Metal surface fine defect detection method based on vision

A metal surface and defect detection technology, applied in the field of computer vision, can solve the problems of missed detection and false detection, high missed detection rate, low positive detection rate, etc., and achieve the effect of solving high missed detection rate and rapid identification

Pending Publication Date: 2019-03-26
WUYI UNIV
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Problems solved by technology

However, this method has a low positive detection rate and a high missed detection rate for subtle defects on the metal surface, and the detection method is inefficient. check

Method used

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  • Metal surface fine defect detection method based on vision
  • Metal surface fine defect detection method based on vision
  • Metal surface fine defect detection method based on vision

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Embodiment Construction

[0021] An embodiment of the present invention provides a vision-based detection method for fine defects on a metal surface.

[0022] like Figure 1-7 As shown, a vision-based metal surface fine defect detection method provided by the embodiment of the present invention, its specific steps are:

[0023] S1. Collect 4 images of the metal surface to be tested at different illumination angles through the four-point light source three-dimensional detection system; the four-point light source three-dimensional detection system in the step S1 uses a red light type point light source, and calculates each image in the step S2 The corresponding light source direction adopts the highlight black ball calibration method.

[0024] S2. Calculate the light source direction corresponding to each image;

[0025] S3, restore the curvature image of object surface by gradient information; The specific process of described step S3 is: S31, define N as the normal vector of a point on the sphere su...

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Abstract

The invention discloses a metal surface fine defect detection method based on vision. The metal surface fine defect detection method comprises the following steps that S1, collecting four to-be-detected metal surface images with different illumination angles through a four-point light source three-dimensional detection system; S2, calculating a light source direction corresponding to each image; S3, restoring the curvature image of the surface of the object through the gradient information; S4, performing preprocessing operation of gray scale transformation and mean filtering on the curvatureimage in sequence; S5, performing threshold segmentation on the preprocessed image by using an automatic threshold segmentation method; S6, removing misjudged pixel points and tolerable fine defects through the area characteristics, and judging whether the product has defects or not; And S7, extracting the texture features of the defects, and classifying the products with the defects through pattern recognition. The defect that in the prior art, the metal surface defect detection omission ratio is high is overcome, and the purposes of rapidly identifying defective products and efficiently classifying the products are achieved.

Description

technical field [0001] The invention relates to the technical field of computer vision, and more specifically, to a vision-based detection method for fine defects on metal surfaces. Background technique [0002] At present, the automatic detection technology for fine defects on the polished metal surface is relatively immature, the missed detection rate and false detection rate of fine defects are high, and the detection efficiency is low. It mainly relies on manual detection and identification of fine defects. Chinese patent "CN102830123B" discloses an online detection method for tiny defects on the surface of metal strips. This patent separates R, G, and B channel images from the color images collected by the camera, corresponding to the reflected light of red, green, and blue light sources respectively. Intensity distribution, the designed surface inclination calculation method, can calculate the surface inclination distribution map through the R channel image and B chann...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G06T7/00G06T7/62G06T7/11G06T7/136G01N21/88
CPCG06T7/0004G06T7/11G06T7/136G06T7/62G01N21/8851G01N2021/8887G06T2207/30108G06T2207/10004G06T2207/10024G06T2207/20024
Inventor 李澄非吉登清潘海欣
Owner WUYI UNIV
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