Overview of Digital Image Watermarking
Digital media especially image can be copied flawlessly and distributed over the internet. Intellectual property rights of the digital media are misused. Digital watermarking is consider as a possible solution, basically, a digital watermark is adding some kind of information like copyright information, owner name, logo etc. in digital image. In this review paper, we gave some information regarding the digital watermarking. Digital watermark of an image can be visible and invisible. The watermark can be inserted in the pixel level i.e. spatial domain using the technique like Least Significant Bit substitution or patchwork algorithm or in frequency domain i.e. transform domain by modifying the corresponding coefficient after the transformation. The uses of a watermark is being discussed in brief in this paper and most importantly some of the attacksregarding digital watermarking are also mentioned in the presented paper. We also gave the theoretical background of image transform such as Discrete Cosine Transform, Discrete Wavelet Transform, Discrete Fourier Transform and discuss the advantage and disadvantage each transform regarding image watermarking are also discussed.
Keywords - Digital watermarking, Least Significant Bit (LSB), Patchwork, Discrete Cosine Transform (DCT), Discrete Wavelet Transform (DWT), Discrete Fourier Transform (DFT).