Penggunaan Internet telah mendatangkan pelbagai ugutan terhadap keselamatan maklumat. Teknik tera air telah menjadi tumpuan dalam usaha melindungi hak milik. Kebanyakan penyelidikan hanya mengutamakan pembangunan sistem tera air bagi imej hitam putih tetapi imej berwarna jarang digunakan. Suatu sistem tera air bagi imej berwarna untuk tujuan melindungi hak milik telah dicadangkan dalam disertasi ini. Logo berwarna digunakan sebagai tera air dan disembunyikan di dalam imej berwarna. Bagi memperolehi sistem warna yang sesuai bagi sistem tera air, prestasi bagi lima sistem warna yang berlainan ditentukan dengan menggunakan imej dan tera air yang berlainan. Selain itu, dua jenis transformasi wavelet iaitu Discrete Wavelet Transform(DWT) dan Stationary Wavelet Transform(SWT) digunakan dalam eksperimen. Keputusan eksperimen menunjukkan bahawa teknik yang dicadangkan adalah kebal terhadap pelbagai operasi pemprosesan imej termasuk Gaussian filtering, average filtering, circular average filtering, sharpening, JPEG compression, JPEG2000 compression, Gaussian noise, salt and pepper noise, speckle noise, cropping, dan screen capture. Sifat kekebalan terhadap serangan menunjukkan bahawa sistem tera air yang dicadangkan itu merupakan suatu penyelesaian yang boleh dipercayai bagi melindungi hak milik.
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The adoption of Internet in day to day life creates new threats to information security. Digital watermarking technique becomes the limelight in the attempt to address copyright protection. In the past few years, most researches focused on developing watermarking systems for grayscale images whereas the watermarking of color image is comparatively rare. An oblivious color image watermarking system for copyright protection is proposed in this dissertation. The watermark is a color logo and embedded in the wavelet decomposition of the color host image. In order to identify the suitable color model for watermarking, the performances of five different color models are examined using different host images and watermarks. Besides that, two types of wavelet transform, namely Discrete Wavelet Transform (DWT) and Stationary Wavelet Transform (SWT) are applied in the experiments. The experimental results demonstrate that the proposed method is robust to a variety of image processing operations which include Gaussian filtering, average filtering, circular average filtering, sharpening, JPEG compression, JPEG2000 compression, Gaussian noise, salt and pepper noise, speckle noise, cropping, and screen capture. The high robustness of the watermarking system shows that the proposed scheme is a reliable solution for copyright protection.
Teknik tera air berdasarkan imej berwarna untuk tujuan perlindungan hak milik_Yap Shu Shin_E3_2006_NI