Block truncation coding and discrete wavelet transform based robust digital color image watermarking system

Recently, Internet is being increasingly used as the platform for distribution of digital multimedia content. The use of an open medium like Internet gives rise to concerns about protection and enforcement of intellectual property rights of the digital content involved in the transaction. One of the methods for the protection of intellectual property rights is the embedding of digital watermarks into multimedia data.In this thesis work, new invisible and robust digital color image watermarking method is proposed for protection of copyrights of digital images. The proposed method is based on block truncation coding and discrete wavelet transform. In the image watermarking process, 24-bit color bitmap image is used. The watermark that is embedded in image is 1-bit black and white bitmap image. To increase robustness of the image watermarking method; by using a secret key, a watermark permutation process is performed on watermark that will be used for embedded process before image watermarking process. The selected secret key is used in watermark embedding process and watermark extraction process from image.Three performance evaluation measurements are used on watermarked image, original image and extracted watermark, for testing proposed watermarking method. Various types of attacks are applied on watermarked image to prove the robustness of proposed method. The results have shown that the proposed watermarking method is robust against attacks and processes such as JPEG lossy compression, noise addition, filtering, histogram equalization, mosaic, gamma correction, contrast adjustment, scaling, randomize drawing, fake watermark addition, watermark collision, morphologic and JPEG2000 lossy compression.