by David Geer
Contact the author at geercom@alltel.net
Lewis, the Robot
Photographer
At first brush, a robot that snaps people’s pictures might not imbue the mind with
a novel image. But, a photographer that sets its subjects at ease, circumvents their
shy and self-conscious natures and related facial reactions, and captures the essence
of the subject unawares, now that’s a wonder to see!
Full side view of Lewis.
12 SERVO 07.2008
When Lewis the Robot
Photographer first enters a
crowded room, it gets attention. But, once people have adjusted
to its roaming around, looking here
and there, they forget all about it.
After all, it’s just a machine, another
object in their environment.
Lewis’ ability to blend in keeps
it from creating the kind of
apprehension that comes with a
live photographer who roams around
snapping candid pictures of people
(as a wedding photographer might
do, for example).
Because Lewis captures people at
ease, it can take a much higher quality
of photos — no blinking, phony smiles,
or stiff or awkward poses. Because
Lewis recognizes faces and quickly
snaps only the best photos, it takes
many more quality pictures in the
same period at gatherings, functions,
and on special occasions.
Looking for Faces
Lewis starts by scanning the room
for pairs of what appear to be legs.
This way, he can identify people and
then look up to find and identify
their faces. Then, Lewis uses face-recognition technology that identifies
parts of images with lots of skin tones
grouped closely together.
Lewis separates real faces from
things that may look like faces to the
robot eye. Lewis eliminates anything
that is too big, too low, or the wrong
shape. Anything left is assumed to
be a face.
Lewis can take front-on and side
angle pictures of people. It continually
scans images for the criteria that
predict a face or group of faces. Once
it has detected a suitable image, it
adjusts the camera to take a quality
photo, moving it into position via
a series of zooming, tilting, and
panning.
The robot uses object avoidance
technology to guide itself around
objects and people, and maintains its
position within the mass of subjects
by recognizing a given object and
centering itself in the group based on
the position of that object.
Forming Pictures
How does Lewis form pictures of
faces? By following rules. One such
rule is the rule of thirds. The rule of
thirds says that if you split a picture
into thirds, first horizontally, then also
vertically, the primary point of visual
interest in the photo should be where
the lines cross. Lewis makes human
faces the points of greatest interest,
placing them at these cross points.
