US3874796A
Expired / Lapsed
US
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Method of surface contouring
Assignee: General Electric Co
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Filing: 1973-05-25
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Granted: 1975-04-01
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Expires: 1993-05-25
Abstract
Abstract A novel method of surface contouring is described by sensing differential surface displacement orthogonal to the direction of observation resulting from parallax as the relative position between observer and object changes. The object is imaged at two conditions of differential displacement under conditions of illumination providing appreciable surface detail. The images are superimposed to form a composite transparency, which when viewed under coherent illumination and spatially filtered, provides interference fringes at regions of the image which have been displaced by equal amounts. The invention is applicable to the formation of surface contours of small and large objects and land masses.
Inventors
- 👤 Joseph L Chovan
- 👤 Donald E Duffy
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 05:41
CPC Classifications
G; G01; G01B; G01B9/00; G01B9/02; G01B9/021; Y; Y10; Y10S; Y10S101/00; Y10S101/37
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
132 words
The method of surface contouring, comprising: a. imaging an observed object under conditions of illumination providing appreciable surface detail at spatial frequencies suitable for resolving the orthogonal surface displacements to be sensed, b. recording two correlatable images of said object between which surface elements of said object are displaced relative to the observer in a direction orthogonal to the direction of observation as a result of a change in relative viewing position parallel to said orthogonal direction, c. simultaneously superimposing elements of said images without relative rotation upon a transparency with elements at a predetermined distance from The observer coincident, d. illuminating said transparency by a narrow spectral band light source, and e. imaging said transparency through a narrow band spatial filter positioned to form an interference pattern of equal depth contours.
Claim 2
Independent Claim
132 words
The method of surface contouring, comprising: a. imaging an observed object under conditions of illumination providing appreciable surface detail at spatial frequencies suitable for resolving the orthogonal surface displacements to be sensed, b. recording two correlatable images of said object between which surface elements of said object are displaced relative to the observer in a direction orthogonal to the direction of observation as a result of a change in relative viewing position parallel to said orthogonal direction, c. simultaneously superimposing elements of said images without relative rotation upon a transparency with elements at a predetermined distance from The observer coincident, d. illuminating said transparency by a narrow spectral band light source, and e. imaging said transparency through a narrow band spatial filter positioned to form an interference pattern of equal depth contours.
Claim 3
Dependent Claim
18 words
The method set forth in claim 1 wherein said transparency is illuminated by a source of coherent illumination.
Claim 4
Dependent Claim
17 words
The method set forth in claim 1 wherein said source of coherent illumination is a point source.
Claim 5
Dependent Claim
54 words
The method of claim 1 wherein said spatial filter is disposed in the Fourier transform plane and has a narrow slot for selection of a narrow band of spatial frequencies, restricted to the region which is less than a cycle of the cosine factor in the Fourier transform plane of the double input function.
Claim 6
Dependent Claim
18 words
The method of claim 4 wherein said spatial filter is provided with a pair of symmetrically placed slots.
Claim 7
Dependent Claim
38 words
The method of claim 2 wherein said surface detail is provided by speckling laser illumination of said object, the viewing field being expanded by passing said laser beam through a coarse translucent diffuser for impingement in said object.
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) | 1978-03-31 | 1978-09-30 | 1979-04-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-03-31 | 1982-09-30 | 1983-04-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-03-31 | 1986-09-30 | 1987-04-01 | $7700.00 | Window Closed / Lapsed |