Probe Shape Detection Using Lookup Tables to Reduce Processing Time
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Solution Overview
Problem
Conventional probe shape detection methods, such as those using magnetic field detection and Newton-Raphson or multivariate analysis, require extensive calculations and lengthy processing times to determine the position and orientation of magnetic field generation elements in a probe, hindering efficient shape detection during insertion into a subject.
Innovation Solution
A probe shape detection apparatus and method that utilize a drive signal to generate magnetic fields, multiple magnetic field detection sections, candidate position storage, and error calculation to quickly determine the orientation and position of magnetic field generation elements, reducing the computational burden and processing time by minimizing error between detected and estimated electromotive voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional methods using Newton-Raphson or multivariate analysis are used to estimate position information, then measurement precision is improved, but productivity deteriorates due to extremely long detection time
Solution Approach 1:
The patent pre-calculates and stores voltage values for all possible source coil positions and sensor coil positions in lookup tables before actual detection. During detection, the system only needs to query these pre-computed tables and compare values, avoiding time-consuming iterative calculations. This preliminary preparation of data enables rapid position estimation while maintaining accuracy.
Solution Approach 2:
The patent replaces the conventional iterative mathematical calculation system (Newton-Raphson method) with a lookup table-based comparison system. Instead of performing repeated differential equations and matrix operations, the system uses simple table queries and value comparisons, dramatically reducing computational complexity and detection time.
2Measurement precision
If six variables are used to calculate voltage estimate value for positions and orientations, then measurement precision is improved, but device complexity worsens due to considerable calculation requirements
Solution Approach 1:
The patent separates the estimation of position and orientation into independent processing steps. First, the source coil position is determined by comparing voltage values from lookup tables. Then, the orientation is calculated based on the determined position and additional voltage component comparisons. This segmentation reduces the complexity of simultaneous six-variable calculation.
Solution Approach 2:
The patent uses pre-computed lookup tables that contain voltage values copied from theoretical calculations performed in advance. During actual detection, the system copies and compares these pre-stored values rather than performing complex real-time calculations, significantly reducing computational burden while maintaining estimation accuracy.
3Measurement precision
If iterative calculations are performed repeatedly to obtain final estimation result, then measurement precision is improved, but loss of time worsens due to extremely long detection time
Solution Approach 1:
The patent performs all iterative calculations and convergence checks in advance during the lookup table generation phase. The stored voltage values already represent converged, accurate solutions. During actual detection, no iterative calculations are needed—only direct comparisons with pre-computed values, eliminating time loss while preserving measurement precision.
Solution Approach 2:
The patent skips the time-consuming iterative calculation process during actual detection by using pre-computed lookup tables. The system rushes through the detection process by directly comparing measured voltages with stored reference values, achieving rapid results without sacrificing 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
This approach significantly reduces the time required for probe shape detection, improves frame rate, and enhances image quality and responsiveness during insertion operations, while avoiding divergence issues and instability in calculation times.
Implementation Method 1
transmits a drive signal for causing a magnetic field to be generated from a magnetic field generation element
Implementation Method 2
detects the magnetic field emitted from the magnetic field generation element as magnetic field components in three mutually orthogonal axial directions
Data Source
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AI summary
A probe shape detection apparatus includes first and second magnetic field detection sections that detect a magnetic field emitted from a magnetic field generation element provided in a longitudinal direction of an elongated probe as magnetic field components in mutually orthogonal three axial directions and output a magnetic field detection signal in accordance with an electromotive voltage group generated when the magnetic field components are detected, a candidate vector calculation section that calculates a candidate vector indicating the orientation of the magnetic field generation element based on the electromotive voltage group generated in the first magnetic field detection section and one piece of candidate position information, an estimated electromotive voltage calculation section that calculates an estimated electromotive voltage based on the one piece of candidate position information and the candidate vector and an estimated position acquiring section that acquires a candidate position that minimizes an error between the electromotive voltage group generated in the second magnetic field detection section and the estimated electromotive voltage as an estimated position of the magnetic field generation element.