Enhancement of Fourier Image Watermarking Robustness

Rabia RIAD, Frédéric Ros, Rachid Harba, Hassan Douzi, Mohamed Elhajji


Fourier watermarking is often chosen to watermark images that have to be printedand scanned on a physical support, during which the so-called print-scan attack occurs. Onepopular method embeds the watermark in the FFT magnitudes of the image along a circle ofoptimal radius. This paper presents an enhancement of Fourier watermarking robustness bypre-processing data to be watermarked before insertion of the watermark. This pre-processingconsists in reducing the variance of the FFT magnitudes of the image. Two schemes are proposedto reduce the variance: the rst is based on a low pass lter applied on the data, while thesecond selects the FFT magnitudes that lower the variance in a region located between twopredened circles. Results show that the robustness to print-scan attack is increased comparedto traditional Fourier watermarking. The whole scheme is ecient and has a low computationalcost that makes it compatible with industrial constraints


Image; Watermarking; FFT; Pre-processing; Counter attacks

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