Method for visual detection of defects of light guide plate of two-side light-incoming type

Abstract

The invention provides a method for the visual detection of defects of a light guide plate of a two-side light-incoming type, and the method achieves the simultaneous detection of a linear scanning gray scale image of the light guide plate and an area array gray scale image of the light guide plate. The linear scanning gray scale image of the light guide plate can be used for detecting the fine defects, such as scratches, indentations, bright and dark points. The area array gray scale image of the light guide plate can be used for detecting whether the light guide plate has a dark shadow or not after the light guide plate is irradiated by sunlight. The method is high in adaptability to the illumination changes and the type changes of the light guide plate. An area array camera and a linearscanning camera carry out the detection at the same time, thereby improving the detection precision under the condition that the detection time is not increased. The method greatly improves the detection accuracy. The method is high in operation efficiency, stability and robustness, can achieve the recognition of common defects, and has the stronger capability for detecting the unusual fine defects.

Description

technical field [0001] The invention relates to a method for extracting surface defects of a light guide plate based on machine vision technology, which belongs to the field of computer vision, in particular to a defect detection algorithm. Background technique [0002] The main material of Light Guide Plate (LGP) is optical acrylic (PMMA) plate, and its chemical name is methyl methacrylate. The transparent acrylic plate after special scientific processing, as long as it is installed on the side The illuminant (ordinary fluorescent tube, CCFL cold cathode tube, light-emitting diode and other light sources can be selected depending on the size of the light guide plate, generally installed on both sides of the length), the entire plane of the acrylic plate will emit bright, uniform and soft light after power on. Transparent acrylic sheet has high light transmittance, strong expansion and impact ability, and is widely used in the screens of various electronic products. In the ...

AI Technical Summary

Problems solved by technology

There are many limitations and problems in manual detection: (1) The working environment of the employees is poor, and the strong light operation is easy to make the employees' eyesight worse, which may cause the employees to suffer from occupational diseases for a long time; Defects have high requirements on the skills and experience of employees, and it is not easy for employees to master work skills; (3) Affected by employee experience, work mood fluctuations, and reduced concentration, it is not easy to intercept all product defects, resulting in product quality fluctuations; ( 4) Due to the use of human eye recognition judgments, it is difficult for auxiliary measurement tools to form quantifiable quality standards

Using Curvelet transform, non-subsampling Contourlet transform, shearlet transform, wavelet transform and multi-scale analysis technology, the operation efficiency of the algorithm cannot meet the requirements, and it is difficult to realize in the embedded system; the correct recognition rate of some surface defects is relatively low, and the accuracy cannot be satisfied Require

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