Abstract

Backscatter absorption gas imaging (BAGI) is a remote sensing technique that uses active imaging to generate real-time video images of chemical vapor plumes.^1,2 As such, BAGI represents a fusion between absorptive chemical detection LIDAR and imaging laser radar. Plume imaging occurs when a gas that can absorb light at the laser wavelength enters the system field-of-view, thereby attenuating the scene backscatter and causing a cloud image. Instruments based on BAGI have been generated that use a raster-scanning camera in conjunction with a cw laser to make real-time active imagery in the infrared. When a CO₂ laser is used, over 70 different organic species can be detected at concentrations of 1-500 ppm-m. A system using an infrared helium-neon (HeNe) laser has also been developed to detect methane plumes at a sensitivity of 20 ppm-m.

© 1996 Optical Society of America