A Robust Digital Image Watermarking Scheme Based on DWT

In this paper a wavelet-based logo watermarking scheme is presented. The logowatermark is embedded into all sub-blocks of the LLn sub-band of the transformedhost image, using quantization technique. Extracted logos from all sub-blocks aremerged to make the extracted watermark from distorted watermarked image.Knowing the quantization step-size, dimensions of logo and the level of wavelettransform, the watermark is extracted, without any need to have access to theoriginal image.Robustness of the proposed algorithm was tested against thefollowing attacks: JPEG2000 and old JPEG compression, adding salt and peppernoise, median filtering, rotating, cropping and scaling. The promising experimentalresults are reported and discussed.

Keywords:

Wavelet transform , watermarking , quantization technique