光电经纬仪自适应调焦窗口构建

Design of self-adaptive focus window for photoelectrical theodolite

为解决靶场测量中基于图像处理的光电经纬仪自动调焦过程中计算量大和背景干扰的问题,提出一种大小和位置自适应目标变化的调焦窗口构建方法。该方法利用Mean-shift算法进行跟踪获得目标位置信息,并以目标中心位置为参考点,计算图像像素归属度;使用Log-Gabor滤波器组和高斯差分模型模拟人类视觉系统进行显著性检测,以归属度加权的视觉显著性特征确定目标区域,结合Epanechnikov核函数构建自适应核函数,降低目标尺度变化及背景像素的影响,实现目标的有效跟踪。对目标区域利用对角邻域法进行边界扩展,构建自适应目标变化的调焦窗口。在某型号光电经纬仪上的实验结果证明,该方法能够实时、有效地跟踪目标并构建调焦窗口。处理720piexl×576piexl大小的图像,耗时小于20ms,满足光电经纬仪实际需求,具有广泛的工程应用价值。

In order to build a right focus window to cut down the compute time and overcome the disturbance of the background for the photoelectrical theodolite in range measurement,a novel method is proposed.Firstly,the method regards the target＇s centroid gotten by the Mean-shift tracking algorithm as the reference point to compute the adscription of pixel.Secondly,visual saliency weighted by the adscription is detected by Log-Gabor filters and the Gaussian difference model to ascertain the target area.Then,the adaptive kernel function is designed to track the target combined with the Epanechnikov function,which can reduce the effects of fixed track window and background pixels.Finally,the focus window is built with boundary extension by the estimating diagonal area,and the size and position of the focus window are self-adaptive with the target.After plenty of experiments on the photoelectrical theodolite,the results show that the proposed method can effectively track moving targets in real time and build focus window exactly.To deal with image of 720pixel×576pixel,the compute time is less than 20 ms.The proposed method satisfies the practical demand of the photoelectrical theodolite and is of great value for engineering application.