Research And Application Of Encoding And Decoding For Matrix 2D Bar Code

One-dimensional bar code is wildly used in many aspects of production and daily life. It also improves productivity greatly. However, its disadvantages of limited amount of information and dependence on database are exposed gradually. Two-dimensional (2D) Bar Code has a higher capacity, higher density, more powerful error-correction ability and higher security ability. Therefore, two-dimensional Bar Code is playing a more and more important role in the information automatic field.As one kind of two-dimensional Bar Code, matrix two-dimensional bar code is a kind of automatic recognition and treatment code of graphs and symbols. It is based on computer image processing technology and combined coding theory. Two-dimensional bar code has a relatively higher information density, therefore, its encoding and recognition technology is more complex than that of one-dimensional bar. Therefore, effective and rapid encoding and recognizing of 2D bar code is an important field for research.The purpose of this project is to realize of design of the creation and decoding system of two-dimensional bar code. The content of this project includes two parts: the design of creation system and decoding system of two-dimensional bar code. The creation system completes the function from the input data to the creation of corresponding two-dimensional bar code. The decoding system completes the function of translating two-dimensional bar code into relevant information.This paper introduces briefly the characteristics and coding principles of QR two-dimensional bar code. It also introduces in details coding principles and methods realized with computer. It introduces design steps with specific instances, and also raises a programs design method which can realize both English and Chinese encoding at the same time. Two-dimensional bar code possesses the capability of error-correcting which one-dimensional bar code doesn't. Therefore, besides a brief introduction of Reed-Solomon error-correcting code (RS code), this paper also gives a thorough analysis of RS code's application in two-dimensional bar code QR, and gives detailed encoding and decoding principles in GF(256). Meanwhile, a new encoding method is used in the coding of barcode in process of creating system design of QR code, accomplishing the process of creating relevant QR code using input data.The design process of decoding system of QR code includes two parts. The first part is the pretreatment of collecting image, namely, the reform of image. It will ground for the correct decoding. The second part is decoding the bar-code image after pretreatment, getting the information of the barcode. A new algorithm of rotation and alignment of image based on the symbol structure properties of the QR code is hold forth in the recognizing system, Experiments proved that this algorithm can effectively rotate and align the image of QR code, which can also lead to the efficiency and accuracy of the decoding process.The hardware of the system is composed of camera, printer and computer. The program is realized with C and C++.