High-precision screen printing screen plate scanning image registration method

Abstract

The invention provides a high-precision screen printing screen plate scanning image registration method. According to the invention, based on own features of screen plate imaging, selecting a registration feature point suitable for the screen plate image feature; and then carrying out geometric transformation on the screen image based on a planar two-dimensional affine transformation method, so that the screen image has a good registration effect with the template image after transformation, the problem of large calculation amount is solved, overfitting is avoided, and the real-time effectiveness of registration is ensured.

Description

technical field [0001] The invention relates to the technical field of industrial vision, in particular to a high-precision screen printing screen scanning image registration method. Background technique [0002] With the rapid development of industrial technology, many visual inspection and recognition methods in the field of machine vision are inseparable from the registration calculation of images with geometric deformation obtained from actual scanning imaging, so that subsequent processing can be more regular. [0003] In the field of printed circuit board (PCB, Printed Circuit Board) manufacturing industry, the production of screen printing screens is a very important link in the pre-production process of PCBs. Most of the inspections of screen printing screens use linear scanning imaging. However, the stencil imaging image obtained by the actual linear scanning equipment is not only low in contrast, but also due to the property of the enlarged grid pattern of the scre...

AI Technical Summary

Problems solved by technology

However, the stencil imaging image obtained by the actual linear scanning equipment is not only low in contrast, but also due to the property of the enlarged grid pattern of the screen printing stencil itself, the image obtained by scanning during visual inspection is not only not clear enough, but also due to There are large positional and angular deviations between the position where the stencil is placed and the electronic graphics of the template, and the stencil is easy to expand and shrink, which brings great challenges to the registration calculation of the stencil scanning image detection. figure 1 It is the effect picture of the part of the screen printing screen under a 100-fold microscope. The text of the electronic graphic of the template to be screen printed is "01", the left side is the normal screen picture, and the right side is the defect picture. It can be seen from the figure that The effect is different from the comparison algorithm in the traditional visual technology field

[0004] Conventional registration methods generally select registration feature points (such as sift features, orb features, etc.) in the template image and the test image, and then perform a geometric transformation based on the spatial three-dimensional perspective transformation of these feature points, but this Geometric transformation is not suitable for the characteristics of two-dimensional imaging of the stencil, which leads to the phenomenon of data overfitting. The direct result is: a large amount of calculation, the existing computer hardware cannot meet the requirements, and the registration effect is not ideal. mis-match

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