Digital image watermarking using fractional Fourier transform

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Tezin Türü: Yüksek Lisans

Tezin Yürütüldüğü Kurum: Dokuz Eylül Üniversitesi, Mühendislik Fakültesi, Elektrik - Elektronik Mühendisliği Bölümü, Türkiye

Tezin Onay Tarihi: 2024

Tezin Dili: İngilizce

Öğrenci: OLCAY DUMAN

Danışman: Olcay Akay

Özet:

Digital watermarking has gained significant attention in various practical applications. It involves embedding specific information into signal data while maintaining the original data quality. Watermarking can be applied to different types of data, including images, video, text, and audio, to protect them from copyright infringement. This thesis presents a few approaches that exhibit unique features and could be suitable for image watermarking which involves embedding a binary image watermark using a combination of the Discrete Wavelet Transform (DWT) and the Fractional Fourier Transform (FrFT) for blind and robust digital watermarking of images. The DWT domain is utilized to ensure the watermark is imperceptible to the human eye. The FrFT orders serve as secret keys that increase the procedure’s robustness against various attacks. Additionally, the method enables extraction of the watermark from the watermarked image without the knowledge of the primary image. The objective of this thesis is to examine the efficacy of a technique for watermarking binary images within the wavelet domain. The strategy is evaluated through computer simulations, with particular emphasis on several key issues. These include ensuring the binary graphic watermark is embedded into the original image with minimal distortion and that the watermark can be obtained absent of requirement of the original image. The method is effective and resistant against numerous challenges, including JPEG compression, filtering, noise addition, cropping, and rotation. The proposed method also maintains the confidentiality and integrity of the original image while ensuring that the watermark is imperceptible to the human eye. The study aims to demonstrate the effectiveness and reliability of image watermarking within the wavelet spectrum as a feasible approach for protecting image copyright and ownership, as well as providing authentication and security.