Abstract: This paper presents a secure (tamper-resistant) algorithm for watermarking images, and a methodology for digital watermarking that may be generalized to audio, video, and multimedia data. We advocate that a watermark should be constructed as an independent and identically distributed Gaussian random vector that is imperceptibly inserted in a spread-spectrum-like fashion into the perceptually most significant spectral components of the data. Most watermarking ways for pictures and video are projected are supported ideas from unfold spectrum radio communications, specifically additive embedding of a (signal adaptative or non-adaptive) pseudo-noise watermark pattern, and watermark recovery by correlation. Even ways that don't seem to be bestowed as unfold spectrum ways typically hinge on these principles. Recently, some skepticism regarding the strength of unfold spectrum watermarks has arisen, specifically with the final availableness of watermark attack software system that claim to render most watermarks undetectable. In fact, unfold spectrum watermarks and watermark detectors in their simplest kind ar at risk of a spread of attacks. However, with applicable modifications to the embedding and extraction ways, unfold spectrum ways may be created way more resistant against such attacks. During this paper, we have a tendency to consistently review projected attacks on unfold spectrum watermarks. Further, modifications for watermark embedding and extraction ar bestowed to avoid and counterattack these attacks. Vital ingredients are, as an example, to adapt the ability spectrum of the watermark to the host signal power spectrum, ANd to use an intelligent watermark detector with a block-wise multi-dimensional slippery correlator, which might recover the watermark even within the presence of geometric attacks.
Keywords: WM (Watermark), SS (spread-spectrum), DWT (Discrete Wavelet Transform).