METHOD OF SYNCHRONISING DIGITAL WATERMARK OF ELECTRONIC IMAGE Russian patent published in 2015 - IPC H04N19/467 G06K9/00 G06T1/00 G06F21/16 

FIELD: physics.

SUBSTANCE: method comprises, at the sender, dividing an electronic image into macroblocks, each macroblock divided into N≥2 blocks from which K<N synchronisation blocks are selected; calculating a transmission synchronisation sequence and embedding into synchronisation blocks which allow embedding; at the recipient, establishing synchronisation of the digital watermark in the received electronic image for which, beginning with the selected initial point of the recipient, the received electronic image is successively divided into macroblocks and blocks, from which blocks for the intended synchronisation are selected; extracting therefrom verification subsequences and merging into a verification sequence which is compared bitwise with all shifts of the calculated receiving synchronisation sequence; the electronic image received by the recipient is considered an electronic image with established synchronisation of the digital watermark, corresponding to the intended synchronisation sequence with the least number of mismatches. The disclosed method can be used to increase the probability of establishing synchronisation of a digital watermark of an electronic image, divided into component parts of an arbitrary size, and for preventing visually noticeable distortions caused by embedding into blocks of the electronic image with virtually unchanged statistical characteristics of transmission synchronisation sequences.

EFFECT: improved establishment of synchronisation of a digital watermark of an electronic image when dividing the electronic image with an embedded digital watermark into component parts of an arbitrary size.

4 cl, 9 dwg