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Proceedings Paper

Assessment of camera phone distortion and implications for watermarking
Author(s): Aparna Gurijala; Alastair Reed; Eric Evans
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Paper Abstract

The paper presents a watermark robustness model based on the mobile phone camera's spatial frequency response and watermark embedding parameters such as density and strength. A new watermark robustness metric based on spatial frequency response is defined. The robustness metric is computed by measuring the area under the spatial frequency response for the range of frequencies covered by the watermark synchronization signal while excluding the interference due to aliasing. By measuring the distortion introduced by a particular camera, the impact on watermark detection can be understood and quantified without having to conduct large-scale experiments. This in turn can provide feedback on adjusting the watermark embedding parameters and finding the right trade-off between watermark visibility and robustness to distortion. In addition, new devices can be quickly qualified for their use in smart image applications. The iPhone 3G, iPhone 3GS, and iPhone 4 camera phones are used as examples in this paper to verify the behavior of the watermark robustness model.

Paper Details

Date Published: 10 February 2011
PDF: 12 pages
Proc. SPIE 7880, Media Watermarking, Security, and Forensics III, 78800C (10 February 2011); doi: 10.1117/12.873227
Show Author Affiliations
Aparna Gurijala, Digimarc Corp. (United States)
Alastair Reed, Digimarc Corp. (United States)
Eric Evans, Digimarc Corp. (United States)

Published in SPIE Proceedings Vol. 7880:
Media Watermarking, Security, and Forensics III
Nasir D. Memon; Jana Dittmann; Adnan M. Alattar; Edward J. Delp III, Editor(s)

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