The “flutter shutter”
camera’s action is
novel. Rather than
opening and closing
the shutter once, the
researchers flutter it
open and closed in a
mathematically
selected pattern. The
camera preserves
detail from the scene
that would have
been smeared out in
a normal photograph. The results
are striking: A photograph of a moving
car, blurred beyond
the ability to recognize small details,
becomes a clearly
defined Volkswagen
with a readable
license plate.
virtual meeting place. Part of the initiative
involves display surfaces that are not flat but
shaped like the scene to be re-created, much
in the mode of Raskar’s Taj Mahal. In a
1998 paper on this work, Raskar described
techniques that would allow meetings to
occur as if the participants all seemed to be
sitting in the same office, no matter what
their actual location. “That paper put
Ramesh on the map,” Joe Marks said. “It
was a visionary paper, and the amazing thing
is that he’s gone on to display the same kind
of vision again and again.”
mention the NPR camera when describing
the emerging field of computational photography, in which both men are playing a
major role. But Tumblin sees the technique
as significant, a merging of computer vision,
in which computer resources are brought to
bear on an actual image, and computer
graphics, in which a mathematical description is used to create a picture. And he says
it was one of the things that drew Raskar’s
work to his attention in the first place.
Eighteen patents later, Raskar’s work
with cameras and projectors is changing
how we use light to see and understand.
The non-photorealistic (NPR) camera is a
case in point. Shoot a picture with a flash,
and you create a shadow. Raskar looked at
shadows and saw that multiple flashes from
different angles could create a series of
shadows that would define the shape of the
object. The result is a camera that can
detect depth. You may not need one for
vacation photos, but the capability is useful
for doctors doing procedures such as
endoscopies, in which abnormal shapes signify potential tumors. Paleontologists have
put the NPR camera to work in Greenland, where it helps to reveal minute details
of dinosaur bones that are all but impossible to see in conventional photographs.
Computational photography changes
everything we thought we knew about
cameras, even in the digital era. Most digital
cameras today simply replace conventional
film with a grid of picture elements —
“pixels” — rather than fundamentally altering what the camera can do. But what if we
could bring computer power to bear on
problems such as over- and under-exposure,
or contrast, or motion? Any amateur photographer has had the disheartening experience of composing the perfect shot, only to
find that hand motion, or the movement of
something in the scene itself, has hopelessly
blurred the image. Tumblin and Raskar presented a paper at this year’s SIGGRAPH
conference on what they call “coded blur
photography,” a technology becoming better known by its informal name, the “flutter
shutter” camera. The exposure time is long,
but blurs are a thing of the past.
‘This is
a new medium
altogether.
Or one should
say that this is a
new set of tools
that allows a
professional or
even an amateur
photographer
to edit after
the fact.
And yes,
there is a
boundary here
where you get
into the realm
of art.’
Shree Nayar
Professor of computer
science at Columbia
University
So multitudinous are the researcher’s
ongoing projects that Jack Tumblin, an associate professor of computer science at
Northwestern University who is now working on a book with Raskar, almost forgot to
The camera’s action is novel. Rather
than opening and closing the shutter once,
the researchers flutter it open and closed in
a mathematically selected pattern. The
camera gathers detail from the scene that
