High-Resolution Resistance Tomography Through Orthogonal Basis Mapping

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Solution Overview

Problem

Traditional two-dimensional resistance tomography methods suffer from low resolution and inefficient use of computational resources due to reliance on ill-defined mesh problems and poorly placed contact electrodes, leading to non-unique solutions and wasted computing power.

Innovation Solution

Implementing an orthogonal basis with a maximum number of elements N, strategically positioning electrodes for sensitivity to these basis functions, and optimizing current and voltage electrode pairs to maximize signal-to-noise ratio, while using polynomial functions to enhance image resolution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a large number of periphery contact electrodes are used to increase tomographic image resolution, then measurement precision is improved, but device complexity and computational resources required increase significantly

Engineering Contradiction:
Improvetomographic image resolutionVSAvoidnumber of contact electrodes
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent uses a reduced set of periphery contact electrodes that strategically measure and infer resistance values across the membrane surface. Instead of requiring numerous electrodes, the system uses a minimal set to capture sufficient data that can be processed through algorithms to reconstruct high-resolution tomographic images, effectively copying the information from limited measurement points to the entire surface.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The patent transforms the measurement approach by changing from direct point-by-point resistance measurement to measuring voltage drops across the membrane using periphery electrodes. This parameter change enables the system to derive resistance information indirectly through voltage measurements and computational processing, achieving high resolution without increasing electrode count.

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If traditional mesh algorithms are used with limited electrode data, then device complexity is reduced, but manufacturing precision and solution reliability deteriorate due to ill-defined mesh problems

Engineering Contradiction:
Improvealgorithm simplicityVSAvoidsolution uniqueness
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent applies preliminary action by pre-defining the membrane surface with a mathematical basis function expansion (Fourier series or finite element shape functions). This preliminary mathematical framework is established before measurement, providing a structured approach to reconstruct resistance distribution from limited electrode data, ensuring solution uniqueness and reliability without requiring complex adaptive mesh algorithms.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent replaces traditional mechanical mesh-based resistance mapping with a mathematical field theory approach. Instead of using complex mesh algorithms to interpolate resistance values, the system uses basis function expansions to represent the resistance distribution analytically, substituting computational mechanics with mathematical modeling that ensures unique solutions.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Device complexity

If periphery contact electrodes are poorly placed, then device complexity is minimized, but measurement precision and information quality deteriorate leading to non-optimal measurements

Engineering Contradiction:
Improveelectrode configurationVSAvoidsignal-to-noise ratio
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent employs asymmetric placement of periphery contact electrodes around the membrane boundary, strategically positioned to maximize the information content of measurements. The electrodes are placed at specific angular positions and distances from the center that optimize the independence of measured voltage signals, ensuring high signal-to-noise ratio and unique solution recovery without requiring symmetric arrays of numerous electrodes.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The patent introduces mathematical basis functions as intermediaries between the periphery electrode measurements and the internal resistance distribution. These basis functions act as mediators that transform the limited voltage measurements into a complete resistance map, allowing optimal information extraction from minimally placed electrodes through the intermediary mathematical transformation.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

Enhances tomographic image resolution and reduces computational time by ensuring a unique solution and maximizing independent measurements, thereby improving the accuracy and efficiency of resistance tomography.

Implementation Method 1

two-dimensional (2-D) and three-dimensional (3-D) tomographic mapping of contact pressure using a resistive elastomer sensing membrane to produce a change in resistance when contact pressure is applied

Methodology Applied
Scientific EffectPiezoresistive Effect: Piezoresistive Effect

Data Source

PatentUS12357188B2High resolution two-dimensional resistance tomography
Publication Date: 2025.07.15 NORTHWESTERN UNIV
  • US12357188B2 patent drawing
  • US12357188B2 patent drawing
  • US12357188B2 patent drawing

AI summary

The disclosed 2-D and 3-D tomographic resistance imaging method improves tomographic resistance image resolution by adopting an orthogonal basis with the maximum number of elements N to describe the maximum resolution resistivity map ρ(r), where this number of elements N is set according to the number of electrodes Q; by defining the orthogonal basis according to any known constraints in the problem, thereby enhancing the resolution where it is needed; by positioning electrodes to be sensitive to these basis functions; and by choosing current I and voltage V contact electrode pairs that maximize signal-to-noise ratio.