Random Access
Time-Lapse Mining –
the Way of the Future?
Millions of photographs already exist on the internet.
What will historians of the future make of them
and how will they analyse them? One way may be
through time-lapse mining. In traditional time-lapse
photography you fix your camera in one place and
take a picture, and wait, and take a picture, and
wait, and take a picture... When you’ve done this
for long enough to create a reasonable amount
of footage you then compress and compile it into
a bite-sized mega-speeding version of what you
have photographed. Great for one subject on an
occasional day but time consuming on a regular
basis. Ricardo Martin, David Gallup and Steven
Seitz are now creating time-lapses from photos
that people post on the internet. It sounds simple
– find photographs and stitch them together – but
actually involves sifting through tens of millions of
photographs, sorted by timestamp and geolocation;
an enormous computational task of hundreds of
terabytes. The photos then need to line up to look like
they were shot from a single vantage point - a major
amount of digital trickery. Problems include the
wrong datestamps on pictures and people standing
in front of monuments to be photographed. In the
case of the latter the algorithm that has been created
is able to ignore figures, although in one timelapse
sequence of the Vatican, the Swiss Guard stand so
still in the same place over a 6 year period that they
appear as part of the doorway. 11,000 timelapse
sequences have already been created – some, like
the erosion of Briksdalsbreen Glacier in Norway
and the rise of New York City’s Goldman Sachs
Tower work well, others are just incredibly boring!
This technique will be a valuable tool for anyone
who wants to study the effects of time on different
environments. In the meantime check out the first
video released by the team, describing the technique;
it contains 86 Million tourists' photographs. Any day
now they could be mining yours.
Time-lapse Mining from Internet Photos SIGGRAPH 2015 by Ricardo Martin Brualla
(note audio is very quiet)
Embed video:
https://youtu.be/wptzVm0tngc
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