Making 3D pictures

Researchers at the Fraunhofer Institute for Applied Optics and Precision Engineering have developed a novel 3D sensor.

The sensor, which is no larger than a shoebox and weighs only about a kilogram, consists of two cameras with a projector in the centre, said Fraunhofer’s Dr Gunther Notni.

‘The two cameras capture a three-dimensional view of a pattern of stripes that is cast by the projector onto an object. The geometry of the measured object can then be deduced from the deformation of the stripes,’ Notni said.

This type of stripe projection is already an established method of making 3D images. What’s new about the Fraunhofer device is its measuring speed, size, weight, and cordless operation.

Conventional devices weigh about four or five times as much and are more than twice the size, or roughly 50 centimetres long. The researchers reduced the size of the new unit by using light-emitting diodes for the projector instead of the usual halogen lamps.

Dr Notni sees many applications for the new unit. ‘Patients who snore often need a breathing mask when they sleep. To ensure that the mask is not too tight, it has to be specially made for each patient. Our system enables the doctor to scan the patient’s face in just a few seconds and have the breathing mask made to match the data.’

But Notni believes that the most important application will be for quality assurance in the production processes. The portable device makes it possible to measure components in difficult to access areas, such as foot pedals inside a car.