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Quantization index modulation based watermarking using digital holography

Okman, Osman Erman
The multimedia watermarking techniques are evolved very quickly in the last years with the increase in the use of internet. The evolution of the internet makes the copyright issues very important and many different approaches are appeared to protect the digital content. On the other hand, holography is the method to store the 3-D information of an object but it is very applicable to use as a watermark because of the nature of the holographic data. The 3-D object can be reconstructed from the hologram even if the hologram is cropped or occluded. However, watermarking of an image with a hologram is a very novel approach and there are only a few works in the literature which are not very robust against the attacks like filtering or compression. In this thesis, we propose to embed the phase of the hologram to an image using quantization index modulation (QIM). QIM is utilized to make the watermarking scheme blind and degrade the host image as low as possible. The robustness of the proposed technique is also tested against several attacks such as filtering, compression, etc. The evaluated performance of this system is compared with the existing methods in the literature which uses either holograms or logos as the secret mark. Furthermore, the characteristics of the holograms are investigated and the findings about the hologram compression are reported in this work.