Optical fiber probe for position measurement
First Claim
1. An apparatus for determining the location of at least one point in three dimensional space relative to a three dimensional coordinate system defining said space comprising:
- at least one emitter of electromagnetic radiation, comprising a radiation dispersing element which emits said radiation in a substantially conical pattern which at least approaches a solid angle of about 180°
, wherein said radiation emission pattern has a centroid such that it at least closely approximates a point source of said radiation thereby causing said centroid of said electromagnetic radiation to be in a substantially invariant relationship to said emitter of said radiation regardless of the angle from which the centroid of the emitted radiation is viewed;
an electromagnetic radiation generator operatively associated with each of said emitters;
means for transmitting electromagnetic radiation generated by said generator to said emitter;
a plurality of electromagnetic radiation sensors, each of which is adapted to detect at least one electromagnetic ray emitted from at least one of said emitters;
a power supply for said electromagnetic radiation generator;
where there are a plurality of emitters, means to differentiate electromagnetic radiation emitted by at least two of said emitters; and
means for determining the location of said emitter relative to the three dimensional coordinate system;
wherein, as a consequence of said emitters emitting electromagnetic radiation at a solid angle of at least approaching 180°
, determining the location of said emitters with greater accuracy than would have been the accuracy determined had the electromagnetic radiation been generated without said dispersing element.
3 Assignments
0 Petitions
Accused Products
Abstract
Improved point source electromagnetic radiation emitters including a dispersing element that radiates electromagnetic radiation over a very wide conical angle of approaching about 180°. This light dispersing element can be in any one or more of several illustrated forms such as a light diffusing spherical or hemispherical element, a planar diffusing plate, a tapered light guide, a plano-concave lens, a convex mirror, a light pipe with a large numerical aperture, or the like. The emitter of this invention may be fixed to an object and tracked in a 3-dimensional volume by a system using electro-optical position sensors in order to determine the spatial location of the emitters and therefore to determine, by geometry, the position and orientation of the object. The electromagnetic radiation generator is preferably disposed remote from the emitter and is electrically and magnetically isolated from the emitter. A common optical fiber provides transmission of the radiation from the generator to the emitter. The emitted radiation more nearly resembles point source of radiation and therefore enables more accurate determination of the location of the radiating element, and thereby more accurate determination of the position and orientation of the object on which the emitters reside. The preferred electromagnetic radiation generator is an LED, most preferably a laser diode.
260 Citations
48 Claims
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1. An apparatus for determining the location of at least one point in three dimensional space relative to a three dimensional coordinate system defining said space comprising:
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at least one emitter of electromagnetic radiation, comprising a radiation dispersing element which emits said radiation in a substantially conical pattern which at least approaches a solid angle of about 180°
, wherein said radiation emission pattern has a centroid such that it at least closely approximates a point source of said radiation thereby causing said centroid of said electromagnetic radiation to be in a substantially invariant relationship to said emitter of said radiation regardless of the angle from which the centroid of the emitted radiation is viewed;an electromagnetic radiation generator operatively associated with each of said emitters; means for transmitting electromagnetic radiation generated by said generator to said emitter; a plurality of electromagnetic radiation sensors, each of which is adapted to detect at least one electromagnetic ray emitted from at least one of said emitters; a power supply for said electromagnetic radiation generator; where there are a plurality of emitters, means to differentiate electromagnetic radiation emitted by at least two of said emitters; and means for determining the location of said emitter relative to the three dimensional coordinate system; wherein, as a consequence of said emitters emitting electromagnetic radiation at a solid angle of at least approaching 180°
, determining the location of said emitters with greater accuracy than would have been the accuracy determined had the electromagnetic radiation been generated without said dispersing element. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. An electrically neutral system for radiating electromagnetic radiation from an effective point source comprising:
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an electromagnetic radiation generator; an emitter of electromagnetic radiation comprising a radiation dispersing element which emits said electromagnetic radiation in a substantially conical pattern through a solid angle which at least approaches 180°
,wherein said radiation emission has a centroid such that it at least closely approximates a point source of said radiation thereby causing said centroid of said electromagnetic radiation to be in a substantially invariant relationship to the emitter of said radiation regardless of the angle from which the centroid of emitted radiation is viewed, and wherein said emitter is disposed a distance from said generator; at least one optical fiber disposed in operative relationship to both said generator and said emitter such that it is adapted to transmit electromagnetic radiation from said generator to said emitter; and an electric power source operatively associated with said electromagnetic radiation generator, wherein said generator is substantially electrically and magnetically isolated from said emitter. - View Dependent Claims (21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38)
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39. A method of accurately determining the location of a point in three dimensional space which comprises:
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electrically generating electromagnetic radiation; non-electrically transmitting said electromagnetic radiation to an emitter, comprising a radiation dispersing element, so constructed as to emit electromagnetic radiation therefrom in a conical array through a solid angle at least approaching 180°
;non-electrically emitting said electromagnetic radiation from said dispersing element in a substantially conical pattern over a solid angle that at least approaches about 180°
; andthereby causing a centroid of said emitted electromagnetic radiation to at least closely approximate a point source of said radiation which is substantially invariant with respect to the emitter of said radiation regardless of the angle from which said emitted radiation is viewed. - View Dependent Claims (40, 41)
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42. A method of determining the position and orientation of at least one three dimensional object in a three dimensional space defined by a coordinate system which comprises:
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disposing a plurality of electromagnetic emitters, comprising a dispersing element so constructed as to radiate electromagnetic radiation in a substantially conical pattern over a solid angle that at least approaches about 180°
in known spaced apart relationship to each other on a surface of said object;providing at least one electromagnetic radiation generator spaced from said object; providing a non-electric radiation guide operatively associated with each emitter and with said at least one generator; generating electromagnetic radiation from each of said generators; transmitting said radiation, non-electrically through said radiation guides to said emitters; non-electrically radiating a substantially conical pattern of radiation from at least one of said dispersing elements; receiving said emitted radiation by a plurality of electromagnetic radiation receivers; determining the location of each emitter as a function of the angles between said received radiation and respective reference lines; and converting said determined locations of said emitters to a position and orientation of said object in said three dimensional space. - View Dependent Claims (43, 44, 45, 46, 47, 48)
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Specification