电子倍增CCD成像性能测试系统研究

发布时间：2018-01-19 00:36

本文关键词： EMCCD相机调制传递函数倾斜刀口法 Labview　出处：《南京理工大学》2017年硕士论文　论文类型：学位论文

【摘要】：光电系统的成像质量的客观评价一直是备受关注的问题,尤其是一些微光成像器件的成像性能评价对其相应的生产研发起到关键的指导性作用。微光成像器件中,由于EMCCD在性能上具有小型化、全固态器件不易损坏、光电转换效率高、被动式成像不易被发现等优点,使得EMCCD应用在夜间作战、侦察指挥、精确制导、光电对抗等军事应用领域发挥巨大作用。本文采用调制传递函数(MTF)来评价EMCCD相机整体的光学成像质量,EMCCD的光学调制传递函数不仅给器件制造者提出技术要求,还为EMCCD相机的设计和使用者提供了重要的参数。因此,本文对EMCCD相机的光学调制传递函数及其测定方法在以下几个方面进行了研究:本文针对EMCCD的高斯噪声分布特性,研究了倾斜刀口法测量离散采样器件的调制传递函数的理论,在确立了 EMCCD成像性能测试方法之后,搭建了适用于电子倍增CCD的成像性能参数测试的软硬件系统。使用正态分布模拟系统点扩散函数(PSF)对本测试系统软件算法做了仿真实验,对比已知PSF对应的真实MTF与本软件方法测得的MTF,验证了测试系统软件算法在噪声不大(噪声方差在0.015内)的情况下,所测结果MTF平均偏差在0.5%内。对本测试系统做了实际验证对比实验,通过比较同一 EMCCD相机在本测试系统和CI公司测试系统上的测试结果,MTF测量误差在2%范围内,表明本测试系统能满足电子倍增CCD成像性能参数的测试,测试结果能够真实反应EMCCD相机的MTF参数,并且可靠性高。使用本测试系统测试了 EMCCD倍增增益对MTF测量的影响,得出在EMCCD工作的线性范围内,电荷倍增过程略微降低了 EMCCD的MTF;使用本系统研究了刀口倾斜角度对EMCCD相机和PointGrey相机MTF的影响,表明了控制刀口倾斜角度在10度左右,能够精确的代表该相机的真实MTF值;使用本系统研究了不同光谱波段对PointGrey相机MTF测量结果的影响,表明了所测EMCCD相机对全波段的成像性能优于单一波段的成像性能,单一波段的成像性能中长波段成像性能优于短波段成像性能;使用本系统分别对三种不同的CCD相机在不同光照条件下的MTF测试结果并对比得出了三种相机在不同光照环境下成像性能的优劣。为实现EMCCD成像性能测试的高效性,使整个测试以及算法计算过程更加自动化,本系统采用了 Labview软件实现算法流程处理过程以及测试结果显示,使整个测量过程更加便捷。
[Abstract]:The objective evaluation of the imaging quality of optoelectronic systems has been a subject of great concern. In particular, the evaluation of the imaging performance of some LLL imaging devices plays a key guiding role in the production and development of LLL imaging devices, because of the miniaturization of the performance of LLL imaging devices. The advantages of all-solid-state devices, high photoelectric conversion efficiency and passive imaging are not easy to be found, which makes EMCCD used in night operations, reconnaissance and command, precision guidance. In this paper, the modulation transfer function (MTF) is used to evaluate the overall optical imaging quality of EMCCD camera. The optical modulation transfer function of EMCCD not only puts forward technical requirements for device makers, but also provides important parameters for the design and users of EMCCD cameras. In this paper, the optical modulation transfer function of EMCCD camera and its measurement methods are studied in the following aspects: this paper aims at the noise distribution characteristics of Gao Si in EMCCD. The theory of measuring the modulation transfer function of discrete sampling devices by slanting knife edge method is studied. After the EMCCD imaging performance testing method is established. A software and hardware system for testing the imaging performance parameters of the electron multiplication CCD is built. The software algorithm of the test system is simulated by using the point diffusion function of the normal distribution simulation system. By comparing the real MTF corresponding to the known PSF and the MTF measured by the software method, it is verified that the software algorithm of the test system has little noise (the variance of the noise is within 0.015). The average deviation of MTF is within 0.5%. By comparing the test results of the same EMCCD camera in this test system and CI company test system, the measurement error of the same EMCCD camera is in the range of 2%. The results show that the system can meet the performance parameters of electron multiplication CCD imaging, and the test results can truly reflect the MTF parameters of EMCCD camera. And the reliability is high. The effect of EMCCD multiplier gain on MTF measurement is tested with this test system, and the linear range of EMCCD operation is obtained. The charge doubling process slightly reduced the MTF of EMCCD. By using this system, the influence of knife edge tilt angle on EMCCD camera and PointGrey camera MTF is studied, which shows that the angle of controlling edge tilt is about 10 degrees. The true MTF value of the camera can be accurately represented; The influence of different spectral bands on the MTF measurement results of PointGrey camera is studied in this paper. The results show that the imaging performance of the EMCCD camera is better than that of the single band. The imaging performance of single band is better than that of short band. The MTF test results of three different CCD cameras under different illumination conditions were tested by this system, and the advantages and disadvantages of the three kinds of cameras under different illumination conditions were compared. Efficiency of performance testing. The whole test and algorithm calculation process is more automatic. The Labview software is used to realize the algorithm process and the test results show that the whole measurement process is more convenient.
【学位授予单位】：南京理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN386.5

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