Content Based Watermarking Techniques using HSV and Fractal Dimension in Transform Domain

The central idea of the present paper is based on selecting the watermark information from the host image itself. For which, in this work, we select the fractal dimension as the feature of the host image. The proposed method uses three techniques namely DCT, DWT, combined DCT & DWT to embed the watermark by exploiting Fractal Dimension and Human Visual System (HVS), so that a trade-off between imperceptibility and robustness will be maintained. According to the experimentation results, in all the methods, the watermarked images could be recovered effectively. Our method is also useful to detect the tampered location in the watermarked image correctly. INTRODUCTION A digital watermarking is the process that can be used to hide a piece of information into a multimedia content, which is imperceptible to a human observer, but can be easily detected by a computer. The principle advantage is that the watermark is inseparable from the content. Content based Digital Watermarking involves three major phases: (i) Watermark Creation, (ii) Watermark Embedding, (iii) Watermark Extraction. Digital Watermarks may be a pseudo random sequence or a logo of a company or an image. Watermark embedding is done in the watermark carriers such as Discrete Cosine Transform (DCT) or Discrete Wavelet Transform (DWT), etc., of the original data resulting in watermarked data. The watermarked data can be compressed in order to reduce its size, corrupted by noise during its transmission through a noisy channel. It can be subjected to other common image processing operations such as filtering, histogram modification etc. Digital watermark technology has developed extensively during the recent few years and is widely applied to protect the copyright of a digital image. A digital watermark is the information, embedded imperceptibly and robustly in the host data which cannot be removed. By adding a watermark signal to the host data the watermark signal is unobtrusive and secure in the signal mixture. Background: A new public content-based watermarking method for image authentication using ICA and DCT for gray scale images is proposed in (Dr. Latha Parameswaran and Dr. K. Anbumani, 2008). Based upon this paper, this project has been implemented for color images. Watermarks are embedded in the mid-frequency DCT coefficients. DCT is a widely used technique for watermarking (, 2002) ICA is applied to the blocks of the host image and the watermark image. The least-energy independent components of the host are replaced by the high-energy independent components …