A robust image watermarking based on DCT by Arnold transform and spread spectrum

In this paper a robust image watermarking algorithm based on DCT by Arnold transform and spread spectrum is proposed. The watermarking image is scrambled by Arnold transform to enhance its privacy. The specific second high-frequency DCT coefficients of the original image are selected effectively according to Human Visual System (HVS) and characteristic of digital image processing and then encrypted watermarking is embedded into DCT coefficients selected by spread spectrum. The experimental results show that the algorithm is more robust and more effective.