Patent US6307680B1 successfully refreshed from Google Patents.
US6307680B1
Expired / Lapsed
US
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Optical blurring filter which is resistant to digital image restoration
Assignee: Northrop Grumman Systems Corp
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Filing: 1999-10-13
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Granted: 2001-10-23
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Expires: 2019-10-13
Abstract
Abstract An optical filter for intentionally blurring camera images has a generally transparent material and a plurality of optical distortions formed in the transparent material. Placement of the transparent material longitudinally in the optical path of a camera in front of the aperture stop allows contouring the blur across the image plane. That contour is preferably random, so as to defeat digital methods for image restorations. Additionally, a linear gradient is utilized to even-out the ground resolution on oblique cameras or localized to even-out resolution on cameras that have areas of unwanted high resolution.
Inventors
- 👤 Walter Dennis Clark
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 17:58
CPC Classifications
G; G02; G02B; G02B27/00; G02B27/48
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
72 words
A method for forming a lenticular filter, the method comprising the steps of: a) depositing photoresist on a transparent material; b) exposing the photoresist to laser speckle to effect formation of a pattern of random blobs; c) developing the photoresist so as to form a three dimensional structure; and d) etching the transparent material to form a plurality of protrusions and depressions thereupon, the protrusions and depressions defining a plurality of lenslets.
Claim 2
Independent Claim
72 words
A method for forming a lenticular filter, the method comprising the steps of: a) depositing photoresist on a transparent material; b) exposing the photoresist to laser speckle to effect formation of a pattern of random blobs; c) developing the photoresist so as to form a three dimensional structure; and d) etching the transparent material to form a plurality of protrusions and depressions thereupon, the protrusions and depressions defining a plurality of lenslets.
Claim 3
Dependent Claim
28 words
The method as recited in claim 1 , wherein the step of depositing a photoresist on a transparent material comprises depositing a photoresist on a sheet of glass.
Claim 4
Dependent Claim
28 words
The method recited in claim 1 , wherein the step of exposing the photoresist to laser speckle comprises exposing the photoresist to laser speckle generated by a laser.
Claim 5
Dependent Claim
39 words
The method as recited in claim 1 , wherein the step of exposing the photoresist to laser speckle comprises exposing of the photoresist to laser speckle having an intensity distribution which is formed according to a negative exponential function.
Claim 6
Dependent Claim
66 words
The method as recited in claim 1 , wherein the step of exposing the photoresist to laser speckle comprises exposing the photoresist to laser speckle by transmitting the laser speckle to the photoresist via at least one optical fiber, the scale of the laser speckle being determined by the diameter of the optical fiber(s) and by the distance between the optical fiber(s) and the transparent material.
Claim 7
Dependent Claim
24 words
The method as recited in claim 1 , wherein step a) comprises depositing a plurality of generally concentric flat layers upon the transparent material.
Claim 8
Dependent Claim
23 words
The method as recited in claim 6 , wherein the concentric flat layers are formed by applying transparent layers to the transparent material.
Claim 9
Independent Claim
83 words
A method forming a lenticular filter, the method comprising the steps of: a) placing a mask having a plurality of apertures formed therein proximate the transparent material; and b) directing an ion beam toward the mask such that a portion of the ion beam is transmitted through the apertures and is incident upon the transparent material and such that the ion beam etches the transparent material so has to form generally elliptical recesses in the transparent material, the generally elliptical recesses defining lenslets.
Claim 10
Independent Claim
83 words
A method forming a lenticular filter, the method comprising the steps of: a) placing a mask having a plurality of apertures formed therein proximate the transparent material; and b) directing an ion beam toward the mask such that a portion of the ion beam is transmitted through the apertures and is incident upon the transparent material and such that the ion beam etches the transparent material so has to form generally elliptical recesses in the transparent material, the generally elliptical recesses defining lenslets.
Claim 11
Independent Claim
82 words
A method for forming a phase filter, the method comprising the steps of: a) providing a transparent material having a thickness; and b) changing the thickness of the transparent material to form a plurality of protrusions and depressions at selected locations with a movable mask thereof so as to provide a plurality of different random thicknesses of the transparent material; c) wherein the plurality of different random thicknesses of the transparent material effect random changes in longitudinal phase of light transmitted therethrough.
Claim 12
Independent Claim
82 words
A method for forming a phase filter, the method comprising the steps of: a) providing a transparent material having a thickness; and b) changing the thickness of the transparent material to form a plurality of protrusions and depressions at selected locations with a movable mask thereof so as to provide a plurality of different random thicknesses of the transparent material; c) wherein the plurality of different random thicknesses of the transparent material effect random changes in longitudinal phase of light transmitted therethrough.
Claim 13
Dependent Claim
23 words
The method as recited in claim 9 , wherein the step of changing the thickness of the transparent material comprises adding material thereto.
Claim 14
Dependent Claim
32 words
The method as recited in claim 9 , wherein the step of changing the thickness of the transparent material comprises adding material thereto via at least one of evaporative deposition, and sputtering.
Claim 15
Dependent Claim
23 words
The method as recited in claim 9 , wherein the step of changing the thickness of the transparent material comprises removing material therefrom.
Claim 16
Dependent Claim
23 words
The method as recited in claim 9 , wherein the step of changing the thickness of the transparent material comprises etching material therefrom.
Claim 17
Dependent Claim
24 words
The method as recited in claim 9 , wherein the step of changing the thickness of the transparent material comprises ion etching material therefrom.
Claim 18
Dependent Claim
24 words
The method as recited in claim 9 , wherein the step of changing the thickness of the transparent material comprises acid etching material therefrom.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2004-10-22 | 2005-04-23 | 2005-10-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2008-10-22 | 2009-04-23 | 2009-10-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2012-10-22 | 2013-04-23 | 2013-10-23 | $7700.00 | Window Closed / Lapsed |