In order to reduce the interference of atmospheric turbulence and background light on the beacon light,and reduce the influence of turbulence on the optical axis alignment accuracy,optical axis alignment algorithm is studied based on the analysis of Gaussian beam model.First the background light model was analyzed,background noise was filtered according to image model dynamic,then horizontal and vertical mathematical statistics was made according to the beam energy distribution.The spot region was judged by Bayesian discrimination,the spatial filtering of the laser optical axis was achieved in the large field of view.Finally,following the least-squares principle,spot image fitting curve was gained by the Gaussian fitting.And then according to the dynamic curve of each frame image,the extraction of the Gaussian centroid was completed,the optical axis detection accuracy was further improved.The accuracy of the spot image was confirmed by 6.5 km field experiments,the obtained spot image accuracy is 18 μrad,it is about 12 pμ rad higher than traditional centroid fitting accuracy under the same conditions.%为了降低大气湍流和背景光对信标光的干扰,减小湍流对光轴对准精度的影响,在分析高斯光束模型的基础上对光轴对准算法进行了研究.首先分析背景光模型,根据其图像模型动态滤除背景噪声,然后根据光束能量分布做横向与纵向的数学统计.采用贝叶斯判别方法对光斑区域进行判决,进而实现大视场范围内激光光轴的空间滤波,最后在遵循最小二乘原则的前提下进行高斯拟合,获得光斑图像拟合曲线,进而根据每一帧图像的动态曲线完成高斯质心的提取,进一步提高光轴检测精度.通过6.5 km的野外实验证实高斯拟合算法得到的光斑图像精度为18 μrad,比相同条件下的传统质心拟合精度高出约12 μrad.
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