Method and apparatus for determining three-dimensional position, orientation and mass distribution
First Claim
1. Apparatus for characterizing at least one property selected from mass distribution, position and orientation of an electrically conductive mass within a defined space, the apparatus comprising:
- a. a plurality of electrodes disposed proximate to the space and with defined positions relative to each other;
b. an AC source;
c. means for connecting the AC source to one of the electrodes to create an electric field around the mass;
d. means for measuring current levels through a plurality of the electrodes to produce a measurement set; and
e. processor means for inferring, from the measurement set, the instance of the property which, according to a forward model relating a plurality of instances of the property to corresponding expected current levels through a plurality of the electrodes given an AC signal through one of the electrodes, produces expected current levels closest to the measured levels.
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Accused Products
Abstract
A quasi-electrostatic sensing system surrounds an electrically conductive mass with an electric field, the magnitude of which is sensed at one or more locations to resolve a property of interest concerning the mass. The object intercepts a part of the electric field extending beween the AC-coupled "sending" electrode and the other "receiving" electrodes, the amount of the field intercepted depending on the size and orientation of the sensed mass, whether or not the mass provides a grounding path, and the geometry of the distributed electrodes. Because the response of the field to an object is a complex nonlinear function, adding electrodes can always distinguish among more cases. In other words, each electrode represents an independent weighting of the mass within the field; adding an electrode provides information regarding that mass that is not redundant to the information provided by the other electrodes. A "forward model" that relates the behavior of the system to variations in the property to be measured is established, and "inversion" of this model facilitates recovery of the property based on system behavior. The invention is amenable to a wide variety of usages including the detection of user positions and gestures as a means of conveying two- and/or three-dimensional information to, for example, computers, appliances, televisions, furniture, etc.; provision of data input or instructional commands to a device; or sensing of proximity to a reference object for security purposes, to warn of danger, or to conserve energy by withholding power until a potential user approaches the object.
182 Citations
40 Claims
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1. Apparatus for characterizing at least one property selected from mass distribution, position and orientation of an electrically conductive mass within a defined space, the apparatus comprising:
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a. a plurality of electrodes disposed proximate to the space and with defined positions relative to each other; b. an AC source; c. means for connecting the AC source to one of the electrodes to create an electric field around the mass; d. means for measuring current levels through a plurality of the electrodes to produce a measurement set; and e. processor means for inferring, from the measurement set, the instance of the property which, according to a forward model relating a plurality of instances of the property to corresponding expected current levels through a plurality of the electrodes given an AC signal through one of the electrodes, produces expected current levels closest to the measured levels. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. Apparatus for quantifying at least one unknown parameter pertaining to a property selected from size, position and orientation of an electrically conductive mass within a defined space and having a predetermined mass distribution, each parameter representing an independent degree of freedom, the apparatus comprising:
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a. a plurality of electrodes disposed proximate to the space and with defined positions relative to each other, the electrodes being sufficient in number to resolve the unknown parameter; b. an AC source; c. means for connecting the AC source to one of the electrodes to create an electric field around the mass; d. means for measuring current levels through a plurality of the electrodes to produce a measurement set; and e. processor means for inferring, from the measurement set, a value of the unknown parameter which, according to a forward model relating a plurality of instances of the parameter to corresponding expected current levels through a plurality of the electrodes given an AC signal through one of the electrodes, produces expected current levels closest to the measured levels. - View Dependent Claims (11, 12, 13, 14, 15, 19, 20, 21)
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16. Apparatus for obtaining the distribution of an electrically conductive mass within a defined space, the mass having a size within a predetermined range, the apparatus comprising:
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a. a plurality of electrodes disposed proximate to the space and with defined positions relative to each other, the electrodes being sufficient in number to resolve the unknown parameter; b. an AC source; c. means for connecting the AC source to one of the electrodes to create an electric field around the mass; d. means for measuring current levels through a plurality of the electrodes; and e. processor means configured to (i) for each measurement, localize the mass within a spatial region spanning first and second spatial boundaries corresponding to first and second iso-signal shells, the iso-signal shells being established by the predetermined size range of the mass and the measured current level, and (ii) combine the spatial regions into a representation of a composite spatial region containing the mass, the composite spatial region approximating the distribution of the mass. - View Dependent Claims (17, 18)
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22. A position-sensing device for sensing a three-dimensional position of an electrically conductive mass, the apparatus comprising:
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a. at least three electrodes disposed proximate to the space and with defined positions relative to each other; b. an AC source; c. means for connecting the AC source to one of the electrodes to create an electric field around the mass; d. means for measuring current levels through a plurality of the electrodes to produce a measurement set; and e. processor means for inferring, from the measurement set, the three-dimensional position of the mass, the processor being configured to infer the three-dimensional position according to a forward model relating position to corresponding expected current levels through a plurality of the electrodes given an AC signal through one of the electrodes, the inferred position producing expected current levels closest to the measured levels. - View Dependent Claims (24)
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23. A method of sensing a three-dimensional position of an electrically conductive mass, the method comprising the steps of:
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a. disposing at least three electrodes proximate to the space and with defined positions relative to each other; b. providing an AC source; c. connecting the AC source to one of the electrodes to create an electric field around the mass; d. measuring current levels through a plurality of the electrodes to produce a measurement set; and e. inferring, from the measurement set, the three-dimensional position of the mass according to a forward model relating three-dimensional position to corresponding expected current levels through a plurality of the electrodes given an AC signal through one of the electrodes, the inferred position producing expected current levels closest to the measured levels. - View Dependent Claims (40)
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25. A position-sensing device for sensing a two-dimensional position of an electrically conductive mass and an offset, with respect to the two-dimensional position, along a third dimension, the apparatus comprising:
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a. at least three electrodes disposed proximate to the space and with defined positions relative to each other; b. an AC source; c. means for connecting the AC source to one of the electrodes to create an electric field around the mass; d. means for measuring current levels through a plurality of the electrodes to produce a measurement set; and e. processor means for inferring, from the measurement set, the two-dimensional position of the mass and the existence of an offset, along a third dimension, exceeding a predetermined threshold, the processor being configured to infer the two-dimensional position and the offset according to a forward model relating position to corresponding expected current levels through a plurality of the electrodes given an AC signal through one of the electrodes, the inferred position and offset producing expected current levels closest to the measured levels.
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26. A method of sensing a two-dimensional position of an electrically conductive mass and an offset, with respect to the two-dimensional position, along a third dimension, the method comprising the steps of:
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a. disposing at least three electrodes proximate to the space and with defined positions relative to each other; b. providing an AC source; c. connecting the AC source to one of the electrodes to create an electric field around the mass; d. measuring current levels through a plurality of the electrodes to produce a measurement set; and e. inferring, from the measurement set, the two-dimensional position of the mass and the existence of an offset, along a third dimension, exceeding a predetermined threshold, wherein the inferring step comprises providing a forward model relating position to corresponding expected current levels through a plurality of the electrodes given an AC signal through one of the electrodes, and identifying a two-dimensional position and offset producing expected current levels closest to the measured levels.
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27. A method of characterizing at least one property selected from mass distribution, position and orientation of an electrically conductive mass within a defined space, the method comprising the steps of:
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a. disposing a plurality of electrodes proximate to the space and with defined positions relative to each other; b. providing an AC source; c. connecting the AC source to one of the electrodes to create an electric field around the mass; d. measuring current levels through a plurality of the electrodes to produce a measurement set; and e. inferring, from the measurement set, the instance of the property which, according to a forward model relating a plurality of instances of the property to corresponding expected current levels through a plurality of the electrodes given an AC signal through one of the electrodes, produces expected current levels closest to the measured levels. - View Dependent Claims (28, 29)
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30. A method of quantifying at least one unknown parameter pertaining to a property selected from size, position and orientation of an electrically conductive mass within a defined space and having a predetermined mass distribution, each parameter representing an independent degree of freedom, the method comprising the steps of:
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a. disposing a plurality of electrodes proximate to the space and with defined positions relative to each other, the electrodes being sufficient in number to resolve the unknown parameter; b. providing an AC source; c. connecting the AC source to one of the electrodes to create an electric field around the mass; d. measuring current levels through a plurality of the electrodes to produce a measurement set; and e. inferring, from the measurement set, a value of the unknown parameter which, according to a forward model relating a plurality of instances of the parameter to corresponding expected current levels through a plurality of the electrodes given an AC signal through one of the electrodes, produces expected current levels closest to the measured levels. - View Dependent Claims (31, 32, 33, 34, 35, 37, 38, 39)
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36. A method of obtaining the distribution of an electrically conductive mass within a defined space, the mass having a size within a predetermined range, the method comprising the steps of:
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a. disposing a plurality of electrodes proximate to the space and with defined positions relative to each other, the electrodes being sufficient in number to resolve the unknown parameter; b. providing an AC source; c. connecting the AC source to one of the electrodes to create an electric field around the mass; d. measuring current levels through a plurality of the electrodes; e. for each measurement, localizing the mass within a spatial region spanning first and second spatial boundaries corresponding to first and second iso-signal shells, the iso-signal shells being established by the predetermined size range of the mass and the measured current level; and f. combining the spatial regions into a representation of a composite spatial region containing the mass, the composite spatial region approximating the distribution of the mass.
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Specification