Research on Fast Method for Centerline Extraction of Laser Stripe for Vision Inspection System

In the quality inspection system of tailored blanks laser welding, whether the system can quickly and precisely extract the centerline of laser stripe is one of the key factors that influence the performance of quality inspection system. Although traditional Gaussian fitting and Hessian matrix have the feature of sub-pixel precision, the computational complexity is tremendous. Therefore, they can’t satisfy the requirement of real time performance of the inspection system. On the analysis of the characteristic of images of tailored blanks laser welding, the author applies the traditional Geometrical Center method to extracting the centerline of laser stripe and proposes Local Threshold Geometric Centre method which has a precision between pixel and sub-pixel. The experimental results demonstrate that the proposed method which has the advantages of higher precision and stronger anti-interference performance extracts the centerline of laser stripe with a high speed and lays a foundation for the realization of on-line inspection of seam surface quality