Material Identification via Spherical Metric Learning

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Solution Overview

Problem

Existing material identification systems using spectral data face challenges in accurately classifying a large number of material kinds due to similarities in spectral features, leading to insufficient precision when using standard one-dimensional CNNs, especially when dealing with a vast database like the Inorganic Crystal Structure Database (ICSD).

Innovation Solution

A system combining one-dimensional CNNs with deep metric learning algorithms, employing physics-based data augmentation and hierarchical metric learning, to enhance the identification of materials by generating varied spectral data and mapping characteristic vectors onto a spherical surface for improved classification accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If standard one-dimensional CNN is used for material identification, then the system is simple and fast, but the identification precision is insufficient when dealing with similar spectral data

Engineering Contradiction:
Improveidentification precisionVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent transforms the spectral data from a one-dimensional signal into a two-dimensional spherical coordinate system, where the spectral intensity is mapped onto a sphere's surface. This parameter transformation enables the use of deep metric learning algorithms that operate on 2D data, significantly improving the ability to distinguish between similar materials while maintaining computational efficiency through geometric transformation rather than complex architectural changes.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces a spherical coordinate system as an intermediary representation between the input spectral data and the classification algorithm. By mapping spectral intensities onto spherical coordinates and using deep metric learning as an intermediary processing layer, the system bridges the gap between simple 1D CNN input and high-precision classification, achieving both accuracy and efficiency.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If deep metric learning is applied to classify huge number of material kinds, then the identification accuracy improves, but the computational time and data processing complexity increases

Engineering Contradiction:
Improveclassification accuracyVSAvoidcomputational time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent performs preliminary transformation of spectral data into spherical coordinates before applying deep metric learning. This pre-processing step organizes the data in a geometrically meaningful way that accelerates the metric learning process, allowing the system to handle large databases efficiently by establishing clear angular and radial relationships among spectral features before classification begins.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent applies spherical geometry to represent spectral data, where spectral intensities are mapped onto a sphere's surface area. This curvature-based representation naturally handles the periodic and rotational characteristics of spectral data, enabling deep metric learning to operate more efficiently by exploiting the inherent geometric structure of the data manifold, thus reducing computational complexity while maintaining high accuracy.

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Reliability

If physics-based data augmentation is used to generate varied spectral data, then the model robustness improves, but the data processing and generation time increases

Engineering Contradiction:
Improvemodel robustnessVSAvoiddata generation efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent applies physics-based transformations to generate augmented spectral data by modifying physical parameters such as spectral shift, intensity scaling, and noise addition that reflect real measurement conditions. These parameter changes create realistic variations in the spherical coordinate representation, improving model robustness to actual measurement uncertainties while maintaining computational efficiency through straightforward mathematical transformations rather than complex data generation processes.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS12146844B2Material species identification system using material spectral data
Publication Date: 2024.11.19 TOYOTA JIDOSHA KK
  • US12146844B2 patent drawing
  • US12146844B2 patent drawing
  • US12146844B2 patent drawing

AI summary

A system of collating a spectral data of an arbitrary material with spectral data of existing materials to identify the kind of the arbitrary material comprises a one-dimensional CNN processor calculating a characteristic value vector based on a spectral data of a material by a one-dimensional convolution neural network algorithm, and a metric learning processor computing a probability that the kind of the material is each kind of the existing materials from the characteristic value vector by a deep metric learning algorithm. The processors learn with the spectral data of existing materials to compute a probability for the kind of each material such that the probabilities for the kinds of the respective materials inputted for data for learning becomes maximum. When the data of the arbitrary material is inputted, the kind giving the maximum probability is identified as the kind of the arbitrary material with high precision.