This thesis deals with copyright protection and content authentication for still images. New blind
transform domain block based algorithms using one-level and two-level Discrete Wavelet Transform
(DWT) were developed for copyright protection. The mobile number with international code is used as
the watermarking data. The robust algorithms used the Low-Low frequency coefficients of the DWT to
embed the watermarking information. The watermarking information is embedded in the green channel of
the RGB colour image and Y channel of the YCbCr images. The watermarking information is scrambled
by using a secret key to increase the security of the algorithms. Due to the small size of the watermarking
information comparing to the host image size, the embedding process is repeated several times which
resulted in increasing the robustness of the algorithms. Shuffling process is implemented during the multi
embedding process in order to avoid spatial correlation between the host image and the watermarking
information. The effects of using one-level and two-level of DWT on the robustness and image quality
have been studied. The Peak Signal to Noise Ratio (PSNR), the Structural Similarity Index Measure
(SSIM) and Normalized Correlation Coefficient (NCC) are used to evaluate the fidelity of the images.
Several grey and still colour images are used to test the new robust algorithms. The new algorithms
offered better results in the robustness against different attacks such as JPEG compression, scaling, salt
and pepper noise, Gaussian noise, filters and other image processing compared to DCT based algorithms.
The authenticity of the images were assessed by using a fragile watermarking algorithm by using hash
function (MD5) as watermarking information embedded in the spatial domain. The new algorithm
showed high sensitivity against any tampering on the watermarked images. The combined fragile and
robust watermarking caused minimal distortion to the images. The combined scheme achieved both the
copyright protection and content authentication.
| Identifer | oai:union.ndltd.org:BRADFORD/oai:bradscholars.brad.ac.uk:10454/6460 |
| Date | January 2014 |
| Creators | Jassim, Taha D. |
| Contributors | Abd-Alhameed, Raed |
| Publisher | University of Bradford, School of Engineering, Design and Technology |
| Source Sets | Bradford Scholars |
| Language | English |
| Detected Language | English |
| Type | Thesis, doctoral, PhD |
| Rights | <a rel="license" href="http://creativecommons.org/licenses/by-nc-nd/3.0/"><img alt="Creative Commons License" style="border-width:0" src="http://i.creativecommons.org/l/by-nc-nd/3.0/88x31.png" /></a><br />The University of Bradford theses are licenced under a <a rel="license" href="http://creativecommons.org/licenses/by-nc-nd/3.0/">Creative Commons Licence</a>. |
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