A wavelet transform based digital image watermarking scheme

Digital image watermarking techniques have been proposed to prevent unauthorized distribution of multimedia data. A digital watermark encodes the owner's license information and embeds it into the image. Several discrete wavelet transform (DWT) based techniques are used for watermarking. In this paper, a watermarking scheme is proposed in which the image is decomposed into wavelet coefficients and a visual recognizable logo is embedded in the wavelet coefficients. Wavelet coefficients corresponding to the points located in a neighborhood that have maximum entropy are proposed for embedding the watermark. This method embeds the maximum amount of watermark while the watermark is imperceptible. Watermarking techniques must be robust to some attacks such as smoothing, sharpening and compression. These maximum entropy areas can survive a variety of attacks and can be used as reference points for watermark embedding. The experimental results confirmed that the technique is robust to a variety of attacks.