MEMS-based method and system for tracking a femoral frame of reference
First Claim
1. A system for tracking a femoral frame of reference in computer-assisted surgery, comprising:
- a sensor unit adapted to be secured to a distal end of a femur, the sensor unit comprising an accelerometer sensor and a gyroscope sensor both configured for producing orientation data;
a processing unit configured for receiving gyroscope data and accelerometer data and comprising;
a gyroscope-data calculator for providing calculated acceleration data using at least gyroscope data resulting from movements of the femur about a proximal end thereof;
an accelerometer-data calculator for calculating measured acceleration data using accelerometer data resulting from the movements of the femur; and
an acceleration comparator for relating an orientation of the sensor unit to the femur to define the femoral frame of reference, the acceleration comparator performing a numerical optimization to determine the orientation of the sensor unit, the numerical optimization using at least a plurality of estimated radius values between the proximal end and the distal end of the femur with the calculated acceleration data and the measured acceleration data to determine a radius value corresponding to the acceleration data and the measured acceleration data at the distal end of the femur;
a sensor orientation interface for providing orientation data for the femur from a tracking of the femoral frame of reference.
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Accused Products
Abstract
A system for tracking a femoral frame of reference in computer-assisted surgery comprises a sensor unit. The sensor unit is adapted to be secured to the femur. The sensor unit comprises accelerometer and gyroscope sensors that produce orientation data. A processing unit receives gyroscope and accelerometer data. The processing unit comprises a gyroscope-data calculator to provide calculated acceleration data resulting from movements of the femur, an accelerometer-data calculator to calculate measured acceleration data resulting from movements of the femur, and an acceleration comparator to relate an orientation of the sensor unit to the femur to define a femoral frame of reference. The femoral frame of reference is defined from the comparison between the calculated and the measured acceleration data. A sensor orientation interface provides orientation data for the femur from a tracking of the femoral frame of reference. A method for tracking a femoral frame of reference is also provided.
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Citations
16 Claims
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1. A system for tracking a femoral frame of reference in computer-assisted surgery, comprising:
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a sensor unit adapted to be secured to a distal end of a femur, the sensor unit comprising an accelerometer sensor and a gyroscope sensor both configured for producing orientation data; a processing unit configured for receiving gyroscope data and accelerometer data and comprising; a gyroscope-data calculator for providing calculated acceleration data using at least gyroscope data resulting from movements of the femur about a proximal end thereof; an accelerometer-data calculator for calculating measured acceleration data using accelerometer data resulting from the movements of the femur; and an acceleration comparator for relating an orientation of the sensor unit to the femur to define the femoral frame of reference, the acceleration comparator performing a numerical optimization to determine the orientation of the sensor unit, the numerical optimization using at least a plurality of estimated radius values between the proximal end and the distal end of the femur with the calculated acceleration data and the measured acceleration data to determine a radius value corresponding to the acceleration data and the measured acceleration data at the distal end of the femur; a sensor orientation interface for providing orientation data for the femur from a tracking of the femoral frame of reference. - View Dependent Claims (2, 3, 4, 5, 6, 16)
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7. A method for tracking with a tracking system a femoral frame of reference with a sensor unit comprising an accelerometer sensor and a gyroscope sensor secured to a femur, comprising:
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obtaining with the tracking system gyroscope readings and accelerometer readings from the sensor unit and resulting from movements of the femur; calculating acceleration data with the tracking system using at least the gyroscope readings; measuring acceleration data with the tracking system using the accelerometer readings; comparing with the tracking system the calculated and the measured acceleration data using at least a plurality of estimated radius values in a numerical optimization to determine a radius value corresponding to the calculated acceleration data and the measured acceleration data at a distal end of the femur, whereby an orientation of the sensor unit is related to the femur; relating with the tracking system the orientation of the sensor unit to the femur using the comparison to define the femoral frame of reference; and tracking with the tracking system the femoral frame of reference from the gyroscope readings and from the accelerometer readings. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14, 15)
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Specification