US3572882A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Variable reference phase holocamera to compensate for object motion
Assignee: United States Department of the Air Force
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Filing: 1969-11-28
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Granted: 1971-03-30
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Expires: 1989-11-28
Abstract
Abstract A variable reference phased holographic system for recording holograms of objects having some movement with respect to the photographic plate which has the conventional signal beam and reference beam provided by a beam splitter having a phase shifter in the reference beam path to adjust the phase of the reference beam to correspond to phase shifts in the signal beam at the center of the hologram recording plate due to the movement of the object. The reference beam is brought to a focus and passed through an aperture between the phase shifter and hologram recording plate. The aperture is moved to adjust the reference beam for phase shifts in the signal beam at points not at the center of the hologram recording plate. In one embodiment the phase corrections are made by sensing means which sense movement of interference fringes at the center and one edge of the hologram recording plate with the output of the sensing means being applied to phase shifters in the reference beam.
Inventors
- 👤 Don B Neumann
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 12:20
CPC Classifications
G; G03; G03H; G03H1/00; G03H1/04; G03H1/10
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
395 words
In a holocamera system having a hologram photographic recording plate; a laser providing a beam of coherent light; means, in said beam for directing a first light beam toward an object moving with a velocity represented by a vector v for which a hologram is desired whereby light scattered by said object is directed toward said photographic plate and a second reference light beam directed toward said photographic plate; a first lens between said object and said photographic plate for collimating the light scattered by said object; wherein the phase of the light reaching the photographic plate from the moving object is changed due to the velocity of the object as given by the expression: where K is the propagation constant; v is the absolute speed of the object; gamma is the angle between the velocity vector v and the axis of said first beam; Beta is the angle between the velocity vector v and a line L from the center of the photographic plate; passing through the center of the lens; F is the focal length of said lens; x is the distance from the center of the photographic plate and an illumination point P on the plate; and apparatus for providing a compensating phase shift in at least one of said beams; the improvement comprising: a first phase shifting means in one of said beams, for compensating for the portion of the phase chanGe due to the velocity of the object given by the expression: and a second phase shifting means in the reference beam for compensating for the portion of the phase change due to the velocity of the object given by the expression: said second phase shifting means includes a mask having an aperture, a second lens for focusing the reference beam at the aperture and means for moving the second lens and aperture substantially perpendicular to the axis of the beam with a movement described by the following expression: where VR is the velocity of the second lens and aperture; r is the distance between the aperture and the center of the the photographic plate; x is the distance from the center of the photographic plate to an illumination point P on the plate; and theta is the angle between r and a line L from the center of the photographic plate passing through the center of the first lens.
Claim 2
Dependent Claim
395 words
In a holocamera system having a hologram photographic recording plate; a laser providing a beam of coherent light; means, in said beam for directing a first light beam toward an object moving with a velocity represented by a vector v for which a hologram is desired whereby light scattered by said object is directed toward said photographic plate and a second reference light beam directed toward said photographic plate; a first lens between said object and said photographic plate for collimating the light scattered by said object; wherein the phase of the light reaching the photographic plate from the moving object is changed due to the velocity of the object as given by the expression: where K is the propagation constant; v is the absolute speed of the object; gamma is the angle between the velocity vector v and the axis of said first beam; Beta is the angle between the velocity vector v and a line L from the center of the photographic plate; passing through the center of the lens; F is the focal length of said lens; x is the distance from the center of the photographic plate and an illumination point P on the plate; and apparatus for providing a compensating phase shift in at least one of said beams; the improvement comprising: a first phase shifting means in one of said beams, for compensating for the portion of the phase chanGe due to the velocity of the object given by the expression: and a second phase shifting means in the reference beam for compensating for the portion of the phase change due to the velocity of the object given by the expression: said second phase shifting means includes a mask having an aperture, a second lens for focusing the reference beam at the aperture and means for moving the second lens and aperture substantially perpendicular to the axis of the beam with a movement described by the following expression: where VR is the velocity of the second lens and aperture; r is the distance between the aperture and the center of the the photographic plate; x is the distance from the center of the photographic plate to an illumination point P on the plate; and theta is the angle between r and a line L from the center of the photographic plate passing through the center of the first lens.
Claim 3
Dependent Claim
54 words
The device as recited in claim 1 wherein said means for directing the first beam toward the object and the second reference beam toward the photographic plate is a beam splitter and wherein said first phase shifting means is located in said reference beam between the beam splitter and the second phase shifting means.
References Cited (Backward Citations)
US3494698A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-03-29 | 1974-09-28 | 1975-03-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-03-29 | 1978-09-28 | 1979-03-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-03-29 | 1982-09-28 | 1983-03-30 | $7700.00 | Window Closed / Lapsed |