US3677651A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Focus and magnification adjustment of a high-performance camera
Assignee: AT&T Inc
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Filing: 1970-09-29
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Granted: 1972-07-18
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Expires: 1990-09-29
Abstract
Abstract A method and apparatus are disclosed for adjusting the location of the image and object planes of a camera to minimize focus and magnification errors. A special test reticle is used comprised of at least one, and preferably nine, test patterns on one side of the reticle. Over each pattern a first prism is mounted to tilt the apparent plane of the test pattern as seen in the prism and a second prism is ordinarily mounted to the other side of the reticle to compensate for the refraction due to the first prism. In use, the test reticle is placed in the object plane of the camera and a test image plate is exposed and developed. The sharpest points in the image of each of the tilted test patterns as well as the spacing between certain fiducial marks are then measured. From this data are derived the corrections that should be made in the positions of the object and image planes. With six to eight iterations of this procedure, good adjustment of the camera is achieved.
Inventors
- 👤 Donald Richard Herriott
- 👤 Eric Gordon Rawson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 10:33
CPC Classifications
G; G03; G03F; G03F7/00; G03F7/70; G03F7/708; G03F7/70858; G03F7/70883; G03F7/70891; G01; G01B; G01B9/00; G02; G02B; G02B27/00; G02B27/40; G03B; G03B3/00; G03F7/70216; G03F7/70241; G03F7/70808; G03F7/70825; G03F9/00; G03F9/70; G03F9/7003; G03F9/7023; G03F9/7026
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
67 words
A test reticle for use in aligning an object plane and the corresponding conjugate image plane of a lens in order to minimize focus and magnification errors comprising: a transparent medium having a first and second surface; at least one test pattern and one fiducial mark disposed on the first surface; and a prism mounted on the first surface of the transparent medium over each test pattern.
Claim 2
Dependent Claim
67 words
A test reticle for use in aligning an object plane and the corresponding conjugate image plane of a lens in order to minimize focus and magnification errors comprising: a transparent medium having a first and second surface; at least one test pattern and one fiducial mark disposed on the first surface; and a prism mounted on the first surface of the transparent medium over each test pattern.
Claim 3
Dependent Claim
32 words
The test reticle of claim 1 wherein there are at least three noncollinear test patterns disposed on the first surface and at least three noncollinear fiducial marks disposed on the first surface.
Claim 4
Dependent Claim
25 words
The test reticle of claim 2 wherein there are nine test patterns and nine fiducial marks disposed on the first surface in a three-by-three matrix.
Claim 5
Dependent Claim
27 words
The test reticle of claim 1 further comprising a prism mounted on the second surface of the transparent medium behind each prism mounted on the first surface.
Claim 6
Dependent Claim
27 words
The test reticle of claim 1 wherein each prism mounted on the first surface of the transparent medium covers both a test pattern and a fiducial mark.
Claim 7
Independent Claim
203 words
A method of aligning for best focus and desired magnification an object plane and the corresponding conjugate image plane of a camera comprising the steps of: determining to a first approximation the location of the object plane and the corresponding conjugate image plane; positioning at the approximate location of the object plane both at least one substantially planar test pattern that, as seen from the lens of the camera, intersects the object plane at a non-zero angle and at least one fiducial mark; positioning at the approximate location of the conjugate image plane an image test surface; forming an image of the test pattern and fiducial mark on the image test surface; detecting and calculating focus and magnification errors of the camera from an image formed on the image test surface; deriving from the above calculated errors the location of the object plane and the location of the corresponding image plane; repositioning at the derived location of the object plane both at least one substantially planar test pattern that, as seen from the lens, intersects the derived object plane at a non-zero angle and at least one fiducial mark; and repositioning at the derived location of the image plane an image test surface.
Claim 8
Independent Claim
203 words
A method of aligning for best focus and desired magnification an object plane and the corresponding conjugate image plane of a camera comprising the steps of: determining to a first approximation the location of the object plane and the corresponding conjugate image plane; positioning at the approximate location of the object plane both at least one substantially planar test pattern that, as seen from the lens of the camera, intersects the object plane at a non-zero angle and at least one fiducial mark; positioning at the approximate location of the conjugate image plane an image test surface; forming an image of the test pattern and fiducial mark on the image test surface; detecting and calculating focus and magnification errors of the camera from an image formed on the image test surface; deriving from the above calculated errors the location of the object plane and the location of the corresponding image plane; repositioning at the derived location of the object plane both at least one substantially planar test pattern that, as seen from the lens, intersects the derived object plane at a non-zero angle and at least one fiducial mark; and repositioning at the derived location of the image plane an image test surface.
Claim 9
Dependent Claim
60 words
The method of claim 6 further comprising the step of: repeating the steps of claim 6 of forming, detecting, deriving, and repositioning in order to align the object plane And the corresponding conjugate image plane of the camera in order to correct for any errors due to inaccurate original repositioning at the derived locations of the object and image planes.
Claim 10
Dependent Claim
63 words
A test reticle for use in aligning an object plane and the corresponding conjugate image plane of a lens in order to minimize focus and magnification errors comprising: a transparent medium having a first and second surface; at least one test pattern disposed on the first surface; and a prism mounted on the first surface of the transparent medium over each test pattern.
Claim 11
Dependent Claim
63 words
A test reticle for use in aligning an object plane and the corresponding conjugate image plane of a lens in order to minimize focus and magnification errors comprising: a transparent medium having a first and second surface; at least one test pattern disposed on the first surface; and a prism mounted on the first surface of the transparent medium over each test pattern.
Claim 12
Independent Claim
121 words
A method for determining focus and magnification errors of a camera comprising the steps of: determining to a first approximation the location of the object plane and the corresponding conjugate image plane; positioning at the approximate location of the object plane both at least one substantially planar test pattern that, as seen from the lens of the camera, intersects the object plane at a non-zero angle and at least one fiducial mark; positioning at the approximate location of the conjugate image plane an image test surface; forming an image of the test pattern and fiducial mark on the image test surface; and detecting and calculating focus and magnification errors of the camera from an image formed on the image test surface.
Claim 13
Independent Claim
121 words
A method for determining focus and magnification errors of a camera comprising the steps of: determining to a first approximation the location of the object plane and the corresponding conjugate image plane; positioning at the approximate location of the object plane both at least one substantially planar test pattern that, as seen from the lens of the camera, intersects the object plane at a non-zero angle and at least one fiducial mark; positioning at the approximate location of the conjugate image plane an image test surface; forming an image of the test pattern and fiducial mark on the image test surface; and detecting and calculating focus and magnification errors of the camera from an image formed on the image test surface.
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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) | 1975-07-18 | 1976-01-17 | 1976-07-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-07-18 | 1980-01-17 | 1980-07-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-07-18 | 1984-01-17 | 1984-07-18 | $7700.00 | Window Closed / Lapsed |