Scattering Absorber Measurement Using Wavelength Ratio Constraints
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Solution Overview
Problem
Conventional methods for noninvasive measurement of internal information in scattering absorbers, such as living tissues, face accuracy issues due to decreased signal-to-noise ratio and increased errors in reduced scattering coefficient calculations, especially when the distance between light incidence and detection positions is large or when light-absorbing material concentration is high.
Innovation Solution
A scattering absorber measurement device and method that determine the ratio of reduced scattering coefficients among multiple wavelengths, using this ratio to improve the accuracy of reduced scattering and absorption coefficient calculations through fitting and weighting based on time-resolved measurement profiles, thereby enhancing the reliability of detection results.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If photon diffusion theory is applied to calculate reduced scattering coefficient and absorption coefficient for each wavelength, then the measurement can be performed noninvasively, but the accuracy of reduced scattering coefficient calculation decreases when distance is long or light-absorbing material concentration is high
Solution Approach 1:
The patent changes the approach by determining the ratio of reduced scattering coefficients at different wavelengths and using this ratio to constrain the calculations. Instead of directly calculating the reduced scattering coefficient for each wavelength independently, the system uses the wavelength-dependent ratio relationship to improve accuracy, especially in regions with low signal-to-noise ratio or high absorption.
Solution Approach 2:
The system uses detection results from multiple wavelengths to feedback-correct the reduced scattering coefficient calculations. By comparing detection signals at different wavelengths and using the determined ratio relationship, the system iteratively improves the accuracy of the calculated optical parameters, particularly in challenging measurement conditions.
2Device complexity
If Mie scattering approximation is used to describe wavelength dependence of reduced scattering coefficient, then the theory is simplified, but error increases in actual scattering absorbers like living body tissue
Solution Approach 1:
The patent determines the actual wavelength dependence of the reduced scattering coefficient by analyzing detection signals from multiple wavelengths in the specific scattering absorber being measured. This empirical approach replaces the generic Mie scattering approximation with measured data-specific parameters, allowing the system to adapt to the actual tissue properties and improve measurement accuracy.
Solution Approach 2:
Instead of relying on a universal theoretical model (Mie scattering), the system creates a customized wavelength dependence profile by copying the actual measurement characteristics from the specific tissue sample. The determined ratio of reduced scattering coefficients at different wavelengths serves as a template that reflects the actual tissue properties rather than theoretical assumptions.
3Ease of manufacture
If reduced scattering coefficient and absorption coefficient are calculated separately for each wavelength, then the calculation process is straightforward, but the S/N ratio of detection signal decreases with long distance or high concentration
Solution Approach 1:
The patent merges the analysis of multiple wavelength detection signals into a unified approach. By determining the ratio of reduced scattering coefficients across wavelengths and using this combined information to constrain the calculations, the system improves the effective signal-to-noise ratio. The multi-wavelength data is integrated to provide mutual verification and reduce the impact of noise in individual measurements.
Solution Approach 2:
The system uses detection results from multiple wavelengths to feedback-correct the optical parameter calculations. The determined ratio relationship between wavelengths provides a constraint that feeds back into the calculation process, improving the reliability of the results even when individual wavelength measurements have low signal-to-noise ratio.
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 more accurate calculation of reduced scattering and absorption coefficients, improving the precision of internal information measurement even under conditions with low signal-to-noise ratios or varying light absorption, such as in living tissues.
Implementation Method 1
a light source unit (31) that emits multiple light pulses P(1) to P(N) having different wavelengths to a scattering absorber B
Implementation Method 2
a photodetector that detects each light pulse P(n) output from the light source unit (31)
Data Source
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AI summary
A scattering absorber measurement device includes a light source for outputting a plurality of light pulses having different wavelengths input to a scattering absorber, a photodetector for detectting each light pulse propagating inside the scattering absorber and output a detection signal, and a computation unit for calculating a reduced scattering coefficient and an absorption coefficient according to a time-resolved spectroscopic measurement method on the basis of the detection signal. The computation unit determines data related to a ratio of reduced scattering coefficients among wavelengths of the plurality of light pulses and calculates the reduced scattering coefficient and the absorption coefficient on the basis of a time-resolved measurement profile of each wavelength based on the detection signal and the data related to the ratio.