US4653909A
Expired / Lapsed
US
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Sinusoidal determination of limiting optical resolution
Assignee: United States Department of the Air Force
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Filing: 1985-11-01
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Granted: 1987-03-31
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Expires: 2005-11-01
Abstract
Abstract An optical system limiting resolution determination arrangement employing sinusoidal intensity modulated bar pattern input stimuli including two sequences for determining the modulation transfer function (MTF) component of limiting resolution; one of these and the disclosed aerial image modulation (AIM) curve determination are based on sinusoidal intensity modulated bar patterns, while the other MTF determination uses a Heaviside edge function stimulus and a sinusoidally determined AIM curve. The disclosed limiting resolution is especially useful in the consideration of aerial image devices such as cameras.
Inventors
- 👤 Gilbert G. Kuperman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 14:50
CPC Classifications
G; G01; G01M; G01M11/00; G01M11/02; G01M11/0292
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
140 words
A method for determining limiting resolution of an optical device comprising the steps of: generating a modulation transfer function curve relating spatial frequency and modulation percentage for said optical device; forming a plurality of sinusoidal intensity modulated bar patterns of varied spatial frequency and intensity modulation percentage; recording said patterns of sinusoidal intensity modulated bars on photo-responsive media; determining from subjective observations of said media recorded patterns using said optical device, the pattern modulation percentage yielding a predetermined degree of visual resolution for each recorded spatial frequency pattern; establishing an image modulation curve function relating recorded bar pattern spatial frequency and determined modulation percentage values for said optical device; and identifying the limiting resolution determining common point intercept of said modulation transfer function curve and said image modulation curve function with respect to values of modulation percentage and spatial frequency.
Claim 2
Independent Claim
140 words
A method for determining limiting resolution of an optical device comprising the steps of: generating a modulation transfer function curve relating spatial frequency and modulation percentage for said optical device; forming a plurality of sinusoidal intensity modulated bar patterns of varied spatial frequency and intensity modulation percentage; recording said patterns of sinusoidal intensity modulated bars on photo-responsive media; determining from subjective observations of said media recorded patterns using said optical device, the pattern modulation percentage yielding a predetermined degree of visual resolution for each recorded spatial frequency pattern; establishing an image modulation curve function relating recorded bar pattern spatial frequency and determined modulation percentage values for said optical device; and identifying the limiting resolution determining common point intercept of said modulation transfer function curve and said image modulation curve function with respect to values of modulation percentage and spatial frequency.
Claim 3
Dependent Claim
41 words
The method of claim 1 wherein said modulation transfer function curve generation also includes using sinusoidal intensity modulated patterns; whereby both said modulation transfer curve function and said image modulation curve function are derived from compatible sinusoidal intensity modulated image patterns.
Claim 4
Dependent Claim
15 words
The method of claim 1 wherein said predetermined degree of visual resolution is fifty percent.
Claim 5
Dependent Claim
39 words
The method of claim 3 wherein said fifty-percent value is determined from the quotient of the difference between maximum and minimum optical transmittance values divided by the summation of maximum and minimum transmittance values in said spatial frequency pattern.
Claim 6
Dependent Claim
18 words
The method of claim 4 wherein said media recorded pattern includes three complete cycles of sinusoidal intensity variation.
Claim 7
Dependent Claim
19 words
The method of claim 1 wherein said recording of said patterns includes the use of an intensity modulated laser.
Claim 8
Dependent Claim
19 words
The method of claim 1 wherein said determining from subjective observations includes observations by a plurality of human observers.
Claim 9
Dependent Claim
24 words
The method of claim 1 wherein said modulation transfer function curve and said image modulation curve function are stored as arrays of mathematical values.
Claim 10
Dependent Claim
25 words
The method of claim 8 wherein said identifying of curve function common point intercept comprises a sequence of mathematical steps performed in a digital computer.
Claim 11
Dependent Claim
32 words
The method of claim 1 wherein said modulation transfer function curve and said image modulation curve function are plotted as graphical relationships and said identifying of the common point is accomplished graphically.
Claim 12
Dependent Claim
29 words
The method of claim 1 wherein said forming of sinusoidal intensity modulated bar patterns includes the use of digital values and manipulating of digital values in a digital computer.
Claim 13
Dependent Claim
25 words
The method of claim 1 wherein said step of generating a modulation transfer curve function includes exposing a Heaviside function edge through said optical device.
Claim 14
Independent Claim
97 words
A method for determining a threshold function for an optical device comprising the steps of: forming an image having a plurality of sinusoidal intensity modulated bar patterns of predetermined varied spatial frequency and intensity modulation percentage; recording said image of sinusoidal intensity modulated bar patterns on photo-responsive media; determining from trained subjective observations of said media recorded bar patterns, accomplished with said optical device, the pattern modulation percentage yielding predetermined degrees of visual resolution for each recorded spatial frequency pattern; and recording the determined modulation percentage values and related bar pattern spatial frequencies as said threshold function.
Claim 15
Independent Claim
97 words
A method for determining a threshold function for an optical device comprising the steps of: forming an image having a plurality of sinusoidal intensity modulated bar patterns of predetermined varied spatial frequency and intensity modulation percentage; recording said image of sinusoidal intensity modulated bar patterns on photo-responsive media; determining from trained subjective observations of said media recorded bar patterns, accomplished with said optical device, the pattern modulation percentage yielding predetermined degrees of visual resolution for each recorded spatial frequency pattern; and recording the determined modulation percentage values and related bar pattern spatial frequencies as said threshold function.
Claim 16
Dependent Claim
25 words
The method of claim 13 wherein said threshold function is an aerial image modulation curve and said optical device is an aerial optical retina apparatus.
Claim 17
Dependent Claim
20 words
The method of claim 13 wherein said recording step includes graphic plotting of said spatial frequency and modulation percentage data.
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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) | 1990-03-30 | 1990-09-29 | 1991-03-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-03-30 | 1994-09-29 | 1995-03-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-03-30 | 1998-09-29 | 1999-03-31 | $7700.00 | Window Closed / Lapsed |