Abstract:The central idea of this paper is to develop an algorithm that embeds the watermark information, with out much distortion to the image, while making it possible to extract the watermark by use of correlation. We begin by modifying the frequency coefficients of the image based on the Human Visual systems perception of image content, which is used to embed a watermark such that its amplitude is kept below the distortion sensitivity of the pixel and thus preserving the image quality. The operation of embedding and extraction of the watermark is done in the frequency domain, thereby providing robustness against common frequency-based attacks including image compression and filtering. We use spread spectrum algorithm for watermarking such as pseudo random sequences enabling an easier generation, encryption and a much better detection, of the watermark. Our watermarking scheme deals with the extraction of the watermark information in the absence of the original Image, i.e., blind watermarking. Hence we make use of correlation -based watermark detection. A performance evaluation is carried with regard to quality, compression ratio and different signal to noise ratios. These properties were chosen because they have the greatest impact on the implementation effort.

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