Optical fiber image transmission-based detection system for cylinder surface microscratch defect

Abstract

The invention discloses an optical fiber image transmission-based detection system for cylinder surface microscratch defects. A fiber optics bundle image transmission principle is used to regularly arrange image transmission optical fibers on one concentric circumference, thus realizing image acquisition and defect detection on the circumference of the outer surface of a cylinder. A device mainly comprises a spherical condensation mirror, a point light source, a focusing lens system, light transmitting optical fibers, a self-focusing bar lens, the image transmission optical fibers, a cylindrical lens and a linear array CCD (Charge Coupled Device). On one hand, external illumination light is led in by the light transmitting optical fibers, so that an annular detection area of a detected surface is sufficiently illuminated; on the other hand, the image transmission optical fibers are used for transmitting reflected light on the detected surface to a CCD focusing lens system; finally, outer surface defects of a cylinder-type object are analyzed and detected by an image capture card and computer software. The device is simple in structure; when a closed revolving surface is detected, the microscratch defects of the whole circumference of the surface of the cylinder can be detected in real time without rotating the to-be-detected object or the linear array CCD.

Description

Technical field [0001] The invention belongs to the field of photoelectric detection technology, and more specifically, relates to a detection system for micro-mark defects on the cylindrical surface based on optical fiber image transmission. Background technique [0002] With the development of modern production and processing technology, there are higher requirements for the inspection speed and accuracy of processed parts or other products, and the inspection technology is also developing in the direction of high-speed, high-precision, non-contact and online inspection. At present, there have been some researches on the non-contact circumferential surface detection technology based on photoelectric detection at home and abroad. In summary, there are mainly laser projection method and CCD imaging method. [0003] The working principle of the laser projection method is to place the object to be measured in a parallel light source and project it onto the receiving surface of the ph...

AI Technical Summary

Problems solved by technology

[0005] Among the two technologies mentioned above, although the circumference detection can be realized, there are many deficiencies: ① Whether it is the laser projection method or the CCD imaging method, only the local information of the cylindrical object to be measured can be obtained each time; the former laser sensor The probe needs to rotate 180° back and forth around the product, and the latter CCD camera needs to scan and shoot circumferentially along the cylinder to complete the defect detection on the entire outer cylindrical surface of the part

Such a measurement method is not only inefficient, but also requires a corresponding rotating mechanism and a complex control system. The mechanical and electrical structure is cumbersome, the operation is complicated, and coordination and control are difficult. It cannot meet the needs of high-efficiency, low-cost, and high-intelligence social production; ②The above The image acquisition terminal obtained by the measurement method has a photoelectric conversion device (such as a CCD), and the anti-interference is weak, and it is easy to cause signal distortion in the occasion of interference such as a magnetic field and an electric field; ③ the above-mentioned measurement method, especially the CCD imaging method, is very difficult Difficult to adapt to occasions where the light is insufficient, and the measurement accuracy will be affected when the light is insufficient; ④The above measurement methods, especially the CCD imaging method, when the imaging system is located outside the cylindrical surface, due to the different distances from the points on the same circumference of the cylindrical surface to the imaging system , and the image formed by the closer point is clearer, so different points will produce different errors, which greatly reduces the detection accuracy

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