Research On Two-dimensional Barcode Acquisition And Recognition System Based On CIS And ARM9

Barcode technology which is the most economical and practical automatic identification technology has been applied in various secotors. The application of one-dimensional barcode is alread quiet mature. But it contains few information and generally needs external database supports. Two-dimensional barcode (2D) overcomes this defects and completely divorced from external databases through encoding a large amount of information into the small area. 2D barcode itself is a separate data file and is a ideal way to achieve the carrying of certificates, cards and other information, and can be automatically read by machine. PDF417 applications is the most widely used among a variety of 2D dimensional barcodes .In this paper, a 2D barcode image acquisition terminal based on contact image sensor and ARM9 processor is designed. And taking PDF417 barcode as an example, the auto-recognition algorithm of barcode with complex background is introduced. This system uses CIS as image sensor, with the horizontal scanning to complete the acquisition. The horizontal resolution can be automatically adjusted according to the length of barcode carrier. And it satisfies the requiement of the recognition algorithm on the image resolution. To solve the problem of the real-time data acquisition, we uses high-speed A/D, large capacity FIFO as well as a series of high-speed devices and the DMA high-speed storage solution. In view of the particularity of the barcode image, this topic combines the image processing and pattern recognition and proposes a complete set of algorithm of barcode region positioning, rotating and recognition. Region positioning algorithm makes more accurate positioning with three steps.Experimental results show that this platform can perform real-time, steady to complete barcode image acquisition. The recognition algorithm can effectively overcome difficulty of barcode recognition because of the uneven illumination, and signnificantly increased the recognition rate. The resarch on this system can play a positive role in expanding the application fields of 2D barcode technology in our country.