US4765714A
Expired / Lapsed
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Binary phase-only optical correlation system
Assignee: United States Department of the Air Force
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Filing: 1986-02-27
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Granted: 1988-08-23
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Expires: 2006-02-27
Abstract
Abstract A binary phase-only optical correlation system incorporating therein a binary phase-only filter. The binary phase-only optical filter is made by mathematically generating preselected phase-only information by a fast Fourier Transform technique. This generated phase-only information is binarized into a function having two values. This binarized function is utilized to produce a mask which in turn is used in conjunction with an appropriate optical substrate to produce the binary phase-only filter. The manufacture of the binary phase-only filter is substantially easier than the production of a phase-only filter yet virtually the same correlation results when the binary phase-only filter when it is used in an optical correlation system.
Inventors
- 👤 Joseph L. Horner
- 👤 James R. Leger
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 06:27
CPC Classifications
G; G02; G02B; G02B27/00; G02B27/42; G02B27/46; G06; G06V; G06V10/00; G06V10/88; G06V10/89; G06V10/893; G06V10/895
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
185 words
A binary phase-only optical correlation system comprising: means for providing a beam of low power electromagnetic radiation at a preselected wavelength and directing said beam along a preselected optical axis; means in optical alignment with said beam for taking the Fourier Transform of a preselected first signal and forming said Fournier Transform at a first preselected position coincidental with said optical axis; a binary phase-only filter located at said first preselected position and in optical alignment with said preselected optical axis, said binary phase-only filter providing binarized phase-only information obtained from a second signal which is to be correlated with said first signal, and means in optical alignment with said binary phase-only filter for taking the Fourier Transform of the product of said first signal and said binarized phase-only information of said second signal forming said Fournier Transform at a second preselected position coincidental with said optical axis, said Fourier Transform being substantially equivalent to the mathematical correlation function between said first signal and said second signal; whereby said binary phase-only optical correlation system provides substantially 100 percent utilization of said electromagnetic beam of radiation.
Claim 2
Dependent Claim
185 words
A binary phase-only optical correlation system comprising: means for providing a beam of low power electromagnetic radiation at a preselected wavelength and directing said beam along a preselected optical axis; means in optical alignment with said beam for taking the Fourier Transform of a preselected first signal and forming said Fournier Transform at a first preselected position coincidental with said optical axis; a binary phase-only filter located at said first preselected position and in optical alignment with said preselected optical axis, said binary phase-only filter providing binarized phase-only information obtained from a second signal which is to be correlated with said first signal, and means in optical alignment with said binary phase-only filter for taking the Fourier Transform of the product of said first signal and said binarized phase-only information of said second signal forming said Fournier Transform at a second preselected position coincidental with said optical axis, said Fourier Transform being substantially equivalent to the mathematical correlation function between said first signal and said second signal; whereby said binary phase-only optical correlation system provides substantially 100 percent utilization of said electromagnetic beam of radiation.
Claim 3
Dependent Claim
49 words
A binary phase-only optical correlation system as defined in claim 1 wherein said binary phase-only filter is produced on an optical flat having a pattern thereon defined by indented portions having a preselected depth, said indented portions being representative of said binarized phase-only information obtained from said second signal.
Claim 4
Dependent Claim
63 words
A binary phase-only optical correlation system as defined in claim 2 wherein said binary phase-only filter is produced on said optical flat from a mask which is developed by transferring said binarized phase-only information obtained from said signal such that said indented portions are of preselected depth equal to λ/(2(n-1)) where λ=said preselected wavelength and n=the index of refraction of said optical flat.
Claim 5
Dependent Claim
22 words
A binary phase-only optical correlation system as defined in claim 3 wherein said low power of said laser is approximately 10 mW.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-08-23 | 1992-02-22 | 1992-08-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-08-23 | 1996-02-22 | 1996-08-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-08-23 | 2000-02-22 | 2000-08-23 | $7700.00 | Window Closed / Lapsed |