Device and method for detecting micro defects on bright and clean surface of metal part based on machine vision

Abstract

The invention relates to a device and method for detecting micro defects on the bright and clean surface of a metal part based on machine vision. The device comprises an imaging, positioning and adjusting mechanism and a processing unit, wherein the imaging, positioning and adjusting mechanism comprises a base plate, a guide rod, a fixed support, a sliding support, a stepping motor, a CCD (Charge Coupled Device) camera, a telecentric lens and parallel light sources, wherein the imaging and coaxial lighting of the CCD camera are primarily adjusted; an image collection card, an industrial personal computer, an equipment control card and an alarm are electrically connected in the processing unit and are used for collecting, transmitting, storing, processing, displaying and alarming image. The method comprises coaxial lighting adjustment and image processing, wherein coaxial lighting adjustment comprises the steps of triggering the equipment control card via software of the industrial personal computer to drive the stepping motor, and adjusting the rotating angles of the parallel light sources until the coaxial lighting condition is satisfied; and image processing comprises the steps of detecting defects on the internal surface of the detected part, respectively detecting large and small defects on the outer edge on the surface of the detected part, displaying the processing images in real time and judging the results.

Description

technical field [0001] The invention relates to the field of intelligent detection, in particular to a device and method for detecting micro-defects on the smooth surface of metal parts based on machine vision. Background technique [0002] During automatic or manual processing and assembly of metal parts, defects such as cracks, scratches, bubbles, stains, pits, holes and other defects that are prone to appear on the smooth surface affect the appearance, use, and even safety performance of the product. Therefore, it is very important to efficiently and accurately detect the surface of smooth parts. Realizing the automatic detection of parts surface quality has become a necessary prerequisite for related enterprises to improve product quality and core competitiveness. [0003] At present, various parts manufacturers still generally adopt the traditional manual picking method, which has disadvantages such as heavy workload, high false detection rate and missed detection rate...

AI Technical Summary

Problems solved by technology

Its shortcomings are: the structure of the three-station camera installed on the gantry frame is complicated, which is not conducive to installation and debugging, and the structure is not stable and reliable enough, which affects the image processing effect, and it is difficult to apply to industrial sites; the three-station camera shoots When the image is differentially processed, it needs to go through the sequential processing process of image contour acquisition, cropping, translation, scaling, matching and 8 differential rules. The calculation error of each link will affect the final detection accuracy, especially for the identification of slowly changing defects.

A system for online detection of the surface quality of finished coins using bright and dark composite fields of view is disclosed. However, the characteristics of small defects in coins are not obvious, and it is easy to cause missed detection.

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