Gray image watermarking algorithm base on LWT and SVD
Min Zhang · Jisuanji yingyong yanjiu · 2009
This paper proposed a gray image watermark algorithm based on LWT and SVD.Firstly,divided the original image into many blocks.Then implemented the middle-high frequency of two-level LWT with each block by LWT,and applied SVD to the selected sub-frequency,divided the new matrix constructed with singular values into many blocks by rule,which were decomposed with SVD again.Through twice partition blocks,twice LWT and the use of quartic SVD,the matrix would re-allocation and combination for extraction's singular value after SVD,and finally embedded the watermarking image with Logistic chaos scramble into the matrix.The algorithm achieved optimal balance between robustness and imperceptibility,and increased embedded capacity.Experimental results show that the proposed method has a good transparence and robustness against attacks,such as JPEG compression,filtering,adding noise and other image processing.The method's performance is much better than the existing and similar watermark algorithms.