Defect detection system based on space step-by-step frequency shift illumination

A defect detection, step-by-step technology, used in optical testing flaws/defects, measuring devices, analyzing materials, etc., which can solve the problem of large incident light divergence angle, reduced accuracy of sub-aperture spectral information, and surface microscopic observation of non-transparent samples. Inapplicability and other problems, to avoid missed detection and false detection, and improve the effect of spatial bandwidth product

CN112326665APending Publication Date: 2021-02-05ZHEJIANG LAB +1
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Patent Information

Authority / Receiving Office
CN · China
Current Assignee / Owner
Publication Date
2021-02-05

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Abstract

The invention discloses a defect detection system based on space step-by-step frequency shift illumination. The system comprises a light source, a microscope objective, a tube lens, an image detector,a control module and a data processing module, and the light source comprises a vertical illumination light source and an inclined illumination unit. Emergent light of the vertical illumination lightsource and the inclined illumination unit can irradiate an observed sample to excite a scattering field, and the scattering field is collected by the microscope objective, shaped by the tube lens, incident to the image detector and converted into a far-field intensity graph by the data processing module. The control module controls the lightening of each light source and the acquisition of an observed sample scattering field signal by the image detector under the illumination of each light source according to a time sequence. The data processing module reconstructs the spatial frequency spectrum information of the observed sample, and finally realizes detection imaging of complex defect feature contour information and detail feature information of the surface of the observed sample no matter under a transmission type illumination condition or a reflection type illumination condition.
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Description

Technical field

[0001] The invention relates to a product surface defect detection device and belongs to the field of surface defect detection.Background technique

[0002] Defect detection on product surface is one of the important means to achieve product quality control, improve production technology, and optimize product performance. Manual inspection is the traditional method of product surface defect inspection, but with the development and progress of society, traditional inspection methods can no longer meet the requirements of inspection speed and inspection accuracy. With the development of industrial automation, with the advantages of non-contact, no damage, safety and reliability, wide spectral response range and high production efficiency, defect detection technology based on machine vision has developed rapidly. For example, the patent document with publication number CN105973912A discloses a leather surface defect detection device based on linear array light source illumina...

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Embodiment Construction

[0023]The technical scheme of the invention will be further described below in conjunction with the drawings and specific embodiments.

[0024]Such asfigure 1 As shown, the defect detection system based on the spatially stepped frequency shifted illumination of the present invention mainly includes a light source, a microscope objective lens 105, a tube lens 107, an image detector 108, a control module 101 and a data processing module 113. Among them, the light source includes a vertical lighting source 102 and an inclined lighting unit 110. The inclined lighting unit 110 may choose to use light sources such as LED light sources, LD light sources, and fiber bundle output light sources. Preferably, an optical collimating device can be provided at the exit port of the vertical illumination light source and each inclined illumination unit to project the emitted light into the imaging field of view of the optical microscope objective lens 105 to improve the direction collimation of the ill...