US 10,371,627 B2Granted

Systems and methods for multispectral imaging and gas detection using a scanning illuminator and optical sensor

AssigneeMultiSensor Scientific, Inc.

InventorsAllen M. Waxman, Terrence K. Jones, Jason M. Bylsma, Stefan Bokaemper

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Abstract

Presented herein are systems and methods directed to a multispectral absorption-based imaging approach that provides for rapid and accurate detection, localization, and quantification of gas leaks. The imaging technology described herein utilizes a scanning optical sensor in combination with structured and scannable illumination to detect and image spectral signatures produced by absorption of light by leaking gas in a quantitative manner over wide areas, at distance, and in the presence of background such as ambient gas and vapor. Moreover, the specifically structured and scannable illumination source of the systems and methods described herein provides a consistent source of illumination for the scanning optical sensor, allowing imaging to be performed even in the absence of sufficient natural light, such as sunlight. The imaging approaches described herein can, accordingly, be used for a variety of gas leak detection, emissions monitoring, and safety applications.

Claims30

Dependent claims

A system for obtaining a multispectral absorption image of a scene using a structured illumination beam that is scanned in a synchronized fashion with an instantaneous field of view (ifov) of an optical sensor, the system comprising:

(a) an illumination source aligned and operable to produce the structured illumination beam and direct the structured illumination beam towards a target surface within the scene, thereby illuminating an illumination spot corresponding to a projection of the structured illumination beam onto the target surface, the illumination spot having a length and a width, wherein the length is greater than or equal to the width;
(b) a beam scanner operable to scan the illumination spot in a beam scan direction that is substantially parallel to the width of the illumination spot;
(c) an optical sensor comprising one or more spectral detectors, each aligned and operable to detect light having wavelengths within a particular associated spectral band, wherein the optical sensor is aligned and operable to capture light from the scene within a sensor instantaneous field of view (ifov) corresponding to a combined ifov of the one or more spectral detectors and direct the captured light, for detection, onto the one or more spectral detectors, thereby detecting light from a particular sampled image location corresponding to a projection of the sensor ifov onto the target surface;
(d) an optical sensor scanner aligned and operable to scan the projection of the sensor ifov across the scene, so as to detect light from a plurality of sampled image locations within the scene, wherein the optical sensor scanner is synchronized with the beam scanner so as to maintain overlap between the projection of the sensor ifov and the illumination spot as both are scanned;
(e) a processor of a computing device;
and
(f) a memory having instructions stored thereon, wherein the instructions, when executed by the processor, cause the processor to:
retrieve and/or access data corresponding to the detected light from each of the sampled image locations;
and
use the data to create a multispectral absorption image of the scene,
wherein the optical sensor scanner is aligned and operable to scan the projection of the sensor ifov along a first scan axis aligned along the length of the illumination spot and along a second scan axis aligned along the width of the illumination spot, wherein the first scan axis is a fast axis along which the optical sensor scanner is operable to scan the projection of the sensor ifov at a fast scan rate, and wherein the fast scan rate is sufficiently fast so as to allow for the projection of the sensor ifov to be scanned through multiple sampled image locations along the length of the illumination spot before the illumination spot moves an appreciable distance.

8 more elements

A system for obtaining a multispectral absorption image of a scene using a structured illumination beam produced by an illumination source mechanically coupled to a scanning optical sensor, the system comprising:

(a) an illumination source aligned and operable to produce a structured illumination beam and direct the structured illumination beam towards a target surface within the scene, thereby illuminating an illumination spot corresponding to a projection of the structured illumination beam onto the target surface, the illumination spot having a length and a width, wherein the length is greater than or equal to the width;
(b) an optical sensor comprising one or more spectral detectors, each aligned and operable to detect light having wavelengths within a particular associated spectral band, wherein the optical sensor is aligned and operable to capture light from the scene within a sensor instantaneous field of view (ifov) corresponding to a combined ifov of the one or more spectral detectors and direct the captured light, for detection, onto the one or more detectors, thereby detecting light from a particular sampled image location corresponding to a projection of the sensor ifov onto the target surface;
(c) an optical sensor scanner aligned and operable to scan the projection of the sensor ifov along a first scan axis directed along the length of the illumination spot;
(d) a rotational stage on which the illumination source, optical sensor, and optical sensor scanner are mounted and aligned such that at least a portion of the first scan axis is held substantially coincident with a long axis directed along the length of the illumination spot, and scanning the projection of the sensor ifov along the first scan axis scans the sensor ifov over the illumination spot, along the length of the illumination spot,
wherein the rotational stage is operable to rotate about a rotational axis, such that (i) rotation of the rotational stage scans the illumination spot and projection of the sensor ifov together across the scene in a second scan direction that is substantially orthogonal to the first scan axis, and (ii) scanning of the projection of the sensor ifov by the optical scanner in combination with rotation of the rotational stage raster scans the projection of the sensor ifov across the scene, thereby detecting light from a plurality of sampled image locations within the scene, each corresponding to a particular position of the projection of the sensor ifov within the raster scan;
(e) a processor of a computing device;
and
(f) a memory having instructions stored thereon, wherein the instructions, when executed by the processor, cause the processor to:
retrieve and/or access data corresponding to the detected light for each of the sampled image locations;
and
use the data to create a multispectral absorption image of the scene.

8 more elements

A method of obtaining a multispectral absorption image of a scene using a structured illumination beam that is scanned in a synchronized fashion with an instantaneous field of view (ifov) of an optical sensor, the method comprising:

(a) directing the structured illumination beam from an illumination source towards a target surface within the scene, thereby illuminating an illumination spot corresponding to a projection of the structured illumination beam onto the target surface, wherein the illumination spot has a length and a width, wherein the length is greater than or equal to the width;
(b) scanning the illumination spot in a beam scan direction that is substantially along the width of the illumination spot;
(c) detecting, with one or more spectral detectors of an optical sensor, light from the scene and captured within the ifov of the optical sensor, thereby detecting light from a particular sampled image location corresponding to a projection of the sensor ifov onto the target surface;
(d) scanning the projection of the sensor ifov across the scene, so as to detect light from a plurality of sampled image locations within the scene, wherein the optical sensor scanner is synchronized with the beam scanner and so as to maintain overlap between the projection of the sensor ifov and the illumination spot as both are scanned, wherein the optical sensor scanner is aligned and operable to scan the projection of the sensor ifov along a first scan axis aligned along the length of the illumination spot and along a second scan axis aligned along the width of the illumination spot, wherein the first scan axis is a fast axis along which the optical sensor scanner is operable to scan the projection of the sensor ifov at a fast scan rate, and wherein the fast scan rate is sufficiently fast so as to allow for the projection of the sensor ifov to be scanned through multiple sampled image locations along the length of the illumination spot before the illumination spot moves an appreciable distance;
(e) retrieving and/or accessing, by a processor of a computing device, data corresponding to the detected light for each of the sampled image locations;
and
(f) creating, by the processor, using the data, a multispectral absorption image of the scene.

4 more elements

A method for obtaining a multispectral absorption image of a scene using a structured illumination beam produced by an illumination source mechanically coupled to a scanning optical sensor, the method comprising:

(a) directing the structured illumination beam from the illumination source towards a target surface within the scene, thereby illuminating an illumination spot corresponding to a projection of the structured illumination beam onto the target surface, wherein the illumination spot has a length greater than or equal to a first dimension of a target region of the target surface and a width less than the length;
(b) detecting, with one or more detectors of an optical sensor, light from the scene and captured within the ifov of the optical sensor, thereby detecting light that originates from a particular sampled image location corresponding to a projection of the sensor ifov onto the target surface;
(c) scanning the projection of sensor ifov along a first scan axis, substantially parallel to a direction along the length of the illumination spot and at least a portion of which is substantially coincident with a long axis aligned along the length of the illumination spot, such that scanning the projection of the sensor ifov along the first scan axis scans the sensor ifov over the illumination spot, along the length of the illumination spot;
(d) rotating, via a rotational stage on which both the illumination source and optical sensor are mounted and maintained in substantially fixed alignment with respect to each other, the illumination source and optical sensor about a rotational axis, such that (i) rotation of the rotational stage scans the illumination spot and the projection of the sensor ifov together across the scene in a second scan direction that is substantially orthogonal to the first scan axis, and (ii) scanning of the projection of the sensor ifov along the first scan axis in combination with rotation of the rotational stage raster scans the projection of the sensor ifov across the scene, thereby providing for detection of light from a plurality of sampled image locations within the scene, each corresponding to a particular position of the projection of the sensor ifov within the raster scan;
(e) retrieving and/or accessing, by a processor of a computing device, data corresponding to the detected light for each of the sampled image locations;
and
(f) creating, by the processor, using the data, a multispectral absorption image of the scene.

4 more elements

Dependencies are inferred from the claim text.

Facts

Application: 16/129,731Filed 12 Sep 2018 · us provisional application
Priority: 16 Nov 2017
Published: US 2019/0145891 A116 May 2019
Granted: 6 Aug 2019
Term ends: Not estimatedThe source records don’t support an estimate.

Classification27 codes

G01N 21/3504
Using infrared light: for analysing gases, e.g. multi-gas analysis
G01F 1/661
By measuring frequency, phase shift or propagation time of electromagnetic or other waves, e.g. using ultrasonic flowmeters: using light
G01J 3/0208
Optical elements not provided otherwise, e.g. optical manifolds, diffusers, windows: using focussing or collimating elements, e.g. lenses or…
G01J 3/021
Optical elements not provided otherwise, e.g. optical manifolds, diffusers, windows: using plane or convex mirrors, parallel phase plates, or…

Family

Application62/587,304Us provisional application · filed 16 Nov 2017
US 2019/0145891 A1Pre-grant publication · published 16 May 2019
US 10,371,627 B2This patent

From the US filing history. Foreign family members aren’t listed.

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