Thesis (Ph.D.) - Cairo University - Faculty of Engineering - Department of Electronics and Communication

Digital watermarking has been employed for many years as one of the effective means for securing the multimedia from piracy. Most of its applications require a robust embedding, which affects the watermarking quality. Optimization methods are utilized to provide an optimum trade off between the watermark robustness and the watermarking quality. In this work, a modification of a recent embedding method is performed, and then the optimization is applied. Two watermarking optimization challenges were addressed and solved by designing their proper fitness function. The first challenge is an attempt to provide a better compromise, between the quality and robustness, than that of the traditional methods. It was performed through applying the optimization for embedding each watermark bit individually, which introduced a problem of measuring the achieved robustness for a single bit. The proposed fitness function solved that problem by using the achieved quality as an estimate to the robustness degree. The second challenge is the design of a quality guaranteed robust watermarking optimization. A new fitness function is proposed for guiding the optimization to the optimum embedding parameters, which achieves the maximum possible robustness along with a watermarking quality that satisfies a quality condition

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