US3754814A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Coherent imaging with reduced speckle
Assignee: Battelle Development Corp
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Filing: 1971-01-19
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Granted: 1973-08-28
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Expires: 1991-01-19
Abstract
Abstract An improved technique for imaging a multiplicity of planes of non-diffuse objects, including non-diffuse transparencies, with coherent illumination which utilizes a diffusion structure having a periodic phase thereacross.
Inventors
- 👤 E Leith
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 00:31
CPC Classifications
G; G03; G03H; G03H1/00; G03H1/32
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
122 words
A method for illuminating a non-diffuse object with coherent light, comprising the steps of: directing a beam of coherent light toward the non-diffuse object, positioning a light diffuser in the path of said coherent light beam, said diffuser characterized by a continuous smoothly varying periodic relative phase function and substantially uniform intensity transmittance thereacross, thereby alone forming several planes of substantially uniform intensity thereover across the diffused beam at various intervals along its length, said substantially uniform intensity planes occurring only where the diffuser self-images, and positioning the object in the path of the diffused beam a distance from the diffuser with at least one plane of the object coinciding with a self-imaging plane of the diffused beam having substantially uniform intensity.
Claim 2
Independent Claim
122 words
A method for illuminating a non-diffuse object with coherent light, comprising the steps of: directing a beam of coherent light toward the non-diffuse object, positioning a light diffuser in the path of said coherent light beam, said diffuser characterized by a continuous smoothly varying periodic relative phase function and substantially uniform intensity transmittance thereacross, thereby alone forming several planes of substantially uniform intensity thereover across the diffused beam at various intervals along its length, said substantially uniform intensity planes occurring only where the diffuser self-images, and positioning the object in the path of the diffused beam a distance from the diffuser with at least one plane of the object coinciding with a self-imaging plane of the diffused beam having substantially uniform intensity.
Claim 3
Independent Claim
110 words
A method of illuminating a non-diffuse object and forming an image thereof, comprising the steps of: directing coherent light in an illuminating beam toward said object, diffusing said illuminating beam prior to striking the object to illuminate some portions of the object with light of substantially equal intensity, and other portions with light of different intensity forming a first image of the illuminated object, sampling portions of said first image corresponding to portions of the object illuminated with light of substantially equal intensity, and forming a second image of said object only from the sampled portions of said first image, thereby to discard information of the object between sampled areas.
Claim 4
Independent Claim
110 words
A method of illuminating a non-diffuse object and forming an image thereof, comprising the steps of: directing coherent light in an illuminating beam toward said object, diffusing said illuminating beam prior to striking the object to illuminate some portions of the object with light of substantially equal intensity, and other portions with light of different intensity forming a first image of the illuminated object, sampling portions of said first image corresponding to portions of the object illuminated with light of substantially equal intensity, and forming a second image of said object only from the sampled portions of said first image, thereby to discard information of the object between sampled areas.
Claim 5
Dependent Claim
38 words
The method according to claim 2 wHerein the step of diffusing the coherent beam includes passing said beam through a diffusing structure which is characterized by substantially uniform intensity transmittance and by a periodically varying phase function thereacross.
Claim 6
Dependent Claim
59 words
The method according to claim 3 wherein the step of sampling portions of the first image includes the step of placing a mask over said first image of the object to block all but the sampled portions, and wherein the step of forming a second image includes spatially filtering the mask from the sampled first image of the object.
Claim 7
Independent Claim
143 words
A method of illuminating a non-diffuse object and forming an image thereof, comprising the steps of: directing coherent light in an illuminating beam toward said object, diffusing said illuminating beam across a diffusing surface prior to striking the object by altering the relative phase across said beam according to a periodically varying relative phase function across said surface, whereby at least one plane along the diffused beam has substantially equal light intensity areas distributed periodically thereacross and other areas of different light intensity, positioning said object in the path of the diffused beam so that at least one plane of said object is coincident with said at least one plane of said diffused beam, and forming a sampled image only from portions of the object''s said at least one plane that are illuminated by said substantially equal light intensity areas of said beam.
Claim 8
Independent Claim
143 words
A method of illuminating a non-diffuse object and forming an image thereof, comprising the steps of: directing coherent light in an illuminating beam toward said object, diffusing said illuminating beam across a diffusing surface prior to striking the object by altering the relative phase across said beam according to a periodically varying relative phase function across said surface, whereby at least one plane along the diffused beam has substantially equal light intensity areas distributed periodically thereacross and other areas of different light intensity, positioning said object in the path of the diffused beam so that at least one plane of said object is coincident with said at least one plane of said diffused beam, and forming a sampled image only from portions of the object''s said at least one plane that are illuminated by said substantially equal light intensity areas of said beam.
Claim 9
Dependent Claim
69 words
The method according to claim 5 wherein the step of diffusing said beam includes adjusting the relative phase function period across the diffusing surface so that said substantially equal light intensity areas occur periodically across said at least one plane of the diffused beam with a period substantially equal to or less than an object element size which is desired to be resolved in the image of the object.
Claim 10
Dependent Claim
74 words
The method according to claim 5 wherein the step of forming a sampled image includes the steps of placing a mask over a first image of the object to block all but areas thereof corresponding to portions of the object that are illuminated by said substantially equal light intensity areas of said beam, and spatially filtering the mask from the masked first image of the object, thereby forming said sampled image of the object.
Claim 11
Independent Claim
109 words
A system for illuminating a non-diffuse object with coherent light, comprising, a source of a coherent light beam, a diffuser located in the path of said light beam, said diffuser characterized by a continuous smoothly varying periodic relative phase function thereacross and a substantially uniform light transmittance thereover, thereby producing a diffused light beam with a plurality of planes therealong of substantially uniform intensity across the beam, said substantially uniform intensity planes ocurring only where said diffuser self-images, and a non-diffuse object positioned in the path of said diffused light beam coincident with at least one of said plurality of substantially uniform intensity planes a distance from the diffuser.
Claim 12
Independent Claim
109 words
A system for illuminating a non-diffuse object with coherent light, comprising, a source of a coherent light beam, a diffuser located in the path of said light beam, said diffuser characterized by a continuous smoothly varying periodic relative phase function thereacross and a substantially uniform light transmittance thereover, thereby producing a diffused light beam with a plurality of planes therealong of substantially uniform intensity across the beam, said substantially uniform intensity planes ocurring only where said diffuser self-images, and a non-diffuse object positioned in the path of said diffused light beam coincident with at least one of said plurality of substantially uniform intensity planes a distance from the diffuser.
Claim 13
Dependent Claim
40 words
The improved system according to claim 8 wherein the period of said phase varying structure is small enough so the self-imaging planes repeat within a distance equal to the smallest object element size desired to be resolved in an image.
Claim 14
Dependent Claim
52 words
The improved system according to claim 8 wherein the period of said phase varying structure is small enough so that points of substantially equal intensity repeat across planes intermediate of self-imaging planes with a period equal to or less than the smallest object element size desired to be resolved in an image.
Claim 15
Independent Claim
136 words
A system for viewing a non-diffuse object with coherent light, comprising: a source of a coherent light beam, a diffuser positioned in the path of said coherent light beam, said diffuser characterized by a periodic relative phase varying function thereacross, thereby generating a diffused coherent light beam characterized bY a plurality of diffuser self-imaging planes recurring periodically along the duffused beam with planes intermediate of said self-imaging planes having repetitive points thereacross of substantially equal intensity and other points of different intensity, a non-diffuse object positioned in the path of said diffused coherent light beam for illumination thereby, and means for sampling the illuminated object at points thereacross corresponding to said points of substantially equal intensity that recur across intermediate planes of said diffused light beam for forming an object image from the sampled object points.
Claim 16
Independent Claim
136 words
A system for viewing a non-diffuse object with coherent light, comprising: a source of a coherent light beam, a diffuser positioned in the path of said coherent light beam, said diffuser characterized by a periodic relative phase varying function thereacross, thereby generating a diffused coherent light beam characterized bY a plurality of diffuser self-imaging planes recurring periodically along the duffused beam with planes intermediate of said self-imaging planes having repetitive points thereacross of substantially equal intensity and other points of different intensity, a non-diffuse object positioned in the path of said diffused coherent light beam for illumination thereby, and means for sampling the illuminated object at points thereacross corresponding to said points of substantially equal intensity that recur across intermediate planes of said diffused light beam for forming an object image from the sampled object points.
Claim 17
Dependent Claim
21 words
A coherent viewing system according to claim 11 wherein said means for sampling includes a mask of periodically varying light transmission.
Claim 18
Dependent Claim
29 words
A coherent viewing system according to claim 12 wherein said means for sampling additionally includes appropriate low pass spatial filtering apparatus for removing said mask from said object image.
Claim 19
Dependent Claim
20 words
A coherent viewing system according to claim 11 wherein said diffuser is additionally characterized by substantially uniform light transmittance thereover.
Claim 20
Dependent Claim
40 words
A coherent viewing system according to claim 14 wherein the periodic relative phase varying function of said diffuser consists of at least three distinct levels of relative phase change in each period across the diffuser in at least one direction.
Claim 21
Independent Claim
91 words
A method of illuminating a non-diffuse object and forming an image thereof, comprising the steps of: generating a coherent light beam with at least one plane therealong having distributed thereacross predetermined areas of substantially equal light intensity and other areas of different light intensity, positioning a non-diffuse object in the path of said beam coincident with said at least one plane, and forming a sampled image only from portions of said object coincident with said at least one light beam plane that are illuminated by said substantially equal light intensity areas.
Claim 22
Independent Claim
91 words
A method of illuminating a non-diffuse object and forming an image thereof, comprising the steps of: generating a coherent light beam with at least one plane therealong having distributed thereacross predetermined areas of substantially equal light intensity and other areas of different light intensity, positioning a non-diffuse object in the path of said beam coincident with said at least one plane, and forming a sampled image only from portions of said object coincident with said at least one light beam plane that are illuminated by said substantially equal light intensity areas.
Claim 23
Dependent Claim
64 words
The method according to claim 16 wherein the step of generating a coherent light beam includes passing a light beam from a coherent light source through a diffuser having in at least one direction across the beam a plurality of distinct relative phase values joined together thereacross in the nature of a step function as opposed to a continuous smoothly varying relative phase function.
Claim 24
Dependent Claim
26 words
The method according to claim 17 wherein said diffuser includes at least three distinct relative phase values across the beam in said at least one direction.
Claim 25
Dependent Claim
36 words
The method according to claim 17 wherein said diffuser includes at least three distinct relative phase values which form a period of phase variation that is repeated across the diffuser in said at least one direction.
Claim 26
Independent Claim
139 words
A method of illuminating and imaging a non-diffuse object with coherent light, comprising the steps of: directing a beam of coherent light toward the non-diffuse object, positioning a light diffuser in the path of said coherent light beam, said diffuser characterized by a continuous smoothly varying periodic relative phase function and substantially uniform intensity transmittance thereacross, thereby generating a diffused coherent light beam characterized by a plurality of diffuser self-imaging planes recurring periodically along the diffused beam and having substantially uniform intensity thereacross only at said self-imaging planes, positioning the non-diffuse object in the path of the diffused beam a distance from the diffuser coincident with a self-imaging plane of the diffused beam that has substantially uniform intensity thereacross, and imaging the illuminated object with an optical system that captures substantially all spatial frequencies developed by said light diffuser.
Claim 27
Independent Claim
139 words
A method of illuminating and imaging a non-diffuse object with coherent light, comprising the steps of: directing a beam of coherent light toward the non-diffuse object, positioning a light diffuser in the path of said coherent light beam, said diffuser characterized by a continuous smoothly varying periodic relative phase function and substantially uniform intensity transmittance thereacross, thereby generating a diffused coherent light beam characterized by a plurality of diffuser self-imaging planes recurring periodically along the diffused beam and having substantially uniform intensity thereacross only at said self-imaging planes, positioning the non-diffuse object in the path of the diffused beam a distance from the diffuser coincident with a self-imaging plane of the diffused beam that has substantially uniform intensity thereacross, and imaging the illuminated object with an optical system that captures substantially all spatial frequencies developed by said light diffuser.
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) | 1976-08-27 | 1977-02-26 | 1977-08-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-08-27 | 1981-02-26 | 1981-08-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-08-27 | 1985-02-26 | 1985-08-28 | $7700.00 | Window Closed / Lapsed |