An anti-counterfeiting method for printed image by digital halftoning method

Anti-counterfeiting technology has been widely used in many fields, especially in printing industry for banknotes and security documents. This paper introduces an anti-counterfeiting method with varied screening angle and gives the realization procedure of this method. Firstly, the continuous-tone cover image is halftoned by ordered dithering halftoning method with 0o and 45o screening angle, respectively. Then, a binary figurative image which represents the hidden information is generated by using Photoshop software for serving as a mask image. Finally, the latent image is generated by combining the two halftoning images with different screening angle according to the figurative image. The diagonal edge detector is designed for extracting the hidden information. The experimental result shows that the proposed method can better generate the desired latent image and the hiding message can easily be exposed by the simply image processing method.