CN102058393B - Method for measuring kin physiology parameters and optical property parameters based on reflective spectral measurement - Google Patents

Abstract

The invention provides a method and system for measuring skin physiology parameters and optical property parameters based on reflective spectral measurement. The measuring system is composed of measuring equipment for a skin reflection spectrum and a computation and display device. By utilizing an analysis method of combining experimental data with the Monte Carlo simulation, the measuring system provides more accurate corresponding data of reflection light intensity and skin optical property; during the practical measurement of sample skin, on the basis of a practically measured reflection spectrum, the data and more physiology parameters are calculated and fit to obtain the skin physiology parameters and the optical property parameters based on reflective spectral measurement; finally, the optical property parameters of the skin adsorption coefficient mu a, a reduction scattering coefficient mu s' and the like as well as physiological information, such as melanin content, deoxygenated haemoglobin content, oxygenated haemoglobin content, moisture content and the like are also measured are measured in real time in a non-invasive and lossless mode.

Description

Based on the skin physiology parameter of reflective spectral measure and the measuring method of optical property parameter

Technical field

The invention belongs to spectral technique and use and biomedical engineering field, relate to a kind of based on the skin physiology parameter of reflective spectral measure and the measuring method of optical property parameter.

Background technology

In recent years, utilize optical instrument to carry out medical diagnosis and receive biomedical researcher's extensive concern just gradually with treatment.With respect to other medical science detection techniques such as X ray, CT, nuclear magnetic resonance, NMR, no damage structure and Function detection that optical technology can be implemented to organize with the mode of non-intrusion type, and have advantages such as applied widely, portable high, with low cost.The tissue optical property parameter is described the response of biological tissue to the different wave length incident illumination through the evaluation to optical characteristics such as absorption and scattering in the tissue.Optical property parameter in the quantitative assessment tissue will help to optimize the diagnosis degree of depth and optical image technology the image quality in biological tissue of optical diagnostic method in biological tissue on the one hand.On the other hand, can provide quantitative analysis, help to optimize the therapeutic dose of optical therapeutic the energy intensity that optical therapeutic arrives therapentic part.In addition, the tissue optical property parameter itself is to be determined by physiological status in the tissue, and for example: mainly be by melanin in the skin to visible and near-infrared wavelength absorption down in the skin histology, the Oxygenated blood red eggs are white, and deoxyhemoglobin and moisture are contributed.Absorption intensity in this wave-length coverage has just reflected the height of these content of material.Therefore, the skin optical parameter measurements can further reflect the variation of skin physiology parameter, thereby the physiological status of skin surface is provided the evaluation of objective science.

Maximum and the most important organ as human body, the thickness of skin is about 0.5～4mm, and gross weight accounts for 8% of human body, has held the blood circulation of human body about 1/3 and about 1/4 moisture in the skin.Optical property parameters such as the absorptance μ a of skin histology and reduced scattering coefficient μ ' s have very important meaning for laser diagnostics, laser therapy, light dosage scheduling theory research and clinical practice.Melanin is the main absorbing material in the skin epidermis, and pale degree of its concentration and skin and mottle are formed with direct relation, and the melanin of debita spissitudo can stop the influence of excessive ultraviolet radiation to skin; Healthy subjects epidermal area melanin concentration between 1%-10% (referring to S.L.Jacques; " Origins of tissue optical properties inthe UVA, visible, and NIR regions; " In Advances in Optical Imaging andPhotonMigration; R.R.Alfano and J.G.Fuj imoto, eds. (Optical Society of America), 1996).The Oxygenated blood red eggs are white in the skin, and deoxyhemoglobin is relevant with the skin histology microcirculating state, reacted the power of tissue metabolism's ability; Healthy subjects skin Oxygenated blood red eggs total concentration white and deoxyhemoglobin be total hemoglobin content between 0.2%-7% (referring to E.Angelopoulou, " Understanding the color of human skin, " Proc.SPIE 4299; 243-251,2001), and Oxygenated blood red eggs proportion in total hemoglobin in vain; Be blood oxygen saturation between 0%-100% (referring to D.Yudovsky and L.Pilon; " Rapid and accurate estimation of bloodsaturation, melanin content, and epidermis thickness from spectral diffusereflectance "; Applied Optics, 2010).Moisture in the skin is the important indicator that influences skin elasticity and physiological status; The moisture of healthy subjects skin between 15%-70% (referring to R.R.Warner; M.C.Myers and D.A.Taylor; " Electron Probe Analysis of Human Skin:Determination of the WaterConcentration Profi le ", Journal of Investigative Dermatology, 1988).

The method of measuring the tissue optical property parameter mainly contains two kinds; A kind of is the spatial distribution of measuring light behind the process tissue, through the space distribution information of analyzing light the reduced scattering coefficient of tissue is separated from the decay of tissue absorption coefficient to light intensity the contribution of light intensity attenuation.Another kind is to utilize pulse laser as light source, and the time domain light intensity signal that utilizes detector to obtain calculates the signal that receives and receives tissue scatter's effect, thereby confirms the optical properties of tissue parameter.Utilize the method for luminous intensity distribution measurement tissue optical property parameter to need a plurality of detectors to receive the decay light intensity of light source, and the tissue optical property parameter in distance range must be consistent through the tissue transmission with different distance.(referring to F.Bevilacqua; D.Piguet etc.; " In vivolocal determination of tissue optical properties:applications to human brain " .Applied Optics; 1999) in order to be absorbed preferably and the scattering resolving effect, need bigger measuring range, but the complexity of skin histology structure makes large-scale measurement can't satisfy the condition of organizing homogeneity.Therefore be difficult on skin histology, be suitable for.And time domain approach is measured the tissue optical property method and need be adopted pulse laser and the time resolution detector at picosecond magnitude; (referring to B.J.Tromberg; N.Shah etc., " Non-Invasive In Vivo Characterization ofBreast Tumors Using Photon Migration Spectroscopy ", Neoplasia; 2000) equipment price is expensive, and exploitativeness is poor.

Summary of the invention

In view of the limitation of above-mentioned art methods for the measurement of skin optical characterisitic parameter; Technical problem to be solved by this invention is the corresponding data that accurate more reflective light intensity and skin optical characterisitic parameter are provided through the analytical method that experimental data and Monte Carlo simulation combine; When actual measurement sample skin, be the basis with the actual measurement reflectance spectrum; Calculate match to obtain skin physiology parameter and optical property parameter through these data and a plurality of physiological parameter, finally can't harm, measure in real time skin absorbs coefficient μ with non-invasive mode based on reflective spectral measure _aWith reduced scattering coefficient μ _s' wait optical property parameter and melanin content, deoxyhemoglobin, the white content of Oxygenated blood red eggs, physiologic informations such as moisture.

The present invention at first utilizes Monte Carlo Calculation to obtain mock standard data Tmc; Utilize fat milk solution mixing india ink imitated biological tissue to carry out organize models's experiment; Acquisition is based on the experimental standard data Texp of the corresponding optical property parameter undertissue reflective light intensity of experimental record; And through experimental standard data Texp calibrated analog normal data Tmc, thereby obtain final optimization pass normal data T.

To the actual measurement sample, obtain sample reflectance spectrum curve, utilize final optimization pass normal data T, through to melanin concentration M, total hemoglobin content B, blood oxygen saturation S, moisture W, reduced scattering coefficient μ when wavelength is 500nm _s' _500nmParameters such as Ruili scattering content f are carried out match and are obtained the simulated reflectance spectrum curve near sample reflectance spectrum curve; Calculate physiological parameter melanin concentration M, total hemoglobin content B, blood oxygen saturation S this moment; Moisture W, and further try to achieve absorptance μ a and the reduced scattering coefficient μ s ' of skin under all wavelengths.

The present invention simultaneously further comprises a kind of skin physiology parameter and optical property parameter measuring system with computing module, and this system comprises: the spectrographic measuring device of skin reflex, calculating and display device.Wherein the spectrographic measuring device of skin reflex comprises: broad spectrum light source, spectroscopic detector, incident optical, reflection probe, reception optical fiber, reflection probe support, data line.Comprise analog-to-digital conversion module, computing module, memorizer, display process module, display, data/address bus in calculating and the display device.The organize models's experimental data that measures is imported into by data line and is calculated and display device.Through being stored in after the analog digital conversion in the memorizer; Computing module utilizes Monte Carlo Calculation to obtain mock standard data Tmc; And call the organize models's experimental data that is stored in the memorizer and obtain experimental standard data Texp mock standard data Tmc is calibrated; Thereby obtain final optimization pass normal data T, and be stored in the memorizer.

When measuring skin reflex spectrum to be measured, measure the reflectance spectrum of skin to be measured and the reflectance spectrum of reflectance standards sheet respectively, measurement data is imported into by data line and is calculated and display device.Through being stored in after the analog digital conversion in the memorizer, computing module utilizes reflectance standards sheet data calibration skin measurement data to obtain measuring skin reflex spectrum.Computing module calls optimisation criteria data T, utilizes skin match reflectance spectrum corresponding under the nonlinear iteration algorithm computation different skin tissue physiology parameter.To calculate the match reflectance spectrum and compare, and obtain the pairing physiological parameter of skin reflex spectrum to be measured, and further calculate skin optical property parameter μ under all wavelengths with measuring skin reflex spectrum _aAnd μ _s', measurement result and skin reflex spectrum picture are shown on the display.

Task of the present invention provides a kind of skin physiology parameter and optical property parameter measuring method and skin physiology parameter and optical property parameter measuring system based on reflective spectral measure.

Realize that concrete technical scheme of the present invention is:

This skin physiology parameter and optical property parameter measuring method based on reflective spectral measure provided by the invention comprise the steps:

Step 1: the optimization data T of the function contact between represents optical property parameter and the reflective light intensity comprises step by step following:

A) configuration standard organize models solution;

B) optical property parameter of measurement standard organize models solution;

C) incident optical and mirror based fiber optica front end are inserted in the normal structure model solution abreast; The incident optical other end links to each other with light source; Light source provides the incident illumination that covers the 400-1000nm wave-length coverage; The mirror based fiber optica other end links to each other with spectrogrph, the corresponding experimental data Texp that organizes reflective light intensity of record 400-1000nm wave-length coverage optical property parameter;

D) utilize DSMC simulation under the situation of input organize models solution optical property parameter to obtain the analog data Tmc of reflective light intensity;

E) ask and make the variance of KTmc-Texp be hour constant K value;

F) be the optimization data T that shows the function contact between optical property parameter and the reflective light intensity with KTmc

Step 2: measure skin physiology parameter and optical property parameter, comprise step by step following:

1) will with step 1 c) in the front end end face of identical incident optical and mirror based fiber optica contact with clean smooth skin surface to be measured; The incident optical other end links to each other with light source; Light source provides the incident illumination that covers the 400-1000nm wave-length coverage; The mirror based fiber optica other end links to each other with spectrogrph, record 400-1000nm wave-length coverage skin reflex light intensity M (λ);

2) the front end end face with incident optical and mirror based fiber optica places reflectance standards sheet top, record standard sheet reflective light intensity M _Std(λ);

3) normalized measurement skin reflex spectrum does $\mathrm{MSPR}\left(\mathrm{\λ}\right)=\frac{M\left(\mathrm{\λ}\right)}{M_{\mathrm{Std}}\left(\mathrm{\λ}\right)};$

4) four physiological parameters and two scattering parameters are set: melanin content M0 initial value scope is 1%-10%, preferred 5%; Content of hemoglobin B0 initial value scope is 0.2%-7%; Preferred 0.3%; Blood oxygen saturation S0 initial value scope is 0%-100%, preferred 75%; Moisture W0 initial value scope is 15%-70%, preferred 60%; The reduced scattering coefficient μ of wavelength 500nm _s' _500nmThe initial value scope is 20-200, preferred 50; Ruili scattering content f0 initial value scope is 0%-100%, preferred 50%;

5) calculate absorptance and the reduced scattering coefficient of skin histology under each wavelength through physiological parameter, the standard reflection light intensity that the optimization data T that obtains from step 1 to this absorptance and reduced scattering coefficient falls into a trap and gets it right and answer;

6) combination step 2 1) reflective light intensity that calculates under the measured wavelength obtains predicting reflectance spectrum pSPR (λ);

7) calculate prediction reflectance spectrum and step 2 4) error u=∑ between the measurement skin reflex spectrum that obtains | mSPR (λ)-pSPR (λ) |;

8) the cycle repeats step 2 4)-7), obtain making error u to reach minimum tested sample corresponding physiological parameters;

9) calculate the absorptance μ of tested sample skin through the tested sample corresponding physiological parameters _aWith reduced scattering coefficient μ _s

Normal structure model solution in the inventive method is to obtain with fat milk solution and india ink configuration; The normal structure model solution of configuration is made up of 32 groups of variable concentrations solution, and the concentration of fat milk is one of following 4 in the solution: 20%, 5%; 1.25%, 0.3125%; The concentration of india ink is one of following 8 in the solution: 0,0.0015%, 0.003%, 0.013%, 0.023%, 0.048%, 0.073%, 0.098%;

The optical property parameter of measurement standard of the present invention organize models solution may further comprise the steps:

I) the selected wavelength of measuring;

Ii) at the luminous flux M that measures said measurement wavelength apart from light source position r place to said normal structure model solution _(r)

Iii) change for n time between mirror based fiber optica probe and the light source apart from r, and measuring light flux M respectively _(r)I, i=2 wherein, 3,4 ... N;

Iv) with ln (r * M _(r)) for carrying out linear fit, calculate slope 1/ δ of matched curve apart from r ₀

V) in solution, drip ink, the absorptance in organize models's solution of increase is Δ μ _a, said absorptance Δ μ _aObtain through spectrophotometer measurement ink absorbance;

Be object vi), carry out step I i again to said wavelength with the solution that has dripped ink)-iv), calculate slope 1/ δ of matched curve this moment ₁

Vii) through the equation group

$\left\{\begin{array}{c}\frac{1}{{\mathrm{\&delta;}}_0}=\sqrt{{3\mathrm{\&mu;}}_{a0}({\mathrm{\&mu;}}_{\mathrm{<figure-callout\; id="0"\; label="a"\; filenames="HDA0000030168970000031.png"\; state="\{\{state\}\}">a</figure-callout>}0}+{{\mathrm{\&mu;}}_{\mathrm{<figure-callout\; id="0"\; label="s"\; filenames="HDA0000030168970000031.png"\; state="\{\{state\}\}">s</figure-callout>}0}}^{\&prime;})}\\ \frac{1}{{\mathrm{\&delta;}}_1}=\sqrt{{3\mathrm{\&mu;}}_{a1}({\mathrm{\&mu;}}_{a1}+{{\mathrm{\&mu;}}_{\mathrm{<figure-callout\; id="0"\; label="s"\; filenames="HDA0000030168970000031.png"\; state="\{\{state\}\}">s</figure-callout>}0}}^{\&prime;})}\\ {{\mathrm{\&mu;}}_{a1}=\mathrm{\&mu;}}_{a0}+\mathrm{\&Delta;}{\mathrm{\&mu;}}_a\end{array}\right.$

Calculate the optical property parameter μ of said normal structure model solution _A0And μ _S0';

Reflectance standards sheet described in the said method is 99.9% at visible near-infrared wavelength reflectance.

Skin physiology parameter provided by the invention and optical property parameter measuring system; Form by skin reflex spectral measurement device and calculating and display device; Described skin reflex spectral measurement device is made up of broad spectrum light source, spectroscopic detector, incident optical, reception optical fiber, reflection probe, adjustable-height reflection probe support, data line; Described reflection probe by incident illumination optical fiber front end, receive the optical fiber front end, this incident optical front end and receive the peripheral metal shell of optical fiber front end and incident illumination optical fiber front end and receive the optical fiber front end and and the metal shell inwall between implant constitute; Receive the optical fiber front end and be fixed on the reflection probe center, the incident optical front end is surrounded on around the reception optical fiber front end equally spacedly with the annulus arrangement; Described calculating and display device are made up of analog-to-digital conversion module, computing module, memorizer, display process module, display and data/address bus; In described skin reflex spectral measurement device, incident optical links to each other with light source, receives optical fiber and links to each other with spectroscopic detector, and spectroscopic detector passes through data line and calculating and is connected with analog-to-digital conversion module in the display device; In described calculating and display device, computing module is through data/address bus and analog-to-digital conversion module, memorizer, the display process module mutually in succession, the display process module directly links to each other with display.The computing module of measuring system of the present invention can adopt 32 8-digit microcontrollers, and the display process module can adopt the VGA chip for driving.

The measuring principle of skin physiology parameter of the present invention and optical property parameter

Specifically introduce the measuring principle of skin physiology parameter and optical property parameter below according to the design of native system, this example is divided into three parts: the reflective spectral measure method; The foundation of final optimization pass normal data T; Obtaining of skin physiology parameter and optical property parameter.

One, reflective spectral measure method

When measuring skin reflex spectrum, make reflection probe vertically contact (contact but deformation does not take place) with skin tissue surface is soft, the complex light that is produced by light source gets into incident optical through bonder, gets into skin histology through incident optical.Fibre-optical probe 4 directly contacts with skin tissue surface, experiences fiber medium/air, twice interface loss of air/skin histology after having avoided incident illumination to leave incident optical.Because fibre-optical probe 4 directly contacts with skin tissue surface, 80 microns intervals between incident optical and the reception optical fiber make incident illumination must pass through the skin histology transmission could get into reception optical fiber simultaneously.Incident illumination is after incident optical gets into skin histology in the present embodiment; Pass through epidermal area melanin respectively; The skin corium HbO2 Oxyhemoglobin, deoxyhemoglobin, the scattering of scattering mediums such as the absorption of absorbing mediuies such as moisture and skin corium collagen is received optical fiber and receives.Reflective light intensity gets into spectrogrph through receiving the transmission of optical fiber.In the raster pattern CCD spectrogrph, incident illumination is scatter by grating according to its wavelength, and 3648 pixel CCD are record respectively, the reflectance spectrum in the wave-length coverage 400-1000nm.Because the incident illumination of different wave length is fully disperseed by the high-resolution grating, what each pixel was surveyed respectively is the light intensity value under the different wave length.The memorizer that luminous intensity measurement data M (λ) under all wavelengths is imported in calculating and the display device is preserved.

Because the detected light intensity M of spectrogrph also receives light source intensity S (λ) except that receiving reflective light intensity R (λ) influence that transmission attenuation produces in skin, optical fiber collection efficiency G, the influence of detector response D (λ), that is:

M(λ)＝S(λ)R(λ)GD(λ)

For other factors such as dependency of light source in the elimination system and detector wavelength to measuring the spectrographic influence of skin, adopting reflectance is that

standard film (U.S. marine optics company) of 99% is measured reflective light intensity with detecting head surface fixed range place:

Mstd(λ)＝S(λ)Rstd(λ)Gstd?D(λ)

When calibration measurement was carried out in the intensity of light source and detector wavelength response, the difference of measuring with skin histology was to utilize prefabricated firmware adjustment fibre-optical probe position to make the upper surface of fibre-optical probe end face and reflectance standards sheet apart from being fixed value d, d=5cm in this example.

Then the result can be used for the calibration of reflective light intensity according to this:

$\frac{M\left(\mathrm{\&lambda;}\right)}{M_{\mathrm{std}}\left(\mathrm{\&lambda;}\right)}=\frac{S\left(\mathrm{\&lambda;}\right)R\left(\mathrm{\&lambda;}\right)\mathrm{GD}\left(\mathrm{\&lambda;}\right)}{S\left(\mathrm{\&lambda;}\right)R_{\mathrm{std}}\left(\mathrm{\&lambda;}\right)G_{\mathrm{std}}D\left(\mathrm{\&lambda;}\right)}=\frac{R\left(\mathrm{\&lambda;}\right)G}{R_{\mathrm{std}}\left(\mathrm{\&lambda;}\right)G_{\mathrm{std}}}=K\frac{R\left(\mathrm{\&lambda;}\right)}{R_{\mathrm{std}}\left(\mathrm{\&lambda;}\right)}$

K is the constant of relevant no wavelength dependence with optical fiber efficient, R _Std(λ) also be constant 99% under visible near-infrared wavelength.If constant k=R _Std(λ)/and K, then the skin histology reflective light intensity is calibrated to:

$R\left(\mathrm{\&lambda;}\right)=k\frac{M\left(\mathrm{\&lambda;}\right)}{M_{\mathrm{std}}\left(\mathrm{\&lambda;}\right)}$

R among Fig. 9 (λ) curve is measures the spectrographic typical data of skin reflex.

Two, the foundation of final optimization pass normal data T

For analyzing skin is organized reflectance spectrum, measure the tissue optical property parameter.This example has at first been set up final optimization pass normal data T, and this example combines Monte Carlo simulation analysis to obtain skin absorbs coefficient μ through model experiment _aWith reduced scattering coefficient μ _s' and the corresponding relation of probe measurement reflective light intensity.Concrete steps can be divided into model experiment, Monte Carlo simulation with utilize three parts of experimental data calibrated analog result:

1) the solutions simulate biological tissue of organize models that fat milk solution (Guangzhou Baite Jiaoguang Medical Product Co., Ltd) and india ink (Beijing Suo Laibao Science and Technology Ltd.) are prepared is adopted in organize models's experiment.Fat milk solution provides the scattering in organize models's solution, and india ink solution provides the absorption in organize models's solution.Through the concentration of adjustment fat milk solution and india ink, obtain the normal structure model solution of different optical characterisitic parameter.Mirror based fiber optica probe inserted in many group models solution measure reflectance spectrum.Because organize models's solution all has differing absorption coefficient and reduced scattering coefficient under each wavelength in spectral measurement ranges.Only need configuration 32 group model solution (4 concentration of fat milk: 20%, 5%, 1.25%, 0.3125%; 8 concentration of india ink: 0,0.0015%, 0.003%; 0.013%, 0.023%, 0.048%; 0.073%, 0.098%) can cover the optical property parameter scope of skin histology, thereby obtain the experimental standard data Texp that organizes reflective light intensity based on experimental record.Fat milk and india ink solution concentration are shown in table one in every group of normal structure model solution.

Table one

The optical property parameter of organize models's solution that the organize models solution good to every configuration set, the method that adopts luminous flux measurement to combine to add absorber are confirmed to configure:

Under specific wavelength, utilize an end of two 400 microns core diameter multimode stepped-index optical fibers to connect light source and spectrogrph respectively, the other end is with apart from the parallel organize models's solution that places of r, and the light intensity value that measures is M _(r), then according to the diffusion approximate calculation of point source:

$M_{\left(r\right)}=K*F_{\left(r\right)}=K*\frac{e^{-r/\mathrm{\&delta;}}}{4\mathrm{\&pi;Dr}}$

The light intensity M that obtains that measures _(r)With range points light source in the solution be that the luminous flux F (r) at r place differs constant K doubly, wherein K be and the intensity of light source, the optical fiber collection efficiency, spectrogrph to light intensity response be correlated with.D is a mean free path, and δ is the optics penetration depth, and these two parameters all can be calculated by absorptance μ a and reduced scattering coefficient μ s ':

$D=\frac{1}{3}\frac{1}{{\mathrm{\&mu;}}_a+{{\mathrm{\&mu;}}_s}^{\&prime;}}$

$\mathrm{\&delta;}\sqrt{\frac{D}{{\mathrm{\&mu;}}_a}}=\sqrt{\frac{1}{{3\mathrm{\&mu;}}_a({\mathrm{\&mu;}}_a+{{\mathrm{\&mu;}}_s}^{\&prime;})}}$

For same sample and same wavelength, parameter K, D and δ are the constant that does not change with r, so M _(r)Calculating formula can be rewritten as:

$\ln (r*M_{\left(r\right)})=-\left(\frac{1}{\mathrm{\&delta;}}\right)r+\ln \left(\frac{\mathrm{<figure-callout\; id="4"\; label="K"\; filenames="HDA0000030168970000021.png"\; state="\{\{state\}\}">K</figure-callout>}}{4\mathrm{\&pi;D}}\right)$

For same solution, its absorptance and reduced scattering coefficient are made as μ _A0And μ _S0', change between the measuring optical fiber apart from r, measure the luminous flux M at different distance place _(r), with ln (r*M _(r)) for carrying out linear fit apart from r, 1/ δ then ₀Be the slope of matched curve, and because:

$\frac{1}{{\mathrm{\&delta;}}_0}=\sqrt{{3\mathrm{\&mu;}}_{a0}({\mathrm{\&mu;}}_{a0}+{{\mathrm{\&mu;}}_{s0}}^{\&prime;})}$

Try to achieve slope 1/ δ ₀After, promptly confirmed sign μ _A0And μ _S0The first party formula of ' relation,

And, can increase the absorptance Δ μ in organize models's solution through in solution, dripping ink _a, and do not change its reduced scattering coefficient μ _S0', Δ μ wherein _aFor adding the absorptance that ink produced, can obtain through spectrophotometer measurement ink absorbance, then again through measuring M _(r)Matched curve can obtain 1/ δ ₁, at this moment:

$\frac{1}{{\mathrm{\&delta;}}_1}=\sqrt{{3\mathrm{\&mu;}}_{a1}({\mathrm{\&mu;}}_{a1}+{{\mathrm{\&mu;}}_{s0}}^{\&prime;})}$

Through the group of solving an equation:

$\left\{\begin{array}{c}\frac{1}{{\mathrm{\&delta;}}_0}=\sqrt{{3\mathrm{\&mu;}}_{a0}({\mathrm{\&mu;}}_{a0}+{{\mathrm{\&mu;}}_{s0}}^{\&prime;})}\\ \frac{1}{{\mathrm{\&delta;}}_1}=\sqrt{{3\mathrm{\&mu;}}_{a1}({\mathrm{\&mu;}}_{a1}+{{\mathrm{\&mu;}}_{s0}}^{\&prime;})}\\ {{\mathrm{\&mu;}}_{a1}=\mathrm{\&mu;}}_{a0}+\mathrm{\&Delta;}{\mathrm{\&mu;}}_a\end{array}\right.$

Can calculate the optical property parameter μ of every group of organize models's solution _A0And μ _S0'.

The reflectance spectrum that connects in this example is surveyed device, and the reflectance spectrum probe is inserted in the model solution, measures the reflectance spectrum of every group of organize models's solution example.And calibrate with the reflectance standards sheet, be recorded in the reflective light intensity under each wavelength in the measured wave-length coverage.Because the optical characteristics of organize models's solution example under each wavelength is all different; And the optical property parameter of respectively organizing in the sample is overlapped; Therefore can be through 32 groups of organize models's solution in this example measure in the skin optical characterisitic parameter scope different absorptance μ _aWith reduced scattering coefficient μ _s' the corresponding experimental standard data Texp that organizes reflective light intensity.

2) further utilize Monte Carlo simulation analysis in this example time photon leave that the transmission in this skin histology distributes behind the incident optical.Fig. 3 representes, works as μ _a=2.1870cm ^-1, μ _s'=64cm ^-1The time, incident illumination leaves the Monte Carlo simulation result of skin histology reflected light distribution in the reflection probe surface range behind an incident ray entering tissue on right side.It is strong that calculating finally receives the total reflected light of overflowing in the fiber optic scope from the reflection probe contact surface, thereby obtain the reflection probe receiving light power of theoretical modeling.

Through repeatedly simulation, calculate different absorptance μ in the skin optical characterisitic parameter scope respectively _aWith reduced scattering coefficient μ _s' under the condition, reflection probe institute can detected receiving light power.Thereby obtain mock standard data Tmc according to the Monte Carlo simulation acquisition.

Fig. 4 is the reflective light intensity normal data Tmc that utilizes Monte Carlo simulation to obtain to the contrive equipment instance.Visible from figure, reduced scattering coefficient is constant in tissue, when absorptance increases gradually, probe detection to reflective light intensity weaken gradually.And absorptance is constant in the tissue, and the reflective light intensity that probe detection arrives in tissue scatter hour strengthens with the enhancing of reduced scattering coefficient; In tissue scatter when big, weaken with the enhancing of reduced scattering coefficient.And can find out also that from the result of reflective light intensity normal data the probe that this instance adopts is responsive to the variation of scattering, when absorptance is low to the variation that absorbs insensitive and when absorptance is higher variation to absorptance responsive.And to skin histology, nearer because skin corium has a large amount of blood capillaries apart from skin surface, a large amount of absorption in the skin histology in the probe detection scope is provided.Therefore the variation of the very suitable detection of skin tissue physiology of this probe parameter changes absorption and reduced scattering coefficient in the tissue.

3) because the Texp that experiment measuring obtains exists experimental error to have certain fluctuation; And the Tmc that Monte Carlo simulation obtains; Be theoretic perfect value, do not consider experiment such as optical fiber receiving efficiency and loss decay in the actual experiment, cause analog result and measurement result difference constant k doubly.Therefore the result of present embodiment experimental standard data Texp that experiment measuring is obtained introduces with calibrated analog normal data Tmc; It is T=k * Tmc that the optimisation criteria data are set; Ask for the variance of T-Texp to all data, and the coefficient k=k ' when obtaining this variance and being minima.

Then the final optimization pass normal data is T '=k ' * Tmc, and this final optimization pass normal data T has provided different skin absorptance μ _aWith reduced scattering coefficient μ _s' the following reflective light intensity of popping one's head in and measuring.Be probe measurement reflective light intensity R=T (μ _a, μ _s').

Three, skin physiology parameter and optical property parameter obtains

1): in being directed against the measurement of actual sample, what the CCD spectrogrph obtained is the reflectance spectrum curve to dermatological specimens, its result such as the represented curve of accompanying drawing 9 mid points.

Because the melanin in the skin histology; Deoxyhemoglobin, Oxygenated blood red eggs are white; The concentration relationship of physiologically substances such as moisture has determined the variation of the absorptance in the skin; Therefore and the absorptance of each composition is constant with the dependence of wavelength variations, can directly utilize the concentration of physiologically substance in the tissue to calculate the absorptance of different wave length undertissue.

The transmission of light is divided into two parts of epidermal area decay and skin corium reflection in the skin, so the reflectance spectrum computing formula of dermatological specimens can be expressed as:

pSPR＝T _epi’*R _derm

T wherein _EpiBe the transmitance of light in the skin epidermis, R _DermBe skin corium reflection of light rate.

The decay of light only receives the influence of melanin absorption in the skin epidermis, so light can be expressed as in the transmitance of skin epidermis:

T _epi(λ)＝exp(-M*μ _{a_mel}(λ)*L _epi)

Wherein M is a melanin concentration, and Lepi is the epidermal area optical thickness, and the value of healthy human body is 0.03cm, μ _{A_mel}Be one group of constant (numeric reference document S.L.Jacques (λ) with wavelength variations for the melanin absorption coefficient; " Origins of tissueoptical properties in the UVA, visible, and NIR regions; " In Advances in Optical ImagingandPhoton Migration; R.R.Alfano and J.G.Fujimoto, eds. (Optical Society ofAmerica), 1996).

The reflection of skin corium is by the absorptance and the reduced scattering coefficient decision of skin corium; And among the resulting final optimization pass data of the analytical method T that experimental data through before this and Monte Carlo simulation combine; Provided in skin optical property parameter in the scope that can obtain, absorptance and reduced scattering coefficient might make up pairing reflective light intensity.

Be R _Derm(λ)=T (μ _a(λ), μ _s' (λ))

This moment is as long as given absorptance and reduced scattering coefficient just can obtain corresponding reflective light intensity data through final optimization pass data T.

2): the absorbing medium of skin corium mainly contains deoxyhemoglobin, the Oxygenated blood red eggs are white and moisture.Its absorptance can be calculated as:

μ _a(λ)＝B*(S*μ _{a_oxy}(λ)+(1-S)*μ _{a_deoxy}(λ))+W*μ _{a_water}(λ)

B wherein, S, W represent total hemoglobin content, blood oxygen saturation, moisture, μ respectively _{A_oxy}(λ), μ _{A_deoxy}(λ), μ _{S_water}(λ), be respectively HbO2 Oxyhemoglobin, the absorptance of deoxyhemoglobin and water; Be constant (numeric reference document W.G.Zijlstra with wavelength variations; A.Buursma and O.W.van Assendelft, " Visible and Near Infrared Absorption Spectraof Human and Animal Haemoglobin ", VSP Publishing; Utrecht, 2000; G.M.Hale, M.R.Querry, " Optical constants ofwater in the 200-nm to 200-μ m wavelength region " Applied Optics, 1973).The scattering of skin corium mainly is made up of scattering particle size in the skin less Ruili scattering and Mie scattering.If the reduced scattering coefficient of skin corium when wavelength is 500nm is μ _s' _500nmThen the wavelength dependence of Ruili scattering and Mie scattering is respectively μ _s' _500nm* (λ/500) ^-4, μ _s' _500nm* (λ/500) ^-1Therefore the skin corium reduced scattering coefficient can be calculated as: μ _s' (λ)=μ _s' _500nm* (f* (λ/500) ^-4+ (1-f) * (λ/500) ^-1)

Wherein f is the parameter of expression skin corium Ruili scattering content.

Therefore, at given three physiological parameter total hemoglobin content B, blood oxygen saturation S, reduced scattering coefficient μ when moisture W and two skin scattering nature parameter wavelength are 500nm _s' _500nm, just can calculate absorptance μ a and these two optical property parameters of reduced scattering coefficient μ s ' of dermal layer of the skin behind the Ruili scattering content f.

3): according to the above principle, when setting four physiological parameter melanin concentration M, total hemoglobin content B, blood oxygen saturation S, moisture W and two skin scattering nature parameter μ _s' _500nm, behind the Ruili scattering content f according to equation group:

$\left\{\begin{array}{c}\mathrm{pSPR}\left(\mathrm{\&lambda;}\right)=\exp (-M*{\mathrm{\&mu;}}_{a_{\mathrm{mel}}}\left(\mathrm{\&lambda;}\right)*0.03).*T({\mathrm{\&mu;}}_a\left(\mathrm{\&lambda;}\right),{{\mathrm{\&mu;}}_s}^{,}\left(\mathrm{\&lambda;}\right))\\ {\mathrm{\&mu;}}_a\left(\mathrm{\&lambda;}\right)=B*(S*{\mathrm{\&mu;}}_{a_{\mathrm{oxy}}}\left(\mathrm{\&lambda;}\right)+(1-S)*{\mathrm{\&mu;}}_{a_{\mathrm{deoxy}}}\left(\mathrm{\&lambda;}\right))+W*{\mathrm{\&mu;}}_{a_{\mathrm{water}}}\left(\mathrm{\&lambda;}\right)\\ {{\mathrm{\&mu;}}_s}^{,}\left(\mathrm{\&lambda;}\right)={{{\mathrm{\&mu;}}_s}^{,}}_{500\mathrm{nm}}*(f*{(\mathrm{\&lambda;}/500)}^{-4}+(1-f)*{(\mathrm{\&lambda;}/500)}^{-1})\end{array}\right.$

Can obtain the match reflectance spectrum curve of dermatological specimens, the represented curve of solid line in its result such as the accompanying drawing 9.

4): can see the influence of the variation of single physiological parameter when other parameter is definite value to the reflectance spectrum curve through accompanying drawing 5-8, wherein the definite value parameter is set to: M=0.02, B=0.004, S=0.9, W=0.60, μ _s' _500mn=43.6, f=0.62.

So different melanin concentration M, total hemoglobin content B, blood oxygen saturation S, moisture W, skin scattering nature parameter μ _s' _500nmThe setting of Ruili scattering content f can cause the variation of match reflectance spectrum curve; Is that variable carries out curve fitting and calculates the reflectance spectrum that simulates and the array variance between actual measurement spectrum through fitting algorithm with these six parameters; And obtain this variance hour six values of parameters, obtain the value of calculation of four physiological parameters thus, and obtain corresponding optical property parameter: skin absorbs coefficient μ a and reduced scattering coefficient μ s ' through these six calculation of parameter.

Description of drawings

Fig. 1: be that the spectrographic measuring device structure of a kind of skin reflex is formed sketch map, wherein:

1---broad spectrum light source;

2---spectroscopic detector;

3---incident optical;

4---reflection probe;

5---receive optical fiber;

6---the reflection probe support;

7---data line;

8---calculate and display device;

Fig. 2: be the structure chart of reflection probe in the contrive equipment instance, wherein:

3---incident optical;

5---receive optical fiber;

9---fibre cladding;

10---reflection probe;

Fig. 3: be to work as μ to contrive equipment _a=2.1870cm ^-1, μ _s'=64cm ^-1The time reflective light intensity organized in the reflection probe Monte Carlo simulation result that distributes;

Fig. 4: be the reflective light intensity mock standard data of utilizing Monte Carlo simulation to obtain to the contrive equipment instance;

Fig. 5: be the changing trend diagram of reflectance spectrum with physiological parameter total hemoglobin content B;

Fig. 6: be the changing trend diagram of reflectance spectrum with physiological parameter melanin content M;

Fig. 7: be the changing trend diagram of reflectance spectrum with physiological parameter blood oxygen saturation S;

Fig. 8: be the changing trend diagram of reflectance spectrum with physiological parameter moisture W;

Fig. 9: be to obtain to match of contrive equipment example spectra and physiological parameter, the corresponding M=1.3%B=0.4%S=92%W=65% of this routine reflectance spectrum:

Figure 10: computing module obtains skin physiology parameter and tissue optical property parameter workflow diagram.

The specific embodiment

Embodiment 1: the formation of reflective spectral measure system

Referring to Fig. 1, introduce the structure composition of measuring skin physiology parameter and optical property parameter system based on reflective spectral measure:

The spectrographic measuring system of skin reflex comprises the spectrographic measuring device of skin reflex and calculating and display device, and wherein the spectrographic measuring device of skin reflex comprises 1, broad spectrum light source; 2, spectroscopic detector; 3, incident optical; 4, reflection probe; 5, receive optical fiber; 6, the reflection probe support; 7, data line; Calculate with display device and form by analog-to-digital conversion module, computing module, memorizer, display process module, display, data/address bus.Because the light-intensity variation of halogen tungsten lamp is less and better with the seriality under the wavelength variations in visible near-infrared wave-length coverage under burning voltage, so adopt halogen tungsten lamp the continuous incident light spectrum in the visible near-infrared wave-length coverage to be provided in this instance as broad spectrum light source.According to application conditions, also can use xenon lamp, other broad spectrum light sources such as LED composite light source replace.Incident ray is connected with light source through the SMA905 joint, and inserts in the reflection probe, and the wide spectrum incident illumination that light source is provided conducts to skin surface.Reflection probe is as shown in Figure 2, and incident optical 3 is 400 microns core diameter multimode stepped-index optical fibers with reception optical fiber 5.6 incident optical symmetrical rings are around in and receive around the optical fiber.Incident optical with receive 480 microns of fiber cores Center Gap, be filled in incident optical and receive around the optical fiber for fibre cladding 9 in 740 microns of the reflection probe center radius.Center radius has been the metal shell 10 of fixation for 740 microns in addition, and in this example, metal shell adopts aluminum alloy materials to process.Receive optical fiber and receive the skin surface reflected light from the reflection probe center, and import reflected light into spectroscopic detector through the SMA905 joint.Spectrogrph adopts raster pattern CCD spectrogrph, 3648 pixel CCD, wave-length coverage 400-1000nm, wavelength resolution＜1.34nm.Reflection probe support 6 can be adjusted the reflection probe position in vertical direction.Spectroscopic detector is connected with analog-to-digital conversion module in the display device through data line and calculating.

Calculate with display device in, computing module is through data/address bus and analog-to-digital conversion module, memorizer, the display process module mutually in succession, the display process module directly links to each other with display.Analog-to-digital conversion module adopts 16 4 channel parallel modulus conversion chips, is responsible for the A/D conversion of spectrogrph dateout.Memorizer is responsible for the storage of reflective spectral measure data and normal data T.It is the microcontroller of ARM32 bit CPU that computing module adopts kernel, is responsible for the normalization of reflectance spectrum and calculates, reflectance spectrum analysis, the obtaining of physiological parameter and optical property parameter.The display process module adopts the VGA chip for driving, is used for the visualization processing of experimental result.

Embodiment 2: the measuring process of skin physiology parameter and optical property parameter

Because when practical application, the reflective light intensity optimization data T that comprises a large amount of experiments and Monte Carlo simulation data has write down and has been kept in the memory element of calculating and display device.Then utilize the process of this measurement device tissue physiology parameter and optical property parameter following:

1) each parts of connecting device vertically place clean smooth skin surface to be measured with reflection probe, record skin reflex light intensity M (λ);

2) vertically place reflectance standards sheet upper fixed apart from the d place reflection probe, record standard sheet reflective light intensity M _Std(λ);

3) then normalized measurement skin reflex spectrum does $\mathrm{MSPR}\left(\mathrm{\&lambda;}\right)=\frac{M\left(\mathrm{\&lambda;}\right)}{M_{\mathrm{Std}}\left(\mathrm{\&lambda;}\right)};$

4) four physiological parameters and two scattering parameters are set: melanin content M0 initial value scope is 1%-10%, preferred 5%; Content of hemoglobin B0 initial value scope is 0.2%-7%; Preferred 0.3%; Blood oxygen saturation S0 initial value scope is 0%-100%, preferred 75%; Moisture W0 initial value scope is 15%-70%, preferred 60%; Reduced scattering coefficient μ s ' the 500nm initial value scope of wavelength 500nm is 20-200, preferred 50; Ruili scattering content f0 initial value scope is 0%-100%, preferred 50%;

5) calculate absorptance and the reduced scattering coefficient of skin histology under each wavelength through physiological parameter, the standard reflection light intensity of falling into a trap and getting it right and answer from optimisation criteria data T to this absorptance and reduced scattering coefficient;

6) the error u=∑ between the measurement skin reflex spectrum that calculating prediction reflectance spectrum and 4) obtains | mSPR (λ)-pSPR (λ) |;

7) repetitive process 4)-6), reach minimum up to error u, then obtain tested sample corresponding physiological parameters: melanin concentration M, total hemoglobin content B, blood oxygen saturation S, moisture W and skin scattering nature parameter μ _s' _500nm, f.

8) calculate the optical property parameter of tested sample through above-mentioned tested sample corresponding physiological parameters: skin absorbs coefficient μ _aWith reduced scattering coefficient μ _s'.

Fig. 9 is the routine healthy male right hand forearm inside skin reflective spectral measure calculating reflectance spectrum pR (λ) that obtains of R (λ) and the reason parameter that obtains according to nonlinear optimization algorithm and optical property parameter as a result.The melanin content M=1.3% that this reflectance spectrum correspondence obtains, total hemoglobin content B=0.4%, blood oxygen saturation S=92%, moisture W=65%.The reduced scattering coefficient μ of 500nm _s' _500nm=20.5cm ^-1, Ruili scattering content f=46%.Utilize example device of the present invention to measure 20 routine healthy male right hand forearm inside skin reflectance spectrums altogether, the skin physiology parameter that is obtained all meets document record parameter area.

For realizing above method, present embodiment uses a kind of like this skin physiology parameter and optical property parameter measuring system with computing module, and this system comprises: the spectrographic measuring device of skin reflex, calculating and display device.Wherein the spectrographic measuring device of skin reflex comprises: broad spectrum light source, spectroscopic detector, incident optical, reflection probe, reception optical fiber, reflection probe support, data line.Comprise analog-to-digital conversion module, computing module, memorizer, display process module, display, data/address bus in calculating and the display device.Through being stored in after the analog digital conversion in the memorizer; Computing module utilizes Monte Carlo Calculation to obtain mock standard data Tmc; And call the organize models's experimental data that is stored in the memorizer and obtain experimental standard data Texp mock standard data Tmc is calibrated; Thereby obtain final optimization pass normal data T, and be stored in the memorizer.

The spectrographic measuring device of skin reflex is measured skin reflex spectrum to be measured, and it measures the reflectance spectrum of skin to be measured and the reflectance spectrum of reflectance standards sheet respectively, and measurement data is imported into by data line and calculated and display device.Through being stored in after the analog digital conversion in the memorizer, computing module utilizes reflectance standards sheet data calibration skin measurement data to obtain measuring skin reflex spectrum.Computing module calls optimisation criteria data T, utilizes skin match reflectance spectrum corresponding under the nonlinear iteration algorithm computation different skin tissue physiology parameter.To calculate the match reflectance spectrum and compare, and obtain the pairing physiological parameter of skin reflex spectrum to be measured, and further calculate skin optical property parameter μ under all wavelengths with measuring skin reflex spectrum _aAnd μ _s', measurement result and skin reflex spectrum picture are shown on the display.It is shown in figure 10 that computing module obtains the workflow diagram of skin physiology parameter and tissue optical property parameter.

In addition, those skilled in the art also can do other variation in spirit of the present invention, and certainly, these all should be included within the present invention's scope required for protection according to the variation that the present invention's spirit is done.

Claims (4)

1. skin physiology parameter and optical property parameter measuring method based on a reflective spectral measure comprise the steps:

Step 1: the optimization data T of the function contact between represents optical property parameter and the reflective light intensity comprises step by step following:

A) configuration standard organize models solution;

B) optical property parameter of measurement standard organize models solution;

C) incident optical and mirror based fiber optica front end are inserted in the normal structure model solution abreast; The incident optical other end links to each other with light source; Light source provides the incident illumination that covers the 400-1000nm wave-length coverage; The mirror based fiber optica other end links to each other with spectrogrph, the corresponding experimental data Texp that organizes reflective light intensity of record 400-1000nm wave-length coverage optical property parameter;

D) utilize DSMC simulation under the situation of input normal structure model solution optical property parameter to obtain the analog data Tmc of reflective light intensity;

E) ask feasible | the variance of KTmc-Texp| is hour constant K value;

F) with KTmc be the optimization data T of the function contact between optical property parameter and the reflective light intensity;

Step 2: measure skin physiology parameter and optical property parameter, comprise step by step following:

1) will with step 1 c) in the front end end face of identical incident optical and mirror based fiber optica contact with clean smooth skin surface to be measured; The incident optical other end links to each other with light source; Light source provides the incident illumination that covers the 400-1000nm wave-length coverage; The mirror based fiber optica other end links to each other with spectrogrph, record 400-1000nm wave-length coverage skin reflex light intensity M (λ);

2) the front end end face with incident optical and mirror based fiber optica places reflectance standards sheet top, record standard sheet reflective light intensity M _Std(λ);

3) normalized measurement skin reflex spectrum is

4) four physiological parameters and two scattering parameters are set: melanin content M0 initial value scope is 1%-10%; Content of hemoglobin B0 initial value scope is 0.2%-7%; Blood oxygen saturation S0 initial value scope is 0%-100%; Moisture W0 initial value scope is 15%-70%; The reduced scattering coefficient μ of wavelength 500nm _s' _500nmThe initial value scope is 20-200; Ruili scattering content f0 initial value scope is 0%-100%;

5) through step 2 4) in the said physiological parameter and the said scattering parameter that are provided with calculate absorptance and the reduced scattering coefficient of skin histology under each wavelength, the standard reflection light intensity that the optimization data T that obtains from step 1 to this absorptance and reduced scattering coefficient falls into a trap and gets it right and answer;

6) the said standard reflection light intensity that calculates under the combination 400-1000nm wavelength obtains predicting reflectance spectrum pSPR (λ);

7) calculate said prediction reflectance spectrum and step 2 3) error u=∑ between the said measurement skin reflex spectrum that obtains | mSPR (λ)-pSPR (λ) |;

8) the cycle repeats step 2 4)-7), obtain making error u to reach minimum corresponding said physiological parameter and the said scattering parameter of tested sample;

9) reach the absorptance μ that minimum tested sample corresponding physiological parameters and scattering parameter calculate tested sample skin through the said error u that makes _aWith reduced scattering coefficient μ _s'.

2. measuring method as claimed in claim 1; It is characterized in that the normal structure model solution is to obtain with fat milk solution and india ink configuration, the normal structure model solution of configuration is made up of 32 groups of variable concentrations solution; The concentration of fat milk is one of following 4 in the solution: 20%; 5%, 1.25%, 0.3125%; The concentration of india ink is one of following 8 in the solution: 0,0.0015%, 0.003%, 0.013%, 0.023%, 0.048%, 0.073%, 0.098%.

3. measuring method as claimed in claim 1 is characterized in that, the optical property parameter of measurement standard organize models solution may further comprise the steps:

I) the selected wavelength of measuring;

Ii) at the luminous flux M that measures said measurement wavelength apart from light source position r place to said normal structure model solution _(r)

Iii) change for n time between mirror based fiber optica probe and the light source apart from r, and measuring light flux M respectively _(r)I, i=2 wherein, 3,4 ... N;

Iv) incite somebody to action | n (r*M _(r)) for carrying out linear fit, calculate slope 1/ δ of matched curve apart from r ₀

The absorptance that v) in solution, increases in the normal structure model solution behind the dropping ink is Δ μ _a, said absorptance Δ μ _aObtain through spectrophotometer measurement ink absorbance;

Be object vi), carry out step I i again to said measurement wavelength with the solution that has dripped ink)-iv), calculate slope 1/ δ of matched curve this moment ₁

Vii) through the equation group

$\left\{\begin{array}{c}\frac{1}{{\mathrm{\&delta;}}_0}=\sqrt{{3\mathrm{\&mu;}}_{a0}({\mathrm{\&mu;}}_{a0}+{{\mathrm{\&mu;}}_{a0}}^{\&prime;})}\\ \frac{1}{{\mathrm{\&delta;}}_1}=\sqrt{3{\mathrm{\&mu;}}_{a1}({\mathrm{\&mu;}}_{a1}+{{\mathrm{\&mu;}}_{a0}}^{\&prime;})}\\ {\mathrm{\&mu;}}_{a1}={\mathrm{\&mu;}}_{a0}+{\mathrm{\&Delta;\&mu;}}_a\end{array}\right.$

Calculate the optical property parameter μ of said normal structure model solution _A0And μ _S0'.

4. measuring method as claimed in claim 1 is characterized in that, the reflectance standards sheet is 99.9% at visible near-infrared wavelength reflectance.

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