Study On Automatic Reading Technology Of 2D Barcode Captured By General Devices

2D barcode was born with the development of information technology. Now, barcode reader is developing to the fourth generation, which bases on image processing, but the cost of the reader is so expensive that 2D barcode can' t be applied far and wide. Now in order to let the technology of 2D barcode serve the society better and more widely, solve the bottleneck problem in the popularization application of 2D barcode, this paper presents to realize the automatic reader of 2D barcode by the way of capturing the 2D Barcode image with general devices based on image-accessed mode.According to the characteristic of PDF417 barcode and the theory of computer vision, this paper accomplishes an automatic reading system. It analyzes systemically the possible problems, such as low resolution, odd illumination, blur, aberrance and incline, at the same time considering the defile and default of 2D barcode, aroused by the way of capturing the 2D barcode using with the general devices.Whatever background the PDF417 barcode lies. The first step is to get the effective area of 2D barcode according to initial symbol and terminal symbol' s character of PDF417 barcode. This effective area should include the possible default part and exclude the defile part connecting with barcode. Considering the unitary aberrance is the accumulation of all partial aberrances, so the second step of this system is to divide barcode into several rows. Then amend every row, and in terms of the character of PDF417 barcode image, threshold every row image using a gradual thresholding method, which effectively solves the problems such as odd illumination and blur. Then present a good method to accomplish barcode reading. At last, compose the obtained code words into a sequence, and then correct the sequence using the theory of correct code. The experiment results show thatthis system presented by this paper is effective, and has practicality.