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

• US 20080265162A1
• Filed: 10/16/2006
• Published: 10/30/2008
• 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: Ahlstrom, Mats, Hamrelius, Torbjorn
• Granted Patent: US 8,289,372 B2
• Time in Patent Office: Days
• US Class Current: 250/330
• 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

Abstract

The invention is achieved by using a method for displaying a thermal image in an infrared (IR) thermal camera, comprising the steps of 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 thermal image.

The invention allows you to determine immediately, on-site, if a building is well insulated or not. It presents an easily interpreted and understandable thermal image which instantly draws a users attention to an identified critical area.

Claims

1. A method for displaying a thermal image (10) in an infrared (IR) thermal camera (1), comprising the steps of:

registering an outdoor temperature value (T_A);

registering an indoor temperature value (T_B);

calculating an isotherm level (T_ISO) by using the registered temperature values (T_A, T_B) and a temperature color alarm level (T_CAL);

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 (10) to the isotherm level (T_ISO);

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 (T_ISO); and

displaying the colored thermal image (10).

2. A method according to claim 1, wherein said temperature color alarm level (T_CAL) is registered in said IR camera manually.

3. A method according to claim 1, comprising the step of calculating thermal transmission coefficients of an object (8) in said thermal image (10) using said registered temperature values (T_A, T_B).

4. A method according to claim 1, comprising the step of registering the air humidity level when registering a temperature measurement (T_A, T_B) and compensating for the registered air humidity level when displaying said thermal image (10).

5. A method according to claim 1, comprising the step of registering the distance between a captured object (8) and said IR camera (1) as said IR camera (1) captures a thermal image (10) and compensating for the registered distance when displaying said thermal image (10).

6. A infrared (IR) thermal camera (1) comprising focusing means (5) for focusing incoming IR radiation from an object (8) in the IR camera to generate an image signal corresponding to the incoming IR radiation, to be passed to a signal conditioning unit (9) for signal conditioning, the conditioned image signal output being passed to a color adjusting means (17) which in dependence of temperature values registered via temperature input means (11) and temperature calculation means (15), is arranged to display a thermal image (10) via a display (19);

wherein

said calculating means (15) is arranged to calculate, on the basis of at least two registered temperature values (T_A, T_B) and a temperature color alarm level (T_CAL), an isotherm level (T_ISO),

said color adjusting means (17) is arranged to compare the surface area temperature in at least one image point of a thermal image (10) to the isotherm level (T_ISO), and adjust the color in at least one image point of a thermal image (10) in dependence of the relation between the surface area temperature in said at least one image point and the isotherm level (T_ISO).

7. An infrared (IR) thermal camera according to claim 7, comprising receiving means for receiving a temperature color alarm level (T_CAL) manually.

8. An infrared (IR) thermal camera according to claim 7, wherein said calculating means is arranged to calculate, on the basis of said registered temperature values (T_A, T_B), thermal transmission coefficients of an object (8) in said thermal image (10).

9. An infrared (IR) thermal camera according claim 7, comprising humidity input means (13) for receiving at least one atmospheric humidity value and said calculating means being arranged to compensate for said atmospheric humidity value when determining said isotherm level (T_ISO).

10. An infrared (IR) thermal camera according to claim 7, further comprising distance input means (27) for receiving an object distance value and said calculating means being arranged to compensate for said object distance value when determining said isotherm level (T_ISO).