US5003166A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Multidimensional range mapping with pattern projection and cross correlation
Assignee: Massachusetts Institute of Technology
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Filing: 1989-11-07
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Granted: 1991-03-26
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Expires: 2009-11-07
Abstract
Abstract A range camera is provided for the determination of range to an object through the utilization of a system which projects a limited depth of field light pattern onto an object and measures the blurring of the pattern on the object. In one embodiment an anisotropic aperture or astigmatic optics are used in combination with an isotropic pattern to eliminate system error introduced by the camera. The anisotropic aperture provides that blurring takes place only in a given direction, with measurement of blurring in an orthogonal direction providing an output only responsive to the blurring associated with the camera. This blurring can then be subtracted out to eliminate system error from the range measurement. The range camera is operative to produce a range picture or map, with optional outputs providing localized albedo and a conventional brightness image. In another embodiment, the direction of the blur, either in front of or in back of the plane of best focus of the projected pattern, is provided through the utilization of a mask having an aperture devoid of point symmetry. In a further embodiment, direction of blur can be ascertained through the utilization of astigmatic optics.
Inventors
- 👤 Bernd Girod
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 13:58
CPC Classifications
G; G01; G01S; G01S17/00; G01S17/02; G01S17/06; G01S17/08; G01B; G01B11/00; G01B11/24; G01B11/25; G01B11/2513; G01S17/88; G01S17/89
Claims Analysis
Total Claims: 28
Claim 1
Independent Claim
118 words
A multi-dimensional range mapping system, comprising: means for optically projecting a limited depth of field pattern of light and dark areas having high spatial frequency onto an object for permitting determination of the range of surface patches on said object from a predetermined plane, with said pattern being focused to a plane of best focus; and, means including multi-dimensional cross correlation means for simultaneously determining the range of multiple surface patches on said object from said plane of best focus by measuring the degree of blur of said pattern on said object at said surface patch and for generating an instantaneous range mapping corresponding to the range of multiple surface patches on said object from said predetermined plane.
Claim 2
Dependent Claim
118 words
A multi-dimensional range mapping system, comprising: means for optically projecting a limited depth of field pattern of light and dark areas having high spatial frequency onto an object for permitting determination of the range of surface patches on said object from a predetermined plane, with said pattern being focused to a plane of best focus; and, means including multi-dimensional cross correlation means for simultaneously determining the range of multiple surface patches on said object from said plane of best focus by measuring the degree of blur of said pattern on said object at said surface patch and for generating an instantaneous range mapping corresponding to the range of multiple surface patches on said object from said predetermined plane.
Claim 3
Dependent Claim
17 words
The system of claim 1 wherein said projecting means includes a projection system having large aperture optics.
Claim 4
Dependent Claim
19 words
The system of claim 2 wherein said projection system includes a slide projector and a slide carrying said pattern.
Claim 5
Dependent Claim
17 words
The system of claim 1 wherein said range determining means includes a camera having small aperture optics.
Claim 6
Dependent Claim
10 words
The system of claim 1 wherein said pattern is isotropic.
Claim 7
Dependent Claim
13 words
The system of claim 1 wherein said pattern includes a pseudo noise pattern.
Claim 8
Dependent Claim
10 words
The system of claim 1 wherein said pattern includes impulses.
Claim 9
Dependent Claim
10 words
The system of claim 1 wherein said pattern includes lines.
Claim 10
Dependent Claim
13 words
The system of claim 1 wherein said pattern includes a grid of lines.
Claim 11
Dependent Claim
10 words
The system of claim 9 wherein said grid is rectilinear.
Claim 12
Dependent Claim
23 words
The system of claim 1 wherein said range determining means includes a camera aimed at said object, said camera having an image plane.
Claim 13
Dependent Claim
66 words
The system of claim 11 wherein said camera includes means for providing an electronic reproduction of the image at said image plane, and wherein said range determining means includes means for storing said electronic reproduction of the image at said image plane and means for processing said stored image so as to generate signals corresponding to range and location of a surface patch on said object.
Claim 14
Dependent Claim
53 words
The system of claim 12 wherein said range determining means includes means for sampling the blur occurring at said surface patch in a predetermined slice thereacross and for generating corresponding data points, and means for ascertaining from said data points the standard deviation of the curve representing intensity vs. position across said slice.
Claim 15
Dependent Claim
17 words
The system of claim 12 and further including means for removing camera-induced blur from the range determination.
Claim 16
Dependent Claim
19 words
The system of claim 14 wherein said camera-induced blur removing means includes a projection system having an anisotropic aperture.
Claim 17
Dependent Claim
70 words
The system of claim 15 wherein said anisotropic aperture is effectively elongated in a predetermined direction and foreshortened in an orthogonal direction, and wherein said range determining system further includes means for sensing blur in each of said orthogonal directions and means for removing the effect of blur sensed in the direction orthogonal to the elongated aperture direction from said range determination, thereby removing camera-induced blur from the range measurement.
Claim 18
Dependent Claim
24 words
The system of claim 16 wherein said projection system includes a lens and wherein said anisotropic aperture includes a slotted mask at said lens.
Claim 19
Dependent Claim
22 words
The system of claim 17 wherein said slotted mask is oriented such that the slot is at an angle to the horizontal.
Claim 20
Dependent Claim
14 words
The system of claim 15 wherein said projection system includes an astigmatic lens system.
Claim 21
Dependent Claim
45 words
The system of claim 19 wherein said astigmatic lens system produces two planes of best focus and wherein said range determining system includes means for unambiguously ascertaining range based on measurement of blur of said surface patch relative to said two planes of best focus.
Claim 22
Dependent Claim
19 words
The system of claim 11 wherein said camera includes small aperture optics for maximizing the depth of field thereof.
Claim 23
Dependent Claim
23 words
The system of claim 11 and further including means coupled to said range determining means for ascertaining the albedo of said surface patch.
Claim 24
Dependent Claim
24 words
The system of claim 11 and further including means coupled to said range determining means for generating a conventional brightness image of said object.
Claim 25
Dependent Claim
44 words
The system of claim 1 wherein said pattern is a pseudo noise pattern and wherein said range determining means includes correlator means for providing an impulse having a width and corresponding to surface patch blur and means for measuring the width by said impulse.
Claim 26
Dependent Claim
19 words
The system of claim 1 wherein said pattern is formed from light in invisible regions of the electromagnetic spectrum.
Claim 27
Dependent Claim
13 words
The system of claim 25 wherein said pattern is formed from infrared light.
Claim 28
Dependent Claim
13 words
The system of claim 25 wherein said pattern is formed from ultraviolet light.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-03-25 | 1994-09-24 | 1995-03-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-03-25 | 1998-09-24 | 1999-03-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-03-25 | 2002-09-24 | 2003-03-26 | $7700.00 | Window Closed / Lapsed |