US4383734A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Real-time optical correlation system
Assignee: Thales SA
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Filing: 1980-11-04
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Granted: 1983-05-17
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Expires: 2000-11-04
Abstract
Abstract A correlation system providing the correlation function of two objects illuminated with coherent light by using the principle of double diffraction. The correlation system of the invention is essentially characterized in that it uses as recording medium a plate of recyclable material, i.e. inscribable and erasable at will, such as bismuth-silicon oxide. The recording provided in the plate by superimposition of the beams illuminating the objects is read by a beam undergoing angular sweeping so as to optimize the diffraction efficiency for all the correlation peaks in the observation plane.
Inventors
- 👤 Jean-Pierre Huignard
- 👤 Jean-Pierre Herriau
- 👤 Laurence Pichon
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 04:46
CPC Classifications
G; G06; G06E; G06E3/00; G06E3/001; G06E3/005
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
186 words
An optical correlation system for obtaining the correlation function of a first object by a second one, comprising means for illuminating the objects by means respectively of two coherent beams, first focusing means projecting in a first focal plane (PF) an illumination having an intensity substantially proportional to the algebraic sum of the Fourier transforms of the light amplitudes transmitted by the two objects respectively, a photosensitive support medium situated in the first focal plane (PF), recording this illumination in real time and formed from a continuously recyclable material in which the recording forms a three-dimensional grating of fringes, other means for illuminating the photosensitive support medium, second focusing means projecting in a second focal plane (P) an illumination having an intensity substantially proportional to the Fourier transform of the recorded illumination, and means for detecting correlation peaks situated in a zone of the second focal plane (P) and characterizing the correlation function, wherein said other means for illuminating said photosensitive support medium comprise angular sweep means ensuring optimum diffraction efficiency successively for the different points of the observed zone of said second focal plane (P).
Claim 2
Dependent Claim
186 words
An optical correlation system for obtaining the correlation function of a first object by a second one, comprising means for illuminating the objects by means respectively of two coherent beams, first focusing means projecting in a first focal plane (PF) an illumination having an intensity substantially proportional to the algebraic sum of the Fourier transforms of the light amplitudes transmitted by the two objects respectively, a photosensitive support medium situated in the first focal plane (PF), recording this illumination in real time and formed from a continuously recyclable material in which the recording forms a three-dimensional grating of fringes, other means for illuminating the photosensitive support medium, second focusing means projecting in a second focal plane (P) an illumination having an intensity substantially proportional to the Fourier transform of the recorded illumination, and means for detecting correlation peaks situated in a zone of the second focal plane (P) and characterizing the correlation function, wherein said other means for illuminating said photosensitive support medium comprise angular sweep means ensuring optimum diffraction efficiency successively for the different points of the observed zone of said second focal plane (P).
Claim 3
Dependent Claim
50 words
The optical correlation system as claimed in claim 1, wherein said means for illuminating the objects comprise a laser and optical means providing two beams parallel to the axis of the lenses on each side of this axis, said objects being respectively centered on the axes of said two beams.
Claim 4
Dependent Claim
94 words
The optical correlation system as claimed in claim 1, wherein said means for lighting the objects comprise a laser and means for separating the laser beam and thus providing two collimated beams whose axes form therebetween a predetermined angle and intersect adjacent the center of said photosensitive support medium, said first focusing means being formed by two spherical lenses whose axes coincide respectively with the axes of the two beams and whose focal points coincide with the meeting point of these axes, said objects being respectively centered on the axes of said two beams.
Claim 5
Dependent Claim
22 words
The optical correlation system as claimed in claim 1, wherein said other means for illuminating the photosensitive support medium comprise a laser.
Claim 6
Dependent Claim
21 words
The optical correlation system as claimed in claim 1, wherein said photosensitive support medium is a bismuth-silicon oxide monocrystalline photosensitive device.
Claim 7
Dependent Claim
21 words
The optical correlation system as claimed in claim 1, wherein said photosensitive support medium is a bismuth-germanium oxide monocrystalline photosensitive device.
Claim 8
Dependent Claim
27 words
The optical correlation system as claimed in claim 1, wherein said photosensitive support medium is polarized by an electric field obtained by means of a voltage source.
Claim 9
Dependent Claim
64 words
The optical correlation system as claimed in claim 1, wherein there are further provided third means for illuminating said photosensitive support medium for creating in this photosensitive support medium a constant modulation level superimposed on the three-dimensional fringe grating which corresponds to the recording of the illumination representative of the algebraic sum of the Fourier transforms of the light amplitudes transmitted by both objects.
References Cited (Backward Citations)
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Cited
US3544197A
Cited
US3761154A
Cited
US3812496A
Cited
FR2362466A1
Cited
US4138189A
Cited
US4174179A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-05-16 | 1986-11-15 | 1987-05-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-05-16 | 1990-11-15 | 1991-05-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-05-16 | 1994-11-15 | 1995-05-17 | $7700.00 | Window Closed / Lapsed |