Magnetic Tracking Distortion Correction via Optical Feedback
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Solution Overview
Problem
Existing electromagnetic tracking systems for medical procedures face challenges in accurately determining the position of surgical instruments due to distortions in the magnetic field caused by metallic objects in the environment.
Innovation Solution
The system incorporates a magnetic tracking device with both a magnetic signal receiver and a non-magnetic signal receiver, such as a camera, to measure additional data. This data is used to map distortions in the magnetic signal to specific locations in the environment, allowing for more accurate tracking by compensating for these distortions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If electromagnetic tracking is used to determine position of surgical instruments, then tracking capability is provided, but measurement precision deteriorates due to magnetic field distortions from metallic objects
Solution Approach 1:
The patent introduces visual markers and optical tracking as an intermediary system to establish the true position of the magnetic receiver. By comparing magnetic field-based position estimates with optically-verified positions, the system identifies and compensates for magnetic distortions caused by metallic objects in the environment.
Solution Approach 2:
The system implements feedback by continuously comparing magnetic tracking data with optical tracking data. The visual system provides ground truth position information that feeds back into the magnetic tracking algorithm, allowing real-time correction of distortion-induced errors and improvement of measurement precision.
2Measurement precision
If visual markers are added to map magnetic distortions, then measurement precision improves, but device complexity increases
Solution Approach 1:
The magnetic tracking device performs self-calibration by using its own visual markers to establish its position through optical tracking. This self-service approach eliminates the need for separate calibration equipment or complex external reference systems, reducing overall device complexity while maintaining high distortion mapping accuracy.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system achieves more accurate tracking of surgical instruments by effectively compensating for magnetic field distortions, thereby improving the precision and reliability of medical procedures.
Implementation Method 1
a magnetic tracking device (140, 240) including a magnetic signal receiver (130, 230)
Implementation Method 2
The non-magnetic tracking device can include a visual tracking device, such as a camera
Data Source
AI summary
A magnetic tracking device is configured to track an object in an environment by receiving a measurement of the non-magnetic signal and a corresponding measurement of the magnetic signal for a location of the magnetic tracking device in the environment. The magnetic tracking device estimates, based on the measurement of the non-magnetic signal, a non-magnetic pose of the magnetic tracking device in the environment for the location. The device estimates, based on the measurement of the magnetic signal, a magnetic pose of the magnetic tracking device in the environment for the location. The device determines a difference between the magnetic pose estimate and the non-magnetic pose estimate for the location. The device determines a magnetic distortion correction value for the location based on the difference. The magnetic tracking device generates a distortion correction model including the distortion value and outputs a representation of the distortion correction model.