EMCCD电子倍增增益校正方法研究

发布时间：2018-07-05 07:26

本文选题：EMCCD + 增益校正　；参考：《昆明理工大学》2015年硕士论文

【摘要】：由于电子倍增电荷耦合器件(EMCCD)独特的电荷倍增机制,特别合适于对亮度极微弱的目标进行探测和成像。但是由于EMCCD在使用的过程中,电子倍增增益会发生改变,从而影响EMCCD成像系统的成像质量。为了提高EMCCD成像系统的性能,研制具有增益校正功能的EMCCD成像系统,在本课题研究期间,我们对TI公司的EMCCD的倍增过程进行了深入的分析和研究,提出了确定EMCCD电子倍增增益的方法,并设计了增益校正电路。在本学位论文中,首先提出了一种确定EMCCD增益的方法,该方法通过分析Robbins提出的增益模型,利用TI公司提供的EMCCD器件(TC285和TC253)数据资料,分别计算这两种器件在该模型中的参数c值,并用多元回归分析的方法建立了这两种器件的关键参数c的数学模型,从而确定了EMCCD增益校正模型的表达式。该增益校正模型可以准确计算经过一定老化时间后不同的温度条件下的电子信号通过EMCCD多级级联倍增寄存器的平均增益,进而可以用于EMCCD成像系统的增益调整和校正。然后针对EMCCD增益校正模型,根据增益校正模拟电路的整体设计和要求,分别叙述了各模拟单元电路的工作原理,对关键模拟器件进行选型,利用Pspice软件对主要单元电路进行原理图的设计和仿真,整合各单元电路,对增益校正模拟电路系统原理图进行Pspice仿真,仿真计算结果和增益校正模型的理论计算结果基本一致。对于增益校正数字电路,我们采用VHDL编程与Altera提供的IP核相结合的方式,设计了基于CORDIC算法的对数、指数变换器,利用IP核实现乘法、除法、反相等功能。通过功能仿真,实现了各数字单元电路的精确运算。连接各单元电路,比较增益校正数字电路的仿真结果与增益校正模型的理论计算结果,二者几乎一致。最后,从数据处理速度、仿真输出结果的精度、资源消耗和实现的难易程度几个方面分析比较EMCCD增益校正模拟电路和EMCCD增益校正数字电路系统性能,结果表明,EMCCD电子倍增增益校正数字电路更适用于EMCCD成像系统的增益校正。
[Abstract]:Due to the unique charge doubling mechanism of the electron multiplication charge coupled device (EMCCD), it is especially suitable for detecting and imaging targets with very weak brightness. However, during the use of EMCCD, the gain of electron multiplication will change, which will affect the imaging quality of EMCCD imaging system. In order to improve the performance of EMCCD imaging system, an EMCCD imaging system with gain correction function is developed. During this research period, we deeply analyzed and studied the multiplication process of EMCCD produced by TI Company. A method for determining the electron multiplication gain of EMCCD is presented, and a gain correction circuit is designed. In this dissertation, a method to determine the gain of EMCCD is proposed. By analyzing the gain model proposed by Robbins, the data of EMCCD devices (TC285 and TC253) provided by TI are used. The parameter c of the two devices in the model is calculated, and the mathematical model of the key parameter c of the two devices is established by multivariate regression analysis, and the expression of the EMCCD gain correction model is determined. The gain correction model can accurately calculate the average gain of the electronic signal passing through the EMCCD multistage cascade multiplication register at different temperatures after a certain aging time, and then can be used for the gain adjustment and correction of the EMCCD imaging system. Then according to the EMCCD gain correction model, according to the overall design and requirements of the gain correction analog circuit, the working principle of each analog cell circuit is described, and the key analog devices are selected. The principle diagram of the main unit circuit is designed and simulated by using PSpice software. The system schematic diagram of the gain correction analog circuit is simulated by PSpice. The simulation results are basically consistent with the theoretical calculation results of the gain correction model. For the gain correction digital circuit, we design the logarithmic and exponential converter based on Cordic algorithm by combining VHDL programming with IP core provided by Altera. We use IP core to realize multiplication, division and inverse equality. Through the function simulation, the precise operation of each digital unit circuit is realized. The simulation results of the gain correction digital circuits are compared with the theoretical results of the gain correction model. Finally, the performance of EMCCD gain correction analog circuit and EMCCD gain correction digital circuit system are analyzed and compared from the data processing speed, the precision of simulation output, the resource consumption and the degree of difficulty in implementation. The results show that the EMCCD digital circuit is more suitable for the gain correction of EMCCD imaging system.
【学位授予单位】：昆明理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN386.5

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