Patent US6141104A successfully refreshed from Google Patents.
US6141104A
Expired / Lapsed
US
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System for determination of a location in three dimensional space
Assignee: Image Guided Technologies Inc
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Filing: 1998-09-09
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Granted: 2000-10-31
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Expires: 2018-09-09
Abstract
Abstract An optical improvement for angular position sensors, which may be used to determine the spatial coordinates of a small source of light (or other energy) in a 3-dimensional volume. Such sensors normally include a linear photosensitive image detector such as a photodiode array or a charge-coupled device (CCD). An irregular pattern of parallel slits is described which increases the amount of light gathered while avoiding the undesirable characteristics of lens optics for this application. One optimal type of irregular pattern is the uniformly redundant array. A mathematical correlation function together with a polynomial interpolation function can determine the displacement of the image on the detector and thereby the location of the source relative to one angular dimension. Given the locations and orientations of several sensors in a 3-dimensional coordinate system and given the angles measured by each, the location of the point source can be computed.
Inventors
- 👤 Waldean A. Schulz
- 👤 Robert Cormack
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 22:14
CPC Classifications
G; G06; G06F; G06F3/00; G06F3/01; G06F3/03; G06F3/0304; G01; G01D; G01D5/00; G01D5/26; G01D5/32; G01D5/34; G01S; G01S3/00; G01S3/78; G01S3/782; G01S3/783; G01S3/7835; G01S5/00; G01S5/16; G06F3/033; G06F3/0346
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
319 words
In an apparatus for determining a location of at least one substantially point-like radiator of energy in a three dimensional volume comprising: said at least one substantially point-like radiator of energy; at least one detector adapted to be disposed in a known location within said three dimensional volume, and adapted to be positioned to intercept energy radiating from said substantially point-like radiator, wherein said detector comprises at least one array of elements adapted to detect said radiation and to convert said detected radiation into output signals; and at least one pattern member, adapted to be disposed between said array and said radiator, comprising plural gradations of transparency, wherein said pattern is adapted to spatially modulate radiation that is incident thereon as a function of said gradations in transparency, and to project said modulated energy onto said array in the form of at least one real image; and a signal processor adapted to convert output signals representative of said at least one modulated real image into a direction of said radiator relative to an assembly of said detector and said pattern member; the improvement that comprises: at least one substantially ideal reference image of said pattern member on said array; said signal processor being adapted to compare said modulated image with said reference image; said signal processor comprising a discrete mathematical correlation function that is adapted to characterize the degree of match between said modulated image and said reference image for a plurality of discrete displacements of said reference image with respect to said array, said signal processor being adapted to identify at least one of said displacements that produces a correlation that is characterized by a well defined maximum value; and said signal processor being adapted to convert said displacement(s) producing a maximum value into a direction of said radiator in said three dimensional volume with respect to the known location of said detector in said three dimensional volume.
Claim 2
Dependent Claim
319 words
In an apparatus for determining a location of at least one substantially point-like radiator of energy in a three dimensional volume comprising: said at least one substantially point-like radiator of energy; at least one detector adapted to be disposed in a known location within said three dimensional volume, and adapted to be positioned to intercept energy radiating from said substantially point-like radiator, wherein said detector comprises at least one array of elements adapted to detect said radiation and to convert said detected radiation into output signals; and at least one pattern member, adapted to be disposed between said array and said radiator, comprising plural gradations of transparency, wherein said pattern is adapted to spatially modulate radiation that is incident thereon as a function of said gradations in transparency, and to project said modulated energy onto said array in the form of at least one real image; and a signal processor adapted to convert output signals representative of said at least one modulated real image into a direction of said radiator relative to an assembly of said detector and said pattern member; the improvement that comprises: at least one substantially ideal reference image of said pattern member on said array; said signal processor being adapted to compare said modulated image with said reference image; said signal processor comprising a discrete mathematical correlation function that is adapted to characterize the degree of match between said modulated image and said reference image for a plurality of discrete displacements of said reference image with respect to said array, said signal processor being adapted to identify at least one of said displacements that produces a correlation that is characterized by a well defined maximum value; and said signal processor being adapted to convert said displacement(s) producing a maximum value into a direction of said radiator in said three dimensional volume with respect to the known location of said detector in said three dimensional volume.
Claim 3
Dependent Claim
70 words
The improved apparatus of claim 1 further comprising said signal processor being adapted to estimate the displacement of the maximum value of a continuous function, that equals the correlation function at said displacements interpolated between at least two discrete displacements of said correlation function; and said signal processor being adapted to convert said estimate into an interpolated, and therefore more precise, direction of said radiator in said three dimensional volume.
Claim 4
Dependent Claim
26 words
The improved apparatus of claim 1 wherein said plural gradations of transparency comprise a plurality of slits of varying width in an otherwise substantially opaque field.
Claim 5
Dependent Claim
35 words
The improved apparatus of claim 3 wherein said array is substantially one dimensional and comprises a linear strip of said radiation converters, wherein long dimensions of said slits are substantially normal to said linear strip.
Claim 6
Dependent Claim
54 words
The improved apparatus of claim 4 comprising a plurality of said arrays at least two of which are disposed substantially normal to each other; and said signal processor is adapted to determine directions of said radiator with respect to said arrays in at least two dimensions corresponding to the dispositions of said normal arrays.
Claim 7
Dependent Claim
73 words
The improved apparatus of claim 4 comprising a plurality of said arrays at least three of which are disposed not all parallel to each other and said signal processor is adapted to determine directions of said radiator with respect to said arrays in at least three dimensions corresponding to the dispositions of said arrays whereby enabling said signal processor to determine the substantial point location of said radiator in said three dimensional volume.
Claim 8
Dependent Claim
19 words
The improved apparatus of claim 3 wherein the width of said slits are not digitally related to each other.
Claim 9
Dependent Claim
20 words
The improved apparatus of claim 3 wherein the widths of said slits correspond to a uniformly redundant array (URA) pattern.
Claim 10
Dependent Claim
16 words
The improved apparatus of claim 3 wherein said slits are of random width or random spacing.
Claim 11
Dependent Claim
29 words
The improved apparatus of claim 3 wherein said slits are disposed symmetrically about an arbitrary line that is contained in said real image and is transverse to said array.
Claim 12
Dependent Claim
12 words
The improved apparatus of claim 1 wherein said radiation is electromagnetic radiation.
Claim 13
Dependent Claim
12 words
The improved apparatus of claim 11 wherein said radiation is infra red.
Claim 14
Dependent Claim
15 words
The improved apparatus of claim 1 wherein said array comprises a plurality of photodetector elements.
Claim 15
Dependent Claim
16 words
The improved apparatus of claim 13 wherein at least some of said elements are linearly aligned.
Claim 16
Dependent Claim
15 words
The improved apparatus of claim 14 wherein said array comprises a charge coupled device (CCD).
Claim 17
Dependent Claim
18 words
The improved apparatus of claim 15 wherein said CCD comprises at least one linear row of photosensitive pixels.
Claim 18
Dependent Claim
276 words
In a method of determining the direction of at least one unknown point in a three dimensional volume, relative to a different, known location in said volume, which comprises: disposing at least one substantially point source energy radiator in said three dimensional volume in known spatial relationship to at least one of said point(s); disposing at least one detector, that is adapted to detect energy radiated by said radiator and impinged upon at least one linear array of elements that are adapted to detect said radiation and to convert detected radiation into output signals that are proportional to strength of said impinged energy on the elements of said array, wherein said detector is in known spatial relationship to said three dimensional volume; operatively associating said detector(s) with a signal processor that is adapted to convert said output signals to a direction of incidence of said radiation on said detector(s); the improvement that comprises: interposing a pattern member, comprising plural areas having gradations of transparency to said radiation, between said radiator and said array; radiating energy from said radiator to said array through said pattern member such that a modulated image of said pattern member is disposed on said array; generating an output of said array that is representative of at least one displacement of a substantially ideal reference image of said pattern member; in said signal processor, comparing said modulated image with at least one of said displaced reference images until a best match is found between a specific displaced reference image and said modulated image; and in said signal processor, from said best match, determining a direction of said radiator with respect to said detector.
Claim 19
Dependent Claim
276 words
In a method of determining the direction of at least one unknown point in a three dimensional volume, relative to a different, known location in said volume, which comprises: disposing at least one substantially point source energy radiator in said three dimensional volume in known spatial relationship to at least one of said point(s); disposing at least one detector, that is adapted to detect energy radiated by said radiator and impinged upon at least one linear array of elements that are adapted to detect said radiation and to convert detected radiation into output signals that are proportional to strength of said impinged energy on the elements of said array, wherein said detector is in known spatial relationship to said three dimensional volume; operatively associating said detector(s) with a signal processor that is adapted to convert said output signals to a direction of incidence of said radiation on said detector(s); the improvement that comprises: interposing a pattern member, comprising plural areas having gradations of transparency to said radiation, between said radiator and said array; radiating energy from said radiator to said array through said pattern member such that a modulated image of said pattern member is disposed on said array; generating an output of said array that is representative of at least one displacement of a substantially ideal reference image of said pattern member; in said signal processor, comparing said modulated image with at least one of said displaced reference images until a best match is found between a specific displaced reference image and said modulated image; and in said signal processor, from said best match, determining a direction of said radiator with respect to said detector.
Claim 20
Dependent Claim
35 words
An improved method as claimed in claim 17 further comprising repeating said direction determination with said detectors at different spatial relationships to said volume, sufficient to establish the three dimensional coordinates of said unknown point.
Claim 21
Dependent Claim
48 words
An improved method as claimed in claim 18 wherein said array is a plurality of linear aligned plural elements that are adapted to convert impinged energy into output signals and further comprising repeating said improved method with at least three arrays disposed not all parallel to each other.
Claim 22
Dependent Claim
48 words
An improved method as claimed on claim 18 wherein said plural gradations of transparency comprise a plurality of slits of differing, non-digital widths that are longitudinally disposed normal to said array; and further comprising causing said modulated image to comprise a set of lines transverse to said array.
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) | 2003-10-31 | 2004-05-01 | 2004-10-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2007-10-31 | 2008-05-01 | 2008-10-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2011-10-31 | 2012-05-01 | 2012-10-31 | $7700.00 | Window Closed / Lapsed |