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Paper data
Use of synchronisation pattern to estimate geometric distortions

Baudry Severine, Thales communications
Ngueyen Philippe, Thales communications
Maitre Henri, ENST

Page numbers in the proceedings:
Volume I pp 709-712


Paper abstract
Watermarking can be modeled as a communication over a steganographic channel. The channel may comprise additive noise which modifies the data value, as well as geometric noise which modifies the data location. We propose here a general model for geometric channels by introducing a random variable, the index variable. We model the jitter attack by a Markov chain. To enhance the watermark retrieval after a jitter, we propose to embed a synchronisation pattern in the cover picture. We use this pattern to estimate the geometric distortions at the receiver side.

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