A small Silicon Valley start-up called Canesta has embarked on an almost mythological quest to give computers the gift of sight.

Tales of secret powers bestowed upon men by Greek gods may still have a theatrical edge over Canesta's technology, but the company's plans to let computers see the world in three dimensions is dramatic all the same.

The technology could lead to new uses for computers as well as new tools for end users, from virtual keyboards that float in mid-air to powerful security systems for guarding access to a house or a car.

By combining its chip technology and image-processing software, Canesta has made it possible for a PC or handheld device to look out at the world via a small lens and create a three-dimensional picture of the objects around it, according to the company.

Unlike standard imaging products that measure only light, Canesta's system takes both light and distance readings of the objects in front of its lens. Light is bounced off the objects and Canesta's chips measure how far away the objects are, creating a 3D image of the surroundings. The distance information is gathered and processed in real time and can create a detailed view of the outside world that computers can understand and ultimately interact with.

"Traditional cameras operate in a two-dimensional world that makes it difficult for them to tell the difference between a person and a picture of the person," said Jim Spare, vice president of marketing at Canesta. "We can provide a much richer set of information that would be able to show the contours of a person's face, for example."

The company hopes that by early 2003, some manufacturers will place a lens the size of a fingertip in mobile phones and handheld computers. The lens could project a keyboard in front of a user that would process hand movements, allowing a person to type 'virtually' without the need for a physical keyboard, Spare said. The technology could be particularly useful for small, wireless devices, said one analyst.

Easy-to-use input methods will become even more crucial as handheld devices mature and offer more complicated types of information to users, he said. "You will need to manage very extensive menuing systems," Levin said.

One day, he projected, users may be able to hold up a mobile phone in a crowded room and have the device match faces with contact information, giving a user the names of any friends or associates present at the event.