为了进一步提高激光主动探测系统对光学目标的探测识别能力, 提出了一种利用扫描干涉场将目标的空间分布特征加载到反射光时间序列信号中, 通过反射光时间分布的特征差异在复杂漫反射背景中探测光学目标的新方法。基于马赫-曾德尔干涉光发生体制, 得到了远场干涉图样条纹间距与传输距离、M-Z干涉光发生装置参数和激光波长的关系式。分析了条纹间距对不同目标原路返回点处光强时间分布特性的影响。搭建了演示验证平台, 结果显示, 随着干涉场的条纹间距减小, 光学目标的反射光时间分布峰峰数增多, 峰峰比降低, 而漫反射目标没有明显变化。漫反射目标和光学目标的反射光时间分布的方差、偏度和峰度等统计特征差异明显, 其中峰度值分别为(4.37,62.8)、(4.03,34.97)和(3.91,35.4), 整体相差一个数量级。利用反射光时间分布的包络形态和统计特征的较大差异可快速区分光学目标与漫反射背景。

A new method has been proposed to improve the detection and recognition of optical targets using a laser active detection system. The proposed method uses the scanning interference field to transform the spatial distribution of the target into the time distribution of the detected light, and uses the characteristics of the time distribution of the reflected light for identifying optical targets in a complex background. Expressions giving the optical path difference of coherent beams at any point in the far-field interference light field based on the principle of the Mach-Zehnder interferometer, and the fringe spacing in the interference pattern are obtained. The influence of the fringe spacing in the interference pattern on the time distribution of the light intensity at the point of reflection onthe original target was analyzed. The results revealed that a decrease in the fringe spacing, while causing an increase in the number of peaks in the time distribution of light reflected from the optical target and a decrease in the peak ratio, resulted in no significant change in the time distribution of light reflected from the diffuse background The variance, skewness, and kurtosis of the time distribution of light reflected from the diffuse backgroundand optical target are evidently different. For example, we have observed kurtosis values of 4.37, 4.03, 3.91, and 62.8, 34.97, 35.4, respectively, for the two time distributions, reflecting an overall difference of one order of magnitude. The results indicate that the large differences in the time distribution of reflected light, envelope shape, and statistical characteristics can be used to easily distinguish between the optical target and diffuse background.