Presswork quality and flaw inspection method

Abstract

The invention belongs to the field of presswork full-screen quality inspection and control, and provides a presswork full-screen quality and flaw inspection method, which comprises the following steps of: acquiring a standard specimen sheet and a digital image of presswork to be inspected by using an optoelectronic coupler; zoning the digital image, extracting red, green and blue (RGB) values of each pixel in each zone, and converting the RGB values into CIELAB values; calculating color differences, DeltaL*, Deltaa* and Deltab* on the CIELAB values of each pixel in the image of the presswork to be inspected and the CIELAB values of corresponding pixels in the image of the standard specimen sheet; and judging the difference and flaw of the presswork according to threshold values of the color difference, the DeltaL*, the Deltaa* and the Deltab* meeting different quality requirements. The invention provides the chromaticity-recognition-method-based presswork full-screen quality and flaw inspection method, and compared with the prior art, does not require a conventional control strip, takes variable quality inspection and variable zone division into accounts and can be more flexibly adapted to the change of printing conditions.

Description

Technical field [0001] The invention belongs to the field of full-image quality inspection and control of printed matter, and in particular relates to a method for detecting printing quality and defects. Background technique [0002] Whether it is traditional printing or digital printing, people have to face a very important problem in the printing process, that is, printing quality detection and control. The speed of modern printing presses continues to increase, and higher requirements are put forward for the quality inspection and control of printed matter. Traditional printing quality inspection and control methods can no longer meet and guarantee the high quality, high efficiency, and low cost requirements of modern printing. Therefore, printing manufacturers dream of realizing the automatic inspection of printing quality. It is not only the basis for the digitalization and standardization of printing quality, but also a necessary link for subsequent automatic control of pr...

AI Technical Summary

Problems solved by technology

[0004] The invention provides a printed matter quality and defect detection method, aiming to solve the problem that there are few automatic detections of printed matter color images at home and abroad, especially the defect automatic detection based on the chromaticity contrast of printed matter color images and the existing methods for printed matter color images. The cost of automatic image detection technology is high, the equipment is expensive, the detection accuracy is not high, and the error is large

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