IMAGE-WATERMARKING METHOD AND DEVICE

摘要

The invention relates to a method of watermarking an image comprising at least three components. The inventive method comprises the following steps consisting in: breaking down at least one component of the image into detail subbands along different directions and comprising coefficients, each coefficient being characterised by amplitude and the position thereof in the detail subband to which it belongs; for each position, determining information that is representative of local amplitude variations from the amplitudes of the coefficients at said position in the different detail subbands and the coefficients close to said position in the different detail subbands; determining a marking force at each position from the local amplitude variation representative information determined for said position and forming a watermark comprising a plurality of binary information in the image, by inserting each piece of binary information at a position of the image according to the marking force determined for a position corresponding to the position at which the binary information is inserted.