INFRARED CAMERA FOR GAS DETECTION

• US 20100301214A1
• Filed: 06/02/2009
• Published: 12/02/2010
• Est. Priority Date: 06/02/2009
• Status: Active Grant

• Current Assignee: Flir Systems AB (Teledyne Technologies Incorporated)
• Original Assignee: Flir Systems AB (Teledyne Technologies Incorporated)
• Inventors: Jõnsson, Henrik
• Granted Patent: US 8,803,093 B2
• Time in Patent Office: Days
• US Class Current: 250/332
• CPC Class Codes: G01N 21/3518 Devices using gas filter correlation techniques; Devices using gas pressure modulation techniques

Abstract

An IR camera is disclosed, comprising two IR detectors for detecting a first and a second image of the imaged area. A beamsplitter is operable to split the incoming radiation into a first beam comprising a first wavelength spectrum and a second beam comprising a second wavelength spectrum different from the first wavelength spectrum. The first beam is received at the first IR detector and the second beam is received at the second IR detector. A processor is operable to calculate properties of the imaged area based on the first and the second image in relationship to each other. The information obtained may be used, for example, to detect the presence or identity of a gas or to determine the material properties of an imaged object.

Claims

1. An infrared (“

IR”

) camera comprising;

an optical system for receiving incoming radiation in a full wavelength range from an imaged area;

a beamsplitter for splitting the incoming radiation into a first beam having a first wavelength spectrum and a second beam having a second wavelength spectrum different from the first wavelength spectrum;

a first IR detector for receiving the first beam and detecting a first image of the imaged area based on the first beam;

a second IR detector for receiving the second beam and detecting a second image of the imaged area based on the second beam; and

a processor for calculating properties of the imaged area based on a relationship of the first and the second images.

2. The IR camera according to claim 1, wherein the camera is operable to detect the presence of a gas in the imaged area, said gas having a particular gas wavelength range, and the beamsplitter is operable to split the incoming radiation so that the relationship between the gas wavelength range and the full wavelength range in the first beam is different from the relationship between the gas wavelength range and the full wavelength range in the second beam.

3. The IR camera according to claim 2, wherein the beamsplitter is operable to split the incoming radiation so that the first image has a stronger contribution of radiation in the frequency spectrum of the gas as compared to the contribution of radiation in the frequency spectrum of the gas in the second image and the second image has a stronger contribution of radiation outside the frequency spectrum of the gas as compared to the contribution of radiation in the frequency spectrum of the gas in the second image.

4. The IR camera according to claim 1, wherein the processor is operable to compare the second image to the first image to obtain a gas image indicating the presence of the gas in the imaged area.

5. The IR camera according to claim 1, wherein the processor is operable to determine a first total energy registered by the first detector, a second total energy registered by the second detector, and a value of the temperature of an imaged object or an emissivity factor for the object, based on the first total energy and the second total energy.

6. The IR camera according to claim 1, wherein the processor is operable to determine a first total energy registered by the first detector in the first wavelength spectrum, a second total energy registered by the second detector in the second wavelength spectrum, and a value representative of a first emissivity factor of an imaged object based on the first total energy and a value representative of a second emissivity factor based on the second total energy.

7. The IR camera according to claim 6, wherein the processor is operable to determine the first emissivity factor and the second emissivity factor based on the first and second total energy, respectively, and a temperature of the imaged object.

8. The IR camera according to claim 6, wherein the processor is operable to determine a relationship between the first emissivity factor and the second emissivity factor.

9. A method of using an infrared (“

IR”

) camera, the method comprising;

receiving, in an IR camera, incoming radiation in the IR wavelength range from an imaged area;

splitting the incoming radiation into a first beam in a first wavelength range and a second beam in a second wavelength range;

receiving the first beam at a first detector of the IR camera to detect a first image;

receiving the second beam at a second detector of the IR camera to detect a second image; and

performing calculations regarding the imaged area based on the relationship between the first and second image.

10. A method according to claim 9 further comprising:

detecting the presence of a gas in the imaged area by subtracting the second image from the first image to obtain a gas image indicating the presence of the gas in the imaged area, wherein the second wavelength range excludes the wavelength of the gas and the wavelength of the gas is a subset of the first wavelength range.

11. The method according to claim 9 further comprising:

displaying the gas image.

12. The method according to claim 11 further comprising:

obtaining a visual image of the area; and

fusing the gas image with the visual image.

13. The method according to claim 9, further comprising:

determining a first total energy registered by the first detector;

determining a second total energy registered by the second detector; and

determining a value of the temperature of an imaged object or an emissivity factor for the object, based on the first total energy and the second total energy.

14. The method according to claim 9, further comprising:

determining a first total energy registered by the first detector in the first wavelength spectrum;

determining a second total energy registered by the second detector in the second wavelength spectrum; and

determining a value representative of a first emissivity factor of an imaged object based on the first total energy and value representative of a second emissivity factor based on the second total energy.

15. The method according to claim 14, wherein determining the first emissivity factor and the second emissivity factor based on the first and second total energy, respectively, is also based on a temperature of the object.

16. The method according to claim 14, further comprising:

determining a relationship between the first emissivity factor and the second emissivity factor.