Digital Image Watermarking by Spread Spectrum

One digital watermarking method, based on the spread spectrum technique, is described in this paper. This method uses the frequency hopping spread spectrum in order to determine positions for watermark embedding in an original image, while the direct spread spectrum technique is used to provide robustness to the watermark signal. To embed the watermark signal, the selected bits are used to carry the watermark signal. The performance of the watermarking scheme can be evaluated by the Peak Signal-to-Noise Ratio (PSNR). Some simulation results indicate that the proposed method gained higher PSNR, and more watermark bits could be embedded into an original image. Key-Words: watermarking, image, data hiding, spread spectrum, bits, PSNR, embedding