基于回波闪烁效应识别光学目标的方法研究

为获取光学目标更多的特征信息、达到目标识别的目的，文中利用不同目标回波特征受到湍流大气调制作用的差异性，将目标回波的闪烁效应作为目标识别的手段之一。采用功率谱反演法生成随机相位屏模拟双程湍流大气扰动，利用硬边光阑展开为有限级数和的形式以及Collins衍射积分公式推导角反射器、镜头目标和朗伯漫反射体的反射光的复振幅分布，通过原路返回处的光强分布得到反射光的闪烁指数。分析了湍流强度和目标尺寸对上述三种目标回波的闪烁指数的影响，并进行了实验验证。研究结果表明:光学目标与漫反射目标回波的闪烁指数差别明显，整体相差一个数量级，随着口径的增大，光学目标回波闪烁指数整体上呈现减小的趋势；角反射器和镜头目标回波的闪烁指数在数值上差别不明显，但可以通过多组测试结果绘制回波闪烁指数随时间的变化曲线的方法将二者进行大致的区分。该方法可以快速地从漫反射背景中识别出光学目标，同时也为光学目标的分类识别提供了参考价值。

Research on optical target identification based on echo scintillation effect

In order to obtain more characteristic information of optical targets and achieve the goal of target recognition, the scintillation of target echo was considered as one of the means of target recognition by utilizing the difference of modulation characteristics of different target echoes in turbulent atmosphere. The random phase screen was used to generate round trip atmospheric turbulence by power spectrum inversion, using hard edged apertures to expand into finite series sum forms and Collins diffraction integral formula, the complex amplitude distribution of the reflected light of corner reflector, lens and reflector of Lambertian diffuse target was derived. The influence of turbulence intensity and target size on the scintillation index of the three target echoes was analyzed and verified by experiments. The results show that the scintillation index of optical target and diffuse reflection echo have obvious differences, the overall difference is an order of magnitude. With the increase of diameter, optical target echo scintillation index shows a decreasing trend on the whole; The scintillation index of corner reflector and lens target echoes in the numerical difference is not obvious, but the method of plotting the echo scintillation index over time by multiple test results can be used to distinguish the two roughly. This method can quickly identify the optical target from the diffuse background, and also provide a reference value for the classification and recognition of the optical object.