A Wavelet Transform Based Digital Image Watermarking and Authentication

The techniques for watermarking of digital images are available to prevent unauthorized distribution of multimedia data image. In this paper, a watermarking scheme is proposed in which the image is decomposed in to wavelet coefficients and a visual recognizable logo and content based watermark information is embedded in the wavelet coefficients. The wavelet coefficients corresponding to the points located in a neighborhood that have maximum entropy are used for embedding the visual logo and the relations between the neighboring coefficients in the selected wavelet sub bands are embedded into middle frequency pairs of the first scale coefficients. This method embeds the maximum amount of watermark while the watermark is imperceptible. This technique provides two levels of protection while maintaining the image quality. The embedding of relation coefficients provide the capability to identify malicious changes made on the image. The experimental results confirm that the proposed techniques provide secure watermarking and robust to a variety of attacks.