Motion tracking system with inertial-based sensing units
Inventors
Mahfouz, Mohamed R. • To, Gary
Assignees
Interested in licensing this patent?
MTEC can help explore whether this patent might be available for licensing for your application.
Publication Number
US-11004561-B2
Publication Date
2021-05-11
Expiration Date
Abstract
Systems, apparatus, and method of monitoring a position of a joint. An inertial monitoring unit is configured to be coupled to a portion of a patient, such as a thigh. Another inertial monitoring unit is configured to be attached to another portion of the patient, such as a shank, that is connected to the other portion by a joint, such as a knee. The inertial monitoring units detect motion of their respective portions of the patient and transmit data indicative of this motion. These transmissions may be received by a computer and used to determine an orientation of the joint. The inertial monitoring units may also be coupled to vibration detection units and/or ultrasound modules that provide additional data regarding a condition of the joint.
Core Innovation
The invention provides an in-vivo joint monitoring system for tracking orientation of an anatomical feature in three dimensions during a medical diagnosis procedure. A brace comprising inertial monitoring units is mounted proximate the anatomical feature to be tracked, including a thigh and shank for monitoring a knee joint. The inertial monitoring units wirelessly transmit motion data for real-time joint orientation estimation.
Each inertial monitoring unit includes accelerometer, gyroscope, and magnetometer sensing, and generates orientation information using a processor and accelerometer data as part of a prediction model. A gravity and magnetic-field vectors define a global reference, while gyroscope data provides rotational updates. Data output from the gyroscope is at least one of verified and corrected to address gyroscopic drift using the generated orientation information, and the orientation of the anatomical feature is determined in real-time using at least one of the verified and corrected data.
The disclosed system optionally incorporates additional modules for joint-state sensing and compensation, including vibration detection and pulse-echo ultrasound modules with dynamic gain. These modules track relative bone pose to compensate for inertial monitoring unit-to-bone displacement. Joint state estimation and sensor fusion are detailed conceptually using Kalman-filter-based orientation models using Euler angles or quaternions and a non-linear particle-filter quaternion formulation on Stiefel manifolds using von Mises-Fisher and non-uniform/Bingham-like distributions, with particle maintenance and resets for robustness.
Claims Coverage
The independent claim includes 6 inventive features centered on brace-mounted accelerometer and gyroscope data collection, prediction-model-based orientation generation, gyroscopic drift verification and correction, real-time orientation determination, and real-time virtual model display with updated orientation. A dependent refinement specifies drift correction that generates three-dimensional position information.
Brace-mounted accelerometer and gyroscope for real-time data collection
Providing a brace comprising at least one accelerometer and at least one gyroscope, where the brace is mounted proximate the anatomical feature to be tracked in three dimensions as part of the medical diagnosis procedure; collecting data from the at least one accelerometer in real-time; and collecting data from the at least one gyroscope in real-time.
Accelerometer-based prediction model for generating orientation information
Generating orientation information using a processor and the data collected from the at least one accelerometer as part of a prediction model.
Gyroscopic drift verification and correction using generated orientation information
Verifying and correcting data output from the at least one gyroscope to address gyroscopic drift using the generated orientation information.
Real-time orientation determination of the anatomical feature from verified and corrected gyroscope data
Determining the orientation of the anatomical feature in real-time using at least one of the data verified and corrected.
Real-time virtual model display with updated orientation
Displaying a virtual model of the anatomical feature and updating an orientation of the virtual model in real-time to match the determined orientation of the anatomical feature.
Drift correction generating three-dimensional position information
At least one of verifying and correcting data output from the at least one gyroscope to address gyroscopic drift includes generating three dimensional position information using the processor with the accelerometer data as part of the prediction model.
The claim coverage is centered on real-time three-dimensional orientation tracking during a medical diagnosis procedure using a brace with accelerometers and gyroscopes, where accelerometer data drives a prediction model and gyroscope drift is addressed by verifying and correcting gyroscope output using the generated orientation information. The method determines orientation in real-time and updates a virtual model accordingly, with a dependent refinement specifying that drift correction includes generating three-dimensional position information using the processor with accelerometer-derived prediction-model data.
Stated Advantages
Enables tracking the orientation of an anatomical feature in three dimensions in real-time during a medical diagnosis procedure.
Addresses gyroscopic drift by at least one of verifying and correcting gyroscope output using generated orientation information.
Provides real-time visualization by displaying a virtual model of the anatomical feature and updating its orientation to match the determined orientation.
Documented Applications
Human and veterinary joint diagnosis and navigation using joint orientation estimation for monitored joints such as a knee joint.
Equine joint diagnosis and navigation.
Canine joint diagnosis and navigation.
Interested in licensing this patent?