The Gas Cloud Imaging (GCI) camera technology is based on infrared absorption spectroscopy: different gases have different absorption signatures in the infrared. Figure 1 shows absorption signatures for three example hydrocarbon gases.
Most hydrocarbons show a strong absorption feature in the 3.2-3.5um range due to a C-H molecular stretching mode centered there — this is the “functional group” spectral region for hydrocarbon gases. The longwave spectral region (7.5 – 14 um), on the other hand, is called the “fingerprint region” due to the fact that each gas species demonstrates a substantially different spectral shape. Most infrared gas detection cameras operate in only the midwave infrared range (functional group region), the GCI however operates in the longwave infrared making it possible to differentiate and quantify.
THE REBELLION ADVANTAGE
What makes our technology possible is a hardware innovation called “snapshot hyperspectral imaging”. While conventional spectral cameras acquire an image by slowly scanning across a scene, the GCI acquires an image, and the spectral signature at each pixel, simultaneously. Figure 2 provides a visual comparison between the two. Not only does snapshot collection allow faster measurement, but it also improves sensitivity, so that measurements that were previously starved for light are now possible.
THE FUTURE IS IN THE SPECTRUM
Unlike infrared cameras, the GCI not only detects gases in the infrared but also their unique spectral signature. This allows the system to automatically remove false alarms such as steam, rain, snow, clouds, moving people, cars, etc. Each of these sources generate an emission/absorption signature that is substantially different from that of the hydrocarbon gases — their “fingerprints” are different. The GCI uses advanced algorithms to identify hydrocarbon fingerprints and automatically alert operators to potential hazards at their site.