Optical Pathlength Calibration for Temperature-Shifted Spectral Estimation
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Solution Overview
Problem
Existing methods for non-invasive bio-information measurement, such as Raman spectroscopy and NIRS, face limitations when temperature changes occur during spectrum measurement due to simultaneous changes in absorption and scattering coefficients, which affect optical pathlength distribution, making quantitative analysis using the Beer-Lambert law inaccurate.
Innovation Solution
An apparatus and method that modulates the temperature of an object, measures its spectrum at various temperatures, and uses effective optical pathlength vectors to estimate target components like blood glucose, using a processor to calculate representative optical pathlengths and generate a target component estimation model based on absorbance changes and Monte Carlo simulations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If temperature modulation is performed to account for temperature-induced changes, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The system performs preliminary temperature modulation and spectrum measurement across multiple temperatures to pre-determine effective optical pathlength vectors and representative values before actual bio-information measurement. This preliminary calibration phase accounts for temperature-induced changes in advance, allowing the main measurement to use pre-computed correction factors rather than requiring complex real-time temperature compensation during measurement.
Solution Approach 2:
The patent introduces effective optical pathlength vectors as an intermediary parameter that mediates between temperature changes and absorbance measurements. Instead of directly compensating for temperature effects on absorption and scattering coefficients, the system uses temperature-modulated spectrum measurements to determine effective optical pathlength vectors that inherently capture temperature-induced changes, simplifying the compensation mechanism.
2Reliability
If effective optical pathlength vectors are calculated based on temperature-modulated spectra, then reliability of quantitative analysis is improved, but loss of time increases
Solution Approach 1:
The system performs the time-consuming temperature modulation and effective optical pathlength vector calculation as a preliminary calibration step that is executed once or periodically, rather than continuously during each measurement. The pre-determined representative effective optical pathlength values are then reused for subsequent bio-information measurements, amortizing the time investment over multiple measurements and improving overall efficiency.
Solution Approach 2:
Temperature modulation and spectrum measurement for determining effective optical pathlength vectors are performed periodically rather than continuously. The system establishes temperature-dependent effective optical pathlength characteristics at discrete temperature points, then interpolates or uses the nearest calibrated values for measurements between these points, reducing the frequency of full calibration cycles.
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 allows for accurate estimation of bio-components by accounting for temperature-induced changes in optical pathlengths, improving the precision of bio-information measurement beyond the limitations of the Beer-Lambert law.
Implementation Method 1
a heater configured to provide thermal energy to the object
Implementation Method 2
a temperature sensor configured to measure the temperature change of the object
Implementation Method 3
a detector configured to detect light scattered or reflected from the object
Implementation Method 4
measure a spectrum for each temperature of the object
Data Source
AI summary
Provided is an apparatus for estimating a target component, the apparatus including a temperature controller configured to modulate temperature of an object, a measurer configured to measure a spectrum for each temperature of the object that changes based on the modulation, and a processor configured to obtain effective optical pathlength vectors corresponding to a temperature change based on the spectrum for each temperature of the object, obtain a representative effective optical pathlength based on the obtained effective optical pathlength vectors, and obtain a target component estimation model based on the obtained representative effective optical pathlength.