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, where at least one of the wand or receiver are configured to be coupled to an anatomical system;
determining paired transmit-receive ranges between the ultrasonic wand and the ultrasonic receiver from time of flight and phase differential measurements, where the time of flight and phase differential measurements are measured by the receiver;
tracking the ultrasonic wand by way of, and relative to, the ultrasonic receiver during constrained rotational and translational movement of at least one of the wand or receiver 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, where tracking of the wand is performed by a processor using data from at least one of the receiver and wand;
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 the geometric center 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.
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Citations
8 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, where at least one of the wand or receiver are configured to be coupled to an anatomical system; determining paired transmit-receive ranges between the ultrasonic wand and the ultrasonic receiver from time of flight and phase differential measurements, where the time of flight and phase differential measurements are measured by the receiver; tracking the ultrasonic wand by way of, and relative to, the ultrasonic receiver during constrained rotational and translational movement of at least one of the wand or receiver 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, where tracking of the wand is performed by a processor using data from at least one of the receiver and wand; 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 the geometric center to an anatomical pivot point. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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Specification