Image Acquisition for Pressed Protuberant Characters on Metal Label

Abstract

The pressed protuberant characters on metal label are the difference of reflectance. It is very difficult to obtain the character of full binary image directly. It has presented a novel method of image acquisition on metal label pressed protuberant character based on moiré contour. At first, the principles of moiré contour were analyzed; Secondly, the experiment parameters were designed by using of shadowing moiré equipment and pressed characters’ height. The moiré image of metal label is captured through experiment by using of CCD camera. The binary image of pressed characters was output using moiré fringe image modulated by the characters’ height as input image contrast enhancing, complement, middle filter, automatic threshold etc. The binary image of pressed character was obtained using image preprocessing. At last, the binary images of moiré contour obtained and direct obtained were compared. The experiments show that the binary image of moiré contour obtained is better than direct obtained image.