Strobe Step Lighting Defect Inspection System

Abstract

The invention discloses a stroboscopic ladder lighting defect detection system, which is used for the appearance defect detection of products, comprising: an image extraction unit (101), a light and dark adjustment unit (102), a data processing unit (103) and a stroboscopic control unit (104). The image extraction unit (101) is connected to the stroboscopic control unit (104), and is used to obtain stable and clear images in various transmission / reflection vision bright field / dark fields; the light and shade adjustment unit (102) , connected with the stroboscopic control unit (104), used to set various transmission / reflection vision bright fields / dark fields, and switch among various transmission / reflection vision bright fields / dark fields. Under the condition of using multiple cameras, the defect detection system of the present invention achieves multi-directional detection of various defects by controlling the stroboscopic step of the light source, that is, changing the open pulse width and working current value of the light source at the same time, and using multiple light sources to work together. imaging purposes.

Description

technical field [0001] The invention relates to the technical field of machine vision defect detection, in particular to a machine vision appearance defect detection system and an implementation method with multiple cameras and strobe step lighting. Background technique [0002] The machine vision system converts the captured target into an image signal through an image capture device (CMOS and CCD sensors), and transmits it to a dedicated image processing system. The image system performs various operations on these signals to extract the features of the target. Its basic components usually include cameras, lenses, light sources, image acquisition cards, image processors, image processing software and algorithms. [0003] At present, machine vision systems have been deeply used in industrial inspection systems for identifying product information, measuring product sizes, and detecting product defects. Among them, since users have very high requirements on the appearance of...

AI Technical Summary

Problems solved by technology

3D vision technology includes binocular vision, structured light, TOF (time of flight), triangular distance measurement, laser radar, etc. These technologies are currently widely used in three-dimensional physical recognition, measurement, and positioning, but they are rarely used in defect detection. And it is also difficult to meet the micron-level high-precision requirements of 3C products

[0009] However, in the prior art, the images of the four scenes (reflected bright field, reflected dark field, transmitted bright field, and transmitted dark field) obtained by the detection system of the detected object through the line array camera often reflect limited defects, because the linear array The speed at which the camera takes pictures is fixed, and the driving current of the light source corresponding to the shooting angle is fixed. Therefore, it is often necessary to change the pulse width of the corresponding light source when shooting different defects, and the maximum pulse width of the light source is the exposure of the line scan camera. Time, no matter how wide the pulse width is, it has no effect on the line scan camera, so this greatly limits the number of pictures taken, and also limits the types of defect detection

Moreover, because the current of the driving circuit corresponding to a single light source is fixed, when changing the illumination angle to take pictures of different bright field or dark field, often this light source will not be used for each defect at the same time, so the utilization rate of the light source is very high. Low, fewer types of defects for simultaneous shooting

At this time, the number of light sources and cameras can only be increased to take the required photos or more types of defects, which increases the cost and complexity of the system

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