为实现对运动目标实时指示激光束的非机械电控制,建立了基于光学相控阵的目标指示系统.首先,根据光学相控阵原理和空间光调制特性,对预设指示图添加共轭对称项,利用快速傅里叶变换计算全息法生成的全息图进行制表.其次,在图像传感器采集视频下,运用基于核函数密度估计的改进Mean-shift目标跟踪算法,获取多目标位置信息,查表并载入全息信息,完成全息图的实时更新.最后,利用空间光滤波特性,设计光电再现环节,消去冗余项并完成全息再现过程.实验发现:对8bit灰度全息图,系统每秒的指示速度均在60帧以上,各部件效能达到最大化.满足了目标指示系统稳定性、实时性、准确性等要求,理论算法和实验结果也验证了该系统的有效性.
In order to realize non-mechanical electric control for the laser beam for real-time moving target indication,a target indication system was established based on optical phased array.First,according to the principle of optical phased array and spatial light modulation characteristics,conjugate symmetric key to the default indicator diagram was added,then the calculating holography method of fast Fourier transform was used to generate holograms for tabulation.Secondly,under the charge-coupled device video capture environment,the improved Mean-shift tracking algorithm based on kernel density estimation was used to obtain information of target position,looked up in the table and loaded the holographic information to complete hologram real-time update.Finally,taking advantage of spatial light filtering characteristics, optoelectronic reconstruction step was designed,superfluous term was eliminated and the holographic reproduction process was completed.Experimental results show that the system speed is in more than 60 frames per second on 8bit gray scale hologram and all parts to maximize effectiveness.It can satisfy the system requirements of real time,higher precision and stabilization.The theoretical algorithm and experimental results also verify the effectiveness of the system.