A Secure Blind Semi-Fragile Watermarking Technique for Digital Image Authentication

S.S. Sujatha, Dr.M.Mohamed Sathik


In digital watermarking system, information carried by the watermark is embedded in an original image. The watermarked image is transmitted or stored, and then decoded so that it is resolved by the receiver. The aim of Semi-fragile Watermarking technique is to discriminate malicious manipulations from admissible manipulations. This paper proposes a semi-fragile watermarking technique which embeds watermark signal into the host image in order to authenticate it. Some pixels are randomly selected from original image, so that all of them have a valid 3x3 neighborhoods. A binary sequence is constructed from those pixels by comparing them against average values of neighborhoods. The binary sequence is then converted into a watermark pattern in the form of a Hankel matrix to improve security of watermarking process and is then embedded within the high frequency sub band in the wavelet domain. In our previous work[1], we addressed only the robustness of the algorithm. The central idea of this paper is to study about the fragile nature of the watermarking technique. Peak Signal to Noise Ratio (PSNR) and Similarity Ratio (SR) are computed to measure image quality. Simulation results show that this technique still preserves high image quality after the embedding process and is robust against some of the incidental image processing operations while indicating the forgery if the image is heavily processed.


Keywords – Semi-Fragile, Digital watermarking, Hankel Matrix, Image Authentication, Content based watermarking.

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DOI: https://doi.org/10.26483/ijarcs.v3i4.1256


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