The Research Of Two-Dimension Barcode Recognition Technology

The two-dimension barcode (2D barcode) is a symbol which record data information using black and white graphics modules with a certain regular in two-dimension directions (horizontal and vertical). Unlike one-dimension barcode, 2D barcode can express information in two directions, which determines its higher data density. The 2D barcode can be categorized into two classes, matrix mode and stack mode. And the most popular 2D barcode present are QR code, Data Matrix code, PDF417 code, etc.The bar code recognition technology, which is based on computer technologies, pattern recognition, image processing, photo-electricity technologies and communication technologies, is an important approach to automatic input and recognition.Because of various limitations, such as shooting angle, distance, illumination, we cannot sample ideal 2D barcode image, which include only the barcode symbol and has no noise. Thus we need to process the sampled image previously before recognizing the 2D barcode. The job is to locate the symbol and to pre-process the image. Then, we have to position the barcode symbol accurately and translate the black and white graphics modules into binary data information. On account of recognition error or the destruction of 2D barcode image, the data information after recognition may be ruined or missed partially, thus Reed-Solomon algorithm is introduce to control and correction the error.Based on image process method, we do research to get the best recognition technology of 2D barcode. Reed-Solomon algorithm, which is the most popular error correction method, is researched as well in this article. Beside, the date encode and decode of the 2D barcodes are also introduced.