الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Nowadays, images constitute a noteworthy part in multimedia in which images can be in the form of diagrams, photographs and digitized cultural heritage paintings. Digital watermarking has appeared as an essential tool to protect the multimedia data from copyright infringement. It has been a technique for labeling multi-media data, including a lot of kinds such as; digital images, text documents, video and audio clips, by hiding secret information inside the data.Also, making security on medical images is essential to protect the privacy of patients and assure data integrity. Consequently, encryption and watermarking were introduced to improve the security of medical images. So, the last two methods are triple-layer encryption-based watermarking technique for improving security of medical images.This study mainly aims to present the six different digital image watermarking methods through implementation, comparing and evaluation. One of the primary objectives in this research is to introduce the limitations and strengths of the current watermarking methods and develop new solutions to overcome these shortcomings. In addition, the new proposed methods are involved in application scenarios of watermarking for the purpose of evaluating these methods.Among the six watermarking methods used in the present study, the first method is in the discrete cosine transformed domain and has been used for comparison. The second method presented in the wavelet domain approach by adaptively adding a scaled logo to the qualified significant wavelet coefficients at the third bands of the DWT of an image. The third method that has been presented to compare the Hybrid Fusion Technique (HFT). The fourth method is a proposed combined method Improved DWT/DCT (IMD-WC-T) that is used for enhancing imperceptibility, gives less execution time and enhances robustness when making the comparison to DWT, DCT and HFT techniques and gives more robustness against the attacks;Gama Correction and Histogram Equalization, also as well improve the quality of recovered watermark image.The combinations had introduced strength of the two common frequency domain methods; DWT and DCT, for two reasons of robustness as well as visual impact. The embedding process in the DCT domain has been proved to be highly resistant to JPEG compression attack as well as to significant amounts of random noise.A watermarking method with mild robustness, good capacity, and low visual impact, has been produced by anticipating which coefficients would be modified by the subsequent transform and quantization. This generally holds reality for watermarking; if the later degradation methods are known, robustness can be considerably improved. This is applied especially to compression methods, where the algorithms of compression are well established.Establishing two new methods that aim to assure secure medical images based on triple-layer encryption. Thus, they achieve low processing time and are able to resist several attacks. The fifth method presents a multi-level Encryption-based DWT method (EbDT) that combines the wavelet-induced multi-resolution decomposition capability of DWT with the energy compaction capacity of DCT into a powerful strategy for enhanced robustness and security of medical images is proposed. In the first layer of the proposed EbDT method, one of the DWT decomposed sub-bands of the cover image is further modified using the DCT transform. Next,a 64-bit hex is used as the first key to create secure force (SF) keys (K1-K5) that are further utilized to encrypt the host image as well as to generate a second key to encrypt the watermark.Finally, in the third layer of the EbDT method, a PN-sequence is generated to be embedded onto DCT coefficients to produce the watermarked image .Finally, the sixth method uses a multi-level Encryption-based Hybrid Fusion Technique EbHFT). It expects to fuse the wavelet-induced multi-resolution decomposition capability of DWT with the energy compaction capacity of DCT in order to enhance the imperceptibility,robustness and security of medical images.