Mean quantization based image watermarking

In this paper, a mean quantization based watermarking technique for the copyright protection of still digital images is proposed. Watermark embedding is performed in the wavelet transform domain by encoding each watermark bit into a set of wavelet coefficients. Watermark extraction does not require the existence of the original image. The proposed technique also integrates the human visual system characteristics and complementary hiding strategy to achieve the highest possible robustness without degrading image quality. Experimental results show that the proposed watermarking scheme is robust to a wide range of image distortions and is superior to the conventional quantization based technique. (C) 2003 Elsevier Science B.V. All fights reserved.