Determining forward pointing direction of a handheld device
First Claim
Patent Images
1. A device comprising:
- an accelerometer for sensing an acceleration of said device and outputting at least one acceleration output associated therewith;
at least one sensor for sensing rotation of said device and outputting at least one angular velocity output associated therewith; and
a processing unit for processing said acceleration output and said at least one angular velocity output to determine a forward pointing direction of said device, wherein the determination of the forward pointing direction of the device is based on a calculation of a center of rotation of said device using the processed acceleration and at least one angular velocity outputs and a gravitational constant.
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Abstract
A forward pointing direction associated with a handheld device is estimated or determined by, for example, calculating a center of rotation of the device. A resultant combined or selected bias estimate may then be used to compensate the biased output of the sensor in, e.g., a 3D pointing device.
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Citations
31 Claims
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1. A device comprising:
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an accelerometer for sensing an acceleration of said device and outputting at least one acceleration output associated therewith; at least one sensor for sensing rotation of said device and outputting at least one angular velocity output associated therewith; and a processing unit for processing said acceleration output and said at least one angular velocity output to determine a forward pointing direction of said device, wherein the determination of the forward pointing direction of the device is based on a calculation of a center of rotation of said device using the processed acceleration and at least one angular velocity outputs and a gravitational constant. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method for determining a forward pointing direction of a device, said method comprising:
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collecting data, by sensors, associated with said device'"'"'s acceleration and rotation while said device is in motion; and determining, by a processor, said forward pointing direction of said device based on the collected data, wherein the determining includes calculating a center of rotation of the device using; - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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22. A method for determining a forward pointing direction of a device, said method comprising:
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collecting data, by sensors, associated with said device'"'"'s acceleration and rotation while said device is in motion; and determining, by a processor, said forward pointing direction of said device based on the collected data, wherein the step of determining further comprises calculating a center of rotation of the device and wherein said calculating can be expressed as;
bc=((b{dot over (Ω
)}2+bΩ
22)−
(I+bΩ
TΔ
t)(b{dot over (Ω
)}1+bΩ
12))−
1(ba2−
(I+bΩ
TΔ
t)b a1),where; Omega dot pre-superscript b subscript 1 is an angular acceleration matrix of a first sample associated with said device in a body frame of reference, Omega dot pre-superscript b subscript 2 is an angular acceleration matrix of a second sample associated with said device in a body frame of reference, Omega squared pre-superscript b subscript 1 is the square of the angular velocity matrix of said first sample associated with said device in said body frame of reference, Omega squared pre-superscript b subscript 2 is the square of the angular velocity matrix of said second sample associated with said device in said body frame of reference, a pre-superscript b subscript 1 is a linear acceleration of said first sample associated with said device in said body frame of reference, a pre-superscript b subscript 2 is a linear acceleration of said second sample associated with said device in said body frame of reference, Omega pre-superscript b post-superscript T delta t is the average angular velocity between said first sample and said second sample and I is an identity matrix. - View Dependent Claims (23, 24, 25, 26, 27)
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24. The method of claim 22 wherein said Omega pre-superscript b squared can be expressed as:
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25. The method of claim 22 wherein multiple calculations of said device'"'"'s center of rotation vector are combined to optimize the center of rotation vector calculation.
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26. The method of claim 25 wherein said combining comprises at least one of low-pass filtering, Kalman filtering and Bayesian filtering.
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27. The method of claim 22, wherein said body frame of reference is adjusted based on calculating said forward direction.
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28. A system for allowing a user to determine a forward direction for a handheld pointing device, said system comprising:
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a handheld pointing device comprising; an accelerometer for sensing an acceleration of said device and outputting at least one acceleration output associated therewith; a plurality of angular velocity sensors for sensing rotation of said device and outputting at least one angular velocity output associated therewith; and a processing unit for processing said acceleration output and said at least one angular velocity output and determining a forward direction of said device based on a calculation of a center of rotation of said device using processed outputs and a gravitational constant; and a host computer comprising; communication capabilities to said handheld pointing device; and an output display. - View Dependent Claims (29, 30, 31)
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Specification