Patent US3633987A successfully refreshed from Google Patents.
US3633987A
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Method of and apparatus for holographically contour mapping of distant objects
Assignee: Northrop Grumman Space and Mission Systems Corp
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Filing: 1970-06-01
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Granted: 1972-01-11
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Expires: 1990-06-01
Abstract
Abstract A hologram is generated from which an image may be reconstructed of a distant object. This image has a brightness which is modulated so that areas or fringes of maximum or minimum brightness represent contours of equal range. This contour pattern is obtained when the beam of light used to record the hologram has a coherence function which is periodic with differences in path length. This periodic coherence function in turn is obtained by periodically modulating a coherent beam of radiant energy. The modulation may be either amplitude or phase modulations, the latter including frequency modulation, or a combination thereof. Since the optical path difference depends directly on the range to different points on the object, the resulting contour pattern directly reflects these differences in length. The hologram may be made by using brief pulses of the light beam, the light being pulsed by pulsing the laser, the hologram, or else the object or the reference beams.
Inventors
- 👤 Robert E Brooks
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 16:49
CPC Classifications
G; G01; G01B; G01B9/00; G01B9/02; G01B9/021
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
110 words
The method of generating a contour map of an object on a hologram, said method comprising the steps of: a. generating a coherent beam of radiant energy; b. splitting said coherent beam into a reference beam and a scene beam; c. reflecting said scene beam from an object, the contours of which are to be mapped; d. recombining said reflected scene beam and said reference beam for recording a hologram in a predetermined plane; and e. periodically modulating said coherent beam, whereby the hologram is formed from which an image may be reconstructed with contour lines indicative of variations in distance of the object with respect to the scene beam.
Claim 2
Independent Claim
110 words
The method of generating a contour map of an object on a hologram, said method comprising the steps of: a. generating a coherent beam of radiant energy; b. splitting said coherent beam into a reference beam and a scene beam; c. reflecting said scene beam from an object, the contours of which are to be mapped; d. recombining said reflected scene beam and said reference beam for recording a hologram in a predetermined plane; and e. periodically modulating said coherent beam, whereby the hologram is formed from which an image may be reconstructed with contour lines indicative of variations in distance of the object with respect to the scene beam.
Claim 3
Dependent Claim
28 words
The method as defined in claim 1 wherein the phase of said coherent beam is periodically modulated to generate contour lines on the reconstructed image of the hologram.
Claim 4
Dependent Claim
33 words
The method as defined in claim 1 wherein the amplitude of said coherent beam is periodically modulated to generate frequency sidebands causing contour lines to appear on the reconstructed image of The hologram.
Claim 5
Independent Claim
99 words
The method of generating a contour map of an object on a hologram comprising the steps of; a. generating a coherent light beam; b. periodically modulating the frequency of said light beam; c. splitting said modulated light beam into a reference beam and scene beam; d. reflecting said scene beam for an object to be mapped; e. recombining said reference beam and said reflected scene beam in a predetermined plane for recording a hologram to provide contour lines on the reconstructed image of the hologram indicative of variations in distance of the object with respect to said scene beam.
Claim 6
Independent Claim
99 words
The method of generating a contour map of an object on a hologram comprising the steps of; a. generating a coherent light beam; b. periodically modulating the frequency of said light beam; c. splitting said modulated light beam into a reference beam and scene beam; d. reflecting said scene beam for an object to be mapped; e. recombining said reference beam and said reflected scene beam in a predetermined plane for recording a hologram to provide contour lines on the reconstructed image of the hologram indicative of variations in distance of the object with respect to said scene beam.
Claim 7
Dependent Claim
13 words
The method as defined in claim 4 wherein said scene beam is pulsed.
Claim 8
Dependent Claim
18 words
The method as defined in claim 4 wherein both said scene beam and said reference beam are pulsed.
Claim 9
Dependent Claim
39 words
The method as defined in claim 4 wherein said reference beam is additionally reflected so that its length approximately equals that of said scene beam at said predetermined plane to insure coherence of said reference and said scene beams.
Claim 10
Dependent Claim
120 words
Holographic apparatus for providing a hologram of an object which may be reconstructed to show a two-dimensional contour map of the object, said apparatus comprising: a. means for generating a coherent beam of radiant energy; b. means for periodically modulating said coherent beam to cause a periodical variation of the phase thereof; c. means for splitting said modulated beam into a scene beam and a reference beam, said scene beam being reflected by an object to be mapped; d. means for directing and for recombining said scene beam and said reference beam in a predetermined plane; and e. a radiation-sensitive recording material disposed in said plane for generating a hologram from which an image with contour lines may be reconstructed.
Claim 11
Dependent Claim
120 words
Holographic apparatus for providing a hologram of an object which may be reconstructed to show a two-dimensional contour map of the object, said apparatus comprising: a. means for generating a coherent beam of radiant energy; b. means for periodically modulating said coherent beam to cause a periodical variation of the phase thereof; c. means for splitting said modulated beam into a scene beam and a reference beam, said scene beam being reflected by an object to be mapped; d. means for directing and for recombining said scene beam and said reference beam in a predetermined plane; and e. a radiation-sensitive recording material disposed in said plane for generating a hologram from which an image with contour lines may be reconstructed.
Claim 12
Dependent Claim
18 words
Apparatus as defined in claim 8 wherein said means for modulating said coherent beam modulates the phase thereof.
Claim 13
Dependent Claim
18 words
Apparatus as defined in claim 8 wherein said means for modulating said coherent beam modulates the amplitude thereof.
Claim 14
Dependent Claim
153 words
Apparatus for creating a hologram of an object, said hologram bearing an image having a two-dimensional contour map of said object, said apparatus comprising: a. a laser for generating a coherent light beam; b. an electro-optic modulator disposed in the path of said light beam for periodically modulating the phase of said light beam; c. means for splitting said modulated light beam into a reference beam and a scene beam; d. means for directing said scene beam onto an object and reflecting it therefrom; e. means for directing said reference beam to recombine it with said reflected subject beam in a predetermined plane; and f. a radiation-sensitive recording material disposed in said plane for recording a hologram, whereby the variation in phase of said reference and scene beams will create a hologram having a reconstructed image with contour lines corresponding to differences in the time of arrival between said reference and scene beams.
Claim 15
Dependent Claim
153 words
Apparatus for creating a hologram of an object, said hologram bearing an image having a two-dimensional contour map of said object, said apparatus comprising: a. a laser for generating a coherent light beam; b. an electro-optic modulator disposed in the path of said light beam for periodically modulating the phase of said light beam; c. means for splitting said modulated light beam into a reference beam and a scene beam; d. means for directing said scene beam onto an object and reflecting it therefrom; e. means for directing said reference beam to recombine it with said reflected subject beam in a predetermined plane; and f. a radiation-sensitive recording material disposed in said plane for recording a hologram, whereby the variation in phase of said reference and scene beams will create a hologram having a reconstructed image with contour lines corresponding to differences in the time of arrival between said reference and scene beams.
Claim 16
Dependent Claim
38 words
Apparatus as defined in claim 11 where means is provided for repeatedly reflecting said reference beam so that its path length substantially equals that of said scene beam at said plane to insure temporal coherence of said beams.
Claim 17
Dependent Claim
19 words
Apparatus as defined in claim 11 wherein means is provided for pulsing one of said reference and scene beams.
Claim 18
Dependent Claim
14 words
Apparatus as defined in claim 11 where means is provided for pulsing said laser.
Claim 19
Dependent Claim
23 words
Apparatus as defined in claim 11 wherein said laser includes an optical cavity, and wherein said electro-optical modulator is disposed in said cavity.
Claim 20
Dependent Claim
39 words
Apparatus as defined in claim 11 wherein a laser amplifier is disposed solely in the path of said scene beam before it is reflected from the object, and means associated with said laser amplifier for pulsing said laser amplifier.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-01-10 | 1975-07-12 | 1976-01-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-01-10 | 1979-07-12 | 1980-01-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-01-10 | 1983-07-12 | 1984-01-11 | $7700.00 | Window Closed / Lapsed |