US3762818A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Contour measurement apparatus
Assignee: Lockheed Martin Corp
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Filing: 1971-07-14
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Granted: 1973-10-02
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Expires: 1991-07-14
Abstract
Abstract A technique for measuring the contour of a surface by generating a pattern of optical interference between a periodic shadow pattern cast onto the surface and a periodic reference pattern. Translating the shadow pattern and the reference pattern at least one complete cycle of spatial frequency causes the average intensity of the shadow pattern, the reference grid pattern, and various extraneous optical noise images to be minimized or cancelled, so that only contour lines accurately describing the contour of the surface remain on the surface to be viewed or photographed.
Inventors
- 👤 W Johnson
- 👤 D Meadows
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 19:01
CPC Classifications
G; G01; G01B; G01B11/00; G01B11/24; G01B11/25; G01B11/254
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
96 words
In contour measuring apparatus, in combination comprising: a source of illumination directed toward an object space in which an object to be examined may be positioned; shadow casting structure disposed in the optical path between said source of illumination and said object space, said shadow casting structure having a periodically repetitive pattern of segments which are alternately opaque and transmissive with respect to illumination from said source; and motive means operatively connected with said shadow casting structure for selectively translating said shadow casting structure in a direction substantially parallel to the direction of said Periodic repetition.
Claim 2
Dependent Claim
96 words
In contour measuring apparatus, in combination comprising: a source of illumination directed toward an object space in which an object to be examined may be positioned; shadow casting structure disposed in the optical path between said source of illumination and said object space, said shadow casting structure having a periodically repetitive pattern of segments which are alternately opaque and transmissive with respect to illumination from said source; and motive means operatively connected with said shadow casting structure for selectively translating said shadow casting structure in a direction substantially parallel to the direction of said Periodic repetition.
Claim 3
Dependent Claim
41 words
The combination as in claim 1, wherein said motive means includes means to serially translate said shadow casting structure to a plurality of stationary positions each of which is displaced a predetermined spatial phase distance from the immediately preceding stationary position.
Claim 4
Dependent Claim
25 words
The combination as in claim 1, wherein said motive includes means to translate said shadow casting structure at a substantially constant velocity in said direction.
Claim 5
Dependent Claim
39 words
The combination as in claim 3, wherein said motive means includes means to translate said shadow casting structure at said constant velocity for a minimum predetermined distance equal to an integral number of periods of said periodically repetitive pattern.
Claim 6
Dependent Claim
103 words
In a contour measuring system, apparatus for casting multiple images onto a surface, comprising: means for selectively casting a first periodically repetitive shadow pattern having a certain spatial frequency into an object space whereat a surface being measured may be positioned; and means for selectively casting into said object space a second repetitive periodic shadow pattern having the same certain spatial frequency to occupy a region coextensive with at least a portion of the region occupied by said first shadow pattern and displaced in phase by a predetermined amount of a cycle of said spatial frequency with respect to said first shadow pattern.
Claim 7
Dependent Claim
103 words
In a contour measuring system, apparatus for casting multiple images onto a surface, comprising: means for selectively casting a first periodically repetitive shadow pattern having a certain spatial frequency into an object space whereat a surface being measured may be positioned; and means for selectively casting into said object space a second repetitive periodic shadow pattern having the same certain spatial frequency to occupy a region coextensive with at least a portion of the region occupied by said first shadow pattern and displaced in phase by a predetermined amount of a cycle of said spatial frequency with respect to said first shadow pattern.
Claim 8
Dependent Claim
115 words
In a contour measuring system, apparatus for casting multiple images onto a surface, comprising: first projection means for selectively casting a first shadow pattern having a periodically repetitive pattern of parallel grid lines of a certain spatial frequency into an object space whereat a surface to be measured may be positioned; second projection means for selectively casting a second shadow pattern identical to said first shadow pattern into the object space such that the grid lines of said first and second shadow patterns are parallel with each other and such that the spatial frequency of said second shadow pattern is displaced in phase a predetermined amount from the spatial frequency of said first shadow pattern.
Claim 9
Dependent Claim
115 words
In a contour measuring system, apparatus for casting multiple images onto a surface, comprising: first projection means for selectively casting a first shadow pattern having a periodically repetitive pattern of parallel grid lines of a certain spatial frequency into an object space whereat a surface to be measured may be positioned; second projection means for selectively casting a second shadow pattern identical to said first shadow pattern into the object space such that the grid lines of said first and second shadow patterns are parallel with each other and such that the spatial frequency of said second shadow pattern is displaced in phase a predetermined amount from the spatial frequency of said first shadow pattern.
Claim 10
Dependent Claim
99 words
Apparatus as in claim 6, wherein: said first projection means includes a first projection slide bearing an image for projection of said first shadow pattern; first lens means to focus said first shadow pattern at the object space; said second projection means includes a second projection slide bearing an image for projection of said second shadow pattern; second lens means to focus said second shadow pattern at the object space; and projection slide positioning means for maintaining said first and second projection slides in place in the respective projection means to maintain said phase displacement between said shadow patterns.
Claim 11
Dependent Claim
47 words
Apparatus as in claim 7, wherein: said projection slide positioning means comprises a unitary slide carrier operably received in both of said projection means and containing both of said projection slides spatially positioned with respect to each other to maintain said phase displacement between said shadow patterns.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-10-01 | 1977-04-02 | 1977-10-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-10-01 | 1981-04-02 | 1981-10-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-10-01 | 1985-04-02 | 1985-10-02 | $7700.00 | Window Closed / Lapsed |