Methods and apparatus for compensating a radiation sensor for temperature variations of the sensor

• US 20020074499A1
• Filed: 04/27/2001
• Published: 06/20/2002
• Est. Priority Date: 05/01/2000
• Status: Active Grant

• Current Assignee: BAE Systems Incorporated (BAE Systems Plc)
• Original Assignee: BAE Systems Incorporated (BAE Systems Plc)
• Inventors: Butler, Neal R.
• Granted Patent: US 6,730,909 B2
• Time in Patent Office: Days
• US Class Current: 250/338.1
• CPC Class Codes: G01J 5/10 using electric radiation detectors
• CPC Class Codes: G01J 5/16 Arrangements with respect to the cold junction; Compensating influence of ambient temperature or other variables
• CPC Class Codes: G01J 5/20 using resistors, thermistors or semiconductors sensitive to radiation, e.g. photoconductive devices
• CPC Class Codes: G01J 5/22 Electrical features thereof
• CPC Class Codes: H04N 23/23 from thermal infrared radiation
• CPC Class Codes: H04N 25/63 applied to dark current
• CPC Class Codes: H04N 25/671 for non-uniformity detection or correction
• CPC Class Codes: H04N 25/673 by using reference sources
• CPC Class Codes: H04N 25/76 Addressed sensors, e.g. MOS or CMOS sensors
• 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

Methods and apparatus for compensating a radiation sensor for temperature variations of the sensor. In one example, the radiation sensor is a thermal sensor having at least one property that varies as a function of temperature. The thermal sensor outputs signals based on thermal radiation of interest from a particular radiating body in its view. These signals may contain significant undesirable components due in part to changes in temperature of the sensor itself. Methods and apparatus of the invention compensate the sensor for temperature variations of the sensor that are not due to the radiation of interest, so as to significantly reduce undesirable components in the instantaneous signals output by the sensor. In one example, this is accomplished without thermally stabilizing the sensor itself (i.e., dynamic temperature compensation). In another example, the sensor is thermally stabilized selectively at various predetermined temperatures as a function of the ambient temperature in the proximity of the sensor.

Claims

1. A method of compensating a radiation sensor for changes in at least one operational characteristic of the sensor due to a temperature variation of the sensor, comprising an act of:

dynamically adjusting at least one of at least one operating parameter associated with the radiation sensor and at least one calibration parameter associated with the radiation sensor based on the temperature variation of the sensor.

2. The method of claim 1, wherein the at least one operational characteristic of the sensor that changes due to the temperature variation of the sensor includes a resistance of the sensor.

3. The method of claim 1, wherein the at least one operating parameter associated with the sensor includes at least one of a DC bias voltage applied to the sensor, a DC bias current applied to the sensor, and an AC bias waveform applied to the sensor.

4. The method of claim 1, wherein the sensor includes a plurality of radiation detectors, and wherein the at least one calibration parameter associated with the sensor includes at least one of an offset error value for each radiation detector and a gain value for each radiation detector.

5. The method of claim 4, wherein the at least one operational characteristic of the sensor that changes due to the temperature variation of the sensor includes at least one of an offset error variation and a gain variation.

6. An apparatus, comprising:

a controller to compensate a radiation sensor for changes in at least one operational characteristic of the sensor due to a temperature variation of the sensor, the controller dynamically adjusting at least one of at least one operating parameter associated with the radiation sensor and at least one calibration parameter associated with the radiation sensor based on the temperature variation of the sensor.

7. The apparatus of claim 6, wherein the at least one operational characteristic of the sensor that changes due to the temperature variation of the sensor includes a resistance of the sensor.

8. The apparatus of claim 6, wherein the at least one operating parameter includes at least one of a DC bias voltage applied to the sensor, a DC bias current applied to the sensor, and an AC bias waveform applied to the sensor.

9. The apparatus of claim 6, wherein the sensor includes a plurality of radiation detectors, and wherein the at least one calibration parameter associated with the sensor includes at least one of an offset error value for each radiation detector and a gain value for each radiation detector.

10. The apparatus of claim 9, wherein the at least one operational characteristic of the sensor that changes due to the temperature variation of the sensor includes at least one of an offset error variation and a gain variation.

11. A method of compensating a radiation sensor for changes in at least one operational characteristic of the sensor due to a temperature variation of the sensor, comprising:

dynamically adjusting at least one operating parameter associated with the radiation sensor or at least one calibration parameter associated with the radiation sensor based on the temperature variation of the sensor.

12. An apparatus, comprising:

a controller to compensate a radiation sensor for changes in at least one operational characteristic of the sensor due to a temperature variation of the sensor, the controller dynamically adjusting at least one operating parameter associated with the radiation sensor or at least one calibration parameter associated with the radiation sensor based on the temperature variation of the sensor.