In this paper, an affine invariant watermarking scheme, robust to geometric attacks, is proposed and applied to face regions. Initially, face regions are unsupervisedly extracted from an initial image and a normalization procedure, invariant to geometric attacks is applied on each of these regions using a set of specific moment criteria. A spread spectrum-based DS-CDMA watermarking scheme is then used in order to provide a multi bits watermark. The multi bits watermark embedding and detection procedures are then applicable to each normalized face region. Finally, performance of the proposed face regions watermarking scheme is tested under various distortions, providing efficient and robust watermark retrieval.
Paraskevi K. Tzouveli, Klimis S. Ntalianis, Stefan