生物芯片扫描仪CCD背景噪声研究

Study on the background noise of CCD in biochip scanner

冷CCD(Cool CCD)是生物芯片扫描仪的核心检测器件,其背景噪声直接影响到检测精度。CCD背景噪声可分为光子噪声、热噪声、读出噪声和量化噪声。其中热噪声Hn与读出噪声Rn最为核心,采用拍摄暗场帧的方法对其进行实验研究。实验表明对于某一指定曝光时刻,背景噪声图像各像素的强度可认为符合正态分布,并可将均值与标准方差的估计值即■与■作为其相应正态分布的表征参数。■与■的95%置信区间较小,最大区间长度分别占■与■的0.16%和28.36%。在此基础上讨论了温度、曝光时间对均值与方差的影响。

Cool CCD is the key detecting parts in microarray scarmer, whose background noise is important to detection precision. The background noise of cool CCD consists of photon noise, thermal noise, readout noise and quantization noise. Dark frame of the cool CCD was taken to analyze the thermal noise （Hn） and reading noise （Rn）, which are the main part of the background noise. From the experiment, it is shown that intensity of the pixel in dark frame follows the normal distribution. The estimated ^μ and ^σ could be used to analyze the parameter of the distribution. The ^μ and ^σ and a have small section with 95% confidence interval. The maximum distance of ^μ and ^σ are 0.16% and 28.36% individually. Special attention is given to the effect of cooling temperature and exposure time on median and standard variance.