Title: Combined-transforms-based robust colour image watermarking schemes

Authors: Dejey, R.S. Rajesh

Addresses: Department of Computer Science and Engineering, Manonmaniam Sundaranar University, Tirunelveli, Tamil Nadu 627 012, India. ' Department of Computer Science and Engineering, Manonmaniam Sundaranar University, Tirunelveli, Tamil Nadu 627 012, India

Abstract: In this paper, two combined transforms are explored for colour image watermarking namely: Discrete Wavelet Transform–Fan Beam Transform (DWT-FBT); Spatio-Chromatic Discrete Fourier Transform–Fan Beam Transform (SCDFT-FBT). In the first approach, a host image is subject to DWT and FBT is applied after careful selection of the suitable band of wavelet coefficients. Watermarking is done by altering the fan beam transformed coefficients. Hence, this domain is termed as DWT-FBT domain. In the second approach, watermarking is done on selected SCDFT coefficients that are transformed using FBT and hence termed as SCDFT-FBT. The DWT-FBT domain shows superior performance than SCDFT-FBT domain in its resistance to compression, cropping, colour conversion and rotation. Results of the proposed combined transforms are compared with the two existing DWT-DCT domain watermarking schemes to show their effectiveness.

Keywords: DWT; FBT; SCDFT; robust watermarking; colour image watermarking; discrete wavelet transform; spatio-chromatic DFT; discrete Fourier tansform; fan beam transform; imaging systems; image compression; image cropping; colour conversion; image rotation.

DOI: 10.1504/IJSISE.2010.036887

International Journal of Signal and Imaging Systems Engineering, 2010 Vol.3 No.3, pp.155 - 163

Published online: 15 Nov 2010 *

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