Rechearch Of The Quality-Checking System Of The Printed Bar Code Based On Machine Vision

Bar code is used in various fields. However, in the process of printing bar code, there are different kinds of quality problems due to the accuracy of machines and techniques. Since the traditional way of quality-checking can not satisfy the needs of production and the market, a new way based on machine vision has become a popular trend.In this thesis, according to the practical needs of some printing enterprises and the application of bar code techniques, the author combines techniques of machine vision, automatic bar code recognition, image processing with printing to give a complete and basic study of the quality-checking system of printed bar code. First, this thesis analyzes the differences between the online checking system of printing bar code and the online checking system of the common printing deficiency in the practical use of software and hardware. Then, it sets up a plan to realize the system. It puts great emphasis on the analysis of several classic image-processing methods utilized in the inspection of bar code recognition and designs a checking and recognition system based on the features of bar code edge. This helps to realize the online quality-checking of most bar code and develops an online quality checking based on the hardware platform of virtual printing experiment and the software platform of Visual C++6.0. This system can automatically inspect the appearance defect, size of clear area, size of the bars, enlargement index, and the accuracy of recognition code at any time in the printing process. Besides, it can also analyzes the inspection results and carries out alarming information.The quality-checking system of the printed bar code designed in this thesis satisfies the instant needs of production, and it has fairly prefect function and simple performance. Thus, it is of practical use.