVI模型结果的精度达到76.47%,能够满足农作物病虫害面积遥感监测要求。

CCD光电自准直仪工作原理及误差源分析

主要介绍了CCD光电自准直仪的工作原理并进行了误差源分析。

电容器铝壳表面缺陷检测的CCD图像处理

在铝电解电容器铝壳生产过程中,为了确保产品品质,降低消耗,应快速检测铝壳表面发生的质量情况,对异常现象能及时地作出报警、停机或自动分离提供判断依据。首先对采集到的铝壳图像进行灰度处理、中值滤波、二值化和边缘检测等处理,然后通过缺陷特征的提取,确定铝壳样件是否存在表面缺陷,根据检测结果将有缺陷的样件筛选出来。通过对主要缺陷样件的检测结果表明通过机械辅助设备可以实现在1s内同时检测约20个样件,能够满足整体加工流程对快速检测表面缺陷的技术要求。

基于Kerr电光效应的冲击电压下液体电介质空间电荷高速CCD测量

空间电荷的存在直接影响液体电介质的绝缘击穿性能,为了更好地研究空间电荷的动态变化过程,建立了基于Kerr电光效应的冲击电压下液体电介质空间电荷的高速电荷耦合器件(CCD)测量系统。运用高精度光电传感器的测量方法,得到了室温下液体碳酸丙烯酯的Kerr常数。进而通过高速CCD的动态光电测量,并结合图像处理技术,求取了冲击电压下平行板铜电极间电场和空间电荷的动态分布曲线。实验研究表明:在平行板铜电极间,当液体介质中电场达到一定程度时会出现空间电荷的注入与输运,使得极间电场呈现出中间高两边低的分布情况。另外还分析了空间电荷的分布和输运对液体绝缘特性的影响,该研究为分析冲击电压作用下液体介质中空间电荷的产生机制及空间电荷对流注放电的影响奠定了基础。

基于CCD成像的侧向散射激光雷达几何标定方法

通过分析CCD成像特点,设计了侧向散射激光雷达几何标定实验,得到CCD各像元的角宽度,并确定了CCD像元与散射光位置之间的对应关系.对两次实验中采集的回波信号进行标定,并分别与POM02进行相函数比对、与后向散射激光雷达进行探测信号比对,结果表明:相函数廓线和POM02测量结果相吻合;侧向散射激光雷达信号与后向散射雷达的距离修正信号在650m以上的变化趋势一致.侧向散射激光雷达弥补了后向散射激光雷达在近地面段不能探测气溶胶的不足,该标定方法可靠,为进一步利用侧向散射激光雷达研究近地面气溶胶的时空分布奠定了坚实的基础.

运用彩色CCD测量火焰温度场的校正算法

讨论了基于彩色ＣＣＤ（ 电荷耦合器件） 的火焰温度测量的比色法，对其主要的两个误差来源（带宽和灰度）进行了分析，提出了误差校正方法。在某电厂的锅炉上进行了验证性试验，结果表明，这种测温方法方便可行，具有一定的应用前景。

高速CCD相机系统设计

采用KAF-1001芯片研制出了高速科学CCD相机。详细介绍了CCD相机的数据采集原理,CPLD在CCD时序中的控制,FX2系列CY7C68013 USB芯片在高速CCD相机数据传输上的运用及利用VC++开发的相机图像采集软件。通过对开发的样机所做的实验及数据分析表明,相机性能达到了高速科学CCD相机的要求,并提供了CCD相机的各项技术指标。