Analysis of Comparators for Binary Watermarks
Comparator is one of key components of watermarking system that determines its performance. However, analysis and development of comparator is an undermined objective in the field of watermarking. In this paper, the core contribution is that five comparators for binary watermarks are analysed by theory and experiments. In the analysis, it is explored that negative pair of binary watermarks provide same information. Receiver operating characteristic curve is used for experimental analysis. It is observed that comparators based on similarity measure functions of symmetric normalized Hamming similarity (SNHS) and absolute mean subtracted normalized correlation coefficient (AMSNCC) have outstanding performance. Further, a range of threshold of SNHS based comparator that maximizes decision accuracy of a watermarking system is found by theoretical analysis. This range is verified by experiments.
KeywordsComparator Threshold Watermarking Binary watermarks Receiver operating characteristic curve
The author, Himanshu Agarwal, acknowledges the grants of the University Grant Commission (UGC) of New Delhi, India under the JRF scheme and Canadian Bureau for International Education under the Canadian Commonwealth Scholarship Program. He also acknowledges research support of the Maharaja Agrasen Technical Education Society of India and Jaypee Institute of Information Technology of India.
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