3-D imaging tracks museum visitors
Electroland (Los Angeles, CA, USA; www.electroland.net), a company that creates large-scale public art projects and electronic installations, has used 3-D vision technology to create LUMEN, a site-specific interactive installation that senses and tracks visitors throughout the main stairwell of the Smithsonian Institution’s Cooper-Hewitt National Design Museum in New York City. LUMEN is a 70-ft-long translucent light box that immerses visitors in sound and light as they ascend and descend the stairs.
The LUMEN 3-D network can individually track up to 30 visitors accurately with a low error rate, showing that the system can provide the location and movement of each individual precisely, even in a crowded environment under changing lighting conditions. Electroland used a distributed person-tracking system from TYZX (Menlo Park, CA, USA; www.tyzx.com) that has two networked stereo cameras.
Data from the TYZX tracking system is used to calculate assumptions about the location of individuals relative to the staircase. The system then reconciles the tracking data with the real-world situation of the stairwell lighting and assigns “light personalities,” or avatars, to track each individual. The system creates special zones that can trigger ambient effects such as slowly pulsing lights or racing patterns. If an individual stays longer in a particular space, their influence over the light skin grows, for instance, creating a larger, more persistent area of light. Electroland is now working on a project using an 8- to 12-camera array for the new Indianapolis, IN, airport.
Advanced rocket-engine design aided by IR imaging
Ad Astra Rocket Company (Houston, TX, USA; www.adastrarocket.com) is developing a high-power, electric space-propulsion engine, VASIMR (variable specific impulse magnetoplasma rocket), to enable faster, cheaper manned flights to Mars and a potential platform for a cargo-ferrying service to any future manned bases on the moon. This technology is an improvement over conventional chemical rocket stages because the specific impulse can be adjusted to provide optimum performance for every stage of the trip.
One of the technological hurdles to be overcome to put this rocket engine into space is thermal control. Unlike chemical rockets, which fire for a short period of time and then are discarded, the VASIMR engine will fire continuously during a mission. This means that a proper thermal system must be designed to reject the waste heat and maintain a stable steady-state operating temperature within the limits of the materials available.
To meet this requirement, Ad Astra uses a remote IR camera capable of operating in a vacuum environment exposed to a high magnetic field. The rocket engine is fired, and image data are recorded with an IR-TCM 640 infrared camera from Jenoptik Laser, Optik, Systeme (Jena, Germany; www.jenoptik-los.com). By understanding how the temperature of the inner structure of the rocket changes over time while the rocket is firing, the heat load can be calculated. This calculation enables a cooling system to be designed that can run the rocket for months at a time in the vacuum of space without overheating.