Device and method for quantification of gases in plumes by remote sensing
View Patent ↗In one aspect, the present invention relates to a device quantifying absolute amounts of ingredients of a plume. In one embodiment, the device comprises a source for emitting a beam of light and transmitting the emitted light through the plume to a surface on which the transmitted light is scattered, a detector for acquiring an image of the exhaust plume, the acquired image containing information of absorption of the scattered light scattered from the surface, and a processor for processing the acquired image to determine an absolute amount of at least one of components of the exhaust plume.
1. A device for quantifying absolute amounts of ingredients of a plume, comprising:
(a) a light source for emitting a beam of light through the plume to a surface on which the light is scattered;
(b) a detector for acquiring an image of the plume containing information of absorption of the scattered light scattered from the surface; and
(c) a processor for processing the acquired image to determine an absolute amount of at least one of ingredients of the plume.
2. The device of claim 1 , wherein the processor is configured to perform the functions of:
(a) choosing a plurality of pixels from the acquired image along a section crossing the plume, each pixel having a pixel area projected on to a surface;
(b) characterizing an absorption rate of light of each chosen pixel from the acquired image;
(c) calculating optical mass of each pixel from the characterized absorption rate of the pixel;
(d) multiplying the optical mass of each pixel and the corresponding adjusted projected pixel area to obtain the number of molecules in each pixel; and
(e) summing the number of molecules of each pixel to obtain the total number of molecules in the plume.
3. The device of claim 2 , wherein the processor is configured to perform further the functions of:
(f) calculating the number of moles, thereby grams of and ingredients of the plume; and
(g) calculating the width of the area covered by the pixels to obtain the grams per distance of which the vehicle is leaving behind.
4. The device of claim 2 , wherein the optical mass μ of each pixel is determined by the Beer's Law:
μ=−ln( I/I 0 )/κ( v ),
wherein (I/I 0 ) is associated with the absorption rate, and κ(v) is an absorption cross-section.
5. The device of claim 1 , wherein the detector comprises at least one of an infrared camera and an ultraviolet camera with one or more narrow bandpass filters, wherein the one or more narrow bandpass filters incorporate the absorption bands of specific gases.
6. The device of claim 1 , wherein the detector comprises a plurality of photosensors, each photosensor generating an electrical signal responsive of the scattered light scattered from the surface, wherein the electrical signal is indicative of the absorption of the received light by the plume.
7. The device of claim 1 , wherein the detector comprises a detector array capable of capturing images of the plume.
8. The device of claim 1 , wherein the light source comprises a halogen light source and/or glowbar.
9. The device of claim 8 , further comprising a collimating/spreading optics for collimating/spreading the emitted light and transmitting the light through the plume to the surface.
10. The device of claim 9 , wherein the collimating optics comprises a first concave mirror and a second concave mirror positioned in relation to the source such that the first concave mirror receives the beam of light emitted from the source and reflects the received light to the second concave mirror, the second concave mirror, in turn, collimates the reflected light and transmits the collimated light through the plume to the surface.
11. The device of claim 10 , wherein the first concave mirror and the second concave mirror define a focus between, and a chopper is placed on the focus.
12. The device of claim 1 , wherein the light source comprises one or more modulated lasers, and/or modulated LEDs.
13. A method for quantifying absolute amounts of ingredients of a plume, comprising the steps of:
(a) directing a beam of light through the plume to a surface on which the beam of light scattered;
(b) acquiring an image of the plume containing information of absorption of the scattered light scattered from the surface; and
(c) processing the acquired image to determine an absolute amount of at least one of ingredients of the plume.
14. The method of claim 13 , wherein the processing step comprising the steps of:
(a) choosing a plurality of pixels from the acquired image along a section crossing the plume, each pixel having a pixel area;
(b) characterizing an absorption rate of light of each chosen pixel from the acquired image;
(c) calculating optical mass of each pixel from the characterized absorption rate of the pixel;
(d) multiplying the optical mass of a pixel and the corresponding pixel area to obtain the number of molecules in the pixel; and
(e) summing the number of molecules of each pixel to obtain the total number of molecules in the plume.
15. The method of claim 14 , wherein the processing step further comprising the steps of:
(a) calculating the number of moles, thereby grams of and ingredients of the plume; and
(b) calculating the width of the area covered by the pixels to obtain the grams per distance of which the vehicle is leaving behind.