Side-Informed Image Watermarking Scheme Based on Dither Modulation in the Frequency Domain

Osama Hosam*
The City for Scientific Research and Technology Applications, IRI, Alexandria, Egypt

© 2013 Osama Hosam.

open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International Public License (CC-BY 4.0), a copy of which is available at: This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

* Address correspondence to this author at the City for Scientific Research and Technology Applications, IRI, Alexandria, Egypt, Tel: +20125966704; Fax: +20125966704; Email:


Digital communication and media sharing have extensively increased in the last couple of years. Research is focused on protecting digital media through copyright protection. The digital media is secured by watermarking. We have developed an image watermarking technique in the frequency domain to hide secure information in the Discrete Cosine Transform (DCT) coefficients of the carrier image. DCT coefficients are modulated by Dither Modulation (DM). We have increased the modulation step to be able to entirely recover the embedded data (watermark) and increase the robustness of our proposed algorithm to affine transforms and geometrical attacks. Our algorithm showed lower complexity and robustness against different attacks.

Keywords: Watermarking, DCT, side-informed, decoding, encoding, robustness.