A Review of Different Techniques on Digital Image Watermarking Scheme

In this paper we aim to present a survey of different techniques on digital image watermarking. Digital watermarking technique is becoming more important in this developing society of internet. Digital watermarking is used as a key solution to make the data transferring secure from illegal interferences. Digital watermark techniques are used in various areas such as copyright protection, broadcast monitoring and owner identification. In this paper we mainly discussed about two methods via spatial domain and frequency domain. In spatial (pixel) domain, watermark is inserted directly by modifying the pixel values of host image. Such algorithms are very easy at the time of implementation. However they have some problems like Low hiding capacity of watermark information, less PSNR, less correlation between original and extracted watermark and less security, so anyone can detect such algorithms. In frequency domain such as DCT, DFT, DWT, SVD etc, the watermark is inserted into transformed coefficients of image giving more information hiding capacity and more robustness against watermarking attacks because information can be spread out to entire image.