Automatic detection method for printed product four-color register partial difference

Abstract

The invention relates to an automatic detection method for four-color register deviation of printing, more particularly to a method, adopting image processing to calculate the four-color axial direction and circumferential direction register deviation. The method mainly comprises following steps: register marker image is pretreated, comprising color division, edge detection, and location of the register marker image; then object image is reversed; benchmark is selected optimally; the calculated register deviation outcome is exported; the invention gives the register deviation data of black, cyan, fuchsin, and yellow marker in axial and circumferential direction automatically after the register marker image is analyzed. The automatic detection method for four-color register deviation of printing has the advantages of high efficiency, high speed and easy operation.

Description

technical field [0001] The invention relates to an automatic detection method for four-color register deviation of printed products, in particular to a method for automatically calculating four-color axial and circumferential register deviation by image processing. Background technique [0002] In the process of four-color overprinting, special marks such as crosshairs and cat's eye graphics are often printed near the edge of the printed product. The operator adjusts the registration mechanism by estimating the size of the registration deviation. Finally, it is hoped that the black (B) mark, cyan ( C) mark, magenta (M) mark and yellow (Y) mark overlap as much as possible so that the printed matter can achieve the best clarity. Register control is a key link in four-color printing technology. [0003] At present, the detection and control of registration deviation is still in the way of manual visual inspection. The operator prints multiple printed products through the offs...

AI Technical Summary

Problems solved by technology

This visual method has the following shortcomings: (1) low precision and poor efficiency, the minimum scale of the magnifying glass is generally around 20 microns to 50 microns, coupled with the visual error of the human eye, the visual accuracy of the registration deviation is low , the adjustment of the registration mechanism often requires experienced operators, and the entire registration adjustment process usually takes a long time to complete; (2) The operation process is cumbersome and difficult, which is easy to cause operator fatigue. Very careful, easy to cause eye fatigue and damage

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