Calibration systems and methods for infrared cameras

• US 8,049,163 B1
• Filed: 09/02/2008
• Issued: 11/01/2011
• Est. Priority Date: 09/02/2008
• Status: Expired due to Fees

• Current Assignee: Teledyne FLIR LLC (Teledyne Technologies Incorporated)
• Original Assignee: FLIR Systems, Inc. (Teledyne Technologies Incorporated)
• Inventors: Kent, Michael, Nalam, Neela, Martin, Tim, Hoelter, Ted, Ernst, Robert, Cutcliffe, Neil, Speake, George, Graff, John, Takagi, Ted, Boulanger, Pierre, Granneman, Russell, Goeden, Richard M., Lyon, Stephen, Nagahawatte, Nuwan, Kostrzewa, Joseph, Hughes, Gary B., Sharp, Barbara
• Primary Examiner(s): Porta; David
• Assistant Examiner(s): Vu; Mindy
• Application Number:
  US12/202,896
• Time in Patent Office: 1,155 Days
• Field of Search: 250/252.1, 250/495.1, 250/504.R
• US Class Current: 250/252.1
• CPC Class Codes: G01J 5/53 Reference sources, e.g. standard lamps; Black bodies
• CPC Class Codes: H04N 17/002 for television cameras
• CPC Class Codes: H04N 23/20 for generating image signals from infrared radiation only
• CPC Class Codes: H04N 25/673 by using reference sources
• 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

Systems and methods directed to calibration techniques for infrared cameras are disclosed. For example, a method of obtaining calibration information for an infrared device includes providing a calibration target adapted to provide a low-emissivity scene; performing a calibration operation on the infrared device to obtain the calibration information; and storing the calibration information.

Claims

1. A calibration target for calibrating an infrared device, the calibration target comprising:

a first surface adapted to provide a low-emissivity scene for the infrared device during calibration of the infrared device; and

wherein the calibration target is one of a plurality of calibration targets on a target pallet for calibrating a corresponding plurality of the infrared devices.

2. The calibration target of claim 1, wherein the first surface of the calibration target comprises a coating made of gold.

3. The calibration target of claim 1, wherein the calibration target provides a uniform flux scene during calibration of the infrared device.

4. The calibration target of claim 1, wherein the calibration target comprises an infrared mirror.

5. The calibration target of claim 1, wherein the infrared device is an infrared camera core without a lens.

6. The calibration target of claim 1, wherein the infrared device is an infrared detector vacuum package assembly.

7. A method of obtaining calibration information for an infrared device, the method comprising:

providing a calibration target adapted to provide a low-emissivity scene, wherein the calibration target is one of a number of calibration targets on a target pallet within an environmental chamber;

performing a calibration operation on the infrared device to obtain the calibration information, wherein the infrared device is one of a number of the infrared devices on a production pallet within the environmental chamber;

controlling a temperature of the infrared device during the calibration operation; and

storing the calibration information.

8. The method of claim 7, wherein the infrared device is a vacuum package assembly having an array of microbolometers, and wherein the vacuum package assembly is not within an infrared camera core.

9. The method of claim 7, wherein the calibration target provides a reflective surface made of gold.

10. The method of claim 7, wherein the infrared device is an infrared camera core without a lens.

11. The method of claim 10, further comprising:

coupling a lens to the infrared camera core;

performing a gain calibration operation to obtain gain calibration information for the infrared camera core with the lens; and

storing the gain calibration information with the calibration information.

12. The method of claim 11, further comprising performing an acceptance test procedure on the infrared camera core with the lens.

13. An infrared device system comprising the infrared device, which comprises the infrared camera core with the lens, and a memory within the infrared camera core and containing the associated calibration information, wherein the calibration information is produced according to the method of claim 12.

14. An infrared device system comprising the infrared device, which comprises the infrared camera core without a lens, and a memory within the infrared camera core and containing the associated calibration information, wherein the calibration information is produced according to the method of claim 10.

15. The method of claim 7, wherein the controlling a temperature of the infrared device comprises controlling a temperature of the infrared device over a number of temperature values during the calibration operation with a thermo-electric cooler.

16. The method of claim 15, wherein the infrared device is not within an infrared camera core and is without a lens, and wherein the calibration information comprises offset and bias values.

17. The method of claim 7, wherein the performing of the calibration operation further comprises:

driving image frame data received from the infrared devices within the environmental chamber to test electronics located outside of the environmental chamber; and

determining the calibration information based on the image frame data.

18. The method of claim 7, further comprising:

coupling the target pallet to the production pallet to align the calibration targets to the infrared devices; and

coupling the infrared devices to a test system located outside of the environmental chamber, wherein the test system determines the calibration information for the corresponding infrared devices based on image frame data received from the infrared devices.

19. An infrared device system comprising the infrared device, which comprises an infrared sensor vacuum package assembly not within an infrared camera core, and a memory containing the calibration information associated with the infrared sensor vacuum package assembly, wherein the calibration information is produced according to the method of claim 7.

20. A calibration test system comprising:

an environmental chamber;

a target array, within the environmental chamber, having a plurality of low-emissivity calibration targets;

a production rack, within the environmental chamber, adapted to hold a plurality of infrared devices adjacent to the target array; and

a computer system, outside of the environmental chamber, adapted to control the infrared devices and the environmental chamber to generate calibration information for the infrared devices.

21. The calibration test system of claim 20, wherein each of the low-emissivity calibration targets provides a reflective surface made of gold.

22. The calibration test system of claim 20, wherein each of the infrared devices comprises an infrared sensor vacuum package assembly.

23. The calibration test system of claim 20, wherein each of the infrared devices comprises an infrared camera core without a lens.

24. The calibration test system of claim 23, wherein the production rack is configured to couple to the target array, and wherein the computer system is configured to receive information from the infrared devices to generate the calibration information.

25. The calibration test system of claim 24, further comprising:

test electronics disposed outside of the environmental chamber and adapted to be in communication with the computer system; and

driver boards, within the environmental chamber, adapted to couple to the infrared devices and transfer the information between the test electronics and the infrared devices.

26. The calibration test system of claim 25, further comprising thermo-electric coolers adapted to couple to the infrared devices to actively control a temperature of the infrared devices, and wherein the computer system is adapted to receive the information from the test electronics to generate the calibration information and is further adapted to control a temperature within the environmental chamber and to control a temperature of the infrared devices via the thermo-electric coolers to perform a calibration temperature profile for the infrared devices.

27. The calibration test system of claim 26, wherein the information comprises infrared image data, and wherein the calibration information comprises offset and bias values.