论文部分内容阅读
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 quantitatively evaluate the size of image noise of electron multiplying CCD (EMCCD), the noise parameter of EMCCD image is estimated accurately, and the noise distribution model of EMCCD and its parameter estimation method are studied. First of all, the sources of noise and its statistical properties of EMCCD images are discussed, and a noise distribution model suitable for EMCCD is established. Then, two EMCCD noise parameter estimation methods - moment estimation method and Gauss-Newton method are proposed, and their performances are verified by Monte Carlo simulation. The simulation results show that the average relative error and the relative standard deviation of the moment estimation method and the Gauss-Newton method are all 10-2 orders of magnitude, and the estimation accuracy is high. Moreover, the estimation accuracy of the Gauss-Newton method is higher than that of the moment estimation method. A series of dark field images with integral time of 50 s without gain and background images with gain of 50 were collected. The dark current noise, clock induced charge noise and readout of EMCCD were estimated respectively by moment estimation method and Gauss-Newton method The experimental results show that the estimated values are consistent with the EMCCD values, which shows that the moment estimation method and the Gauss-Newton method can effectively estimate the noise parameters with high accuracy.