Citation:
Graham Gibson, Ben van Well, Jane Hodgkinson, Russ Pride, Rainer Strzoda, Stuart Murray, Steve Bishton and Miles Padgett. Imaging of methane gas using a scanning, open-path laser system. New Journal of Physics 8, 26, 2006
Abstract:
We have developed an imaging system for the detection and
visualization of methane gas leaks. The system is based on a distributed feedback
InGaAs laser diode emitting at 1.65μm, the beam from which is directed at
neighbouring objects. The backscattered light is collected by a Fresnel lens and the
gas concentration is deduced from the reduction in collected intensity as measured
using a second derivative wavelength modulation technique. The incident laser
and the collected beam are both scanned over an area to form an image of the gas
emission. To ease the task of locating the source of the emission, we combine the
resulting low-resolution image of the gas emission with a high-resolution colour
image of the scene. Our results show that the system can image a gas cloud of
1mm effective thickness at a range of several metres, sufficient to detect a gas
leak of 1 litre min−1 in light to moderate winds.
