Patent ID: 8814810
Filing Date: 2014-08-26
Classification: G06F

Abstract:
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.