Date of Award:

5-2012

Document Type:

Thesis

Degree Name:

Master of Science (MS)

Department:

Computer Science

Committee Chair(s)

Xiaojun Qi

Committee

Xiaojun Qi

Committee

Stephen J. Allan

Committee

Heng-Da Cheng

Abstract

More and more digital images are being distributed over the Internet to an evergrowing number of people for sharing, studying, or other purposes. However, most of those digital products are exposed without any protection, and such information can be easily transferred, copied, and tampered without authorization simply by using readily available digital multimedia editing software. Digital watermarking techniques have been developed as a tool to discriminate whether the original content of digital media is tampered or not. A digital watermark is embedded on digital images as an invisible message and is used to demonstrate the proof by the owner.

In this thesis, we propose a novel localized geometric-distortion resilient digital watermarking scheme to embed two invisible messages to images. Our proposed scheme utilizes two complementary watermarking techniques, namely, local circular region (LCR)-based techniques and block discrete cosine transform (DCT)-based techniques, to hide two binary sequences in two different kinds of regions within the image and extract these two sequences from their individual embedding regions.

Working in tandem, these two methods safeguard against several common attacks to digital media. We ran several tests, the results of which demonstrate that our proposed method is more robust and has a better overall performance as compared with some peer systems in the literature.

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Comments

This work made publicly available electronically on May 10, 2012.

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