3D holography technique lets firefighters see through flames

Posted by Kate Taylor

An Italian team has developed a new infrared holography technique that allows firefighters to see through flames and find people trapped inside burning buildings.

Current IR cameras are blinded by the intense infrared radiation emitted by flames, which overwhelm the sensitive detectors and limit their use in the field. But by using a specialized lens-free technique, the new system can cope.

"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," says Pietro Ferraro of the Consiglio Nazionale delle Ricerche (CNR) Istituto Nazionale di Ottica in Italy. Eliminating the need for the zoom lens avoids this drawback.

"It became clear to us that we had in our hands a technology that could be exploited by emergency responders and firefighters at a fire scene to see through smoke without being blinded by flames, a limitation of existing technology," Ferraro says.

"Perhaps most importantly, we demonstrated for the first time that a holographic recording of a live person can be achieved even while the body is moving."

In the new imaging system, a beam of infrared laser light is widely dispersed throughout a room. Unlike visible light, which cannot penetrate thick smoke and flames, the IR rays pass through largely unhindered. They do, however, reflect off of any objects or people in the room - and the information carried by this reflected light can be recorded by a holographic imager.

It's then decoded to reveal the objects beyond the smoke and flames, delivering a live, 3D movie of the room and its contents.

"Besides life-saving applications in fire and rescue, the potential to record dynamic scenes of a human body could have a variety of other biomedical uses including studying or monitoring breathing, cardiac beat detection and analysis, or measurement of body deformation due to various stresses during exercise," says Ferraro.

"We are excited to further develop this technology and realize its application for saving and improving human life."