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NOVA scienceNOW: Profile: Hany Farid
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Program Overview
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This segment describes the work of Hany Farid, a professor of
computer science at Dartmouth College, who has done pioneering work
the field of digital forensics by analyzing how people alter digital
images and developing techniques to detect manipulated images.
This NOVA scienceNOW segment:
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points out that photographs have been manipulated since the
1800s, but that the digital age has given rise to a great
increase in the number of altered images.
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explains that digital images contain distinct patterns and that
software tools can detect inconsistencies in these patterns.
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relates how Farid's team developed algorithms and software to
analyze pixel patterns in images.
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notes that the most common manipulation is the addition or
removal of an element in an image.
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discusses cloning—pasting one image or parts of an image
over another—and describes how it leaves a mismatch of
pixel values that can be statistically analyzed and detected.
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describes how in a cloned image the lighting of subjects does
not match and that the differences in shadows and light
direction can be detected with Farid's light-direction tool.
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explains that Farid modified his light-detection software, which
analyzed lighting differences in two dimensions, to pinpoint a
lighting source three-dimensionally by analyzing the light
reflecting off a subject's eyeballs.
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offers many examples of faked images that were presented as
authentic.
Taping Rights: Can be used up to one year after the program
is taped off the air.
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