Passive Standoff Detection of Chemical Vapors by Differential FTIR Radiometry
Abstract
This report presents a novel method for the passive standoff detection of chemical vapors by differential Fourier Transform Infrared (FTIR) radiometry. The originality of the method lies on the use of a double-input beam FTIR interferometer optimized for optical subtraction. For implementing this method, a radiative transfer model is formulated for the general case ot slant path scenarios containing any type of background scenes. A procedure of radiometric calibration adapted for differential detection with a double-input beam FTIR interferometer is developed. A detection algorithm (GASEM) that controls the interferometer data acquisition and performs the on-line monitoring of chemical vapor parameters is described and validated The differential detection method has been successfully tested in the field on several chemical vapors. In particular, it has been used to map the integrated concentration and the temperature of a plume of methanol vapor. In this case, the uncertainties on the methanol plume measurements have been estimated to be of the order of 15 to 30% for concentration, and 2 to 5" for temperature which represents an acceptable result for this type ot passive sensing.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 2001
- Accession Number
- ADA637772
Entities
People
- Jean-marc Theriault