An Image Anti-Forgery Algorithm Based on Conceal Zone Special Halftoning

Based on analysis of current situation, this paper develops a new anti-forgery algorithm based on conceal zone special halftoning, which realizes image anti-forgery in printing process. It brings forward the algorithm thought, and then sets up two halftoning models of template and threshold matrix. By numbering and extracting the manuscript pixels, it realizes the exact dividing of conceal zone and common zone through scan line filling algorithm. Then the method of generating halftone image by using the two halftoning models is studied. An experiment is performed to study the interior dot structure of the halftone image and its character. The experiment testifies that this algorithm can implant special shape dots different from traditional dot shapes in special zones of one image or multiple images, in which the anti-forgery is realized by observing the special zone’s dots.