In a paper published in the journal Optics Express, researchers from the University of Glasgow’s School of Physics and Astronomy and Scottish photonics company M Squared Lasers describe how they have used a technique called single-pixel imaging to create real-time video images of methane gas in a typical atmospheric setting.
While gas imaging technology has been commercially available for some time, current systems are expensive, bulky and power-hungry. Single-pixel imaging uses just one light-sensitive pixel to build digital images instead of using conventional multi-pixel sensor arrays, which can be prohibitively expensive for infrared imaging. This allows the researchers to build a much smaller, cheaper gas detection system.
The scene in front of the sensor is illuminated using a sequence of infrared patterns created using a laser tuned to 1.65μm, the absorption wavelength of methane, and display technology commonly found in digital data projectors. Using sophisticated sampling techniques to correlate the projected patterns and the gas, the researchers can create a real-time, coloured coded, image of the gas overlaid on an image of the scene using a conventional colour camera.
The collaboration between the University of Glasgow and M Squared Lasers was facilitated by QuantIC, the UK’s quantum imaging technology hub, which is based at the University. QuantIC aims to bring a range of new sensing technologies into the market. The global gas sensing market was estimated at $1.78 billion in 2013 and is expected to be worth $2.32 billion by 2018, offering an attractive opportunity for new technology.
Dr Graham Gibson, lead author of the paper, said, “Our detector allows us to produce images which refresh 25 times a second, equivalent to the standard frame rate of video, which provides a highly accurate real-time picture of the scene in front of the detector.
“Working with M Squared Lasers, with the support of QuantIC, has been of immense benefit to the project. M Squared’s advanced laser systems allowed us to effectively ‘tune in’ to the wavelength of methane gas, and opens up the possibility of using the system to detect other types of gases in the future.”
Nils Hempler, head of M Squared Lasers’ innovation business unit, said, “Close collaboration with QuantIC has helped M Squared to identify and create lower cost, compact, greatly improved imaging solutions that are suitable for a range of industries.
“We’re keen to continue our collaboration to bring this project to market and to build on this foundation to create single-pixel sensors capable of detecting a wide range of other sources.”
The team’s paper, titled ‘Real-time imaging of methane gas leaks using a single-pixel camera’, is published in Optics Express.
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