A Fragile Watermarking Scheme with Discrimination of Tampers on Image or Watermark
Lei F. Tian · Dianzi xuebao · 2005
The existing fragile watermarking algorithms can't recognize whether the modification made to the watermarked image is on the image contents or the embedded watermark or both tampered by attackers.In this paper a fragile watermarking scheme with discrimination of tampers on image or watermark is proposed.The low-frequency compressed image,whose low-frequency wavelet coefficients of 7 Most Significant Bits(MSBs) of original image are nonuniform scalar quantization,is converted into a binary sequence as the watermark is to be embedded.The improved security watermark scrambled by chaotic systems is embedded into the LSB of the image data.During image authentication,the proposed method is able to detect the tampered location and discriminate tampers on Image or watermark from the difference image between the low-frequency compressed image and reconstructed image by watermark.Theoretic analysis and simulation results show that the proposed algorithm may not only provide excellent results of detecting the tampered location,but also indicate whether the modification made to the watermarked image is on the image contents or the embedded watermark or both.