recordings. The graph at top shows the Electric Network Frequency (ENF)
extracted from a one-hour (3,600-second) recording to be used as evidence.
The middle graph depicts the computer-determined correlation between
the variations of the evidentiary ENF (red) and the ENF variations for the USA
West grid for the twenty-four hours of 14 February 2011 (86,400 seconds)
as archived by the National Center for Media Forensics (black). The bottom
graph shows an enlarged view of the matching portion of the middle graph
(the red line should lie precisely on the black line, but has been shifted here
for the sake of visual clarity). The recording is thus dated to the second on
the day in question. Courtesy Catalin Grigoras.
From
THE FREEDOM OF SPEECH ITSELF
LAWRENCE ABU HAMDAN
Cabinet Magazine: Forensics.
http://www.forensic-architecture.org/docs/cabinet_43_the_freedom_of_speech_itself_0.pf
No comments:
Post a Comment