Researches on digital image watermarking

To meet well the requirements of transparence, robustness, and security of digital image watermarks at one time, the scrambling technique of digital images and discrete wavelet transform have been organically combined, the watermarking technique of digital images in wavelet transform domain has been seriously studied according to the basic characteristic of human visual system. The performances of the embedding and extracting algorithm of watermarking images are mainly discussed in two cases, namely the watermarked image resists the disturbing of Gaussian white noise and being cropped. To successfully extract the watermarking image from the watermarked image disturbed and attacked, some effective measures should be taken for the embedding and extracting algorithm of the watermarking image, and the preprocessing of the watermarked image disturbed and attacked.