Method for displaying a thermal image in an IR camera, and an IR camera

• US 9,191,583 B2
• Filed: 10/15/2012
• Issued: 11/17/2015
• 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
• Primary Examiner(s): Bailey, Frederick
• Application Number:
  US13/652,291
• Publication Number:
  US 20130088604A1
• Time in Patent Office: 1,128 Days
• Field of Search: None
• US Class Current: 1/1
• 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 of a scene in an infrared (IR) thermal camera, the method comprising:

registering a first air temperature value (T_A);

registering a second air temperature value (T_B);

calculating a threshold temperature level value (T_Iso) based on the registered T_A, the registered T_B, and a temperature color alarm level (T_CAL);

imaging, by the IR thermal camera, a surface area to capture the thermal image, wherein the thermal image represents a 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 T_ISO;

adjusting the color of the at least one image point in dependence of the relation between the surface area temperature in the at least one image point and the T₁₃₀ to create a colored version of the thermal image; and

displaying the colored version of the thermal image.

2. The method of claim 1, wherein:

the scene comprises a partition separating an outside and an inside of a construction, and at least a portion of the partition comprises the surface area;

the T_A is on the outside of the construction;

the T_B is on the inside of the construction;

in a first mode, normal temperature values are temperature values above the T_ISO and abnormal temperature values are temperature values below the T_ISO and, in a second mode, normal temperature values are temperature values below the T_Iso and abnormal temperature values are temperature values above the T_ISO; and

the adjusting comprises;

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

adjusting the color of the at least one image point in dependence of whether the temperature of the image point is normal or abnormal.

3. The method of claim 2, comprising:

calculating thermal transmission coefficients of the partition based, at least in part, on the registered T_A and the registered T_B; and

superimposing the thermal transmission coefficients onto the displayed colored version of the thermal image and/or storing the thermal transmission coefficients in connection with the thermal image.

4. The method of claim 1, comprising:

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

retrieving the field of view (FOV) of the IR thermal camera;

calculating to scale information related to the thermal image based on the retrieved FOV and the registered distance information, wherein the calculated to scale information is superimposed onto the colored version of the thermal image and/or stored in connection with the thermal image.

5. The method of claim 4, wherein the calculated to scale information is related to the length, size, and/or area of at least a part of the surface area.

6. The method of claim 1, comprising determining a direction from the IR thermal camera to the surface area and/or the imaged scene.

7. The method of claim 6,

wherein the direction information is determined using a compass device, the method comprising:

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

determining additional information relating to characteristics of any image points having an abnormal temperature, based, at least in part, on the determined direction and/or the registered distance information, wherein the adjusting the color of the at least one image point depends, at least in part, on any determined additional information; and

compensating for the determined direction when calculating the T_ISO.

8. The method of claim 1, comprising:

registering the air humidity level; and

compensating for the registered air humidity level when registering the T_A, registering the T_B, calculating the T_ISO, adjusting the color of the at least one image point, and/or displaying the colored version of the thermal image.

9. The method of claim 1, comprising:

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

determining additional information relating to characteristics of any image points having an abnormal temperature; and

compensating for the registered distance and any determined additional information when adjusting the color of the at least one image point and/or displaying the colored version of the thermal image.

10. An infrared (IR) thermal camera comprising:

a lens configured to focus incoming IR radiation from an object for the IR camera to capture a thermal image corresponding to the incoming IR radiation;

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

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 the thermal image via a display;

wherein the color adjusting unit is configured to compare a surface area temperature in at least one image point of the thermal image to the T_ISO and adjust the color in the at least one image point in dependence of the comparison to create a colored version of the thermal image.

11. The IR thermal camera of claim 10, comprising a distance measuring device configured to register the distance between the IR thermal camera and the object as the IR thermal camera captures the thermal image, wherein:

the object represents a portion of a structure;

the T_A corresponds to an outside temperature of the structure;

the T_B corresponds to an inside temperature of the structure;

the processor is configured to receive the registered distance information and determine additional information relating to the characteristics of any defects or abnormalities present on a surface area of the object and/or structure, dependent on the registered distance information; and

the color adjusting unit is configured to adjust the color in the at least one image point in dependence of any determined additional information.

12. The IR thermal camera of claim 10, wherein the processor is configured to:

retrieve a field of view (FOV) of the IR thermal camera;

calculate to scale information related to the thermal image, based on the retrieved FOV and the registered distance information; and

superimpose the calculated to scale information onto the colored version of the thermal image.

13. The IR thermal camera of claim 12, wherein the calculated to scale information is related to the length, size, and/or area of at least a part of the surface area.

14. The IR thermal camera of claim 12, comprising a storage unit configured to store the calculated to scale information in connection with the thermal image.

15. The IR thermal camera of claim 10, comprising a direction determination unit configured to determine the direction from the IR thermal camera to the surface area, the object, and/or a corresponding imaged scene.

16. The IR thermal camera of claim 15, wherein:

the direction determination unit comprises a compass device; and

the processor is configured to compensate for the determined direction when calculating the T_ISO and/or determining any additional information.

17. The IR thermal camera of claim 10, wherein the processor is configured to calculate thermal transmission coefficients of the object based, at least in part, on the T_A and the T_B.

18. The IR thermal camera of claim 10, comprising a humidity input device for receiving at least one atmospheric humidity value, wherein the processor is configured to compensate for the atmospheric humidity value when calculating the T_ISO.

19. The IR thermal camera of claim 10, comprising a distance measuring device configured to register the distance between the IR thermal camera and the object as the IR thermal camera captures the thermal image, wherein the processor is configured to compensate for the registered distance information when calculating the T_ISO.

20. An infrared (IR) thermal camera comprising:

a focusing means for focusing incoming IR radiation from an object, representing a portion of a structure, for the IR camera to generate a thermal image signal corresponding to the incoming IR radiation;

a signal conditioning unit for receiving the thermal image signal and conditioning the thermal image signal; and

a color adjusting means for receiving the conditioned thermal image signal and for displaying a colored thermal image via a display in dependence of temperature values registered via a temperature input means and a temperature calculation means, wherein;

the calculation means is configured to calculate, on the basis of at least a first registered air temperature value (T_A), a second registered air temperature value (T_B), and a temperature color alarm level (T_CAL), a threshold temperature level value (T_ISO); and

the color adjusting means is configured to compare a surface area temperature in at least one image point of the thermal image to the T_ISO and adjust the color in the at least one image point in dependence of the comparison to create the colored thermal image.