a robust digital image watermarking scheme based on dwt

in this paper a wavelet-based logo watermarking scheme is presented. the logo watermark is embedded into all sub-blocks of the lln sub-band of the transformed host image, using quantization technique. extracted logos from all sub-blocks are merged to make the extracted watermark from distorted watermarked image. knowing the quantization step-size, dimensions of logo and the level of wavelet transform, the watermark is extracted, without any need to have access to the original image.robustness of the proposed algorithm was tested against the following attacks: jpeg2000 and old jpeg compression, adding salt and pepper noise, median filtering, rotating, cropping and scaling. the promising experimental results are reported and discussed.