Spatially resolved gas detection
AssigneeNederlandse Organisatie voor toegepast-natuurwetenschappelijk onderzoek TNO
InventorsHuibert Visser, Hedser van Brug
Life of this patent
Estimating the term…
Abstract
The invention pertains to a method of spatially resolved detection of a gas substance in an area, comprising: imaging the area on a first image sensor, in a wavelength spectrum including an absorption wavelength peak corresponding to said gas substance; imaging the area on a second image sensor, to provide for each pixel of the first image a corresponding pixel of the second image for respective on- and off-peak wavelengths relative to the absorption wavelength; and providing a difference image as a function of the two pixel values of first and second image sensors to produce an image of the spatially resolved absorption wavelength corresponding to said gas substance.
Claims8
A gas detector system for spatially resolved detection of a gas substance in an area, comprising;
- a detector comprising first and second image sensors;
- a broad band filter arranged in the optical beam path before the detector;
- for transferring a broad band beam with a wavelength spectrum including an absorption wavelength peak corresponding to said gas substance;
- a telescope, splitter;
- and relay optics;
- wherein the telescope is arranged to imaging the area onto the image sensors;
- wherein the splitter is arranged to produce split beams;
- and
- wherein said relay optics are arranged to relay said split beams respectively to produce first and second images on first and second image sensors;
- to provide for each pixel of the first image a corresponding pixel of the second image for respective on- and off-peak wavelengths relative to the absorption wavelength and wherein the relay optics are provided with an interferometric stage combining said split beams with an optical path difference into a first image, and into a second image, thereby each image having a spectral fringe pattern corresponding to theoptical path difference that matches absorption dips pertaining to the gas being measured, to produce the first image and second image with a phase difference corresponding to half of the central wavelength of the broad beam, thereby producing said first and second images with relative phase differences corresponding to respective on- and off-peak wavelengths relative to the absorption wavelength;
- and
- a controller coupled to the detector, arranged to provide a difference image as a function of the two pixel values of first and second image sensors to produce an image at the spatially resolved absorption wavelength corresponding to said gas substance.
A gas detector system for spatially resolved detection of a gas substance in an area, comprising;
- a detector comprising first and second image sensors;
- a broad band filter arranged in the optical beam path before the detector;
- for transferring a broad band beam with a wavelength spectrum including an absorption wavelength peak corresponding to said gas substance;
- a telescope, splitter;
- and relay optics;
- wherein the telescope is arranged to imaging the area onto the image sensors;
- wherein the splitter is arranged to produce split beams;
- and
- wherein said relay optics are arranged to relay said split beams respectively to produce first and second images on first and second image sensors;
- to provide for each pixel of the first image a corresponding pixel of the second image for respective on- and off-peak wavelengths relative to the absorption wavelength;
- and
- wherein the relay optics are provided with an interferometric stage combining said split beams with an optical path difference into a first image, and into a second image, thereby each image having a spectral fringe pattern corresponding to the optical path difference that matches absorption dips pertaining to the gas being measured, to produce the first image and second image with a phase difference corresponding to half of the central wavelength of the broad beam, thereby producing said first and second images with relative phase differences corresponding to respective on- and off-peak wavelengths relative to the absorption wavelength a controller coupled to the detector, arranged to provide a difference image as a function of the two pixel values of first and second image sensors to produce an image at the spatially resolved absorption wavelength corresponding to said gas substance;
- and
- wherein the telescope is of a telecentric type having a working distance corresponding to the interferometer length.
Dependencies are inferred from the claim text.