A Method of Illumination Equalization of Two-Dimensional Code Image Based on Compressed Sensing

Abstract

The invention discloses a compressed-sensing-based restoration method of a two-dimensional code image with non-uniform illumination. The method comprises the following steps that: a same two-dimensional code image is collected to obtain two two-dimensional code images and sparsity analysis is carried out on the two-dimensional code images; Fourier transform is carried out on the two two-dimensional code images to obtain spectrum images X1 and X2, a non-correlation sampling matrix is set according to the Fourier features of the two-dimensional code images, wherein the non-correlation sampling matrix is formed by a cross and a concentric circle and the sampling cross width and concentric circle dimension can be adjusted properly, and spectrum sampling is carried out on the spectrum images X1 and X2 at the Fourier zone so as to obtain a Y1 and a Y2; linear fusion is carried out on the Y1 and Y2 to obtain a new Fourier spectrum Y; and quick soft threshold iteration is carried out on the Fourier spectrum Y by using a fast iterative shrinkage-thresholding algorithm (FISTA) to obtain a Y', Fourier transform is carried out on the Y' to obtain a restored image f, and binarization processing is carried out on the image f and a two-dimensional code image is identified. With the method, equalized illumination can be realized; a processing speed of an image with non-uniform illumination can be accelerated; and an original two-dimensional code image can be restored accurately.

Description

technical field

[0001] The present invention relates to the field of recognition of two-dimensional code images, and more particularly, relates to an illumination equalization method for two-dimensional code images based on compressed sensing. Background technique

[0002] The preprocessing of the two-dimensional barcode is a very important link in the two-dimensional code recognition process, and the preprocessing result of the two-dimensional code image directly affects the recognition result. Because the application environment of the two-dimensional code is complex and changeable, and the image quality of the two-dimensional code obtained from the imaging device is different, it often encounters the situation of uneven illumination. Traditional image fusion methods include image fusion based on wavelet transform and compressed sensing image fusion based on Fast Iterative Shrinkage-thresholding Algorithm FISTA. Based on wavelet transform image fusion algorithm, the resto...

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