飞秒激光烧蚀光斑图像灰度特征及应用分析

Gray features and application analysis of ablated spot imageby femtosecond laser

飞秒激光在单晶硅材料表面进行微结构烧蚀过程中,微结构的烧蚀效率与烧蚀过程的工艺参数(烧蚀功率、烧蚀速度等)密切相关。研究、揭示光斑图像特征对光斑进行精确定位和跟踪显得至关重要。据此,对烧蚀过程中衍生的等离子体光斑图像的几何特征进行分析,首先,提取序列光斑图像,研究了光斑的形态特征和灰度的分布情况;其次,对光斑图像进行质心和中心提取,利用中心到质心的指向判断其烧蚀加工方向;最后,以此为基础,选取同一加工方向的光斑进行叠加,对光晕部分有效剔除,使光斑的灰度呈各向异性对称,即光斑灰度由中心到四周逐步均匀递减,其中心和质心基本重合。能有效提高对烧蚀光斑的定位和跟踪精度,对烧蚀速度的研究有着深远意义。

During micro-structure ablation of a single crystal silicon material by femtosecond laser,the ablation efficiency of the micro-structure is closely related to the process parameters of the ablation process such as ablation power,ablation speed,etc.It is very important to research and reveal the characteristics of the spot image to accurately locate and track the spot.Based on this,the geometric features of plasma spot image derived during ablation process are analyzed.Firstly,the spot image is segmented to study spots’morphological characteristics and gray distribution.Secondly,the centroid and the center extraction of spot image are performed.Use the direction from center to centroid to determine the ablation processing direction.Finally,based on this,selecting light spots in the same processing direction to be superimposed and effectively remove the halo part to get the gray scale of light spot anisotropically symmetrical.The gray scale gradually decreases uniformly from the center to the surroundings,and the center and the centroid basically coincide.It can effectively improve positioning and tracking accuracy of the ablation spots,and has profound significance for ablation speed research.