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Proceedings Paper

Compression and rotation resistant watermark using a circular chirp structure
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Paper Abstract

Digital watermarks for images can be made relatively robust to luminance and chrominance changes. More challenging problems are geometric or combined intensity/geometric attacks. In this work we use an additive watermarking model, commonly used in spread spectrum, using a new spreading function. The spreading function is a 2D circular chirp that can simultaneously resist JPEG compression and image rotation. Circular chirp is derived from a block chirp by polar mapping. The resistance to compression is achieved by the available tuning parameters of a block chirp. Tuning parameters include the chirp's initial frequency and chirp rate. These two parameters can be used to perform spectral shaping to avoid JPEG compression effects. Rotational invariance is achieved by mapping the block chirp to a ring whose inner and outer diameters are selectable. The watermark is added in spatial domain but detection is performed in polar domain where rotation translates to translation.

Paper Details

Date Published: 16 February 2006
PDF: 10 pages
Proc. SPIE 6072, Security, Steganography, and Watermarking of Multimedia Contents VIII, 60720S (16 February 2006); doi: 10.1117/12.643535
Show Author Affiliations
Christopher E. Fleming, Villanova Univ. (United States)
Bijan G. Mobasseri, Villanova Univ. (United States)


Published in SPIE Proceedings Vol. 6072:
Security, Steganography, and Watermarking of Multimedia Contents VIII
Edward J. Delp III; Ping Wah Wong, Editor(s)

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