Printed circuit board image skeletonization method based on FPGA

Abstract

The invention relates to an image skeletonization method of a printing circuit board based on an FPGA which firstly inputs an image to analyze the 3*3 neighborhood of each pixel and count the number n with a pixel value of 1 among the surrounding 8 pixels and the pixel with a switch time S between 0 and 1, with an output being 1 and a preservation being 1; then, whether a central pixel is 1 is judged; the central pixel is deleted if the central pixel is zero; when n is more than 1 but is less than or equal to 6, S is equal to 2, and circulating time is odd, the pixels along the right and lower directions of the central pixel and the pixels along the left and right directions of the central pixel are investigated, whether 0 and 1 are cross is judged, 0 is output and the pixel is deleted; when n is more than 1 but is less than or equal to 6, S is equal to 4, n is equal to 4, and the circulating time is odd, the pixels along the upper-left and upper-right directions of the central pixel and the pixels along the lower-left and lower-right directions of the central pixel are investigated; whether the lower side pixel of the central pixel is 1 and whether 0 and 1 are two communicating areas are judged; if the pixel is 0, the pixel is deleted. The image skeletonization method can fast and accurately withdraw the image skeleton.

Description

technical field [0001] The invention relates to a method for detecting defects of printed circuit boards. Background technique [0002] At present, the well-known detection methods for PCB defects are based on simple logical operations such as image addition and subtraction. The analysis of the operation results is relatively simple, and it is difficult to determine the difference between the images and determine the defect type. The detection speed is slow and difficult Real-time processing of the collected images is realized, which affects the detection efficiency. The existing method for extracting image skeleton is a thinning algorithm, which uses binary morphological operations to determine the situation of 8 neighborhoods of pixels. In the process of skeleton extraction, because the speed of deleting pixels in the upper, lower, left, right and diagonal directions is different, some basic features of the image will be lost as a result. Image processing; and the thinni...

AI Technical Summary

Problems solved by technology

[0003] The purpose of the present invention is to provide an FPGA-based printed circuit board image skeletonization method, to solve the technical problems that the existing algorithm for thinning and extracting image skeletons often loses image features, and the detection is time-consuming and difficult to realize real-time processing

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