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ISRN Signal Processing
Volume 2012 (2012), Article ID 781940, 11 pages
Research Article

DCT Watermarking Approach for Security Enhancement of Multimodal System

1C. K. Pithawala College Of Engineering and Technology, Pithawala Educational Complex, Near Malvan Mandir, Via Magdalla Port, Dumas Road, Surat, Gujarat, India
2Sardar Vallabhbhai National Institute of Technology, SVNIT, Ichchhanath Road, Piplod, Surat, Gujarat, India

Received 1 November 2012; Accepted 24 November 2012

Academic Editors: C.-M. Kuo and P.-Y. Yin

Copyright © 2012 Mita Paunwala and S. Patnaik. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


We have addressed a novel watermarking algorithm to support the capacity demanded by the multimodal biometric templates. Proposed technique embeds watermark in low frequency AC coefficients of selected 8 × 8 DCT blocks. Selection of blocks accomplishes perceptual transparency by exploiting the masking effects of human visual system (HVS). Embedding is done by modulating the coefficient magnitude as a function of its estimated value. Neighborhood estimation is used for the weighted DC coefficients from eight neighboring DCT blocks. The weights of the DC coefficients are calculated from local image intrinsic property. For our experimentation we have used iris and finger prints as the two templates which are watermarked into standard test images. The robustness of the proposed algorithm is compared with the few state-of-the-art literature when watermarked image is subjected to common channel attacks.