Semi Fragile Watermarking for Content based Image
Authentication and Recovery in the
DWT-DCT Domains
Jayashree Pillai1 and Padma Theagarajan2
1Department
of Computer Science, Acharya Institute of Management and Sciences, India
2Department
of Computer Applications, Sona College of Technology, India
Abstract:
Content authentication requires
that the image watermarks must highlight malicious attacks while tolerating
incidental modifications that do not alter the image contents beyond a certain
tolerance limit. This paper proposed an authentication scheme that uses content
invariant features of the image as a self authenticating watermark and a
quantized down sampled approximation of the original image as a recovery
watermark, both embedded securely using a pseudorandom sequence into multiple
sub bands in the Discrete Wavelet Transform (DWT) domain. The scheme is blind
as it does not require the original image during the authentication stage and
highly tolerant to Jpeg2000 compression. The scheme also ensures highly
imperceptible watermarked images and is suitable in application with low
tolerance to image quality degradation after watermarking. Both Discrete Cosine
Transform (DCT) and DWT transform domain are used in the watermark generation
and embedding process.
Keywords: Content authentication, self authentication,
recovery watermark, DWT, PQ sequence.