信噪比是微光成像系统的关键参数, 决定了成像系统的性能与成像质量。给出了互补金属氧化物半导体(Complementary Metal-Oxide-Semiconductor, CMOS)图像传感器微光成像系统的信噪比模型, 仿真计算了系统的信噪比与信号、噪声的关系。搭建了信噪比测试环境, 完成了系统信噪比测试实验。实验结果表明, 理论值与实测值一致。最后, 根据信噪比分析结果对给定系统进行了参数优化。计算结果显示, 优化后的系统在1 mLux照度下, 信噪比能达到4.5。信噪比的研究为基于CMOS微光成像系统的总体设计与优化提供了理论依据。

Signal-to-Noise Ratio (SNR) is a key parameter for low light level imaging systems. It determines the performance and image quality of an imaging system. A SNR calculation model of low light level imaging systems based on CMOS imaging sensors is given. The relationship between the SNR and the signal and noise of a system is simulated. A SNR test environment is set up and SNR test experiment is completed. The experimental results show that the theoretical value is consistent with the measured value. Finally, the parameters of a given system are optimized according to the SNR analysis results. The calculation results show that the optimized system improves its SNR up to 4.5 under 1 mlux. This study of SNR provides the theoretical basis for the overall design and optimization of low light level imaging system based on CMOS image sensors.