Detecting Tampering of Digital Images

From: "andrew cooke" <andrew@...>

Date: Sat, 24 Jul 2004 19:21:19 -0400 (CLT)

Intro - http://www.dartmouth.edu/~news/releases/2004/07/01.html

How Realistic is Photo-Realistic? (abstract only) -
http://www.cs.dartmouth.edu/~farid/publications/sp05b.html - we describe a
method for differentiating between photorealistic and photographic images.
Specifically, we show that a statistical model based on first- and
higher-order wavelet statistics reveals subtle but significant differences
between photorealistic and photographic images.

Exposing Digital Forgeries in Color Filter Array Interpolated Images
(abstract only) -
http://www.cs.dartmouth.edu/~farid/publications/sp05a.html - Most digital
cameras, for example, employ a single sensor in conjunction with a color
filter array (CFA), and then interpolate the missing color samples to
obtain a three channel color image. This interpolation introduces specific
correlations which are likely to be destroyed when tampering with an
image.

Exposing Digital Forgeries by Detecting Traces of Re-sampling -
http://www.cs.dartmouth.edu/~farid/publications/sp04.html - we describe
how re-sampling (e.g.,~scaling or rotating) introduces specific
statistical correlations, and describe how these correlations can be
automatically detected in any portion of an image.

Statistical Tools for Digital Forensics -
http://www.cs.dartmouth.edu/~farid/publications/ih04.html - we quantify
statistical correlations that result from specific forms of digital
tampering, and devise detection schemes to reveal these correlations.

A Picture Tells a Thousand Lies (abstract only, New Scientist arcticle) -
http://www.cs.dartmouth.edu/~farid/publications/ns03.html - It had all the
hallmarks of a prizewinning war photograph. Under hostile fire, an armed
British soldier towered over an Iraqi man carrying a baby and directed him
to take cover. The composition was perfect. (you must remember this...)

Higher-Order Wavelet Statistics and their Application to Digital Forensics
- http://www.cs.dartmouth.edu/~farid/publications/sacv03.html - We
describe a statistical model for natural images that is built upon a
multi-scale wavelet decomposition. The model consists of first- and
higher-order statistics that capture certain statistical regularities of
natural images.

Detecting Digital Forgeries Using Bispectral Analysis - assume that in the
frequency domain a "natural" signal has weak higher-order statistical
correlations. We then show that "un-natural" correlations are introduced
if this signal is passed through a non-linearity (which would almost
surely occur in the creation of a forgery). Techniques from polyspectral
analysis are then used to detect the presence of these correlations.

From /. - http://slashdot.org/article.pl?sid=04/07/24/1459257

Andrew

--
__ _ __ ___  ___| |_____   work web site: http://www.ctio.noao.edu/~andrew
/ _ / _/ _ \/ _ \ / / -_)  personal web site: http://www.acooke.org
\__,_\__\___/\___/_\_\___|  list: http://www.acooke.org/cute

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