Digital Watermarking Algorithm Based on Spread Spectrum and Fourier Transform

Abstract

In recent years, computer and the network technology has been developing at breakneck speed, accompanied by a brand new digital era. With the further development of digitalization, an important issue has gradually emerged, that is, the security of digital content. In this context, a new digital technologies-digital watermarking technology is proved. It uses a certain method of embedding digital information hidden in the carrier-specific elements such as images, audio, or video, to determine the authenticity of a digital source, copyright holder information and does not affect the availability of hosted data. There are many kinds of digital watermark embedding and extracting algorithm, in this paper, based on Fourier transform domain Watermarking algorithm. In order to improve the security and robustness of watermarking system, and watermark preprocessing using spread-spectrum technology and use of sequence pairs as PN spread spectrum modulation of the watermark, the spreading sequences generated-code embedded in the DFT transforms the original image, and then through the IDFT transforms images can be watermarked. Watermark is also used in the extraction of sequence pairs on spread spectrum watermark embedding and restores the original image information. Finally was achieved by MATLAB simulation based on DFT-transform domain Watermarking algorithm of sequence spread spectrum and from the experimental results: with the increase of embedding strength, watermarked image distortions become increasingly evident, but to extract the watermark effect is getting better and better. Spread spectrum watermarking technology and engineering simulation for this paper have some reference values.