Single pixel imaging helps with economical visualisation of methane

In a paper published in Optics Express, researchers from Glasgow University’s School of Physics and Astronomy and M Squared Lasers, a Glasgow-based photonics company, describe how they have used single-pixel imaging to create real-time video images of methane gas in a typical atmospheric setting.

Gas imaging technology is already commercially available but current systems are expensive, unwieldy and power-hungry. Single-pixel imaging uses one light-sensitive pixel to build digital images instead of using conventional multi-pixel sensor arrays, which can be too expensive for infrared imaging. This allows the researchers to build a smaller, cheaper gas detection system.

According to Glasgow University, 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 Glasgow University and M Squared Lasers was enabled 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 alone was estimated at $1.78bn in 2013 and is expected to be worth $2.32bn by 2018.

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.

“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.”

The team’s paper, titled ‘Real-time imaging of methane gas leaks using a single-pixel camera’, is available at: https://www.osapublishing.org/oe/abstract.cfm?uri=oe-25-4-2998