Electromagnetic Tracking Distortion Tolerance via Frequency Optimization
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Solution Overview
Problem
Electromagnetic tracking systems suffer from accuracy degradation due to electromagnetic field distortion caused by uncharacterized metal objects within the tracking volume, leading to inaccuracies in position and orientation calculations.
Innovation Solution
The method involves calculating multiple position and orientation values using different coil combinations and transmitter frequencies, analyzing these values to determine differences, and applying optimizing techniques to adjust operating conditions, such as removing specific coils or adjusting frequencies, to reduce distortion and improve tracking accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If electromagnetic tracking systems use standard coil configurations and fixed operating frequencies, then the system operation is simple, but the accuracy degrades in the presence of metal distorters
Solution Approach 1:
The system dynamically adjusts operating frequencies and selects optimal coil combinations based on real-time distortion detection. Multiple frequencies are tested to identify those least affected by metal distorters, and coil combinations are selectively activated or deactivated based on their performance in the presence of distorters, transforming a static system into an adaptive one that maintains accuracy in varying electromagnetic environments
Solution Approach 2:
The system changes key operating parameters including electromagnetic frequency and coil configuration in response to detected distortion. By sweeping through multiple frequencies and measuring field characteristics, the system identifies optimal parameters that minimize distortion effects, thereby maintaining measurement precision without requiring complex hardware modifications
2Reliability
If multiple coil combinations and frequencies are used to calculate position and orientation values, then the distortion tolerance improves, but the calculation complexity and processing time increase
Solution Approach 1:
The system segments the electromagnetic field measurement into multiple independent coil combinations that can be evaluated separately. Each coil combination provides an independent position and orientation calculation, allowing the system to compare results and identify measurements least affected by distortion. This segmentation enables systematic evaluation of multiple pathways without overwhelming computational complexity
Solution Approach 2:
The system implements feedback by continuously comparing position and orientation values derived from different coil combinations and frequencies. When discrepancies exceed thresholds indicating distortion effects, the system uses this feedback to select the most reliable measurement set or to trigger parameter adjustments, creating a closed-loop system that maintains reliability through intelligent data selection
3Measurement precision
If the system continuously monitors and adjusts operating conditions to reduce distortion effects, then the tracking accuracy is maintained, but the processing time and computational load increase
Solution Approach 1:
The system performs distortion monitoring and parameter optimization at periodic intervals rather than continuously. Operating frequencies are swept and coil combinations are evaluated at scheduled moments, allowing the system to maintain tracking accuracy through intermittent optimization while avoiding the computational burden of continuous adjustment, thus reducing processing time overhead
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
This approach enhances the distortion tolerance of electromagnetic tracking systems, minimizing the impact of metal distorters and maintaining accurate position and orientation calculations, thereby improving system reliability and precision.
Implementation Method 1
An alternating drive current signal is provided to each coil in the electromagnetic transmitter, generating an electromagnetic field being emitted from each coil of the electromagnetic transmitter. The electromagnetic field generated by each coil in the electromagnetic transmitter induce a voltage in each coil of the electromagnetic receiver.
Data Source
AI summary
A system and method for improving the tolerability of metal distorters within the electromagnetic field of an electromagnetic tracking system through the use of transmission frequency optimization techniques and/or solution subset measurements.