Robot vies to be wedding snapper

The robot tries to identify faces

Wedding photographers could be put out of a job by a robot developed by scientists at Washington University in St Louis in the US.

The machine, called Lewis, looks like an upside down dustbin with a digital camera on top.

It is programmed to wander around a room, picking out people's faces and taking photographs.

"We have a member of staff who is getting married in November and his wife to be thinks it would be really cool to have Lewis taking pictures at their wedding," said one of scientists Cindy Grimm, "so he'll be at the wedding."

Looking for skin

Lewis is a short, human-sized mobile robot that wanders around taking pictures of people.

Lewis is programmed to avoid people

The robot alternates between detecting faces and adjusting the camera position to take well-composed photographs.

"It is basically looking for skin in the image and it finds people's faces, forearms and legs and it then uses a number of techniques to decide which of those patches of skin are faces," Bill Smart of Washington University told the BBC programme, Go Digital.

"Once it has decided where the faces in the image are, it tries to compose them nicely, something you would want to hang on a wall."

Lewis works out how to frame a picture by following the rule of thirds. This suggests that if you were to split the picture into thirds, both horizontally and vertically, the main points of interest should be located where these lines cross.

Visual landmarks

The robot has been programmed to arrange photos with faces at these strategic points.

A digital camera is mounted on top

Lewis has also been instructed to stay within a predefined area and avoid bumping into people.

This is done by using visual landmarks, brightly coloured lights which the robot looks at to work out where it is.

The team at the Computer Science Department of Washington University believe a robot photographer has numerous advantages over a human one.

They have found that people feel less self-conscious in front of a robot.

After an initial period of fascination, they begin to ignore Lewis as a photographer so that the pictures captures people more naturally.

They are now looking at improving the techniques used by the robot to identify faces and ignore background clutter, as well as giving Lewis control of lighting.