A NOVEL MULTIPURPOSE IMAGE WATERMARKING SCHEME BASED ON BLOCK-RELATION

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International Journal of Innovative

Computing, Information and Control ICIC International c_{°2007 ISSN 1349-4198}

Volume 3, Number 5, October 2007 pp. 1161—1172

Da-Jinn Wang

Department of Information Management National Kaohsiung Marine University

142, Hai-Chuan Rd. Nan-Tzu, Kaohsiung 811, Taiwan wangdaj@mail.nkmu.edu.tw

Tsong-Yi Chen, Thou-Ho (Chao-Ho) Chen and Shang-Wei Lin

Department of Electronic Engineering National Kaohsiung University of Applied Sciences

415, Cheng-Kung Road, Kaohsiung 807, Taiwan { chentso; thouho; 1094320140 }@cc.kuas.edu.tw

Received October 2006; revised February 2007

Abstract. In this paper, we propose a new scheme that uses block-related index and three types of coeﬃcient-scan strategy in image authenticating and recovering. Block-related authenticating information makes the feature codes tolerant in compression pro-cesses. Besides, a block-classification method is used for classifying blocks into flat, vertical-detailed or horizontal-detailed types. With that, a useful coeﬃcient-scan strategy is chosen for preserving and recovering block information. As the experimental results, the watermarked image can provide a PSNR higher than 40.00dB and can mark and recover the blocks which could be maliciously tampered with.

Keywords: Watermarking, Image authentication, Image restoration, Image compres-sion

1. Introduction. More and more watermarking approaches have been proposed for tam-per detection and copyright protection. The reproduction of a digital media element is simple and robust. How to protect and prove the original copies or tampered is an im-portant issue. In the past, several techniques and concepts, such as fragile watermarks, semi-fragile watermarks, and robust watermarks, based on data hiding or stenography have been introduced for tamper detection in digital images and for image authentica-tion.

The fragile watermark is embedded with very low robustness. Therefore, this type of watermark can be destroyed even by the slightest manipulations and thus it is comparable to the hidden message in steganography methods. It can be used to check the situation of the integrity of objects. Neither the fragile nor robust watermarks deal with the information preserving very well. Semi-fragile watermarks are marginally robust and are less sensitive to pixel modifications. So, it is possible to use them for quantifying shuﬄing from malicious changes, such as feature adding and removal. The primary applications of a semi-fragile watermarking system resemble those of fragile watermarking systems.