Laser Scanner Captures 3-D Info in Real Time

A 3-D laser scanner based on the human eye can focus on key sections of an image, capturing it with correspondingly higher resolution.

A team from the three institutes of the Fraunhofer-Gesellschaft — the Institute for Physical Measurement Techniques, the Institute for Intelligent Analysis and Information Systems and the Institute for Photonic Microsystems — has developed the new laser scanner, which functions independent of ambient light. It possesses a high scanning speed of 1.6 kHz, obtaining 3-D information in real time, even over greater distances.

The MEMS-based 3-D laser scanning system. Courtesy of Fraunhofer-Gesellschaft.

Specifically, the researchers have been able to combine pulse run time with laser distance measurement and an adaptive operating MEMS into a laser scanning system.

The researchers recorded a 3-D overview image and directed the scanner toward various image sections, allowing them to be scanned at a high resolution. They said this is the first time that situation-based, high-quality 3-D information has been obtained within such a short period of time.

In the study, the researchers based the new system on a 1-D MEMS array that performs resonant scanning in a vertical direction and can be pivoted and rotated with a conventional electro-dynamic drive.

The visual fill factor was increased via 22 receiving reflectors with individual apertures of 8.4 x 2.3 mm² and integrated reflector position sensors. This subsequently created the technical conditions for performing measurements at distances of up to 30 m.

“The reflector mechanism of our laser scanner directs the time-modulated transmission beam over the object that is to be measured,” said researcher Dr. Thilo Sandner. “The light of the transmission beam that is dispersed over that area is shown on a photodetector with a high bandwidth using several receiving reflectors that move synchronous to the beam, and the distance of the object is determined using the measured phase or pulse run time of the light that is received.”

Similar to conventional laser scanners, the strength of the new technology lies in its ability to disregard the presence of different light conditions. It can also be used for scanning moving objects such as air planes on the runway or vehicles on construction sites.

The new laser scanning system will be presented at the Vision trade fair in Stuttgart, Germany in November.

For more information, visit www.fraunhofer.de.