增益调制激光雷达弱信号的双阈值处理分析

在远距离弱信号条件下，增益调制激光雷达系统的测距精度受到强背景噪声的严重干扰。为了提高系统的测距精度，从系统基本工作原理出发，对增益图像进行双阈值化处理，得出了测距误差最小的阈值条件；考虑到阈值处理对目标与背景存在错误判断，结合增益调制像的概率分布函数定义了增益像和距离像的错误率函数。选取距离分别为1 930 m和1 940 m的两座建筑物作为目标进行成像实验。实验结果表明:双阈值化处理后，系统的测距偏差减小了58.3%，从而验证了双阈值化处理的可行性。通过对目标与背景实验结果的计算发现，目标距离的错误率存在极小值。

Analysis of weak signal processing of gain-modulated laser radar with double thresholds

The characteristics of gain-modulation laser radar images seriously affected by noise in the condition of long distant and weak signal were studied. For the purpose of improving the ranging precision, the processing method with double thresholds was proposed on the basis of the basic principle of the laser radar system. The minimum ranging error equation was obtained from the basic operation principle of gain-modulation laser radar. Considering faulty judgments between target and background with double thresholds processing method, the error probability functions were defined for gain-modulated images and range images. Two buildings at the distance of 1 930 m and 1 940 m were selected as targets for an outdoor experiment. The results show that distance error was reduced by 58.3%; the feasibility of double thresholds processing method was proved. On the other hand, the results show the error probability on double thresholds has a minimum.