Aiming at the problem that security of digital watermarking is imperfect, a new digital watermarking algorithm based on holography is put forward. In embedment watermarking stage, first, original watermarking information is divided into two parts: amplitude and phase information. Then, a hologram which will be used as new watermarking information is generated by interference of the phase information light and the reference beam, and the amplitude information will be the key when original watermarking is extracted. At last, host image is transformed by the multilevel structures wavelet transform, and the new watermarking information is embedded into its suitable wavelet domain. In extraction watermarking information stage, the original watermarking information is obtained by the extracted watermarking information combined with the amplitude information. The theory and simulation show our algorithm has excellent performance in security, shear resistance and anti interference of white noise.
Digital Watermarking Using DCT Fractal Coding without Original Image Infomation
