Method and apparatus for remote optical detection of a gas present in an observed volume
US5306913A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 3, 1992 |
| Grant date | Apr 26, 1994 |
| Priority date | — |
| Expiry date | Dec 3, 2012 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2021/3531
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method and apparatus for remote optical detection of a gas present in an observed volume using a thermal imager or camera including one or more sensitive elements which are sensitive to radiant fluxes in a determined band of wavelengths, two filters interposable on the optical axis of the camera, the filters having similar transmission bands, one of which includes an absorption line characteristic of the looked-for gas, while the other of which is complementary to said absorption line, and signal processing means for taking the difference between the radiated fluxes received from two points at different temperatures in the volume as observed first through one of the filters and then through the other filter, for taking the ratio of said differences, and for deducing therefrom whether the gas is present in the observed volume.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.