US5528035A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Digital signal processing system for removing DC bias in the output of pyroelectric and similar detectors
Assignee: Raytheon Co
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Filing: 1994-04-12
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Granted: 1996-06-18
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Expires: 2014-04-12
Abstract
Abstract A digital signal processing system (100) removes DC bias in the output of a pyroelectric detector and similar types of detectors by adding together a first output signal which is inverted and a second output signal which is not inverted. The system (100) also removes offsets in the detector signal introduced by electronic circuits (readouts, amplifiers, drivers, etc.) between the detector and the system (100).
Inventors
- 👤 David M. Masarik
- 👤 Frank N. Cheung
- 👤 Robert S. Hayes
- 👤 Robert W. Klatt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 05:13
CPC Classifications
H; H04; H04N; H04N5/00; H04N5/44; H04N5/52; G; G01; G01J; G01J5/00; G01J5/10; G01J5/20; H04N5/14; H04N5/20; H04N23/00; H04N23/20; H04N23/23; H04N23/80; H04N23/81; H04N25/00; H04N25/60; H04N25/67; H04N25/671; H04N5/30; H04N5/33
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
78 words
A digital signal processing system for removing DC bias in the output of a pyroelectric detector which provides a first output during a first time interval and a second output during a second time interval, the system comprising: first means for inverting the first output signal; second means for storing the inverted first output signal; and third means for adding the stored inverted first output signal to the second output signal to provide a bias corrected output signal.
Claim 2
Dependent Claim
78 words
A digital signal processing system for removing DC bias in the output of a pyroelectric detector which provides a first output during a first time interval and a second output during a second time interval, the system comprising: first means for inverting the first output signal; second means for storing the inverted first output signal; and third means for adding the stored inverted first output signal to the second output signal to provide a bias corrected output signal.
Claim 3
Dependent Claim
28 words
The invention of claim 1 including means for scaling the bias corrected output signal by one-half to provide a bias corrected output signal with a corrected signal amplitude.
Claim 4
Dependent Claim
24 words
The invention of claim 1 including means for providing a corrected signal for the output of each detector of an array of pyroelectric detectors.
Claim 5
Dependent Claim
27 words
The invention of claim 3 including means for providing a signal for correcting for a DC offset in the signals generated by each detector in the array.
Claim 6
Dependent Claim
29 words
The invention of claim 4 including means for storing each of the signals for correcting for a DC offset in the signals generated by each detector in the array.
Claim 7
Dependent Claim
26 words
The invention of claim 5 including means for subtracting the stored DC offset signal from an instantaneous signal generated by an associated detector in the array.
Claim 8
Dependent Claim
25 words
The invention of claim 3 including means for providing a signal for correcting for gain in the signals generated by each detector in the array.
Claim 9
Dependent Claim
15 words
The invention of claim 7 including means for storing each of the gain correction signals.
Claim 10
Dependent Claim
28 words
The invention of claim 8 including means for multiplying each of the stored gain correction signals by an instantaneous signal generated by an associated detector in the array.
Claim 11
Dependent Claim
16 words
The invention of claim 3 including means for providing automatic global gain control across the array.
Claim 12
Dependent Claim
15 words
The invention of claim 3 including means for providing automatic level control across the array.
Claim 13
Dependent Claim
135 words
A digital signal processing system for removing DC bias in the output of an array of pyroelectric detectors, each detector providing a first output during a first time interval and a second output during a second time interval, the system comprising: first means for inverting the first output signal; second means for storing the inverted first output signal; third means for adding the stored inverted first output signal to the second output signal to provide a bias corrected output signal; fourth means for correcting for DC offset in the signals generated by each detector in the array; fifth means for correcting for gain in the signals generated by each detector in the array; sixth means for providing automatic global gain control across the array; and seventh means for providing automatic level control across the array.
Claim 14
Dependent Claim
135 words
A digital signal processing system for removing DC bias in the output of an array of pyroelectric detectors, each detector providing a first output during a first time interval and a second output during a second time interval, the system comprising: first means for inverting the first output signal; second means for storing the inverted first output signal; third means for adding the stored inverted first output signal to the second output signal to provide a bias corrected output signal; fourth means for correcting for DC offset in the signals generated by each detector in the array; fifth means for correcting for gain in the signals generated by each detector in the array; sixth means for providing automatic global gain control across the array; and seventh means for providing automatic level control across the array.
Claim 15
Independent Claim
69 words
A method for removing DC bias in the output of a pyroelectric detector which provides a first output during a first time interval and a second output during a second time interval, the method including the steps of: inverting the first output signal; storing the inverted first output signal; and adding the stored inverted first output signal to the second output signal to provide a bias corrected output signal.
Claim 16
Independent Claim
69 words
A method for removing DC bias in the output of a pyroelectric detector which provides a first output during a first time interval and a second output during a second time interval, the method including the steps of: inverting the first output signal; storing the inverted first output signal; and adding the stored inverted first output signal to the second output signal to provide a bias corrected output signal.
Claim 17
Dependent Claim
143 words
A signal processing system for removing DC offset in the outputs of an array of detectors and for correcting for variations in sensitivity of each detector comprising: first means for digitizing the output of each detector and providing a digitized detector output signal; second means for processing said digitized detector output and computing a sensitivity correction factor for each detector in said array; third means for using said sensitivity correction factor to correct for sensitivity variations in the output of each detector in said array; fourth means for inverting a first output from each detector during a first time interval; fifth means for storing said inverted first output signal; and sixth means for summing said stored inverted first output signal with a second output signal from said detector during a second time interval to eliminate DC offset in said first and second signals.
Claim 18
Dependent Claim
143 words
A signal processing system for removing DC offset in the outputs of an array of detectors and for correcting for variations in sensitivity of each detector comprising: first means for digitizing the output of each detector and providing a digitized detector output signal; second means for processing said digitized detector output and computing a sensitivity correction factor for each detector in said array; third means for using said sensitivity correction factor to correct for sensitivity variations in the output of each detector in said array; fourth means for inverting a first output from each detector during a first time interval; fifth means for storing said inverted first output signal; and sixth means for summing said stored inverted first output signal with a second output signal from said detector during a second time interval to eliminate DC offset in said first and second signals.
Claim 19
Dependent Claim
61 words
Apparatus for removing DC bias from an infrared detector providing a first output representing a focused scene during a first time interval and a second output representing a defocused scene during a second time interval, said apparatus comprising: means for inverting one of the outputs; and means, responsive to the inverting means, for averaging the inverted output with the non-inverted output.
Claim 20
Dependent Claim
61 words
Apparatus for removing DC bias from an infrared detector providing a first output representing a focused scene during a first time interval and a second output representing a defocused scene during a second time interval, said apparatus comprising: means for inverting one of the outputs; and means, responsive to the inverting means, for averaging the inverted output with the non-inverted output.
Claim 21
Dependent Claim
34 words
The apparatus of claim 15, wherein said averaging means includes adding means for adding the inverted output to the non-inverted output; and dividing means for dividing in half an output from said adding means.
References Cited (Backward Citations)
US4705945A
Cited
US4795904A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-06-18 | 1999-12-18 | 2000-06-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-06-18 | 2003-12-18 | 2004-06-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-06-18 | 2007-12-18 | 2008-06-18 | $7700.00 | Window Closed / Lapsed |