Holographic tech lets firefighters see through flames

A new imaging technology can help firefighters peer through smoke and flames to find living people obscured by a fire. (AP Photo/Pepe Jimenez)

A comparison of a traditional imaging system, in which the view of a man is obstructed by flames (left), and a new technique using digital infrared holography, in which the viewer can see the man standing and waving his hand (right). (Optics Express)

Infrared holography can reveal details hidden behind smoke and flames, potentially life-saving information to help firefighters and emergency responders.

For the first time a holographic recording can be made of a live person even while the body is moving, according to an Italian research team.

Currently firefighters can use IR cameras to try to see through smoke; however, flames give off intense infrared radiation that oversaturates the image, foiling the firefighter’s ability to see, explained Pietro Ferraro of the Istituto Nazionale di Ottica.

“IR cameras cannot ‘see’ objects or humans behind flames because of the need for a zoom lens that concentrates the rays on the sensor to form the image,” Ferraro said.

Essentially, flames blind current IR systems. To solve that problem, Ferraro came up with a new system without a lens. By removing the need to zoom, his camera sees through smoke and is unaffected by the blinding radiation from flames.

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But this tech goes beyond just seeing through flames, providing holographic 3D images of what lies beyond them.

Take the hologram on the average credit card -- the 3D effect was created by a laser beam splitting into two beams: an object beam and a reference one.

The object beam shines on the object being turned into a 3D image. The reflected beam bounding off the object combines with the reference beam to make a 3D image encoded in an interference pattern.

This new hologram system is different. The researchers take an infrared laser light beam and widely disperse it through a room. While visible light can’t make it through thick smoke and flames, the IR rays can for the most part.

Penetrating through the smoke and flames, the IR light then reflects off any people or objects in a room. This reflected light is then recorded by a holographic imager.

Their system -- detailed in the latest issue of Optics Express journal -- then decodes the information contained in the rebounding light, revealing to a firefighter where the person is behind the smoke and flames.

As firefighters search through a structure looking for those in need of rescue, this technology would give them a sort of live 3D movie of each room they enter.

The team is working on a portable system next that would contain both the laser and IR camera.