IP Library › Granted Patent US 12,625,004
Granted Patent B2
US 12,625,004 · App. 18/731,082 · Granted May 12, 2026

Detection threshold determination for infrared imaging systems and methods

Inventors: Henning Hagman (Täby, SE); Per Lilja (Åkersberga, SE)
Assignee: FLIR Systems AB
G01J5/025G01J5/064G01J2005/0077G01J2005/066
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Quick Facts
Patent No.
US 12,625,004
App. No.
18/731,082
Granted
May 12, 2026
Kind
B2
Abstract

Techniques are provided for facilitating detection threshold determination for infrared imaging systems and methods. In one example, a method includes capturing, by an imaging device, a thermal image of a scene. The method further includes determining temperature difference data indicative of a difference between temperature data of the thermal image associated with a background of the scene and temperature data of the thermal image associated with gas detection. The method further includes determining detection threshold data based on sensitivity characteristics associated with the imaging device and the temperature difference data. The method further includes generating a detection threshold image based on the detection threshold data. Each pixel of the detection threshold image corresponds to a respective pixel of the thermal image and has a value indicative of a detection threshold associated with the respective pixel of the thermal image. Related devices and systems are also provided.

Claims (42)

1 . A method comprising:

capturing, by an imaging device, a first thermal image of a scene;

determining first temperature difference data indicative of a difference between temperature data of the first thermal image associated with a background of the scene and temperature data of the first thermal image associated with gas detection;

determining first detection threshold data based on sensitivity characteristics associated with the imaging device and the first temperature difference data; and

generating a first detection threshold image based on the first detection threshold data, wherein each pixel of the first detection threshold image corresponds to a respective pixel of the first thermal image and has a value indicative of a detection threshold associated with the respective pixel of the first thermal image.

2 . The method of claim 1 , further comprising displaying the first detection threshold image.

3 . The method of claim 1 , further comprising receiving user input, wherein the generating the first detection threshold image is in response to the user input.

4 . The method of claim 1 , further comprising:

receiving user input; and

selectively displaying the first thermal image and/or the first detection threshold image in response to the user input.

5 . The method of claim 1 , wherein, for each pixel of the first detection threshold image, the detection threshold is indicative of a concentration length threshold associated with the pixel.

6 . The method of claim 1 , wherein the sensitivity characteristics comprise minimum resolvable temperature difference (MRTD) characteristics.

7 . The method of claim 6 , wherein the MRTD characteristics comprise MRTD values for different spatial frequencies and/or different temperature spans for representing thermal image data of the first thermal image.

8 . The method of claim 1 , further comprising determining spatial noise associated with the background, wherein the first detection threshold data is further based on the spatial noise.

9 . The method of claim 1 , wherein the first thermal image of the scene is captured according to a first set of setup parameters, the method further comprising:

capturing, by the imaging device, a second thermal image of the scene according to a second set of setup parameters;

determining second temperature difference data indicative of a difference between temperature data of the second thermal image associated with the background of the scene and temperature data of the second thermal image associated with the gas detection;

determining second detection threshold data based on the sensitivity characteristics associated with the imaging device and the second temperature difference data; and

generating a second detection threshold image based on the second detection threshold data.

10 . The method of claim 9 , wherein the first set of setup parameters comprises a position of the imaging device, a viewing angle of the imaging device, a temperature span represented in the first thermal image, and/or the background of the scene.

11 . The method of claim 9 , wherein the first set of setup parameters comprises a first position of the imaging device when capturing the first thermal image, and wherein the second set of setup parameters comprises a second position of the imaging device when capturing the second thermal image.

12 . The method of claim 1 , further comprising generating a temperature difference image based on the first temperature difference data, wherein each pixel of the temperature difference image corresponds to a respective pixel of the first thermal image and has a value indicative of a temperature difference associated with the respective pixel of the first thermal image.

13 . The method of claim 12 , further comprising selectively displaying the first thermal image, the temperature difference image, and/or the first detection threshold image.

14 . An infrared imaging system comprising:

an infrared imager configured to capture a first thermal image of a scene;

a logic device configured to:

determine first temperature difference data indicative of a difference between temperature data of the first thermal image associated with a background of the scene and temperature data of the first thermal image associated with gas detection;

determine first detection threshold data based on sensitivity characteristics associated with the infrared imager and the first temperature difference data; and

generate a first detection threshold image based on the first detection threshold data, wherein each pixel of the first detection threshold image corresponds to a respective pixel of the first thermal image and has a value indicative of a detection threshold associated with the respective pixel of the first thermal image.

15 . The infrared imaging system of claim 14 , further comprising a display device configured to selectively display the first thermal image and/or the first detection threshold image in response to user input.

16 . The infrared imaging system of claim 14 , wherein, for each pixel of the first detection threshold image, the detection threshold is indicative of a concentration length threshold associated with the pixel.

17 . The infrared imaging system of claim 14 , wherein the sensitivity characteristics comprise minimum resolvable temperature difference (MRTD) characteristics.

18 . The infrared imaging system of claim 14 , wherein the logic device is further configured to determine spatial noise associated with the background, and wherein the first detection threshold data is further based on the spatial noise.

19 . The infrared imaging system of claim 14 , wherein:

the first thermal image of the scene is captured according to a first set of setup parameters;

the first set of setup parameters comprises a position of the infrared imager, a viewing angle of the infrared imager, a temperature span represented in the first thermal image, and/or the background of the scene;

the infrared imager is further configured to capturing a second thermal image of the scene according to a second set of setup parameters; and

the logic device is further configured to:

determine second temperature difference data indicative of a difference between temperature data of the second thermal image associated with the background of the scene and temperature data of the second thermal image associated with the gas detection;

determine second detection threshold data based on the sensitivity characteristics associated with the infrared imager and the second temperature difference data; and

generate a second detection threshold image based on the second detection threshold data.

20 . The infrared imaging system of claim 14 , wherein the infrared imager comprises a plurality of microbolometers.

Assignments (1)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Jun 3, 2024
From: HAGMAN, HENNING; LILJA, PER
To: FLIR SYSTEMS AB
Reel/Frame 067602/0375 →
Continuity (3)
Continuation PCTUS2022051144 · Nov 29, 2022
Provisional Application 63285987 · Dec 3, 2021
Related Publication 20240319013A1 · Sep 26, 2024
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