US6274869B1
Expired / Lapsed
US
⏱️ 0.0 years remaining
Digital offset corrector
Assignee: Lockheed Martin Tactical Systems Inc
•
Filing: 1996-06-28
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Granted: 2001-08-14
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Expires: 2016-06-28
Abstract
Abstract An offset corrector for a focal plane array. A bolometer array configured in a row and column readout format has dedicated column circuits to measure the resistance of each bolometer in the column. A high speed on-chip analog to digital converter converts the analog sensor signal to a digital representation. Since the response of each bolometer varies, an offset controller, connected to the output of the analog to digital converter, corrects the digital representation for variations in individual bolometer response. Each pixel has a corresponding dynamically computed offset stored in the memory. The offset is computed when a chopper or shutter blocks radiation from the focal plane array. The focal plane array is temperature stabilized to a predetermined temperature to keep bolometer response within a predetermined bandwidth.
Inventors
- 👤 Neal R. Butler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 09:53
CPC Classifications
H; H04; H04N; H04N25/00; H04N25/60; H04N25/67; H04N25/671; G; G01; G01J; G01J5/00; G01J5/02; G01J5/06; G01J5/061; G01J5/10; G01J5/20; G01J5/22; G01J5/80; H04N23/00; H04N23/20; H04N23/23; H04N25/20; H04N25/21; H04N25/673; H04N25/70; H04N25/76; H04N25/77
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
86 words
Apparatus comprising: at least one sensor to detect radiation and to output image signals based on the detected radiation; and offset correction circuitry to compensate errors in the image signals and to output corrected image signals, wherein the sensor and at least a portion of the offset correction circuitry are monolithically integrated on a single semiconductor substrate, and wherein the offset correction circuitry further includes means for providing a time-varying compensation signal for each at least one sensor to compensate the errors in the image signals.
Claim 2
Dependent Claim
86 words
Apparatus comprising: at least one sensor to detect radiation and to output image signals based on the detected radiation; and offset correction circuitry to compensate errors in the image signals and to output corrected image signals, wherein the sensor and at least a portion of the offset correction circuitry are monolithically integrated on a single semiconductor substrate, and wherein the offset correction circuitry further includes means for providing a time-varying compensation signal for each at least one sensor to compensate the errors in the image signals.
Claim 3
Dependent Claim
18 words
The apparatus of claim 1 , wherein the at least one sensor includes a plurality of microbolometer elements.
Claim 4
Independent Claim
24 words
The apparatus of claims 1 , further including an analog to digital converter to output digital image data based on the corrected image signals.
Claim 5
Dependent Claim
27 words
The apparatus of claim 1 , wherein the means for providing a time-varying compensation signal includes means for providing a different time-varying compensation signal for each sensor.
Claim 6
Dependent Claim
20 words
The apparatus of claim 1 , wherein the means for providing the time-varying compensation includes means for receiving digital data.
Claim 7
Dependent Claim
38 words
The apparatus of claim 1 , wherein the means for providing a time-varying compensation signal include a nonlinear compensating voltage supply to compensate changes in the image signals due to current-induced heating of the at least one sensor.
Claim 8
Dependent Claim
18 words
The apparatus of claim 1 , wherein the offset correction circuitry includes means for receiving digital offset data.
Claim 9
Dependent Claim
34 words
The apparatus of claim 7 , wherein: the at least one sensor includes a plurality of sensors; and the offset correction circuitry includes a digital to analog converter to compensate non-uniformities of the sensors.
Claim 10
Dependent Claim
30 words
The apparatus of claim 8 , wherein: the plurality of sensors includes a plurality of microbolometer elements; and the digital to analog converter compensates resistance non-uniformities of the microbolometer elements.
Claim 11
Dependent Claim
59 words
The apparatus of claim 8 , wherein the digital to analog converter includes: a plurality of compensating resistors connected in series; and a corresponding plurality of compensating resistor switches, each compensating resistor switch connected across a respective compensating resistor and responsive to the digital offset data, to selectively short the respective compensating resistor based on the digital offset data.
Claim 12
Dependent Claim
24 words
The apparatus of claim 8 , further including an analog to digital converter to output digital image data based on the corrected image signals.
Claim 13
Dependent Claim
20 words
The apparatus of claim 7 , wherein the means for receiving digital offset data includes a digital to analog converter.
Claim 14
Dependent Claim
127 words
Apparatus comprising: at least one sensor to detect radiation and to output image signals based on the detected radiation; and offset correction circuitry to compensate errors in the image signals and to output corrected image signals, wherein the sensor and at least a portion of the offset correction circuitry are monolithically integrated on a single semiconductor substrate, wherein the offset correction circuitry includes means for receiving digital offset data, wherein: the at least one sensor includes a plurality of sensors; and the offset correction circuitry includes a digital to analog converter to compensate non-uniformities of the sensors, and wherein the offset correction circuitry further includes a nonlinear compensating voltage supply to compensate changes in the image signals due to current-induced heating of the at least one sensor.
Claim 15
Dependent Claim
127 words
Apparatus comprising: at least one sensor to detect radiation and to output image signals based on the detected radiation; and offset correction circuitry to compensate errors in the image signals and to output corrected image signals, wherein the sensor and at least a portion of the offset correction circuitry are monolithically integrated on a single semiconductor substrate, wherein the offset correction circuitry includes means for receiving digital offset data, wherein: the at least one sensor includes a plurality of sensors; and the offset correction circuitry includes a digital to analog converter to compensate non-uniformities of the sensors, and wherein the offset correction circuitry further includes a nonlinear compensating voltage supply to compensate changes in the image signals due to current-induced heating of the at least one sensor.
Claim 16
Dependent Claim
29 words
The apparatus of claim 13 , wherein the offset correction circuitry further includes an analog to digital converter to output digital image data based on the corrected image signals.
Claim 17
Dependent Claim
146 words
Apparatus comprising: at least one sensor to detect radiation and to output image signals based on the detected radiation; and offset correction circuitry to compensate errors in the image signals and to output corrected image signals, wherein the sensor and at least a portion of the offset correction circuitry are monolithically integrated on a single semiconductor substrate, wherein the offset correction circuitry includes means for receiving digital offset data, wherein the means for receiving digital offset data includes a digital to analog converter, and wherein the offset correction circuitry further includes: an amplifier to receive the image signals and to output amplified image signals; and an offset capacitor, coupled to an output of the amplifier and responsive to an analog signal output from the digital to analog converter, to add an offset signal to the amplified image signals so as to provide the corrected image signals.
Claim 18
Dependent Claim
146 words
Apparatus comprising: at least one sensor to detect radiation and to output image signals based on the detected radiation; and offset correction circuitry to compensate errors in the image signals and to output corrected image signals, wherein the sensor and at least a portion of the offset correction circuitry are monolithically integrated on a single semiconductor substrate, wherein the offset correction circuitry includes means for receiving digital offset data, wherein the means for receiving digital offset data includes a digital to analog converter, and wherein the offset correction circuitry further includes: an amplifier to receive the image signals and to output amplified image signals; and an offset capacitor, coupled to an output of the amplifier and responsive to an analog signal output from the digital to analog converter, to add an offset signal to the amplified image signals so as to provide the corrected image signals.
Claim 19
Dependent Claim
26 words
The apparatus of claim 15 , wherein the offset signal is a time-varying compensation signal based on a charging and a discharging of the offset capacitor.
Claim 20
Dependent Claim
46 words
The apparatus of claim 15 , wherein the offset correction circuitry further includes: an integration capacitor to receive the corrected image signals and to provide integrated corrected image signals; and means for discharging the integration capacitor when the integrated corrected image signals exceed a predetermined threshold.
Claim 21
Dependent Claim
55 words
The apparatus of claim 17 , wherein the offset correction circuitry further includes: an overflow counter to output digital overflow data based on a number of times the means for discharging the integration capacitor discharges the integration capacitor; and an analog to digital converter to convert the integrated corrected image signals to digital image data.
Claim 22
Dependent Claim
35 words
The apparatus of claim 18 , wherein the offset correction circuitry further includes an output driver to concatenate the digital overflow data and the digital image data so as to provide a digital data output.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2004-08-13 | 2005-02-12 | 2005-08-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2008-08-13 | 2009-02-12 | 2009-08-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2012-08-13 | 2013-02-12 | 2013-08-14 | $7700.00 | Window Closed / Lapsed |