Construction and decoding method of space-frequency-domain 2-dimensional bar code

A decoding method, two-dimensional code technology, applied in the direction of digital transmission system, electrical components, error prevention, etc., can solve the problems of data redundancy, easy to receive distortion and light pollution, etc., to improve performance, improve error resistance and correction The effect of reducing error capability and reducing redundancy

Active Publication Date: 2012-04-25
SOUTHEAST UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The problem to be solved by the present invention is: the current two-dimensional code is easily affected by the channel of the image acquisition device when decoding, and is easily affected by distortion and light pollution, and there is redundancy in the data. The ability to resist, reduce redundancy, and increase the number of information bits carried by each pixel

Method used

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  • Construction and decoding method of space-frequency-domain 2-dimensional bar code
  • Construction and decoding method of space-frequency-domain 2-dimensional bar code
  • Construction and decoding method of space-frequency-domain 2-dimensional bar code

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Embodiment 1

[0049] Now it is necessary to generate an N*N (N=5) pixel matrix. A 5*5 complex matrix can accommodate ((N-1) / 2-1)*N*log2(L) bits if QAM mapping is used. L is the number of points in the constellation diagram.

[0050] 1. In step 3), the RS code of (255,223) is selected as the outer code, and the convolutional code whose parameter is (2,1,3) generating polynomial is (111,101) is used as the inner code. In step 4), block interleaving is used, such as image 3 As shown, the input bit sequence is written into the memory in columns, each column has M=4 data, and K=5 columns in total. The interleaver reads data from the memory row by row.

[0051] Let the data obtained after steps 1)-4) be: 1001111011.

[0052] 2. In step 5), common constellation diagrams are selected for mapping from 0, 1 to complex data. In this embodiment, QAM mapping is selected. The rule is: two consecutive bits are mapped to a complex constellation symbol, see Table 1 for details.

[0053] Table 1 4QAM...

Embodiment 2

[0087] This embodiment will introduce how to insert pilot codes and use two channels to express a two-dimensional code.

[0088] Now it is necessary to generate an N*N (N=5) pixel matrix. A 5*5 complex matrix can accommodate (N-2)*N*log2(L) bits if QAM mapping is used (because 2*N rows of pilots need to be inserted). L is the number of points in the constellation diagram.

[0089] 1. In step 3), the RS code of (255,223) is selected as the outer code, and the convolutional code whose parameter is (2,1,3) generating polynomial is (111,101) is used as the inner code. In step 4), block interleaving is used, such as image 3 As shown, the input bit sequence is written into the memory in columns, each column has M=4 data, and K=5 columns in total. The interleaver reads data from the memory row by row.

[0090] Assuming that the (N-2)*N complex number matrix is ​​obtained after steps 1)-5) are as follows:

[0091] 1 ...

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Abstract

A construction and decoding method of a space-frequency-domain 2-dimensional bar code is disclosed. The method is characterized by: converting data to be converted into the 2-dimensional bar code into a bit stream; uniformly distributing the bit stream; performing concatenated coding; interlacing and grouping the bit stream; carrying out space frequency domain coding. The invention belongs to an information storage, transmission and identification technology field. The space frequency domain is used to store information so that an equalization technology is convenient to be used to resist influences of a channel and light pollution. A pilot frequency or differential coding is used to resist the positioning error and distortion influences. In the invention, the interlacing is combined with a cascaded code so that an error correction capability of the cascaded code can be substantially improved; a redundancy can be reduced. Compared to the 2-dimensional bar code of the prior art, by using the method of the invention, the larger storage information amount can be possessed.

Description

technical field [0001] The invention belongs to the technical field of information storage, transmission and identification, relates to two-dimensional code encoding and decoding methods, and is a two-dimensional code construction and decoding method. Background technique [0002] In recent years, two-dimensional barcodes have been fully applied in fields such as forms, security and confidentiality, tracking, licenses, inventory counts, and data backup. [0003] Existing such as figure 1 The two-dimensional barcode / two-dimensional code (2-dimensional bar code) shown uses a specific geometric figure of black and white distributed on a two-dimensional plane according to certain rules to represent "0", which constitutes the internal logic basis of the computer. The concept of "1" bit. Use several geometric shapes corresponding to binary to represent information such as English, Chinese, numbers, graphics, etc. It can be automatically read by image input equipment or photoele...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04L1/00
Inventor 张在琛裴诚诚方文骁张树剑余旭涛
Owner SOUTHEAST UNIV
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