Method for on-line detection of surface defects of metal arc-shaped workpiece

Abstract

The invention discloses a method for on-line detection of surface defects of a metal arc-shaped workpiece. The method comprises the steps: first, obtaining grayscale images of the surface of a metal arc-shaped workpiece and establishing a data field; if the maximum potential value of the data field is smaller than a set threshold, determining that the metal arc-shaped workpiece has no defect, ending the detection, if not, executing the next step; conducting threshold segmentation on the image data field to obtain a binary image B1W(x, y), and marking defect areas; then for each defect area, determining a contrast threshold T according to its externally connected rectangular area; then, calculating the contrast of any pixel inside the externally connected rectangle of each defect area, andconducting threshold segmentation according to the contrast and T pairs of grayscale images to obtain a binary image B2W(x, y); finally, uniting the B1W(x, y) and the B2W (x, y) and removing the noiseto obtain a final defect image, thereby detecting defects. The problem of low defect detection accuracy caused by uneven reflection, low contrast and many kinds of defects of the surface of the metalarc-shaped workpiece is effectively solved, and the method has good detection precision and robustness for detection of different defects.

Description

technical field [0001] The invention belongs to the technical field of computer vision, in particular to an online detection method for surface defects of metal arc-shaped workpieces. Background technique [0002] Metal curved workpieces are indispensable basic components in many fields such as military weapons, aerospace, automotive and industrial manufacturing. In the process of workpiece production, due to the influence of processing technology, raw materials, casting technology and other factors, it is easy to cause defects such as gaps, pits, curling edges, dents, and wrinkles on the surface, which will affect product performance and the next process to a certain extent. The production efficiency of the process can be seriously affected, and even cause major safety accidents. [0003] At present, for semi-finished metal arc-shaped workpieces, due to the different shapes of defects, most domestic manufacturers still use manual inspection, but manual inspection is ineffi...

AI Technical Summary

Problems solved by technology

2) There are many types of defects, random shapes, small sizes, and the distinction between defects and background gray values ​​is not obvious, making it difficult to segment defect areas

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