US 12,313,561 B2 · Stroboscopic stepped illumination defect detection system

step 1, selecting cameras and light sources, comprising:

according to defect types to be detected by a system and/or the number of pictures to be taken, selecting a first camera, a second camera, a first light source, and a second light source adapted thereto;

step 2, mounting an imaging system, comprising:

according to defects to be imaged, determining angles and positions of the light sources, the first camera, and the second camera preliminarily and structurally, debugging the angles and positions of the first camera and the second camera for each defect to be tested respectively, wherein when image data needs to be added, adding a supplemental third camera and a supplemental fourth camera until a supplemental M-th camera is added, where M is a positive integer greater than 3;

and

fixing positions of devices according to bright field and dark field requirements preliminarily;

step 3, setting encoder parameters, comprising:

according to a speed of detecting a product by the system, setting a rate of a motion system, and obtaining a period of the encoder correspondingly;

step 4, setting a stroboscopic control unit, comprising:

according to the period of the encoder, the number of pictures to be taken, and parameters of the cameras, setting frequency multiplication and frequency division parameters of the stroboscopic control unit, and setting parameters of stroboscopic stepped illumination preliminarily, wherein

the stroboscopic control unit is configured to record signal of the encoder in real time and acquire a rising edge and a period;

the stroboscopic control unit is configured to perform the frequency multiplication and/or frequency division on the signal of the encoder according to a running speed, the number of pictures to be taken or defect types, and camera parameters;

the stroboscopic control unit is configured to control drive circuits of reflection bright field light sources corresponding to various cameras to perform stroboscopic stepped lighting and picture taking, according to the signal having undergone the frequency multiplication and/or frequency division as an output line trigger signal;

the stroboscopic control unit is configured to control drive circuits of reflection dark field light sources corresponding to various cameras to perform stroboscopic stepped lighting and picture taking, according to the signal having undergone the frequency multiplication and/or frequency division as an output line trigger signal;

the stroboscopic control unit is configured to control drive circuits of transmission bright field light sources corresponding to various cameras to perform stroboscopic stepped lighting and picture taking, according to the signal having undergone the frequency multiplication and/or frequency division as an output line trigger signal;

and

the stroboscopic control unit is configured to control drive circuits of transmission dark field light sources corresponding to various cameras to perform stroboscopic stepped lighting and picture taking, according to the signal having undergone the frequency multiplication and/or frequency division as an output line trigger signal;

step 5, debugging optical parameters, comprising:

for each defect to be tested, debugging the angles of the first light source and the second light source respectively, wherein when light supplementation is required, adding a supplemental third light source and a supplemental fourth light source until an N-th supplemental light source is added, where N is a positive integer greater than 3;

and

fixing positions of various devices after the debugging is completed, so that there is no relative displacement or angular rotation therebetween;

step 6, debugging the stroboscopic control unit:

for each defect to be tested, debugging strobing and step parameters respectively, and correcting pulse widths and operation current values of corresponding light sources, so as to ensure that a grayscale value of an image taken falls within an acceptable set range;

step 7, imaging splitting, comprising:

splitting multiple lines of images taken by line scan cameras using a computer system;

step 8, judging imaging definition, comprising:

judging whether image defect imaging definition reaches a set threshold, wherein if the definition does not reaches the set threshold, it returns to step 5;

and

if the definition reaches the set threshold, the next step is performed;

and

step 9, analyzing data, comprising:

debugging software and algorithm defect using a computer system to perform data analysis and complete the detection.

Stroboscopic stepped illumination defect detection system

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Stroboscopic stepped illumination defect detection system

Life of this patent

Abstract

Claims12