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1. (WO2013120850) METHOD FOR INSERTING A DIGITAL MARK INTO AN IMAGE, AND CORRESPONDING METHOD FOR DETECTING A DIGITAL MARK IN AN IMAGE TO BE ANALYSED

Pub. No.:    WO/2013/120850    International Application No.:    PCT/EP2013/052787
Publication Date: Fri Aug 23 01:59:59 CEST 2013 International Filing Date: Wed Feb 13 00:59:59 CET 2013
IPC: G06T 1/00
Applicants: CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE
UNIVERSITE DE NANTES
Inventors: AUTRUSSEAU, Florent
Title: METHOD FOR INSERTING A DIGITAL MARK INTO AN IMAGE, AND CORRESPONDING METHOD FOR DETECTING A DIGITAL MARK IN AN IMAGE TO BE ANALYSED
Abstract:
The invention concerns a method for inserting a digital mark into an image, via an insertion device, comprising the following steps: application of a Fourier transform to said image, producing a two-dimensional Fourier spectrum; insertion of said mark into said Fourier spectrum, producing a modified Fourier spectrum; application of an inverse Fourier transform to said modified Fourier spectrum, producing a watermarked image. Said mark comprises watermark coefficients (wu,v)j each associated with a separate predetermined position (u, v) of a given quadrant from the quadrants of the Fourier domain, whereof the spectral coordinates u and v, measured along the two coordinate axes of the given quadrant and starting from the continuous component, and expressed as a percentage of dimensions U and V of the given quadrant, are such that: u > 66%xU and v > 66%xV. The set of positions associated with said watermark coefficients define a predetermined convex pattern in the given quadrant.