Error diffusion halftone image watermarking based on SVD-DWT technique

In this paper, a new halftone image watermarking is presented based on digital wavelet transform combined with singular value decomposition technique. Halftoning is the process of representing grayscale images using just black and white i.e. binary levels. The original image is an error diffusion halftone image which is decomposed into 2-level wavelet transform. In the second level of wavelet transform, the subband with the midst variance intensity is selected as a place for inserting the watermark. The singular value decomposing is applied to this selected subband and watermark image. The embedding modification is done by combining singular value of selected subband with singular value of watermark image. In extraction process, detector response is computed to obtain the original watermark. Experimental results show good robustness against some common signal processing attacks.