Compact PMMW camera calibration target

• US 9,641,772 B2
• Filed: 11/19/2014
• Issued: 05/02/2017
• Est. Priority Date: 11/19/2014
• Status: Active Grant

• Current Assignee: Northrop Grumman Systems Corporation (Northrop Grumman Corporation)
• Original Assignee: Northrop Grumman Systems Corporation (Northrop Grumman Corporation)
• Inventors: Yujiri, Mikio Larry
• Primary Examiner(s): GUNBERG, EDWIN C
• Application Number:
  US14/547,738
• Publication Number:
  US 20160142652A1
• Time in Patent Office: 895 Days
• CPC Class Codes: G01J 2005/0077 Imaging
• CPC Class Codes: G01J 2005/526 Periodic insertion of emissive surface
• CPC Class Codes: G01J 5/061 by controlling the temperature of the apparatus or parts thereof, e.g. using cooling means or thermostats
• CPC Class Codes: G01J 5/0803 Arrangements for time-dependent attenuation of radiation signals
• CPC Class Codes: G01J 5/53 Reference sources, e.g. standard lamps; Black bodies
• CPC Class Codes: G01J 5/532 using a reference heater of the emissive surface type, e.g. for selectively absorbing materials
• CPC Class Codes: G01J 5/80 Calibration using comparison with reference sources G01J5/52
• CPC Class Codes: H04N 17/002 for television cameras
• CPC Class Codes: H04N 23/23 from thermal infrared radiation
• 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 calibration system for a passive millimeter-wave (PMMW) camera. The calibration system includes a thermal calibrator having a first thermally conducting body, a second thermally conducting body, a first black body target mounted to a front surface of the first conducting body, a second black body target mounted to a front surface of the second conducting body, and a thermo-electric (TE) cooling device having a hot side and a cold side. The hot side of the TE cooling device is thermally attached to the first conducting body and the cold side of the TE cooling device is thermally attached to the second conducting body.

Claims

1. A calibration system for a camera, said calibration system comprising a thermal calibrator including a first thermally conducting body, a second thermally conducting body, a first black body target mounted to a back surface of the first conducting body, a second black body target mounted to a back surface of the second conducting body, and a thermo-electric (TE) cooling device having a hot side and a cold side that are on opposite sides of the device from each other, wherein the hot side of the TE cooling device is thermally attached to the first conducting body and the cold side of the TE cooling device is thermally attached to the second conducting body.

2. The calibration system according to claim 1 further comprising a first track and a second track, said thermal calibrator further including a first track guide mounted to one end of the calibrator and a second track guide mounted to an opposite end of the calibrator so as to allow the calibrator to be slidably positionable along the tracks.

3. The calibration system according to claim 1 wherein the first thermally conducting block is thermally attached to the TE cooling device by a thermal adhesive layer and the second thermally conducting block is thermally attached to the TE cooling device by a thermal adhesive layer.

4. The calibration system according to claim 1 wherein the first and second conducting blocks are rectangular shaped blocks.

5. The calibration system according to claim 1 wherein the first and second conducting blocks are right-angled wedge shaped conducting blocks.

6. The calibration system according to claim 1 wherein the first conducting block is an L-shaped block and the second conducting block is a conducting plate.

7. The calibration system according to claim 1 further comprising a radiator mounted to a back surface of the first conducting block opposite to the first black body target so as to dissipate heat.

8. The calibration system according to claim 1 wherein the camera is a passive millimeter-wave camera.

9. The calibration system according to claim 8 wherein the camera includes a focal plane array having a plurality of receivers, said calibrator being positioned in order to move across the front of the focal plane array.

10. The calibration system according to claim 9 wherein a front face of the calibrator is less than the size of a front face of the focal plane array.

11. The calibration system according to claim 9 wherein the front face of the calibrator is one-half the size of the front face of the focal plane array.

12. A passive millimeter-wave (PMMW) camera comprising:

a focal plane array (FPA) including a plurality of receivers each including a feed horn;

a thermal calibrator including a first thermally conducting body, a second thermally conducting body, a first black body target mounted to a front surface of the first conducting body, a second black body target mounted to a front surface of the second conducting body, and a thermo-electric (TE) cooling device having a hot side and a cold side that are on opposite sides of the device from each other, wherein the hot side of the TE cooling device is thermally attached to the first conducting body and the cold side of the TE cooling device is thermally attached to the second conducting body; and

a track positioned proximate to the FPA, said thermal calibrator being mounted to the track so as to be slidably positionable thereon, said track allowing the calibrator to be selectively moved in front of the FPA.

13. The camera according to claim 12 wherein a front face of the calibrator is equal to or less than the size of a front face of the focal plane array.

14. The camera according to claim 13 wherein the front face of the calibrator is one-half the size of the front face of the focal plane array.

15. The camera according to claim 12 wherein the first thermally conducting block is thermally attached to the TE cooling device by a thermal adhesive layer and the second thermally conducting block is thermally attached to the TE cooling device by a thermal adhesive layer.

16. The camera according to claim 12 wherein the first and second conducting blocks are rectangular shaped blocks.

17. The camera according to claim 12 wherein the first and second conducting blocks are right-angle wedge shaped conducting blocks.

18. The camera according to claim 12 wherein the first conducting block is an L-shaped block and the second conducting block is a conducting plate.

19. The camera according to claim 12 further comprising a radiator mounted to a back surface of the first conducting block opposite to the first black body target so as to dissipate heat.

20. A calibration system for a camera, said calibration system comprising a thermal calibrator including a first thermally conducting body, a second thermally conducting body, and a thermo-electric (TE) cooling device having a hot side and a cold side that are on opposite sides of the device from each other, wherein the hot side of the TE cooling device is thermally attached to the first conducting body and the cold side of the TE cooling device is thermally attached to the second conducting body.