Gesellschaft fr Informatik e.V.

Lecture Notes in Informatics


INFORMATIK 2009 - Im Focus das Leben P-154, 1582-1591 (2008).

Gesellschaft für Informatik, Bonn
2008


Editors

Stefan Fischer, Erik Maehle, Rüdiger Reischuk (eds.)


Copyright © Gesellschaft für Informatik, Bonn

Contents

Towards copy-evident JPEG images

Andrew Lewis and Markus Kuhn

Abstract


We present a technique for adding a high-frequency pattern to JPEG images that is imperceptible to the unaided eye, but turns into a clearly readable largeletter warning if the image is recompressed with some different quality factor. Our technique aims to achieve a goal similar to copy-evident security-printing techniques for paper documents, namely to have an easily recognizable text message appear in lower-quality copies, while leaving the visual appearance of the original unharmed. We exploit non-linearities in the JPEG process, in particular the clipping of the result of the inverse discrete cosine transform.


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Gesellschaft für Informatik, Bonn
ISBN 978-3-88579-241-3


Last changed 24.01.2012 22:09:01