高功率激光光束的自准直算法

Automatic Alignment Algorithm of High-power Laser Beam

为满足高功率激光装置全程光路自动准直快速性及高精度的要求,提出了一种光斑对应椭圆的长短轴差值法对光斑形状调节,并结合重心法快速、高精度的获取光斑图像中心位置.利用大律法、3×3邻域法及8向链码法对光斑图像进行处理,得到面积最大的光斑;分析最大光斑区域中心距,求出最大光斑对应椭圆的长短轴长,并根据长短轴差值调节光斑形状,至长短轴差值近似为零,获得形状最规则的光斑;分析形状最规则光斑的中心位置与其基准位置在x和y方向的偏差,并将该差值转为闭环控制的步进电机所需要调整的步数,实现激光光束的自准直.该算法应用在高功率激光装置中,结果表明,主放大光路的准直时间缩短为15min,近场准直的准确度优于0.2%,远场指向准确度优于1μrad,满足高功率激光光束的准直要求.

A quick and high-precision image center locating algorithm based on the difference between the corresponding ellipse′s long and short axe method was proposed,to meeting the requirements for high precision and time-saving in real time beam automatic alignment process of the high power laser device.The maximum value of the spot′s area is obtained by acting the Big Law Method,3×3 Neighborhood Method and Eight-Neighborhood Method on the spot image in turn;Lengths of the long and the short axis are obtained by the analyzing the center distance of the maximum spot,and adjust the spot shape by the deviation of the ellipse′s long and short axe until to the deviation approach to zero;Through analysis the deviation between the actual spot center and the corresponding reference position,the adjusting steps of stepping motor controlled by the closed-loop control method is obtained,and the automatic alignment is realized.This algorithm is verified in the high-power laser device,the experiment results shows that the alignment time of the main amplification of the optical path is shortened to 15 min,the near-field alignment accuracy is better than 0.2%,and the far-field pointing accuracy is better than 1μrad,all of them meet the alignment requirements of the high-power laser device.