CCD图像传感器降噪技术的研究

Noise reducing scheme on output signal of CCD

根据 CCD输出噪声的特点 ,CCD视频处理电路的目的是消除 KTC噪声 ,抑制低频噪声和宽带白噪声。文中分析了三种抑制噪声的方法 ,相关双采样法、双斜积分法、开关指数滤波法。这三种方法都是在一象素周期内进行前后两次采样 (或积分 ) ,系统的输出为两次采样之差 ,从而获得视频信号。文中不仅介绍它们的工作原理、推导噪声传输函数 ,而且详细分析各自的特性。

Based on properties of noise on the output signal of CCD, signal processing schemes used to reduce the effect of KTC noise and to attenuate 1/f and broadband write noise are analysed. These schemes employ time delay and subtraction to eliminate KTC noise and attenuate 1/f noise. They also include a low pass function to reduce the effect of broadband write noise. Signal processing schemes described in this paper are double correlated sampling, dual slope integration and switched exponential filtering. Each of these schemes' principle is discussed and presented, its transfer functions is deducted in this paper. Performance comparisons are given with emphasis on their applicability in high speed CCD readout applications.