Real-time apparatus for detecting surface defects on objects
First Claim
1. A real-time apparatus for detecting surface defects on an object under test (OUT) comprising:
- a high-frequency (at least 25 KHz) linear light source for generating a linear light to be focused on the surface of a moving OUT;
a linear charge coupled device (CCD) camera for scanning the moving OUT line-by-line and generating a corresponding image signal;
a driving circuit for controlling said linear CCD camera to couple said image signal generated thereby to an image-signal processing circuit;
said image-signal processing circuit coupling with said image signal from said linear CCD camera, compensating said image signal to a compensated signal, digitalizing said compensated signal to a train of digital signals, and determining which said digitalized signals are a HIGH or a LOW signal according to a predetermined gray-scale value;
a combination of said HIGH and LOW signals constituting binary image data in the form of a train of binary pulses;
an image-storing circuit connected to said image-signal processing circuit for storing said binary image data;
a defect-detecting unit connected to said image-storing circuit for detecting whether an area unit is a valid defect, a small defect, or defectless, wherein said valid defect is defined by meeting at least one of a plurality of predetermined defect patterns, said small defect represents defects not meeting said predetermined defect patterns, and said defectless represents no defect at all; and
a defect-detecting statistic unit being connected to said image-data storing means for calculating a total amount of defects, and an area and location of each defect by a well-known connectivity analyzation process.
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Abstract
A real-time apparatus for detecting surface defects on a moving object under test comprises a high-frequency linear light source for generating linear light which is focused on a line position of the tested object, a linear CCD (charge coupled device) camera for scanning the line position and generating an image signal, an image-signal processing device for converting the analog image signal to digital image signal and further converting the digital signal to a HIGH or a LOW signal, a combination of the HIGH and LOW signals constituting constituting binary image data in the form of binary pulses, an image-storing circuit connected to the image-signal processing circuit for storing the binary image data, a defect-detecting unit for detecting if an area unit has a valid defect which meets one of a set of predetermined defect patterns or detecting statistical defects which are not valid defects but a plurality of small defects combined together still counted as defects, and a defect detecting statistic unit connected to the image-storing circuit for calculating a total amount of defect, and the area and location of each defect by a well-known connectivity analyzation process.
14 Citations
5 Claims
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1. A real-time apparatus for detecting surface defects on an object under test (OUT) comprising:
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a high-frequency (at least 25 KHz) linear light source for generating a linear light to be focused on the surface of a moving OUT; a linear charge coupled device (CCD) camera for scanning the moving OUT line-by-line and generating a corresponding image signal; a driving circuit for controlling said linear CCD camera to couple said image signal generated thereby to an image-signal processing circuit; said image-signal processing circuit coupling with said image signal from said linear CCD camera, compensating said image signal to a compensated signal, digitalizing said compensated signal to a train of digital signals, and determining which said digitalized signals are a HIGH or a LOW signal according to a predetermined gray-scale value;
a combination of said HIGH and LOW signals constituting binary image data in the form of a train of binary pulses;an image-storing circuit connected to said image-signal processing circuit for storing said binary image data; a defect-detecting unit connected to said image-storing circuit for detecting whether an area unit is a valid defect, a small defect, or defectless, wherein said valid defect is defined by meeting at least one of a plurality of predetermined defect patterns, said small defect represents defects not meeting said predetermined defect patterns, and said defectless represents no defect at all; and a defect-detecting statistic unit being connected to said image-data storing means for calculating a total amount of defects, and an area and location of each defect by a well-known connectivity analyzation process. - View Dependent Claims (2, 3, 4, 5)
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Specification