从噪声来源出发,基于入射光子、暗电流、偏置信号的涨落均近似满足泊松分布的条件,得到了更为精准的信噪比表达式。实验设置CCD增益、读出速率、冷却温度分别为3、100k Hz、-25°C,得出光子转移曲线。通过设置不同实验条件,分别探讨了暗电流、读出速率和系统增益对该科学级光学CCD信噪比的影响。实验结果与理论预期吻合得很好,为科学级光学条纹相机的设计以及弱光标定实验室自动化平台的搭建提供了良好的实验依据。
Based on the noise source, considering that the fluctuations of incident photons, dark current and biased signal satisfy the Poisson distribution, the corrected signal-to-noise-ratio(SNR) relation is obtained. On condition that the gain, readout rate and cooling temperature of CCD are set experimentally to be 3, 100 k Hz and-25°C respectively, the photon transfer curve is obtained. Meanwhile, by setting different experimental conditions,the effect of the dark current, readout rate and the system gain on the SNR of the scientific grade optical CCD is discussed respectively. The experimental results are in good agreement with the theory, which provides the good experimental basis for design of the scientific grade optical streak camera and building of the automated laboratory platform used for weak light calibration.