Method for extracting contour of image of printed circuit board (PCB)

Abstract

The invention aims to provide a method for extracting a contour of an image of a printed circuit board (PCB). By the method, the defect of inaccuracy in extraction of the contour of the image of the PCB in the conventional contour extraction method is overcome, the accuracy and stability of contour detection are improved, and working efficiency is improved. The method comprises the following steps of: 1) acquisition of an original image of the PCB; 2) Gaussian Laplacian operator processing: processing the original image by using a Gaussian Laplacian operator to obtain a processed Gaussian Laplacian image; 3) gradient operator mutant processing: processing the original image by using a gradient operator to obtain a gradient image which is subjected to mutant processing through the gradientoperator; 4) processing the original image by using high and low threshold values to obtain a binary image; 5) establishing coordinate graphs of sub-pixel contour points, determining the pixel position of the contour according to the boundary of the binary image, and thus obtaining the coordinates of the sub-pixel contour points according to a Gaussian Laplacian value, a pixel value and a gradient value in the corresponding direction of the contour; and 6) connecting the sub-pixel contour points to form the contour, and connecting the sub-pixel contour points into a set in a certain sequence according to the coordinates of the sub-pixel contour points, wherein the coordinates are obtained in the step 5).

Description

technical field [0001] The invention relates to a contour extraction method of a printed circuit board image, which belongs to the technical field of computer vision. Background technique [0002] In the prior art, contour detection is often used to calculate the shape and quality of some precision workpieces, such as the detection of car bodies and the detection of precision machined parts. At present, extracting the outline of the printed circuit board image is an important issue of PCB (Printed Circuit Board, printed circuit board)-AOI (automatic optical inspection), and its accuracy directly affects the performance index of AOI. The invention proposes a new intelligent contour extraction algorithm applied to the printed circuit board industry. [0003] The traditional edge detection method cannot effectively detect all defect contours in the PCB image, resulting in PCB-AOI missed detection. There are many contour extraction methods, each with its own advantages, but th...

AI Technical Summary

Problems solved by technology

[0010] The technical problem to be solved by the present invention is to provide a contour extraction method for detecting printed circuit board defects, avoid the inaccurate defects of the existing contour extraction method when extracting the PCB image contour, enhance the accuracy and stability of contour detection, and then Improved work efficiency

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