Firefighters may soon be able to see through flames and find people trapped in burning buildings, according to details of a new holographic imaging technique described Tuesday.
Some fire departments already use infrared cameras to see through smoke, but these cameras use zoom lenses to collect and focus light. The intense infrared radiation emitted by flames can overwhelm the camera sensors and limit their use, the researchers explain.
The new technique developed by Pietro Ferraro at the National Institute of Optics in Italy and his colleagues makes use of a lens-free digital holography technology in the infrared range.
Holography is a means of producing 3-D images of an object using two beams of light: an object beam and a reference beam. The object beam is shone onto the object being imaged. The reflected light is combined with the reference beam to create a pattern that encodes a 3-D image.
In the new technique described in the journal Optics Express, a beam of infrared laser light is widely dispersed throughout a smoke-and-flame-filled room. A holographic imager records the reflected light and decodes it to reveal what lies behind the inferno.
"The result is a live, 3-D movie of the room and its contents," the Optical Society, which publishes the journal, notes in a news release. "The next step to moving this technology to the field is to develop a portable tripod-based system that houses both the laser source and the IR camera."