Miniaturized Raman Diagnostic System Using Wavelength Interval Selection

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Solution Overview

Problem

Raman diagnostic methods for clinical applications face challenges due to lack of robustness and calibration transfer issues caused by spurious correlations and large spatial footprint of Raman systems, making them unsuitable for clinical use, especially in portable and cost-effective devices like continuous blood glucose monitoring.

Innovation Solution

The use of wavelength interval selection based on non-linear representation, such as support vector regression, to minimize cross-validation error, allowing for a miniaturized Raman system with reduced size and weight, utilizing optical bandpass filters and tunable filters, and improved signal acquisition time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a full spectrograph-CCD system is used to acquire complete spectral information, then measurement precision is improved, but device complexity and spatial footprint increase

Engineering Contradiction:
Improvespectral information accuracyVSAvoidsystem size
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The invention extracts and eliminates uninformative or spurious spectral regions from the full spectrum, retaining only the informative spectral features needed for accurate analyte measurement. This extraction approach allows using a simplified detection system rather than a full spectrograph-CCD system, thereby reducing device complexity and spatial footprint while maintaining measurement precision.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of acquiring the complete spectrum, the invention uses only the partial spectral information that is actually informative for the specific analyte measurement. By applying multivariate calibration to select and use only the relevant spectral regions, the system achieves accurate measurements with reduced spectral data, enabling miniaturization of the Raman system.

Inventive Principle:
Principle #16Partial or excessive action

2Device complexity

If wavelength interval selection based on non-linear representation is used, then device complexity is reduced, but measurement precision may worsen

Engineering Contradiction:
Improvesystem simplificationVSAvoidprediction accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The invention changes the parameter of spectral representation from linear to non-linear (using support vector regression with kernel functions). This parameter change allows the simplified system with wavelength interval selection to maintain or even improve prediction accuracy by capturing non-linear relationships in the spectral data, thereby resolving the contradiction between device simplification and measurement precision.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If CCD detectors are cooled to reduce thermal noise, then measurement precision is improved, but device complexity and weight increase

Engineering Contradiction:
Improvesignal-to-noise ratioVSAvoidcooling system requirements
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The invention extracts and eliminates uninformative spectral regions that contribute to noise, thereby improving the signal-to-noise ratio without requiring additional cooling systems. By focusing detection resources on only the informative spectral features, the system achieves good measurement precision with simpler, uncooled detector designs.

Inventive Principle:
Principle #2Taking out (Extraction)

4Measurement precision

If multivariate calibration is performed on full spectral region, then prediction accuracy is improved, but spurious correlations increase

Engineering Contradiction:
Improveprediction accuracyVSAvoidcalibration robustness
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The invention extracts and removes spurious spectral regions that cause harmful correlations between analyte signals and interferents. By eliminating these uninformative regions before multivariate calibration, the system improves calibration robustness and reliability while maintaining prediction accuracy, directly addressing the contradiction between accuracy and reliability.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentUS9662047B2Portable raman diagnostic system
Publication Date: 2017.05.30 MASSACHUSETTS INST OF TECH
  • US9662047B2 patent drawing
  • US9662047B2 patent drawing
  • US9662047B2 patent drawing

AI summary

The present invention further relates to the selection of the specific filter combinations, which can provide sufficient information for multivariate calibration to extract accurate analyte concentrations in complex biological systems. The present invention also describes wavelength interval selection methods that give rise to the miniaturized designs. Finally, this invention presents a plurality of wavelength selection methods and miniaturized spectroscopic apparatus designs and the necessary tools to map from one domain (wavelength selection) to the other (design parameters). Such selection of informative spectral bands has a broad scope in miniaturizing any clinical diagnostic instruments which employ Raman spectroscopy in particular and other spectroscopic techniques in general.