System and method for detecting thermographic anomalies

• US 8,498,836 B2
• Filed: 11/26/2008
• Issued: 07/30/2013
• Est. Priority Date: 11/26/2008
• Status: Active Grant

• Current Assignee: Fluke Corporation (Fortive Corp.)
• Original Assignee: Fluke Corporation (Fortive Corp.)
• Inventors: Carlson, Paul S.
• Primary Examiner(s): LE, TOAN M
• Application Number:
  US12/324,609
• Publication Number:
  US 20100131225A1
• Time in Patent Office: 1,707 Days
• Field of Search: 702/130, 702/34, 702/40, 702/81, 702/84, 702/127, 702/131, 702134-136, 702/179, 702182-183, 702188-189, 702/199, 374 21- 22, 374 29- 30, 374/100, 374/102, 374110-112, 374/137, 250/200, 250/330, 250/332, 250/334, 250552-553, 250/559.01, 25055904-55908, 250/559.1, 382/141, 382/152
• US Class Current: 702/130
• CPC Class Codes: G01J 2005/0077 Imaging
• CPC Class Codes: G01J 5/02 Constructional details
• CPC Class Codes: G01J 5/025 Interfacing a pyrometer to an external device or network; User interface
• CPC Class Codes: G01J 5/48 Thermography; Techniques using wholly visual means
• CPC Class Codes: G01J 5/80 Calibration using comparison with reference sources G01J5/52
• CPC Class Codes: G01M 99/002 Thermal testing flaw detection G01N25/72

Abstract

A thermographic analysis method and apparatus is provided. The method includes obtaining base-line and operational thermographic profiles of a subject area, calculating a difference profile from the base-line and operational thermographic profiles, and providing an indication from the difference profile. The indication may be also based on thermographic differences in portions of the subject area that are defined as thermographic zones.

Claims

1. A method for detecting thermographic anomalies, comprising:

using a sensor, obtaining a base-line profile of base-line thermographic data corresponding to a subject area, wherein the base-line profile is obtained as a reference for the subject area, and wherein the base-line profile comprises a first set of pixel values;

storing the base-line profile;

using the sensor, obtaining an operational profile of operational thermographic data corresponding to the subject area, wherein the operational profile comprises a second set of pixel values;

automatically aligning the base-line profile and the operational profile;

calculating a difference profile based, at least in part, on a difference between the second set of pixel values of the operational profile and a corresponding first set of pixel values of the stored base-line profile;

receiving a plurality of thermographic zones and at least one condition for each of the plurality of thermographic zones, wherein each thermographic zone defines a portion of the subject area; and

providing an indication based, at least in part, on the calculated difference profile for each of the plurality of thermographic zones, wherein the indication includes whether the at least one condition for each of the plurality of thermographic zones is met, and further wherein meeting the at least one condition for a given thermographic zone indicates a thermographic anomaly.

2. The method of claim 1, wherein the method is performed on a stand-alone thermographic system.

3. The method of claim 1, wherein calculating the difference profile includes:

for each pixel of the operational profile having a corresponding pixel of the stored base-line profile, calculating a difference between a value of the pixel of the operational profile and a value of the corresponding pixel of the stored base-line profile.

4. The method of claim 1, wherein each of the base-line thermographic data and the operational thermographic data includes at least a two-dimensional array of pixels, and wherein each of the pixels substantially corresponds to a temperature of a portion of the subject area.

5. The method of claim 1, wherein providing the indication is further based, in part, on at least one of a minimum, maximum, or average temperature of the subject area.

6. The method of claim 1, wherein the obtaining operational profile and calculating the difference profile are substantially real-time operations.

7. The method of claim 1, further comprising:

providing at least one of the base-line profile, the operational profile, or the difference profile to a host computer system.

8. The method of claim 1, wherein providing the indication is further based, in part, on at least one of a minimum, maximum, or average temperature of the defined portion of the subject area.

9. The method of claim 1, wherein obtaining the operational profile comprises:

compensating for movement in at least a portion of the subject area after the base-line profile is obtained.

10. The method of claim 1, wherein providing the indication is further based, in part, on time-invariant temperature changes of the plurality of thermographic zones.

11. The method of claim 1, further comprising automatically suggesting one or more thermographic zones based on the difference profile.

12. The method of claim 1, wherein not all of the conditions for the plurality of thermographic zones are the same.

13. An apparatus for detecting thermographic anomalies, comprising:

a thermographic sensor configured to capture at least a base-line profile of thermographic data corresponding to a subject area and an operational profile of operational thermographic data corresponding to the subject area, wherein the base-line profile is obtained as a reference for the subject area, and wherein the base-line profile comprises a first set of pixel values, and the operational profile comprises a second set of pixel values;

a storage circuit configured to store at least the base-line profile;

a comparison circuit configured to receive the base-line profile and the operational profile, and to provide a difference profile for a plurality of identified thermographic zones based, at least in part, on a difference between the first set of pixel values of the base-line profile and a corresponding second set of pixel values of the operational profile within the plurality of thermographic zones, and to determine whether a condition for each of the plurality of thermographic zones is met;

an output circuit configured to provide an indication based, at least in part, on the difference profile; and

an alarm circuit configured to provide an alarm signal when the difference profile in one or more of the plurality of thermographic zones meets the condition provided for that thermographic zone, wherein meeting the condition for a given thermographic zone indicates a thermographic anomaly, and wherein each thermographic zone spatially defines a portion of the subject area.

14. The apparatus of claim 13, wherein the apparatus is configured as a stand-alone, real-time thermographic system.

15. The apparatus of claim 13, wherein the thermographic sensor is an infrared sensor configured to capture a thermographic image, and wherein the thermographic sensor has at least a 120-degree field of view.

16. The apparatus of claim 13, further comprising:

a configuration interface configured to interface the apparatus to a host computer;

to receive a definition of the plurality of thermographic zones, and to provide at least one of the difference profile, the base-line profile, or the operational profile to the host computer, wherein the definition of each of the plurality of thermographic zones defines at least one portion of the subject area.

17. The apparatus of claim 13, wherein the comparison circuit is further configured to calculate a difference between a value of each pixel of the operational profile and a value of each corresponding pixel of the base-line profile, wherein the thermographic sensor is a two-dimensional image sensor configured to capture a two-dimensional array of pixels, and wherein each of the pixels substantially corresponds to a temperature of a portion of the subject area.

18. An apparatus detecting thermographic anomalies, comprising:

means for obtaining a base-line profile of base-line thermographic data corresponding to a subject area, wherein the base-line profile is obtained as a reference for the subject area, and wherein the base-line profile comprises a first set of pixel values;

means for storing the base-line profile;

means for obtaining an operational profile of operational thermographic data corresponding to the subject area, wherein the operational profile comprises a second set of pixel values;

means for calculating a difference profile based, at least in part, on a difference between the second set of pixel values of the operational profile and a corresponding first set of pixel values of the stored base-line profile;

means for receiving a plurality of thermographic zones and at least one condition for each of the plurality of thermographic zones, wherein each thermographic zone defines a portion of the subject area; and

means for providing an indication based, at least in part, on the calculated difference profile for each of the plurality of thermographic zone, wherein the indication indicates whether the at least one condition for each of the plurality of thermographic zones is met, and further wherein meeting the at least one condition for a given thermographic zone indicates a thermographic anomaly.

19. the apparatus of claim 18, further comprising:

means for compensating for movement in at least a portion of the subject area.

20. The apparatus of claim 18, wherein each of the base-line thermographic data and the operational thermographic data includes at least a two-dimensional array of pixels, and wherein each of the pixels substantially corresponds to a temperature of a portion of the subject area.