Objective quality evaluation of laser markings for assembly control

This paper presents a novel method for the objective quality evaluation of letterings at the example of laser markings. The proposed method enables an automated quality evaluation during random inspection of small quantities of frequently changing items. The markings are segmented from the image within a first step and compared against a master piece in the second step. Each character and contour is evaluated with regard to completeness, contrast, edge width and homogeneity according to quality criteria based on the human visual perception. Thus our approach provides an user-independent evaluation method with high repeatability and reproducibility for its industrial application.