System and method for scanning and detecting tiny scratch defects of panel

Abstract

The invention provides a scanning detection system and method for tiny scratch defects of a panel, and belongs to the technical field of surface defect detection. The system comprises a multi-spectral-line scanning camera, a light source array and a conveying mechanism; the multi-spectral-line scanning camera is located above the conveying mechanism, scanning lines are perpendicular to the conveying mechanism, and the light source array is located between the multi-spectral-line scanning camera and the conveying mechanism. According to the method, illumination light sources in multiple directions are adopted to cover imaging sectors with tiny scratch defects, so that the tiny scratch defects with sub-pixel sizes are clearly imaged; the multi-spectral-line scanning camera is adopted for scanning and imaging, and dynamic detection is achieved; a detection algorithm eliminates the influence of mirror surface light spots, and the method is suitable for scratch detection of the panel with acurved surface.

Description

technical field [0001] The invention relates to the technical field of surface defect detection, in particular to a scanning detection system and method for fine scratch defects on a panel. Background technique [0002] Products such as mobile phone casings have high requirements on the quality of the panel, and the surface of the panel made of aluminum, stainless steel, plastic, etc. is easily scratched by hard objects to produce subtle scratch defects. Scratch defects are small in width, the smallest reaches the micron scale, and can only be visualized under a specific light angle. Therefore, the quality inspection measures of manual naked eye observation are low in quality inspection efficiency, high in labor costs, and prone to missed inspections. [0003] The automatic surface inspection technology based on machine vision is widely used in the surface quality inspection of panel products, but there are problems in the detection of fine scratch defects: [0004] 1) The ...

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Problems solved by technology

[0005] 2) The specular reflection angle of fine scratches is small and the direction is random. Existing machine vision inspection equipment usually adopts lighting systems with limited directions such as bright field and dark field lighting. The lighting direction cannot cover the "imaging sectors" of different scratches. "; while the dome light source omnidirectional lighting system has a blurring effect similar to that of the shadowless lamp, and it is difficult to distinguish between subtle scratches and background confusion

[0006] 3) For panel products with a certain curved surface, a single-directional light source is prone to produce high-light spots on the curved surface, which interferes with defect detection

The patent application number CN201210292335 uses two strip light sources to scan tiny defects on the metal plane, which improves the imaging quality of horizontal defects, but is not sensitive to vertical defects; the patent application number CN201810099920 uses multiple directional light sources to illuminate in turn, for Measuring the surface roughness of static flat objects is not convenient for fast dynamic detection of panel products on the assembly line

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