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Removable visible image watermarking algorithm in the discrete cosine transform domain

journal contribution
posted on 2008-01-01, 00:00 authored by Y Yang, X Sun, H Yang, Chang-Tsun LiChang-Tsun Li
A removable visible watermarking scheme, which operates in the discrete cosine transform (DCT) domain, is proposed for combating copyright piracy. First, the original watermark image is divided into 16×16 blocks and the preprocessed watermark to be embedded is generated by performing element-by-element matrix multiplication on the DCT coefficient matrix of each block and a key-based matrix. The intention of generating the preprocessed watermark is to guarantee the infeasibility of the illegal removal of the embedded watermark by the unauthorized users. Then, adaptive scaling and embedding factors are computed for each block of the host image and the preprocessed watermark according to the features of the corresponding blocks to better match the human visual system characteristics. Finally, the significant DCT coefficients of the preprocessed watermark are adaptively added to those of the host image to yield the watermarked image. The watermarking system is robust against compression to some extent. The performance of the proposed method is verified, and the test results show that the introduced scheme succeeds in preventing the embedded watermark from illegal removal. Moreover, experimental results demonstrate that legally recovered images can achieve superior visual effects, and peak signal-to-noise ratio values of these images are>50 dB. © 2008 SPIE and IS&T.

History

Journal

Journal of Electronic Imaging

Volume

17

Issue

3

Article number

03308

Pagination

1 - 11

Publisher

SPIE, the International Society for Optical Engineering

Location

Bellingham, Wash.

ISSN

1017-9909

eISSN

1560-229X

Language

eng

Publication classification

C1.1 Refereed article in a scholarly journal