An image-adaptive semi-fragile watermarking for image authentication and tamper detection

Abstract

By taking full advantage of the masking characteristics of the HVS (Human Visual System), this paper first deduces a JND (Just Noticeable Differences) threshold matrix based on blocks, and then presents an image-adaptive semi-fragile watermarking technique operating in DWT (Discrete Wavelet Transform) domain. The proposed technique exploits HVS characteristics and the polarity of the sum of the absolute values of coefficients of the vertical and the horizontal detail subbands of image sub-blocks to embed a binary water-mark with visually recognizable pattern. The embedded watermark is invisible to human eyes and adaptive to the original image characteristics because of the utilization of HVS characteristics. The experimental results show that the proposed algorithm is effective and can classify effectively the attacks made on the watermarked image into malicious attacks and non-malicious attacks by the adaptive threshold. The embedded watermark is sensitive to malicious attacks while is robust to non-malicious attacks. Moreover, the scheme has a good accuracy in locating tampered blocks. © Springer-Verlag Berlin Heidelberg 2007.