US3859460A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Passive image stabilization system
Assignee: Baird Atomic Inc
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Filing: 1972-11-27
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Granted: 1975-01-07
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Expires: 1992-11-27
Abstract
Abstract An image tracking sensor system mounted to an inertial platform generates an analog image displacement signal for passive image stabilization of a scene image viewed from the platform. A radiometric signal having a frequency proportional to the relative motion between the scene image and a reticle is generated by the convolution of the image with the reticle. This signal is detected and electronically processed in a DC squareroot amplifier, a threshold decision logic and an analog to digital converter which generates a digital signal related to image velocity. The digital signal is measured by a digital differential analyzer doppler frequency comparator which generates digital signals defining image velocities relative to boresight. These digital velocities are integrated and displacements accumulated in a digital up-down counter tracking register. The accumulated displacements represent changes of image position relative to boresight. The accumulated digital displacements are read out of the tracking register by means of a digital to analog converter. An analog image displacement signal generated by the digital to analog converter is applied to the inertial platform for gyro-torquing stabilization control thereof.
Inventors
- 👤 William E Westell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 00:29
CPC Classifications
G; G01; G01S; G01S3/00; G01S3/78; G01S3/782; G01S3/785; G01S3/786
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
111 words
An image stabilization system comprising: a. sensor means for imaging a field of view at a focal surface and for providing an optical image signal functionally related to motion of the representation of said field of view in said focal surface; and b. sensor electronic means operatively connected to said sensor means for generating stabilization signals related to said sensOr means signal, said sensor electronic means including threshold decision logic means having an established threshold level, said threshold decision logic means operating to control said stabilization signals, said stabilization signals generated by said sensor electronic means when said threshold level is exceeded before each zero crossing of said optical image signal.
Claim 2
Dependent Claim
111 words
An image stabilization system comprising: a. sensor means for imaging a field of view at a focal surface and for providing an optical image signal functionally related to motion of the representation of said field of view in said focal surface; and b. sensor electronic means operatively connected to said sensor means for generating stabilization signals related to said sensOr means signal, said sensor electronic means including threshold decision logic means having an established threshold level, said threshold decision logic means operating to control said stabilization signals, said stabilization signals generated by said sensor electronic means when said threshold level is exceeded before each zero crossing of said optical image signal.
Claim 3
Dependent Claim
38 words
The image stabilization system as claimed in claim 1 wherein said sensor electronic means includes DC root amplifier means for receiving said optical image signal, said DC square root amplifier means operating as a photon-noise automatic gain control.
Claim 4
Dependent Claim
93 words
The image stabilization system as claimed in claim 2 wherein said sensor electronic means includes doppler comparator means and tracking register means, said doppler comparator means operatively connected to said DC square root amplifier means and said threshold decision logic means, said tracking register means operatively connected to said doppler comparator means, said doppler comparator means generating a difference signal related to motion of the representation of said field of view, said difference signal applied to said tracking register when said threshold is exceeded before each zero crossing of said optical image signal.
Claim 5
Dependent Claim
17 words
The image stabilization system as claimed in claim 3 wherein said sensor means includes rotating reticle means.
Claim 6
Dependent Claim
27 words
The image stabilization system as claimed in claim 4 including clock means for generating clock pulses for synchronizaing said rotating reticle means and said sensor electronic means.
Claim 7
Dependent Claim
62 words
The image stabilization system as claimed in claim 3 wherein said sensor electronic means includes: a. threshold crossing analog to digital converter means operatively connected between said DC square root amplifier means and said threshold decision logic means; and b. zero crossing analog to digital converter means operatively connected between said DC square root amplifier means and said threshold decision logic means.
Claim 8
Dependent Claim
99 words
The image stabilization system as claimed in claim 6 wherein said sensor electronic means includes: a. clock means for generating synchronization pulses; b. reference counter means operatively connected to said clock means; and c. register digital to analog converter means operatively connected to said tracking register means; d. said clock means operatively connected to said doppler comparator means and tracking register means; e. said tracking register means read out through said register digital to analog converter means; f. said register digital to analog converter means generating stabilization signals defining position change of the representation of said field of view.
Claim 9
Dependent Claim
55 words
The image stabilization system as claimed in claim 7 wherein said sensor means includes reticle means and means for rotating said reticle means and said sensor electronic means includes phase lock servo means for controlling said means for rotating, said reference counter means generating a reference signal which is applied to said phase-lock servo means.
Claim 10
Dependent Claim
17 words
The image stabilization system as claimed in claim 3 wherein said sensor means includes fixed reticle means.
Claim 11
Dependent Claim
124 words
The image stabilization system as claimed in claim 9 wherein said sensor electronic means includes: a. clock means for generating synchronization pulses, said clock means operatively connected to said tracking register means; b. counter means operatively connected to said clock means; c. register digital to analog converter means operatively connected to said tracking register means; and d. voltage controlled oscillator means operatively connected between said register digital to analog converter means and said doppler comparator means; e. said clock means operatively connected to said tracking register means; f. said tracking register means read out through said register digital to analog converter means; g. said register digital to analog converter means geneRating stabilization signals defining absolute rate of the representations of said field of view.
Claim 12
Dependent Claim
86 words
The image stabilization system as claimed in claim 1 wherein said sensor electronic means includes doppler comparator means and tracking register means, said doppler comparator means operatively connected to said threshold decision logic means, said tracking register means operatively connected to said doppler comparator means, said doppler comparator means generating a difference signal related to motion of the representation of said field of view, said difference signal applied to said tracking register when said threshold is exceeded before each zero crossing of said optical image signal.
Claim 13
Dependent Claim
17 words
The image stabilization system as claimed in claim 11 wherein said sensor means includes rotating reticle means.
Claim 14
Dependent Claim
27 words
The image stabilization system as claimed in claim 12 including clock means for generating clock pulses for synchronizaing said rotating reticle means and said sensor electronic means.
Claim 15
Dependent Claim
17 words
The image stabilization system as claimed in claim 11 wherein said sensor means includes apodization filter means.
Claim 16
Dependent Claim
90 words
The image stabilization system as claimed in claim 1 wherein said sensor electronic means includes doppler comparator means operatively connected to said threshold decision logic means, said doppler comparator means generating a doppler signal representing the period difference of a stationary image within said field of view and the moving image within said field of view by measuring the frequency period difference between a reference frequency period corresponding to said stationary image and an image frequency period corresponding to said moving image, one measurement being completed in one image period.
Claim 17
Dependent Claim
39 words
The image stabilization system as claimed in claim 15 wherein said sensor electronic means includes DC square root amplifier means for receiving said optical image signal, said DC square root amplifier means operating as a photon-noise automatic gain control.
Claim 18
Dependent Claim
30 words
The image stabilization system as claimed in claim 15 wherein said doppler comparator means includes counter means for digital comparison of said image frequency periods and said reference frequency periods.
Claim 19
Dependent Claim
30 words
The image stabilization system as claimed in claim 17 wherein said doppler comparator includes analog integration means for analog comparison of said image frequency periods and said reference frequency periods.
Claim 20
Dependent Claim
82 words
A radiation sensing system comprising: a. sensor means for sensing radiation and for providing a signal related to said sensed radiation; b. sensor electronic means communicating with said sensor means for providing stabilization signals related to said sensor means signal; and c. incremental gain variation means communicating with said sensor means and said sensor electronic means, the incremental gain of said incremental gain variation means varying inversely as the square root of said sensor means signal for photon-limited signal detection and estimation.
Claim 21
Dependent Claim
82 words
A radiation sensing system comprising: a. sensor means for sensing radiation and for providing a signal related to said sensed radiation; b. sensor electronic means communicating with said sensor means for providing stabilization signals related to said sensor means signal; and c. incremental gain variation means communicating with said sensor means and said sensor electronic means, the incremental gain of said incremental gain variation means varying inversely as the square root of said sensor means signal for photon-limited signal detection and estimation.
Claim 22
Dependent Claim
22 words
The radiometric sensing system as claimed in claim 19 wherein said incremental gain variation means is electronic DC square root amplifier means.
Claim 23
Dependent Claim
57 words
A radiation sensing system comprising: a. sensor means for sensing radiation and for providing a signal related to said sensed radiation; b. incremental gain variation means communicating with said sensor means, the incremental gain of said incremental gain variation means varying inversely as the square root of said sensor means signal for photon-limited signal detection and estimation.
Claim 24
Dependent Claim
57 words
A radiation sensing system comprising: a. sensor means for sensing radiation and for providing a signal related to said sensed radiation; b. incremental gain variation means communicating with said sensor means, the incremental gain of said incremental gain variation means varying inversely as the square root of said sensor means signal for photon-limited signal detection and estimation.
Claim 25
Dependent Claim
22 words
The radiation sensing system as claimed in claim 21 wherein said incremental gain variation means is electronic DC square root amplifier means.
References Cited (Backward Citations)
US3371161A
Cited
US3518372A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-01-06 | 1978-07-08 | 1979-01-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-01-06 | 1982-07-08 | 1983-01-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-01-06 | 1986-07-08 | 1987-01-07 | $7700.00 | Window Closed / Lapsed |