ORTHOPEDIC METHOD AND SYSTEM FOR MAPPING AN ANATOMICAL PIVOT POINT
First Claim
1. A method for determining a geometric center corresponding to an anatomical pivot point, the method comprising the steps of:
- transmitting ultrasonic signals from an ultrasonic wand to an ultrasonic receiver;
determining paired transmit-receive ranges between the ultrasonic wand and the ultrasonic receiver from time of flight and phase differential measurements;
tracking the ultrasonic wand by way of, and relative to, the ultrasonic receiver during constrained rotational and translational movement determined to be within to a hemispherical banded boundary from the paired transmit-receive ranges;
calculating a three-dimensional displacement and orientation time trajectory of the ultrasonic wand relative to the ultrasonic receiver from the tracking of the ultrasonic wand within the hemispherical banded boundary;
generating a hemispherical surface representation of the constrained movement from the three-dimensional displacement and orientation time trajectory; and
calculating a geometric center of the hemispherical surface representation relative to the ultrasonic receiver and applying a coordinate system transformation between the wand and receiver to map it to an anatomical pivot point.
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Accused Products
Abstract
A system and method of touchless interaction is provided for resolving a pivot point of an object where direct placement of a sensor at the pivot point is not practical. It applies to situations where the pivot point of a rigid object is inaccessible but remains stationary, while the other end is free to move and is accessible. The system maps the object'"'"'s pivot point by way of an external sensor that detects constrained motion of the rigid object within a hemispherical banded boundary. It can also detect a geometric pattern and acceleration during the constrained motion to compensate for higher order rotations about the pivot point. Other embodiments are disclosed.
174 Citations
20 Claims
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1. A method for determining a geometric center corresponding to an anatomical pivot point, the method comprising the steps of:
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transmitting ultrasonic signals from an ultrasonic wand to an ultrasonic receiver; determining paired transmit-receive ranges between the ultrasonic wand and the ultrasonic receiver from time of flight and phase differential measurements; tracking the ultrasonic wand by way of, and relative to, the ultrasonic receiver during constrained rotational and translational movement determined to be within to a hemispherical banded boundary from the paired transmit-receive ranges; calculating a three-dimensional displacement and orientation time trajectory of the ultrasonic wand relative to the ultrasonic receiver from the tracking of the ultrasonic wand within the hemispherical banded boundary; generating a hemispherical surface representation of the constrained movement from the three-dimensional displacement and orientation time trajectory; and calculating a geometric center of the hemispherical surface representation relative to the ultrasonic receiver and applying a coordinate system transformation between the wand and receiver to map it to an anatomical pivot point. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method for determining a geometric center corresponding to an anatomical pivot point, the method comprising the steps of:
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producing a three-dimensional acceleration surface according to changes in a local orientation of an ultrasonic receiver due to acceleration; determining whether constrained rotational and translational movement is within a hemispherical banded boundary; generating a hemispherical surface representation of constrained rotational and translational movement from the three-dimensional acceleration surface; and calculating, relative to the ultrasonic receiver, a geometric center of the hemispherical surface representation of the three-dimensional acceleration surface and mapping it to the anatomical pivot point. - View Dependent Claims (10, 11, 12)
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13. A system for determining a geometric center corresponding to an anatomical pivot point, the system comprising:
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an ultrasonic wand including; three or more ultrasonic transmitters to transmit ultrasonic signals through air; an electronic circuit to generate and shape driver signals to the three or more ultrasonic transmitters for producing the ultrasonic signals; an interface to receive user input for registering a wand tip location of the ultrasonic wand, a communications port to relay the user input and or receiving timing information to control the electronic circuit; and a battery to power the electronic circuit and associated electronics, where the wand tip has no sensory electronics, transmitters or labeled markers affixed or attached thereon, and an ultrasonic receiver including; a processor to; generate timing information for synchronizing a transmit and receive of the ultrasonic signals, process the ultrasonic signals received from the wand to determine a location and orientation, track relative movement of the wand determined to be within a hemispherical banded boundary from the timing information, location and orientation, and resolve a geometric center of the relative movement in the hemispherical banded boundary when the ultrasonic wand is in proximity; a communications interface to transmit the timing information to the ultrasonic wand that in response transmits the ultrasonic signals; three or more microphones to receive the ultrasonic signals transmitted through the air; a memory to store received ultrasonic signals to produce a history of received ultrasonics signals, a wireless communication interface to wirelessly convey positional information and alignment of wand tip pointing locations to a remote system; and a battery to power the processor and associated electronics, where the processor selectively references the history of stored ultrasonic signals to track the relative movement over time. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20)
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Specification