Publication: Rekabentuk satu teknik tera air separa rapuh yang berasaskan ‘wavelet’ untuk kegunaan pengesahan imej
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Date
2005-03-01
Authors
Koh, Ling Hock
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Abstract
The enormous popularity of the World Wide Web in the early 1990's demonstrated the commercial potential of offering multimedia resources through the
digital networks. Since commercial interests seek to use the digital networks to offer digital media for profit, they have a strong interest in protecting their ownership rights. Digital watermarking has been proposed as one way to accomplish this. Digital watermarking serves many purposes, such as intellectual property rights protection, content verification and information hiding. Since 1993, the research of digital watermarking for image content authentication has received more and more attentions. Image content authentication tries to embed information in order to identify and localize any malicious attacks on the image. In this dissertation, a wavelet-based semi-fragile watermarking technique for image content authentication is proposed, which is robust against content-preserving operations, while very fragile to content-changing processing. The image is first divided into equal-sized, non-overlapping blocks. Then, the average of pixel intensities is calculated for each of such blocks and embedded as a semi-fragile watermark back into the image for content protection. The experimental results clearly demonstrate that the proposed algorithm is able to detect malicious attacks on the image, secure and robust to common image processing operations.