METHOD FOR DISPLAYING A THERMAL IMAGE IN AN IR CAMERA, AND AN IR CAMERA

• US 20130088604A1
• Filed: 10/15/2012
• Published: 04/11/2013
• Est. Priority Date: 10/16/2006
• Status: Active Grant

• Current Assignee: Flir Systems AB (Teledyne Technologies Incorporated)
• Original Assignee: Flir Systems AB (Teledyne Technologies Incorporated)
• Inventors: Hamrelius, Torbjrn, Ahlstrm, Mats
• Granted Patent: US 9,191,583 B2
• Time in Patent Office: Days
• US Class Current: 348/164
• CPC Class Codes: G01J 2005/0077 Imaging
• CPC Class Codes: G01J 5/10 using electric radiation detectors
• CPC Class Codes: G01J 5/48 Thermography; Techniques using wholly visual means
• CPC Class Codes: H04N 5/33 Transforming infrared radiation cameras or camera modules for generating image signals from infrared radiation H04N23/20; circuitry of SSIS for transforming infrared radiation into image signals H04N25/20

Abstract

A method for displaying a thermal image in an infrared (IR) thermal camera, includes, for an embodiment, registering an outdoor temperature value, registering an indoor temperature value, calculating an isotherm level by using the registered temperature values and a temperature color alarm level, imaging a surface area to create an image of the temperature distribution in at least a part of the surface area, comparing the surface area temperature in at least one image point of the thermal image to the isotherm level, adjusting the color of the at least one image point in dependence of the relation between the surface area temperature in said at least one image point and the isotherm level and displaying the colored version of the thermal image. The method may allow a user to determine immediately, on-site, if a building is well insulated and may present an easily interpreted and understandable thermal image.

Claims

1. ) A method for displaying a thermal image in an infrared (IR) thermal camera to detect thermal transmission through a partition separating an outside and an inside of a construction, the method comprising:

registering a first air temperature value (T_A) on the outside of a construction;

registering a second air temperature value (T_B) on the inside of the construction;

calculating a threshold temperature level value (T_ISO) based on the registered first air temperature value (T_A), the registered second air temperature value (T_B), and a temperature color alarm level (T_CAL), wherein, in a first mode, normal temperature values are temperature values above the threshold temperature level value (T_ISO) and abnormal temperature values are temperature values below the threshold temperature level value (T_ISO) and, in a second case, in a second mode, normal temperature values are temperature values below the threshold temperature level value (T_ISO) and abnormal temperature values are temperature values above the threshold temperature level value (T_ISO);

imaging a surface area of the partition located between the outside and the inside of the construction, to create a thermal image of the temperature distribution in at least a part of the surface area;

comparing a surface area temperature in at least one image point of the thermal image to the threshold temperature level value (T_ISO);

determining, based on the comparison, whether the temperature of the at least one image point is normal or abnormal;

registering the distance between the surface area and the IR thermal camera as the IR thermal camera captures a thermal image;

determining additional information relating to the characteristics of any image points having an abnormal temperature, dependent on the registered distance information;

adjusting the color of the at least one image point in dependence on whether the temperature of the image point is normal or abnormal, and in dependence on any determined additional information, to create a colored version of the thermal image; and

displaying the colored version of the thermal image.

2. ) A method according to claim 1, further comprising retrieving the field of view (FOV) of the IR thermal camera and calculate to scale information related to the image, based on the retrieved FOV and the obtained distance information.

3. ) A method according to claim 2, wherein the calculated to scale information is related to the length, size or area of parts of the surface area.

4. ) A method according to claim 2, wherein the calculated to scale information is superimposed onto a captured IR image and stored in connection with a captured image.

5. ) A method according to claim 2, further comprising determining the direction from the IR thermal camera to the surface area, or imaged scene.

6. ) A method according to claim 5, wherein the direction information is determined using a compass device configured to determine the direction from the IR thermal camera to the surface area, or imaged scene, and where the method further comprises compensating for the determined direction when determining said isotherm level (T_ISO) and said additional information.

7. ) A method according to claim 1, wherein the temperature color alarm level (T_CAL) is registered in the IR camera manually, and wherein the method further comprises calculating thermal transmission coefficients of the partition in the colored version of the thermal image using the registered first temperature value (T_A) and the registered second temperature value (T_B).

8. ) A method according to claim 1, comprising

registering the air humidity level when registering the first air temperature value (T_A) and/or the second air temperature value (T_B);

and

compensating for the registered air humidity level when displaying the colored version of the thermal image (10).

9. ) A method according to claim 1, comprising

registering a distance between the partition and the IR camera as the IR camera captures a thermal image;

and

compensating for the registered distance when displaying the colored version of the thermal image.

10. ) A infrared (IR) thermal camera comprising:

a lens configured to focus incoming IR radiation from an object, representing a portion of a structure, for the IR camera to generate an image an image signal corresponding to the incoming IR radiation

a processor, configured to perform signal conditioning for the image signal, the signal conditioning comprising corrections for inherent offset an gain to provide a conditioned image signal output;

a distance measuring device configured to register the distance between the surface area and the IR thermal camera as the IR thermal camera captures a thermal image;

wherein the processor is further configured to receive the registered distance information and determining additional information relating to the characteristics of any defects or abnormalities present on the surface area, dependent on the registered distance information;

a color adjusting unit, which in dependence of temperature values registered via one or more temperature input devices and processed by the processor, is configured to display a thermal image via a display;

wherein the processor is configured to calculate, on the basis of at least a first registered air temperature value (T_A) for outside the structure, a second registered air temperature value (T_B) for inside the structure, a temperature color alarm level (T_CAL), and a temperature level value (T_ISO); and

wherein the color adjusting unit is configured to compare the surface area temperature in at least one image point of the thermal image to the temperature level value (T_ISO), and adjust the color in at least one image point of the thermal image in dependence of the relation between the surface area temperature in the at least one image point and the temperature level value (T_ISO) and in dependence of any determined additional information, to create a colored version of the thermal image.

11. ) An infrared (IR) thermal camera according to claim 10, wherein the processor is further configured to retrieve the field of view (FOV) of the IR thermal camera and calculate to scale information related to the image, based on the retrieved FOV and the obtained distance information.

12. ) An infrared (IR) thermal camera according to claim 11, wherein the calculated to scale information is related to the length, size or area of parts of the surface area.

13. ) An infrared (IR) thermal camera according to claim 11, wherein the processor is further configured to superimpose the calculated to scale information onto a captured IR image.

14. ) An infrared (IR) thermal camera according to claim 11, further comprising a storage unit configured to store the calculated to scale information in connection with a captured image.

15. ) An infrared (IR) thermal camera according to claim 11, further comprising a direction determination unit configured to determine the direction from the IR thermal camera to the surface area, or imaged scene.

16. ) An infrared (IR) thermal camera according to claim 15, wherein the direction determination unit is a compass, and wherein the processor is further configured to compensate for the determined direction when determining said isotherm level (T_ISO) and said additional information.

17. ) An infrared (IR) thermal camera according to claim 10, comprising a receiving unit for receiving a temperature color alarm level (T_CAL) manually.

18. ) An infrared (IR) thermal camera according to claim 10, wherein the processor is configured to calculate, on the basis of said the first and second registered air temperature values (T_A, T_B), thermal transmission coefficients of the object in the colored version of the thermal image (10).

19. ) An infrared (IR) thermal camera according claim 10, comprising a humidity input device for receiving at least one atmospheric humidity value and wherein the processor is configured to compensate for the atmospheric humidity value when determining the temperature level value (T_ISO).

20. ) An infrared (IR) thermal camera according to claim 10, further comprising a distance input device for receiving an object distance value, and wherein the processor is configured to compensate for the object distance value when determining the temperature level value (T_ISO).