Firefighters have a difficult job, since they are responsible not only for putting out fires, but also for rescuing whoever happens to be trapped inside a burning building. Finding said people may be hard though.
Researchers at Italy’s National Institute of Optics took note of this difficulty, and of the fact that thermographic cameras don't really help alleviate that problem.
In a paper published in Optics Express, they reveal their special technique that uses infrared light to build a clear picture of what is beyond the haze of the conflagration.
Normal thermographic cameras don't provide a good view of what is inside or beyond the fire, since the pixels of the sensor are saturated by the flames' radiation.
With the new method, the light hitting the sensor is unfocused, meaning that an image can be reassembled even if some of the pixels are saturated.
By sampling the view a couple of times and combining everything with numerical methods, a sharp image can be made.
Holographic models of people beyond fire curtains can, thus, be rendered by shining infrared laser light in the room, then capturing a combination of the scattered laser light bouncing back out and light from a reference beam.
The hologram was, thus, made from the resulting interference pattern, through a specially-made decoding algorithm.
The researchers say the images, or rather virtual holograms, can be processed quickly enough that real-time (or close enough) videos of burning room interiors can be made.
The infrared digital holographic (IRDH) system would only need to be mounted on a tripod and voila, a live view of the happenings within. The long wavelength even makes the hologram recording resistant to vibrations.
Each year, about 3,000 deaths in fires happen in the US alone. The new technology could help cut down that number by more than a few percentage points.