Method for detecting damage defect of curved tag based on template matching and similarity calculation

Abstract

The invention discloses a method for detecting the damage defect of a curved tag based on template matching and similarity calculation, and belongs to the technical field of machine vision and video image processing. The method comprises steps of image acquisition, image preprocessing, template area extraction, defect detection and result display. The image acquisition comprises taking different images of a tag to be tested and a template tag from three angles. The preprocessing process realizes the segmentation of a tag area and an image processing operation for converting a curved surface into a flat surface. The template area extraction achieves one-to-one correspondence between the images of the tag to be tested taken from three different angles and a certain area of a template panorama, enables a bottle rotation angle in image extraction not to be restricted, and reduces system implementation difficulty. A defect detection module, based on a method combining the template matching with the similarity calculation, locks possible defective areas by using short time-consuming template matching, determines whether the defect exists by using exact similarity calculation, and improves detection efficiency on the basis of guaranteeing a detection effect.

Description

technical field [0001] The invention relates to the technical field of machine vision and video image processing, and more specifically, to a method for detecting damaged surface label defects based on template matching and similarity calculation. Background technique [0002] In the field of food, beverage and pharmaceutical packaging, labels are often required on the outside of PET plastic, glass and other containers. Labels not only have a very important aesthetic effect on products, but also indicate a large amount of product information. Label defects are serious quality problems for products and cannot be sold on the market. [0003] Traditional bottle label damage detection is mostly done by manual detection at the back end of the filling product production line, which usually has problems such as low efficiency, high cost, poor stability and poor reliability, and cannot meet the needs of large-scale industrial production. With the increasing speed of production, th...

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Problems solved by technology

[0009] The purpose of the present invention is to overcome the deficiencies in the prior art, and provides a method for detecting surface label damage defects based on template matching and similarity calculation. The present invention includes image acquisition, image preprocessing, template region extraction, defect detection, and result Display and other processing steps, image acquisition includes different images taken from three angles of the label to be tested and the template label; the preprocessing process realizes the segmentation of the label area and the image processing operation of converting the curved surface into a plane; the template area extraction step realizes The one-to-one correspondence between the three different angle images of the label to be tested and a certain area of ​​the template panorama makes the rotation angle of the bottle body unrestricted during image acquisition and reduces the difficulty of system implementation; the defect detection is based on the method of combining template matching and similarity calculation , the possible defect area is locked by template matching in a short time-consuming time, and then the precise similarity calculation is used to determine whether the defect exists, which effectively improves the detection efficiency on the basis of ensuring the detection effect

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