Gray Image Watermark Algorithm in Integer Wavelet Transform Domain

Integer wavelet transform based on lifting scheme is a kind of invertible integer to integer transform and can reconstruct original signal simply and accurately. Used this characteristic, reversible image watermark algorithm in integer wavelet transform domain is presented in this paper. A binary meaningful image is encrypted by chaotic encryption algorithm to form watermark. In watermark embedding process, a gray image carrier is done by 2-level 9/7-M(4, 2) integer wavelet transform and the encrypted data are embedded into the coefficients of second level high subband. When the watermark extracted, according to the computing algorithm, the data may be entirely gotten back in the integer wavelet domain of the watermarked image and decoded into original image. From results of experimental test, the presented image watermark technology meets requirements of reversibility, security and imperceptibility.