Machine Design

Recording Reality with 700 Megapixels

A digital camera would be useful for examining competitor’s parts, inspecting hard-to-reach installations, or documenting the scene of an accident.

However, you’d still need a ruler, pencil, and paper to preserve the context of the picture. Unless your camera could take 3D images, that is.

Laser scanners, such as Photon 80 and Photon 20 from Faro Technologies, do just that. Using a near-infrared laser that is safe and invisible and a mirror spinning at up to 2,880 rpm, the scanner rasters the beam over the scene being documented. An avalanche photodiode (ADP) detects the reflected beam, and an onboard PC correlates horizontal and vertical mirror angles with the beam’s phase shift to calculate distances from the camera to points on the target.

Repeat this at a up to 120,000 points/sec and a 3D point cloud with up to 700 million pixels gets stored in the scanner’s 80-Gbyte hard drive. Ethernet and WLAN connections enable remote data storage, viewing, and scanner control. An optional add-on sends images in real time to laptops, cell phones, PDAs, or any wireless device.

Users can import the point cloud into CAD programs for to build a component library, reverse engineer a device, or compare dimensions.

For the Photon line, Faro switched from a photomultiplier to an APD and installed a bigger lens to capture more light. This improves range and boosts detection of less-reflective objects, those in shadows, and surfaces at oblique angles. Software upgrades edit out noise in the point cloud.

Mechanical and encoder hardware place points to within ±2 mm when measured from 25 m. Maximum measurement distance is 2 m for the Photon 20 and 76 m for the Photon 80, farther than older scanners. Both units can scan a 360° horizontal field of view and 320° vertically. An optional camera lends realistic color to scans.

Heat generated by the mechanical and computing components is dissipated by the housings’ ribbed design. A carrying handle, a builtin connector for tripod mounting, and an optional 6-hr battery makes the 35-lb devices suitable for construction- site and shop-floor work.

Make Contact
Faro Technologies Inc.

The laser scanner analyzes the phase shift in reflected laser light to determine the distance to objects in the target area. The result is a 3D cloud of points (inset) that can be interpolated into a solid 3D image.

A near-infrared laser is directed from the left side of the housing onto the central mirror. The mirror rotates, rastering the laser beam over the target area. The housing includes ribs to dissipate heat and a tripod-ready mount.

Hide comments


  • Allowed HTML tags: <em> <strong> <blockquote> <br> <p>

Plain text

  • No HTML tags allowed.
  • Web page addresses and e-mail addresses turn into links automatically.
  • Lines and paragraphs break automatically.