Evaluations of the printing qualities of RFID tag´s conducting line

The printing quality of RFID tag conducting line will influence its electric properties. In this paper, utilizing digital image process techniques, a method for measuring the printed width of the conducting line of RFID tag, and the raggedness and the blurriness of the line´s edges was represented. Firstly, a CCD image capture system was selected, and the relationship between its respond RGB values and their corresponding light reflectivity was built. Secondly, the conducting line image captured by the CCD system was transformed into a reflectivity gray image by the relationship. Finally, utilizing a series of image processing procedures, such as orientation aligning, characteristic gray point extraction, linear fitting, and error calculation, three quality parameters, which are line width, raggedness and blurriness, were obtained. Our experiments on three RFID tag products showed that the method can measure the three printing quality parameters conveniently and quickly, giving their printing quality representations and comparisons.