电子倍增CCD噪声参数的估计方法

Estimation method for noise parameter of electron multiplying CCD

为定量评价电子倍增CCD(EMCCD)图像噪声的大小,实现对EMCCD图像噪声参数的准确估计,研究了EMCCD的噪声分布模型及其参数估计方法。首先,讨论了EMCCD图像的噪声来源及其统计特性,由此建立了适于EMCCD的噪声分布模型。然后,提出了两种EMCCD噪声参数估计方法——矩估计法和高斯-牛顿法,采用Monte Carlo仿真验证其性能。仿真结果表明,矩估计法和高斯-牛顿法的平均相对误差和相对标准偏差均为10-2量级,估计精度较高,且高斯-牛顿法的估计精度要高于矩估计法。采集一系列无增益时积分时间为50 s的暗场图片和增益为50的本底图片,利用矩估计法和高斯-牛顿法分别估计出EMCCD的暗电流噪声、时钟感生电荷噪声和读出噪声,实验结果表明,估计值与EMCCD指标值一致,证明矩估计法和高斯-牛顿法能有效估计噪声参数且具有较高的精度。

In order to evaluate the size of image noise of electron multiplying CCD（EMCCD）quantitatively and achieve an accurate estimation of the EMCCD image noise parameters,the ECMMD noise distribution and its parameter estimation methods were studied.Firstly,the sources and statistical properties of EMCCD noise were discussed,and thereby an EMCCD noise distribution model was established.Then two EMCCD noise parameter estimation methods--the moment estimation method and the Gauss-Newton method were proposed and Monte Carlo simulation was done to verify their performance.The results show that both the average relative error and the relative standard deviation of the two methods are of 10-2magnitude,presenting high estimation accuracy,and the Gauss-Newton method get better performance.With integration time of 50 s,a series of EMCCD images of the dark field with no gain and images of the background with gain of 50 were obtained.Using the moment estimation method and the Gauss-Newton method,the dark current noise,clock induced charge noise and readout noise were estimated.The results present that the estimated value is consistent with the EMCCD index value,which proves the moment estimation method and the Gauss-Newton method are able to estimate the noise parameter effectively and has a high accuracy.