Introducing a new method of Robust Digital Image Watermarking against Cropping and Salt & Pepper Noise using Sudoku

With rapid development of digital technology, protecting information such as copyright, content ownership confirmation has become more important. In image watermarking, information of the image is inserted such that the visual quality of the image is not reduced and the receiver is able to get the required information. Some attacks such as image cropping and salt & pepper noise, destroy the watermark’s information. In this article, a new watermarking scheme is proposed which is robust against salt & pepper noise and tough cropping. A Sudoku table comprises 9 regions, each row and column of the table contains different numbers from 1 to 9. In the proposed scheme, Sudoku table and both watermarking approaches based on spatial domain and transform domain are used. Robustness of watermarking against cropping attack is 86% and its robustness against salt and pepper noise is about 75%, which shows good and effective performance of the proposed scheme.