IR camera and method for processing thermal image information

• US 9,807,318 B2
• Filed: 04/03/2013
• Issued: 10/31/2017
• Est. Priority Date: 10/04/2010
• Status: Active Grant

• Current Assignee: Flir Systems AB (Teledyne Technologies Incorporated)
• Original Assignee: Flir Systems AB (Teledyne Technologies Incorporated)
• Inventors: Ingerhed, Malin, Rohlin, Gran
• Primary Examiner(s): Chio, Tat
• Application Number:
  US13/856,408
• Publication Number:
  US 20130222604A1
• Time in Patent Office: 1,672 Days
• CPC Class Codes: H04N 19/132 Sampling, masking or truncation of coding units, e.g. adaptive resampling, frame skipping, frame interpolation or high-frequency transform coefficient masking
• CPC Class Codes: H04N 19/137 Motion inside a coding unit, e.g. average field, frame or block difference
• CPC Class Codes: H04N 19/152 by measuring the fullness of the transmission buffer
• CPC Class Codes: H04N 19/162 User input
• CPC Class Codes: H04N 19/18 the unit being a set of transform coefficients
• CPC Class Codes: H04N 19/507 using conditional replenishment
• CPC Class Codes: H04N 19/63 using sub-band based transform, e.g. wavelets
• 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 processing information from an IR detector of an IR camera, for an embodiment, comprises receiving a series of frames of data from said IR detector being operable to detect IR radiation from a scene, said frames of IR data representing detected IR radiation; performing a compression of said frames of IR data; wherein each data value together with calibration data uniquely represents measured IR radiation from the scene.

Claims

1. A method for processing information from an infrared (IR) detector of an IR camera, the method comprising:

receiving a series of frames of IR data values from said IR detector being operable to detect IR radiation from a scene, said frames of IR data representing detected IR radiation; and

performing a compression of said frames of IR data values;

wherein each received IR data value together with calibration data uniquely represents measured IR radiation from the scene, wherein calibration data comprises a unique mapping between the received IR data values and the corresponding measured IR radiation from the scene;

wherein the compression substantially maintains a radiometric mapping of the received IR data values after compression and decompression to an original appearance of the received frames; and

wherein the substantially maintained radiometric mapping maps every IR data value to only one temperature value but represents each temperature value by one IR data value or a plurality of adjacent IR data values.

2. The method of claim 1, further comprising storing said compressed IR frames of IR data values in a memory.

3. The method of claim 1, further comprising:

performing a decompression of said frames of IR data values, wherein each IR data value together with calibration data uniquely represents measured IR radiation from the scene.

4. The method of claim 3, further comprising:

transforming decompressed calibrated IR data values of said frames of IR data values to a color space to obtain a series of displayable IR images.

5. The method of claim 4, wherein the transformation to a color space is non-reversible.

6. The method of claim 3, further comprising performing data analysis or other operations on decompressed IR data values.

7. The method of claim 3, further comprising:

performing calibration on said series of IR data values frames in order to render said IR data values frames radiometric, thereby obtaining a series of calibrated frames of IR data values with a unique mapping between the IR data values and the corresponding measured IR radiation from the scene.

8. The method of claim 7, wherein said calibration is performed before compression or after decompression.

9. The method of claim 8, wherein if the calibration is performed before compression, the compression substantially maintains the radiometric mapping at least by controlling a compression ratio of each frame of the IR data values to fall within a predetermined interval while an average compression ratio over a predetermined number of frames corresponds to a compression ratio determined based on at least one system parameter.

10. The method of claim 3, wherein compression and/or decompression comprises applying video compression techniques on frames of IR data values.

11. The method of claim 1, further comprising:

a) receiving a series of frames of IR data values from an IR detector operable to detect IR radiation from a scene;

b) performing calibration operations on said series of IR data values frames in order to render said IR data values frames radiometric, thereby obtaining a series of calibrated frames of IR data values with the unique mapping between the IR data values and the corresponding measured IR radiation from the scene;

c) performing a compression of said calibrated IR data values frames to yield a series of compressed calibrated IR data values frames in such a way that a corresponding decompression of the compressed calibrated IR data values frames can be performed; and

d) performing decompression of said compressed calibrated IR data values frames arriving at a series of calibrated IR data values frames.

12. The method of claim 11, further comprising transforming the decompressed calibrated IR data values to a color space to obtain a series of displayable IR images.

13. The method of claim 1, further comprising:

e) receiving a series of frames of IR data values from an IR detector operable to detect IR radiation from a scene;

f) performing a compression of said calibrated IR data values frames to yield a series of compressed calibrated IR data values frames in such a way that a corresponding decompression of the compressed calibrated IR data values frames can be performed;

g) performing decompression of said compressed calibrated IR data values frames arriving at a series of calibrated IR data values frames with the substantially maintained radiometric mapping, such that the frames of decompressed calibrated IR data values have the unique mapping between the IR data values and the corresponding measured IR radiation from the scene; and

h) performing calibration operations on said series of IR data values frames in order to render said IR data values frames radiometric, thereby obtaining a series of calibrated frames of IR data values with the unique mapping between the IR data values and the corresponding measured IR radiation from the scene.

14. The method of claim 13, further comprising transforming the decompressed calibrated IR data values to a color space to obtain a series of displayable IR images.

27. A non-transitory computer-readable medium encoding a computer program which, when executed by a processor of an IR camera, causes the processor to perform the method of claim 1.

15. A method for processing information from an IR camera, the method comprising:

a) receiving a series of IR images in the form of data from an IR sensor;

b) performing calibration operations on said series of IR images in order to render said IR images radiometric;

c) performing a compression of said IR images to yield a series of compressed IR images in such a way that a corresponding decompression of the compressed IR images can be performed; and

d) after performing the steps a), b) and c) arriving at a series of radiometric IR images;

wherein the compression substantially maintains a radiometric mapping of the received IR data values after compression and decompression to an original appearance of the received series of IR images, and

wherein the substantially maintained radiometric mapping maps every IR data value to only one temperature value but represents each temperature value by one IR data value or a plurality of adjacent IR data values.

16. The method according to claim 15, wherein step b) is performed before step c).

17. The method according to claim 15, wherein step b) is performed after step c).

18. The method according to claim 15, wherein said compression further comprises:

e) analyzing a first image belonging to said series of IR images;

f) determining a combined compression ratio;

g) performing a first compression according to a first compression method on said first image to achieve an intermediate image with a first compression ratio dependent on information from step e);

h) determining a second compression ratio as a difference between said combined compression ratio and said first compression ratio; and

i) performing a second compression according to a second compression method with said second compression ratio on said intermediate image to achieve one of said compressed IR images.

19. The method of claim 18, wherein said system parameter is a transmission bandwidth.

20. The method of claim 18, wherein said system parameter is a property of a memory unit.

21. The method of claim 18, wherein said combined compression ratio is determined by a combined compression ratio of at least one other image belonging to the series.

22. The method of claim 18, wherein said combined compression ratio is a preset value.

23. The method of claim 18, wherein said first compression is a video compression.

24. The method of claim 18, wherein the method is performed by a processor in an IR camera.

25. The method of claim 18, wherein the method is performed by a processor in a processing unit receiving a series of frames of IR data representing detected IR radiation.

28. A non-transitory computer-readable medium encoding a computer program which, when executed by a processor of an IR camera, causes the processor to perform the method of claim 15.

26. An IR camera, comprising:

an IR detector operable to detect IR radiation from a scene; and

a processor operable to process information from the IR detector, said processor adapted to;

receive a series of frames of data from the IR detector, said frames of IR data representing detected IR radiation; and

perform a compression of said frames of IR data;

wherein each data value together with calibration data uniquely represents measured IR radiation from the scene;

wherein the compression substantially maintains a radiometric mapping of the received IR data values after compression and decompression to an original appearance of the received frames; and

wherein the substantially maintained radiometric mapping maps every IR data value to only one temperature value but represents each temperature value by one IR data value or a plurality of adjacent IR data values.