| dc.description.abstract | Watermarking is the process of embedding information in a carrier in order
to protect the ownership of text, music, video and images, while steganography
is the art of hiding information.
Normally watermarks are embedded in images but remain visible in the
majority of commercial image databases, such as Getty (gettyimages.ie) or
iStock Photo (istockphoto.com). Watermarked images display ownership information
in the form of copyright notices super-imposed on the image itself.
However this leaves traditional watermarking techniques vulnerable to
tampering. Thus the advantage of using steganographic techniques for watermarking
is that the watermark is resistant to detection and consequently
to tampering.
Robustness is a characteristic of critical importance, in order that a watermark
is to survive image manipulation and enhancement processes, as well
as intentional attacks, to ensure piracy is prevented.
A review of digital image-based steganography and watermarking techniques
is carried out in this document. This investigation reveals that most
watermarking algorithms demonstrate partial resistance to attacks.
The aim of this work is to produce a novel hybrid digital watermarking
technique, based on the exploitation of both the RGB and the YCbCr colour
spaces, using spatial domain techniques. A text watermark is embedded in
the YCbCr colour space, while an image watermark is embedded in the RGB
colour space. Results demonstrate that the proposed hybrid technique can
withstand levels of geometric attacks and processing attacks up to a point
where the commercial value of the images tested would be lost. Results also
demonstrate technical and performance improvements over existing methods,
in terms of security and algorithm e_ciency, while taking inspiration from
steganography, to avoid drawing attention to the fact that an image contains
hidden information. | en |
