Automatic 3D detection of gas leaks
Researchers have developed a method to create a 3D image that provides detailed information such as the coordinates, volume and concentration of a gas leak. The new detection approach can be used for early warning, risk assessment or remediation of a leak.
A new technology detects leaked gas using 3D tracking. Researchers at the Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences have developed a method to create the 3D image of a leak gas cloud that provides detailed info about the leak, such as location, volume and concentration. The new approach to automatic detection could be used for early warning, risk assessment, or determining the best method to fix gas leaks. Details were published in Optics Express.
Accurate 3D image of the cloud thanks to GPS
"With the rapid development of society, there are now large facilities all over the world that store toxic, harmful, flammable and explosive chemicals. If there is a leak in one of these facilities, it is important to quickly understand the composition, concentration, location and distribution," said Liang Xu, research director. The technique combines info from two Fourier transform infrared spectroscopy (FTIR) imaging systems with precise position data from GPS and gyroscope sensors to create a 3D image of the gas cloud, which is overlaid on a digital Google Earth map.
"Until now, it has not been possible to determine the exact location and direction in which the gas is moving in the event of a leak. Our method of creating a 3D reconstruction of a gas cloud can be used to accurately determine the latitude and longitude of the leaking gas. This information is important for determining who might be at risk and for stopping the leak quickly so that less gas is released into the atmosphere," emphasizes first author Yunyou Hu.
Longitude, latitude, concentration
FTIR spectroscopy is widely used for quantitative remote detection of gaseous pollutants because of its high sensitivity and resolution, and its ability to make real-time measurements with a range of about five kilometers. However, a single FTIR remote sensing system provides only 2D information about a gas leak. To create a 3D image, researchers use two systems to obtain 2D measurements of a gas cloud from different perspectives. This info is spatially registered with location information obtained with GPS and gyroscope sensors. The data is fed into the Simultaneous Algebraic Reconstruction Technique computed tomographic imaging algorithm, which creates a 3D reconstruction of the gas cloud.
"Each voxel or 3D pixel in the reconstructed 3D gas cloud contains 3D information about the longitude, latitude, concentration and height of the gas relative to the ground. Precise positioning of the monitored space using GPS and gyroscope sensors is key to quantitative 3D reconstruction of gas clouds," Hu clarifies.
Detect gas leaks in industry
The researchers tested their new method in a field experiment in which they used two scanning FTIR remote sensing systems to remotely monitor small amounts of sulfur hexafluoride and methane released over two minutes in a space of about 315 cubic meters. They were able to create 3D representations of the gas clouds with longitude, latitude, altitude and concentration distribution for both gases.
"To apply our technique in a real-world scenario, two or more scanning FTIR imaging systems would need to be installed around the monitored area to form a cross-scanning network," Hu said. "Our proposed method could then be used to create a 3D reconstruction of a leaking gas cloud, which in turn could be used to find the leak source and provide early warning information." The researchers are now working to optimize the reconstruction method and plan to test the system in real industrial environments.
