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增强型电荷耦合器件(ICCD)是凝视成像三维激光雷达的关键器件之一。测量了在不同输入光强和不同像增强器增益电压条件下的光强以及噪声。根据光电探测过程,用泊松随机过程理论和最小二乘拟合法对测得的光强噪声数据进行了分析,发现噪声主要由来自于像增强器的等效光电子散粒噪声和电荷耦合器件(CCD)的光电子散粒噪声组成。尽管像增强器对光信号进行了放大,在大部分情况下,CCD的光电子散粒噪声也不可忽略。建立了双随机变量泊松过程的三维成像噪声模型,利用该模型给出了测距误差最小意义下的最优增益距离调制函数。
Enhanced Charge Coupled Device (ICCD) is one of the key components of 3D imaging lidar. The light intensity and the noise were measured under different input light intensities and different image intensifier gain voltages. According to the photoelectric detection process, the measured light intensity noise data are analyzed by Poisson random process theory and least-squares fitting method. It is found that the noise mainly consists of equivalent photoelectron shot noise and charge-coupled device CCD) photoelectron shot noise composition. Although image intensifiers amplify optical signals, the photoelastic shot noise of CCDs can not be neglected in most cases. A three-dimensional imaging noise model of Poisson process with two random variables is established. By using this model, the optimal gain distance modulation function with the smallest range error is given.