Technique for passive scene imaging of gas and vapor plumes using transmission-waveband modulation

A new approach to locating gas and vapor plumes is proposed that is entirely passive. By modulating the transmission waveband of a narrow-band filter, an intensity modulation is established that allows regions of an image to be identified as containing a specific gas with absorption characteristics aligned with the filter. A system built from readily available components was constructed to identify regions of NO. Initial results show that this technique was able to distinguish an absorption cell containing NO gas in a test scene. © 2012 Society of Photo-Optical Instrumentation Engineers (SPIE).