Title
Locally optimum nonlinearities for DCT watermark detection.
Abstract
The issue of copyright protection of digital multimedia data has attracted a lot of attention during the last decade. An efficient copyright protection method that has been gaining popularity is watermarking, i.e., the embedding of a signature in a digital document that can be detected only by its rightful owner. Watermarks are usually blindly detected using correlating structures, which would be optimal in the case of Gaussian data. However, in the case of DCT-domain image watermarking, the data is more heavy-tailed and the correlator is clearly suboptimal. Nonlinear receivers have been shown to be particularly well suited for the detection of weak signals in heavy-tailed noise, as they are locally optimal. This motivates the use of the Gaussian-tailed zero-memory nonlinearity, as well as the locally optimal Cauchy nonlinearity for the detection of watermarks in DCT transformed images. We analyze the performance of these schemes theoretically and compare it to that of the traditionally used Gaussian correlator, but also to the recently proposed generalized Gaussian detector, which outperforms the correlator. The theoretical analysis and the actual performance of these systems is assessed through experiments, which verify the theoretical analysis and also justify the use of nonlinear structures for watermark detection. The performance of the correlator and the nonlinear detectors in the presence of quantization is also analyzed, using results from dither theory, and also verified experimentally.
Year
DOI
Venue
2004
10.1109/TIP.2004.837516
IEEE Transactions on Image Processing
Keywords
Field
DocType
gaussian data,actual performance,watermark detection,theoretical analysis,dct watermark detection,optimal cauchy nonlinearity,gaussian detector,dct-domain image watermarking,gaussian-tailed zero-memory nonlinearity,digital multimedia data,optimum nonlinearities,gaussian correlator,gaussian noise,statistical model,stable distribution,heavy tail,watermarking
Digital watermarking,Watermark,Artificial intelligence,Computer vision,Pattern recognition,Digital signal,Algorithm,Gaussian,Dither,Quantization (signal processing),Gaussian noise,Mathematics,Copy protection
Journal
Volume
Issue
ISSN
13
12
1057-7149
Citations 
PageRank 
References 
55
2.26
24
Authors
2
Name
Order
Citations
PageRank
A. Briassouli11448.00
michael g strintzis2109579.71