CN100554938C - A kind of quantivative approach of measuring the device of optical parameter spectrum and eliminating diffuse transmission influence - Google Patents
A kind of quantivative approach of measuring the device of optical parameter spectrum and eliminating diffuse transmission influence Download PDFInfo
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- CN100554938C CN100554938C CNB2008101063549A CN200810106354A CN100554938C CN 100554938 C CN100554938 C CN 100554938C CN B2008101063549 A CNB2008101063549 A CN B2008101063549A CN 200810106354 A CN200810106354 A CN 200810106354A CN 100554938 C CN100554938 C CN 100554938C
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Abstract
The invention discloses a kind of device of measuring optical parameter spectrum, comprising: light source, first optical fiber, second optical fiber, the 3rd optical fiber, first high-speed optical switch, electronic shutter one, two, three, four, five, diffuse reflection integrating sphere, diffuse transmission integrating sphere, collimation integrating sphere; The measured hole that described diffuse reflection integrating sphere, diffuse transmission integrating sphere, collimation integrating sphere are gone up separately is connected with described first high-speed optical switch by optical fiber respectively, and described first high-speed optical switch is connected with grating, charge-coupled image sensor, acquisition control circuit, controller successively.The present invention can solve in the classical modeling method by the method for absorption coefficient spectrum and chemical score modeling and absorb and the inseparable problem of scattering, the directly influence of weakening scattering from the information source.
Description
Technical field
The present invention relates to the Agricultural Information technical field, particularly relate to a kind of quantivative approach of measuring the device of optical parameter spectrum and eliminating diffuse transmission influence.
Background technology
In recent years; environmentally safe both at home and abroad, food security and drug safety aspect all give to show great attention to; particularly use near-infrared spectrum technique; can realize to sample fast, harmless (on-the-spot, online) detect and needn't carry out the pre-treatment of sample; make it to be applied to the field such as fast detecting, screening of atmosphere and water environment, food, medicine, agricultural product security and quality; for government department relevant accident being made rapid reaction in the very first time offers help; also can be used to instruct production and consumption to guarantee the quality of product, the protection consumer's interests.
In the near-infrared spectra district mainly is the frequency multiplication and the sum of fundamental frequencies absorption of the vibration energy state transition of group, the more weak and peak overlap of intensity, and therefore, the essence of quality of agricultural product near infrared harmless quantitative method is under the complex sample background, extracts specific faint information.Art methods is based on Chemical Measurement thought and comes relation between study sample specific substance concentration (usually claim " chemical score ") and the sample spectra, and sets up forecast model, is referred to as " classical Forecasting Methodology " here.In this light absorption of agricultural product and light scattering and the multi-component complex system of depositing, classical Forecasting Methodology or think that light scattering is constant or it is little to change, or think and use the influence that some bearing calibrations can weaken scattering.Yet in fact scattering and sample state concern complexity, are the comparison difficulties by keeping test condition and sample state to stablize scattering.In case scattering changes, with the chemical score that established model dopes, its error will be very big.Have the researcher to use the influence that some bearing calibrations (as methods such as polynary scatter corrections) attempt to weaken scattering, but the model prediction ability does not obviously improve.In fact " classical Forecasting Methodology " to use the sample spectra that existing spectral instrument measures (or be referred to as " absorbance spectrum " or optical density is composed) be to have absorption, the coefficient spectrum of scattering, scattering can't be separated from sample spectra, see shown in Figure 1.Experimental results show that, the spectrum change that the spectrum change that scattering causes causes greater than sample composition content sometimes, this is with regard to the robustness that has directly influenced mathematical model, the applicability that has reduced model, can only guarantee the prediction accuracy of under certain limited test condition (scattering is very little, and concentration range changes also very little situation).The problems referred to above are that researchers endeavour to solve always for many years, but still unsolved old problem, it has become " bottleneck " that improves agricultural product near infrared quick nondestructive quantivative approach degree of accuracy, robustness and applicability.
Summary of the invention
The purpose of this invention is to provide quantivative approach and the optical parametric comprehensive detection device of eliminating diffuse transmission influence in a kind of quality of agricultural product analysis, a kind of quantivative approach of measuring the device of optical parameter spectrum and eliminating diffuse transmission influence particularly is provided based on the optical parametric separation.
For achieving the above object, on the one hand, technical scheme of the present invention provides a kind of device of measuring optical parameter spectrum, comprising: light source is connected with first optical fiber, second optical fiber, the 3rd optical fiber; First high-speed optical switch is connected with described first optical fiber; The diffuse reflection integrating sphere, described second optical fiber enters the incidence hole of diffuse reflection integrating sphere through electronic shutter one; The diffuse transmission integrating sphere, the light hole of described diffuse reflection integrating sphere is connected through the incidence hole of electronic shutter two with the diffuse transmission integrating sphere, and testing sample one is arranged between described diffuse reflection integrating sphere and the diffuse transmission integrating sphere; The collimation integrating sphere, the light hole of described diffuse transmission integrating sphere is connected by the incidence hole one of electronic shutter three, four with the collimation integrating sphere; Second high-speed optical switch, described the 3rd optical fiber and testing sample two surface couplings, described testing sample two surfaces be provided with at least two with described the 3rd optical fiber detection fiber equidistant, in alignment, described detection fiber is connected with the input end of second high-speed optical switch, and the output terminal of described second high-speed optical switch is connected with the incidence hole two of described collimation integrating sphere by electronic shutter five; The electronic shutter control circuit, be connected with described electronic shutter one, two, three, four, five respectively, the measured hole on the measured hole on the described diffuse reflection integrating sphere, the measured hole on the diffuse transmission integrating sphere, the collimation integrating sphere is connected with described first high-speed optical switch by optical fiber respectively; Controller, described first high-speed optical switch is connected with grating, charge-coupled image sensor, acquisition control circuit, controller successively.
Wherein, described light source is connected with described first optical fiber, second optical fiber, the 3rd optical fiber through collimation lens.
Wherein, the spectral wavelength scope of described first optical fiber, second optical fiber, the 3rd optical fiber is at 600nm～1700nm, and described grating is optimal response in the 600nm-1700nm scope.
Wherein, the incidence hole of described diffuse reflection integrating sphere or light hole area are no more than 2% of described diffuse reflection integrating sphere internal surface area, and the measured hole area of described diffuse reflection integrating sphere is no more than 1% of described diffuse reflection integrating sphere internal surface area; The incidence hole of described diffuse transmission integrating sphere or light hole area are no more than 2% of described diffuse transmission integrating sphere internal surface area, and the measured hole area of described diffuse transmission integrating sphere is no more than 1% of described diffuse transmission integrating sphere internal surface area; The incidence hole one of described collimation integrating sphere, incidence hole two or light hole area are no more than 2% of described collimation integrating sphere internal surface area, and the measured hole area of described collimation integrating sphere is no more than 1% of described collimation integrating sphere internal surface area.
Wherein, the distance between described diffuse transmission integrating sphere and the described collimation integrating sphere is not less than 20cm.
Wherein, the internal diameter of described detection fiber is greater than 800 μ m, and the spacing between the described detection fiber is 3mm～10mm.
On the other hand, the invention provides a kind of quantivative approach of utilizing said apparatus to eliminate diffuse transmission influence, may further comprise the steps: the absorption coefficient that utilizes the device of measuring optical parameter spectrum to obtain agricultural product, biological tissue samples is composed μ a (λ), and scattering coefficient is composed μ s (λ) or reduced scattering coefficient is composed μ s ' (λ); The Applied Chemometrics algorithm is set up the mathematical model between standard absorption coefficient spectrum battle array and described agricultural product, the biological tissue samples chemical score matrix, tries to achieve test substance chemical score in described agricultural product, the biological tissue samples.
Wherein, absorption coefficient spectrum μ a (λ), the scattering coefficient that obtains agricultural product, biological tissue samples composed μ s (λ) and be may further comprise the steps: S1, placement testing sample one are between diffuse reflection integrating sphere and diffuse transmission integrating sphere; S2, electronic shutter control circuit are closed the incident light that electronic shutter one, two, three, four, five, the first high-speed optical switches are selected first optical fiber, and controller obtains incident intensity I
0(λ); S3, described electronic shutter control circuit are closed electronic shutter five, open electronic shutter one, two, three, four, the incident light that described first high-speed optical switch selection is connected with diffuse reflection integrating sphere measured hole, and described controller obtains incident intensity I
1(λ); S4, described electronic shutter control circuit are closed electronic shutter five, open electronic shutter one, two, three, four, the incident light that described first high-speed optical switch selection is connected with diffuse transmission integrating sphere measured hole, and described controller obtains incident intensity I
2(λ); S5, described electronic shutter control circuit are closed electronic shutter five, open electronic shutter one, two, three, four, and described first high-speed optical switch is selected and collimated the incident light that the integrating sphere measured hole is connected, and described controller obtains incident intensity I
3(λ); S6, described controller obtain diffuse reflectance T
1(λ)=I
1(λ)/I
0(λ), diffuse transmittance T
2(λ)=I
2(λ)/I
0(λ), collimated transmittance T
3(λ)=I
3(λ)/I
0(λ); The algorithm of S7, employing iteration and Error Feedback wavelength points one by one calculates, and at interval each wavelength points is calculated one by one by setting wavelength points, and each wavelength points all provides the initial value μ a of optical parametric
0(λ i), μ s
0(λ
i) and g
0(λ
i), i is the wavelength points label; In given thickness of sample scope, first forward calculates its diffuse reflectance and diffuse transmittance, respectively with T
1(λ), T
2(λ) and T
3(λ) relatively, adopt the simplex method match to obtain optical parametric, finally obtain absorption coefficient spectrum μ a (λ), scattering coefficient spectrum μ s (λ) and anisotropy factor g (λ) according to error.
Wherein, the absorption coefficient spectrum μ a (λ), the reduced scattering coefficient spectrum μ s ' that obtain agricultural product, biological tissue samples (λ) may further comprise the steps: S01, electronic shutter control circuit control electronic shutter one, two, three, four are closed, electronic shutter five is opened, first high-speed optical switch is selected the incident light of first optical fiber, detects incident intensity I
0(λ
i), S02, second high-speed optical switch are selected the optical fiber one at least two detection fiber, be transferred to incidence hole two, the first high-speed optical switches on the collimated light integrating sphere and select the light intensity If that comes out from the diffuse reflection of optical fiber one position from the testing sample two that described collimated light integrating sphere measured hole transmits
1(λ
i), S03, second high-speed optical switch are selected the optical fiber two at least two detection fiber, be transferred to incidence hole two, the first high-speed optical switches on the collimated light integrating sphere and select the light intensity If that comes out from the diffuse reflection of optical fiber two positions from the testing sample two that described collimated light integrating sphere measured hole transmits
2(λ
i); S04, described controller obtain diffuse reflectance Rf
1(λ i)=If
1(λ
i)/I0 (λ
i), diffuse reflectance Rf
2(λ
i)=If
2(λ
i)/I0 (λ
i); S05, according to theoretical diffusion rate formula: R=EXP (r μ eff)/[(μ a+ μ s ') r
2], μ eff=[3 μ a in the formula (μ a+ μ s ')]
1/2, under each wavelength, 2 detections of corresponding optical fiber are apart from the theoretical diffuse reflectance R at r1 and r2 place
1(λ
i) and R
2(λ
i): R
1(λ
i)=EXP (r1 μ eff)/[(μ a+ μ s ') r1
2] and R
2(λ
i)=EXP (r2 μ eff)/[(μ a+ μ s ') r2
2], structure objective function, F (λ
i)=[R
1(λ
i)-Rf
1(λ
i)]
2+ [R
2(λ
i)-Rf
2(λ
i)]
2, adopt the nonlinear fitting algorithm, try to achieve the wavelength X that F (λ i) is reached hour
iμ a (the λ at place
i) and μ s ' (λ
i), wavelength points is calculated and can be obtained net result absorption coefficient spectrum μ a (λ) and reduced scattering coefficient is composed μ s ' (λ) so one by one.
Wherein, described quantivative approach is used to measure the chemical composition content to be measured of muddy liquid system testing sample, or the chemical composition content to be measured of blade, powdered substance, fresh meat section, cube meat and live body testing sample is measured.
Technique scheme only is an optimal technical scheme of the present invention, has following advantage: treat light absorption and light scattering effect in the agricultural product tissue again with the viewpoint of " optical parametric separation ", understand the mutual relationship between tissue optical parameter and the spectroscopic data, method by absorption coefficient spectrum and chemical score modeling solves in the classical modeling method and absorbs and the inseparable problem of scattering, the directly influence of weakening scattering from the information source.Agricultural product " optical parametric isolation technics " will provide the theory and technology basis for developing the novel spectrometric instrument that slackens diffuse transmission influence, can become the research method with using value.Because the same set of integration unit of employing has been finished the optical parameter spectrum under the multiple different detection method, satisfies the requirement of different measuring sample, and is easy to use.
Description of drawings
Fig. 1 is existing classical Forecasting Methodology synoptic diagram;
Fig. 2 is a kind of structural representation of measuring the device of optical parameter spectrum of the embodiment of the invention;
Fig. 3 utilizes the method synoptic diagram of the device prediction sample chemical score of measurement optical parameter spectrum of the present invention;
Fig. 4 is the spectrogram that classic method records;
Fig. 5 is the absorption coefficient spectrogram that the method for the employing embodiment of the invention obtains.
Wherein, 11: the secondary color light source; 12: collimation lens; 13: the first optical fiber; 14: the second optical fiber; 15: the three optical fiber; 16: optical fiber one; 17: optical fiber two; 18,19,20,21: optical fiber; 22: electronic shutter one; 23: the diffuse reflection integrating sphere; 24: the diffuse transmission integrating sphere; 25: the collimated light integrating sphere; 26: electronic shutter two; 27: electronic shutter three; 28: electronic shutter four; 29: electronic shutter five; 30: the first high-speed optical switches; 31: the incidence hole of diffuse reflection integrating sphere; 32: the light hole of diffuse reflection integrating sphere; 33: the measured hole of diffuse reflection integrating sphere; 34: the incidence hole of diffuse transmission integrating sphere; 35: the light hole of diffuse transmission integrating sphere; 36: the measured hole of diffuse transmission integrating sphere; 37: the incidence hole one of collimated light integrating sphere; 38: the incidence hole two of collimated light integrating sphere; 39: the measured hole of collimated light integrating sphere; 40: grating; 41:CCD; 42: acquisition control circuit; 43: the electronic shutter control circuit; 44: controller; 45: testing sample one; 46: testing sample two; 47: the second high-speed optical switches; 48: control line.
Embodiment
Below in conjunction with drawings and Examples, the specific embodiment of the present invention is described in further detail.Following examples are used to illustrate the present invention, but are not used for limiting the scope of the invention.
As shown in Figure 2, the typical case who goes out according to the diffused light principle design is applicable to that fast different shape agricultural product measuring light mathematic(al) parameter spectrum detection device is an integration unit, diffuse reflectance, diffuse transmittance and the collimated transmittance of the agricultural product sample that it both can application of synchronized measures obtains absorption of sample coefficient spectrum, this kind mode is decided to be sample measurement mode 1, is applicable to that the agricultural product sample form of testing sample 1 comprises sheet, liquid state, powder; The diffuse reflectance of a plurality of positions of agricultural product sample surfaces that again can application of synchronized measure obtains absorption of sample coefficient spectrum, this kind mode is decided to be sample measurement mode 2, and that the agricultural product sample form that is applicable to testing sample 2 46 comprises is solid-state, liquid, powder or live body sample.Controller 44 among the present invention can be personal computer, server etc., as long as can satisfy control and data processing to whole device.
Concrete enforcement is as follows: secondary color light source 11 is collimated through collimation lens 12 by tungsten light source (halogen tungsten lamp of 12V30W), with by 9 spectral wavelength scopes within 600nm-1700nm, diameter is that the fibre bundle lotus root that the optical fiber of 400 μ m is formed is closed, per 3 optical fiber form a fibre bundle, form the three beams optical fiber that light intensity equates altogether, be respectively first optical fiber 13, second optical fiber 14, the 3rd optical fiber 15, wherein 13 conducts of first optical fiber are with reference to light optical fiber, link to each other with first high-speed optical switch 30, via public grating 40 (in the 600nm-1700nm scope, being optimal response), CCD 41 (Charge Coupled Device, charge-coupled image sensor) (model: TAOS 102 and AvaSpec-NIR256), acquisition control circuit 42 is measured as incident intensity I0 (λ); Second optical fiber 14 is as the incident optical of diffuse reflection integrating sphere 23, enter the incidence hole 31 of diffuse reflection integrating sphere 23 via electronic shutter 1, the area of incidence hole 31 accounts for the integrating sphere internal surface area and is no more than 2%, diffuse reflection integrating sphere 23 has a light hole 32 coaxial with going into perforation 31, this hole accounts for the integrating sphere internal surface area and is no more than 2%, there is the measured hole 33 that diffuses the side vertical with this two axially bored line, its area accounts for the integrating sphere internal surface area and is no more than 1%, measured hole 33 is connected to the input end of first high-speed optical switch 30 by the optical fiber 19 of internal diameter 800 μ m, output terminal via first high-speed optical switch 30 is connected to grating 40, CCD41, acquisition control circuit 42 can be measured light intensity I1 (λ) like this; Testing sample 1 places between diffuse reflection integrating sphere 23 and the diffuse transmission integrating sphere 24, diffuse transmission integrating sphere 24 also includes unthreaded hole 34, light hole 35, measured hole 36, the structure in three holes is consistent with three pore structures of diffuse reflection integrating sphere, measured hole 36 is connected to the input end of the first public high-speed optical switch 30 by the optical fiber 20 of internal diameter 800 μ m, be connected to public grating 40, CCD41, acquisition control circuit 42 via the light output terminal that opens the light, can detect light intensity I2 (λ) like this; Be not less than the 20cm place with diffuse transmission integrating sphere 24 distances a collimated light integrating sphere 25 is arranged, include unthreaded hole 1, incidence hole 2 38, measured hole 39, pore structure requires identical with diffuse reflection integrating sphere pore structure, measured hole 39 is connected to the input end of first high-speed optical switch 30 by the optical fiber 21 of internal diameter 800 μ m, be connected to public grating 40, CCD41, acquisition control circuit 42 via the light output terminal that opens the light, can measure light intensity I3 (λ) like this.Controller 44 is calculated diffuse reflectance T1 (λ)=I1 (λ)/I0 (λ), diffuse transmittance T2 (λ)=I2 (λ)/I0 (λ), collimated transmittance T3 (λ)=I3 (λ)/I0 (λ).In order to calculate the algorithm wavelength points calculating one by one that absorption coefficient spectrum μ a (λ), scattering coefficient spectrum μ s (λ) adopt iteration and Error Feedback; Each wavelength points all provides the initial value μ a of optical parametric
0(λ i), μ s
0(λ i) and g
0(λ i), i are the wavelength points label; In given thickness of sample scope, elder generation's forward calculates its diffuse reflectance and diffuse transmittance, compare with T1 (λ), T2 (λ) and T3 (λ) respectively, adopt simplex method to obtain optical parametric according to error, finally calculate absorption coefficient spectrum μ a (λ), scattering coefficient spectrum μ s (λ) and anisotropy factor.The general solution approach of simplicial method can be summarized as follows: 1. the equation of constraint group of linear programming problem is expressed as the quintessential system of equations, finds out basic feasible solution as initial basic feasible solution.2. if basic feasible solution does not exist, promptly constraint condition is contradictory, and then problem does not have and separates.3. if basic feasible solution exists, as starting point,, introduce nonbasic variable and replace a certain basic variable, find out another more excellent basic feasible solution of target function value according to optimality condition and feasibility condition from initial basic feasible solution.4. 3 carry out iteration set by step, satisfy optimality condition (at this moment target function value can not improve again), promptly obtain the optimum solution of problem up to corresponding check number.5. if the target function value unbounded of pinpointing the problems in the iterative process, then termination of iterations.(concrete document: the Tang Tieqiao that sees reference that explains in detail discusses fitting problems with simplicial method, Shaoyang institute journal: social science version, 2003,2 (5): 14-16).
The 3rd optical fiber 15 is as the incident light optical fiber of testing sample 2 46, directly and the sample surfaces close-coupled of testing sample 2 46; In a side of the 3rd optical fiber 15, place the detection fiber of at least 2 internal diameters greater than 800 μ m, be respectively optical fiber 1 and optical fiber 2 17 in the present embodiment, and with the 3rd optical fiber 15 point-blank, they are spaced apart 3-10mm, and equidistantly, distance is not less than 3mm between every adjacent optical fiber; The position of adjacent nearest optical fiber 1 with the 3rd optical fiber 15 is position, 1 place, and the position of optical fiber 2 17 is position, 2 place.Optical fiber 1, optical fiber 2 17 links to each other with the input end of second high-speed optical switch 47 respectively, the incidence hole 38 of the optical fiber 18 that connects internal diameter 800 μ m through the output terminal of second high-speed optical switch 47 to the collimated light integrating sphere 25 again, electronic shutter 5 29 is installed on the incidence hole 38, diffuse reflection integrating sphere 23, diffuse transmission integrating sphere 24,25 incidence hole 31 on the collimated light integrating sphere, 34,37,38 and light hole 32,35 are provided with by the electronic shutter one 22 of electronic shutter control circuit 43 by control line 48 controls, electronic shutter 2 26, electronic shutter 3 27, electronic shutter 4 28, electronic shutter 5 29 can be blocked light path when needed.Under the control of controller 44, electronic shutter control circuit 43 control electronic shutters 1, electronic shutter 2 26, electronic shutter 3 27, electronic shutter 4 28 cuts out, electronic shutter 5 29 is opened, first high-speed optical switch 30 is selected the incident light of first optical fiber 13, detect incident intensity I0 (λ i), second high-speed optical switch 47 is selected optical fiber 1, be transferred to the incidence hole 38 on the collimated light integrating sphere 25, the light intensity If1 (λ i) that the 1 position diffuse reflection from testing sample 2 46 that first high-speed optical switch, 30 selection optical fiber 21 transmit is come out, in like manner, second high-speed optical switch 47 is selected optical fiber 2 17, be transferred to the incidence hole 38 on the collimated light integrating sphere 25, the light intensity If2 (λ i) that the 2 position diffuse reflections from testing sample 2 46 that first high-speed optical switch, 30 selection optical fiber 21 transmit are come out obtains diffuse reflectance Tf1 (λ i) with If1 (λ i) divided by incident intensity I0 (λ i); Obtain diffuse reflectance Tf2 (λ i) with If2 (λ i) divided by incident intensity I0 (λ i);
Adopt following steps to carry out The Fitting Calculation, accurately try to achieve absorption coefficient spectrum μ a (λ), reduced scattering coefficient spectrum μ s ' (λ).
Utilize said apparatus, realize that with following step sheet or powdered sample absorption coefficient in the 600nm-1700nm scope is composed and the calculating of scattering coefficient spectrum, wavelength resolution is not less than 8nm; Step is as follows:
1) is placed between diffuse reflection integrating sphere and the diffuse transmission integrating sphere less than 2mm sheet or powdered sample for thickness;
2) the electronic shutter control circuit cuts out the incident light that electronic shutter one, two, three, four, five, the first high-speed optical switches are selected first optical fiber, and controller obtains incident intensity I
0(λ); Described electronic shutter control circuit cuts out electronic shutter five, opens electronic shutter one, two, three, four, the incident light that described first high-speed optical switch selection is connected with diffuse reflection integrating sphere measured hole, and described controller obtains incident intensity I
1(λ); Described electronic shutter control circuit cuts out electronic shutter five, opens electronic shutter one, two, three, four, the incident light that described first high-speed optical switch selection is connected with diffuse transmission integrating sphere measured hole, and described controller obtains incident intensity I
2(λ); Described electronic shutter control circuit cuts out electronic shutter five, opens electronic shutter one, two, three, four, and described first high-speed optical switch is selected and collimated the incident light that the integrating sphere measured hole is connected, and described controller obtains incident intensity I
3(λ);
3) collimated transmittance T3 (λ) is obtained divided by incident reference light source light intensity value I0 (λ) by collimated light measuring unit gained light intensity value I3 (λ);
4) diffuse reflection transmissivity T1 (λ) is calculated divided by incident reference light source light intensity value I0 (λ) by diffuse reflection transmissivity measurement unit gained light intensity value I1 (λ);
5) diffuse transmittance T2 (λ) is calculated divided by incident reference light source light intensity value I0 (λ) by diffuse transmittance measuring unit gained light intensity value I2 (λ);
6) compose μ a (λ), scattering coefficient spectrum μ s (λ) and anisotropy factor spectrum g (λ) in order to calculate absorption coefficient, adopt the relatively algorithm wavelength points calculating one by one of the Error Feedback of gained of forward algorithm (prior art) iteration and measurement result; Each wavelength points all is provided with initial value μ a0 (λ i), μ s0 (λ i) and the g0 (λ i) of optical parametric, and i is the wavelength points label; In given thickness of sample scope (thickness of sample is less than 2mm), elder generation's forward calculates its default diffuse reflectance and diffuse transmittance, relatively obtain calculated value and its error amount with T1 (λ), T2 (λ) and T3 (λ) respectively again, adjust optical parametric according to error, finally calculate absorption coefficient spectrum μ a (λ), scattering coefficient spectrum μ s (λ) and anisotropy factor.Preset optical parametric μ a
0(λ i), μ s
0(λ i) and g
0(λ i), them as the iteration initial value;
With this group optical parametric substitution forward algorithm, (detailed annotation of forward algorithm can be referring to following document: 1S.A.Prahl, " The Adding-Doubling Method; " in Optical ThermalResponse of Laser Irradiated Tissue, edited by A.J.Welch and M.J.C.van Gemert, Plenum Press, New York, pp.101-129,1995) come the pairing collimated transmittance of computational physics amount, diffuse reflection transmissivity, diffuse transmittance; Determine the operation of next step by measured value and theoretical value error amount between the two; If reached the precision of setting, the so current optical parametric that sets is exactly last output result, otherwise, reset one group of optical parametric according to comparative result, repeat this process then, up to the output end product or till exceeding the maximum step of iteration.
Utilize said apparatus, following steps realize the calculating of the spectrum of absorption coefficient in the 600nm-1700nm scope and the reduced scattering coefficient spectrum of bulk or live body sample, and wavelength resolution is not less than 8nm; Step is as follows:
1) optical fiber that is connected to light source is closed incident light by optical fiber and the tight lotus root of sample surfaces.
2) being placed on respectively with light source at least 2 detection fiber point-blank uniformly-spaced is on the position of 3-10mm, is adjacent nearest detection fiber position with light source and is not less than 3mm; If do not consider cost factor, many detection fiber can be set, every optical fiber detects light intensity respectively, analyzes according to testing result, thereby obtains accurate more testing result.
3) electronic shutter control circuit control electronic shutter one, two, three, four cuts out, and electronic shutter five is opened, and first high-speed optical switch is selected the incident light of first optical fiber, detects incident intensity I
0(λ
i), second high-speed optical switch is selected optical fiber one, is transferred to incidence hole two, the first high-speed optical switches on the collimated light integrating sphere and selects the light intensity If that comes out from the diffuse reflection of optical fiber one position from the testing sample two that described collimated light integrating sphere measured hole transmits
1(λ
i), second high-speed optical switch is selected optical fiber two, is transferred to incidence hole two, the first high-speed optical switches on the collimated light integrating sphere and selects the light intensity If that comes out from the diffuse reflection of optical fiber two positions from the testing sample two that described collimated light integrating sphere measured hole transmits
2(λ
i).
4) in order to obtain absorption coefficient spectrum μ a (λ), reduced scattering coefficient spectrum μ s ' (λ), wavelength points is carried out following calculating one by one:
The light intensity If1 that a obtains with detection fiber 1 place (λ i) obtains diffuse reflectance Rf1 (λ i) divided by incident intensity;
The light intensity If2 that b obtains with detection fiber 2 places (λ i) obtains diffuse reflectance Rf2 (λ i) divided by incident intensity;
Under a certain wavelength of c, theoretical diffusion rate meets following formula (5-1):
R＝EXP(-rμeff)/[(μa+μs’)r
2] (5-1)
μ eff=[3 μ a in the formula (μ a+ μ s ')]
1/2, according to (5-1) formula, under each wavelength, 2 detections of corresponding optical fiber are apart from the theoretical diffuse reflectance R1 (λ i) and the R2 (λ i) at r1 and r2 place, (5-2) and (5-3) formula:
R1(λi)＝EXP(-r1μeff(λi))/[(μa(λi)+μs’(λi))r1
2](5-2)
R2(λi)＝EXP(-r2μeff(λi))/[(μa(λi)+μs’(λi))r2
2](5-3)
Wherein, EXP is meant e power function, e=2.718.
Structure objective function F (λ i) is seen (5-4) formula
F(λi)＝[R1(λi)-Rf1(λi)]
2+[R2(λi)-Rf2(λi)]
2(5-4)
Adopt nonlinear fitting algorithm (simplex algorithm), try to achieve μ a (λ i) and μ s ' (λ i) that F (λ i) is reached hour, wavelength points is calculated and can be obtained net result absorption coefficient spectrum μ a (λ) and reduced scattering coefficient is composed μ s ' (λ) so one by one.μ a absorption coefficient, the mm of unit
-1, μ s '=(1-g) μ s is a reduced scattering coefficient, the mm of unit
-1, μ eff=(3 μ a* (μ a+ μ s '))
1/2Mm
-1, other parameters are dimensionless.
Above-mentioned dual mode goes for multiple measurement requirement and multiple agricultural product sample form, can be used to measure the chemical composition content to be measured of muddy liquid system testing samples such as milk, fruit juice, also can measure the chemical composition content to be measured of blade, powdered substance, fresh meat section, cube meat and live body wait test sample product.Utilize the device of measuring optical parameter spectrum to obtain absorption coefficient spectrum μ a (λ), the scattering coefficient spectrum μ s (λ) of agricultural product, biological tissue samples; The Applied Chemometrics algorithm is set up the mathematical model between absorption coefficient spectrum μ a (λ) and agricultural product, the biological tissue samples chemical score, and this mathematical model employing multivariate regression model is tried to achieve test substance chemical score in agricultural product, the biological tissue samples.Use the absorption coefficient spectrum μ a (λ) that above-mentioned integration unit obtains and set up model with chemical score, modelling can be adopted the offset minimum binary method, and its forecasting process is seen shown in Figure 3.As seen from Figure 3, eliminate the quantivative approach of diffuse transmission influence in the quality of agricultural product analysis based on the optical parametric separation, comprise two processes, promptly set up model process and prediction chemical score process.Introduce the concrete steps of trying to achieve test substance chemical score in agricultural product, the biological tissue samples below:
(h), i represents different sample number into spectrum and concentration for i=1,2..., and each concentration will have an absorption coefficient spectrum μ ai (λ) to set up before the model earlier concentration value (chemical score) Ci with the composition to be measured of existing chemical measurement sample;
It is as follows to set up the model process: at first select less representative sample h, the P kind component content of measuring h each sample of sample then, be the content of chemical score, the optical parametric μ a, the μ s that utilize above-mentioned measuring light mathematic(al) parameter spectrum detection device to select under the wavelength at h sample measurement obtain absorption coefficient spectrum μ a
Ij(absorbing with scattering separated), set up the chemical score matrix according to chemical score:
C
11......C
1p
……
C
h1......C
hp
According to absorption coefficient spectrum μ a
IjSet up standard absorption coefficient spectrum battle array:
μa
11...μa
1m
……
μa
h1...μa
hm
Wherein, i=1,2...h, j=1,2...m.
Set up multiple predictors according to chemical score matrix and standard absorption coefficient spectrum battle array then:
nir(μa)-C1
nir(μa)-C2
……
nir(μa)-Cp
Prediction chemical score process comprises: at first select a K to be measured sample, the optical parametric μ a, the μ s that utilize above-mentioned measuring light mathematic(al) parameter spectrum detection device to select under the wavelength at k sample measurement obtain absorption coefficient spectrum μ a
Ij(absorbing with scattering separated) is according to absorption coefficient spectrum μ a
IjSet up k to be measured absorption of sample coefficient spectrum battle array:
μa
11...μa
1m
……
μa
k1...μa
km
Wherein, i=1,2...k; J=1,2...m, expression wavelength.
According to absorption coefficient spectrum battle array, utilize and set up the multiple predictors of the same modelling prediction chemical score process of setting up multiple predictors in the model process then:
nir(μa)-C1
nir(μa)-C2
……
nir(μa)-Cp
Set up multiple linear regression model according to chemical score matrix and standard absorption coefficient spectrum battle array then, linear regression method itself is a prior art, and the chemical score computation model is expressed as:
C
k＝μa
k1×a1+μa
k2×a2+.....μa
km×am
A1, a2 ..am return the gained coefficient.
At last, the multiple predictors according to the prediction chemical score process of setting up obtains k to be measured sample chemical value prediction result:
C
11......C
1p
……
C
k1......C
kp
Calculate and finish, try to achieve test substance chemical score in agricultural product, the biological tissue samples.
Below, with one group of concrete experimental result the present invention is described.Test the spectrum that obtains by classic method, as shown in Figure 4.Ordinate is optical density value OD (an optical density value OD dimensionless), and horizontal ordinate is a wavelength.Table 1 is set up model predication value and the contrast of myoglobins true value for adopting traditional spectrum.
Table 1 adopts traditional spectrum to set up model predication value and the contrast of myoglobins true value
| Myoglobins true value (μ M/L) | Model predication value (μ M/L) |
| 1 | 2 |
| 10 | 8 |
| 11 | 8 |
| 12 | 13 |
| 13 | 7 |
| 16 | 14 |
| 18 | 16 |
| 19 | 17 |
| 2 | 1 |
| 20 | 19 |
| 3 | 2 |
| 4 | 5 |
| 5 | 4 |
| 6 | 4 |
| 8 | 7 |
| 9 | 7 |
Model coefficient of variation CV=standard deviation/inequality=23.1%.
Fig. 5 is the absorption coefficient spectrum that adopts the inventive method to obtain, and ordinate is an absorption coefficient value (unit: mm
-1), horizontal ordinate is a wavelength.Table 2 is set up model predication value and the contrast of myoglobins true value for adopting the absorption coefficient spectrum.
Table 2 adopts the absorption coefficient spectrum to set up model predication value and the contrast of myoglobins true value
| Model testing collection true value (μ M/L) | Model testing collection predicted value (μ M/L) |
| 1 | 1.1 |
| 10 | 10.1 |
| 11 | 10.9 |
| 12 | 12.1 |
| 13 | 12.9 |
| 16 | 16 |
| 18 | 17.9 |
| 19 | 19.2 |
| 2 | 2 |
| 20 | 19.8 |
| 3 | 3.05 |
| 4 | 4.1 |
| 5 | 4.95 |
| 6 | 6 |
| 8 | 7.8 |
| 9 | 9 |
CV=standard deviation/inequality=1.1%, model coefficient of variation CV is 1.1%.As seen from Figure 4, five spectral lines that obtained by the classic method test do not overlap fully, and have bigger difference.As seen from Figure 5, adopt apparatus and method of the present invention, five spectral lines overlap basically, and the result shows that the inventive method has significantly improved model accuracy.
This method is used to measure muddy liquid system chemical composition content to be measured such as milk, fruit juice, also can measure the chemical composition content to be measured of samples such as blade, powdered substance, fresh meat section, cube meat and live body.
As can be seen from the above embodiments, present patent application compared with prior art its advantage be:
First, again treat light absorption and light scattering effect in the agricultural product tissue with the viewpoint of " optical parametric separation ", understand the mutual relationship between tissue optical parameter and the spectroscopic data, method by absorption coefficient spectrum and chemical score modeling solves in the classical modeling method and absorbs and the inseparable problem of scattering, the directly influence of weakening scattering from the information source.
The second, agricultural product " optical parametric isolation technics " will provide the theory and technology basis for developing the novel spectrometric instrument that slackens diffuse transmission influence, can become the research method with using value.
The 3rd, because the same set of integration unit of employing has been finished the optical parameter spectrum under the multiple different detection method, satisfy the requirement of different measuring sample, easy to use.
The above only is a preferred implementation of the present invention; should be pointed out that for those skilled in the art, under the prerequisite that does not break away from the technology of the present invention principle; can also make some improvements and modifications, these improvements and modifications also should be considered as protection scope of the present invention.
Claims (9)
1, a kind of device of measuring optical parameter spectrum is characterized in that, comprising:
Light source is connected with first optical fiber, second optical fiber, the 3rd optical fiber;
First high-speed optical switch is connected with described first optical fiber;
The diffuse reflection integrating sphere, described second optical fiber enters the incidence hole of diffuse reflection integrating sphere through electronic shutter one;
The diffuse transmission integrating sphere, the light hole of described diffuse reflection integrating sphere is connected through the incidence hole of electronic shutter two with the diffuse transmission integrating sphere, and testing sample one is arranged between described diffuse reflection integrating sphere and the diffuse transmission integrating sphere;
The collimation integrating sphere, the light hole of described diffuse transmission integrating sphere is connected by the incidence hole one of electronic shutter three, four with the collimation integrating sphere;
Second high-speed optical switch, described the 3rd optical fiber and testing sample two surface couplings, described testing sample two surfaces be provided with at least two with described the 3rd optical fiber detection fiber equidistant, in alignment, described detection fiber is connected with the input end of second high-speed optical switch, and the output terminal of described second high-speed optical switch is connected with the incidence hole two of described collimation integrating sphere by electronic shutter five;
The electronic shutter control circuit, be connected with described electronic shutter one, two, three, four, five respectively, the measured hole on the measured hole on the described diffuse reflection integrating sphere, the measured hole on the diffuse transmission integrating sphere, the collimation integrating sphere is connected with described first high-speed optical switch by optical fiber respectively;
Controller, described first high-speed optical switch is connected with grating, charge-coupled image sensor, acquisition control circuit, controller successively.
2, the device of measurement optical parameter spectrum as claimed in claim 1 is characterized in that, described light source is connected with described first optical fiber, second optical fiber, the 3rd optical fiber through collimation lens.
3, the device of measurement optical parameter spectrum as claimed in claim 2 is characterized in that, the spectral wavelength scope of described first optical fiber, second optical fiber, the 3rd optical fiber is at 600nm～1700nm, and described grating is optimal response in the 600nm-1700nm scope.
4, the device of measurement optical parameter spectrum as claimed in claim 3 is characterized in that,
The incidence hole of described diffuse reflection integrating sphere or light hole area are no more than 2% of described diffuse reflection integrating sphere internal surface area, and the measured hole area of described diffuse reflection integrating sphere is no more than 1% of described diffuse reflection integrating sphere internal surface area;
The incidence hole of described diffuse transmission integrating sphere or light hole area are no more than 2% of described diffuse transmission integrating sphere internal surface area, and the measured hole area of described diffuse transmission integrating sphere is no more than 1% of described diffuse transmission integrating sphere internal surface area;
The incidence hole one of described collimation integrating sphere, incidence hole two or light hole area are no more than 2% of described collimation integrating sphere internal surface area, and the measured hole area of described collimation integrating sphere is no more than 1% of described collimation integrating sphere internal surface area.
5, the device of measurement optical parameter spectrum as claimed in claim 1 is characterized in that, the distance between described diffuse transmission integrating sphere and the described collimation integrating sphere is not less than 20cm.
6, the device of measurement optical parameter spectrum as claimed in claim 1 is characterized in that, the internal diameter of described detection fiber is greater than 800 μ m, and the spacing between the described detection fiber is 3mm～10mm.
7, a kind of quantivative approach of utilizing the device elimination diffuse transmission influence of claim 1 is characterized in that, may further comprise the steps:
Utilize the device of measuring optical parameter spectrum to obtain the absorption coefficient spectrum μ a (λ) and the scattering coefficient spectrum μ s (λ) of agricultural product, biological tissue samples;
The Applied Chemometrics algorithm is set up the mathematical model between standard absorption coefficient spectrum battle array and agricultural product, the biological tissue samples chemical score matrix, tries to achieve test substance chemical score in agricultural product, the biological tissue samples;
Wherein, absorption coefficient spectrum μ a (λ), the scattering coefficient that obtains agricultural product, biological tissue samples composed μ s (λ) and be may further comprise the steps:
S1, placement testing sample one are between diffuse reflection integrating sphere and diffuse transmission integrating sphere;
S2, electronic shutter control circuit are closed the incident light that electronic shutter one, two, three, four, five, the first high-speed optical switches are selected first optical fiber, and controller obtains incident intensity I
0(λ);
S3, described electronic shutter control circuit are closed electronic shutter five, open electronic shutter one, two, three, four, the incident light that described first high-speed optical switch selection is connected with diffuse reflection integrating sphere measured hole, and described controller obtains incident intensity I
1(λ);
S4, described electronic shutter control circuit are closed electronic shutter five, open electronic shutter one, two, three, four, the incident light that described first high-speed optical switch selection is connected with diffuse transmission integrating sphere measured hole, and described controller obtains incident intensity I
2(λ);
S5, described electronic shutter control circuit are closed electronic shutter five, open electronic shutter one, two, three, four, and described first high-speed optical switch is selected and collimated the incident light that the integrating sphere measured hole is connected, and described controller obtains incident intensity I
3(λ);
S6, described controller obtain diffuse reflectance T
1(λ)=I
1(λ)/I
0(λ), diffuse transmittance T
2(λ)=I
2(λ)/I
0(λ), collimated transmittance T
3(λ)=I
3(λ)/I
0(λ);
The algorithm of S7, employing iteration and Error Feedback wavelength points one by one calculates, and at interval each wavelength points is calculated one by one by setting wavelength points, and each wavelength points all provides initial value μ a0 (λ i), the μ s0 (λ of optical parametric
i) and g0 (λ
i), i is the wavelength points label; In given thickness of sample scope, first forward calculates its diffuse reflectance and diffuse transmittance, respectively with T
1(λ), T
2(λ) and T
3(λ) relatively, adopt the simplex method match to obtain optical parametric, finally obtain absorption coefficient spectrum μ a (λ), scattering coefficient spectrum μ s (λ) and anisotropy factor g (λ) according to error.
8, a kind of quantivative approach of utilizing the device elimination diffuse transmission influence of claim 1 is characterized in that, said method comprising the steps of:
The absorption coefficient spectrum μ a (λ) and the reduced scattering coefficient that utilize the device of measuring optical parameter spectrum to obtain agricultural product, biological tissue samples are composed μ s ' (λ);
The Applied Chemometrics algorithm is set up the mathematical model between standard absorption coefficient spectrum battle array and agricultural product, the biological tissue samples chemical score matrix, tries to achieve test substance chemical score in agricultural product, the biological tissue samples;
Wherein, absorption coefficient spectrum μ a (λ), the reduced scattering coefficient that obtains agricultural product, biological tissue samples composed μ s ' and (λ) be may further comprise the steps:
S01, electronic shutter control circuit control electronic shutter one, two, three, four are closed, and electronic shutter five is opened, and first high-speed optical switch is selected the incident light of first optical fiber, detects incident intensity I
0(λ
i);
S02, second high-speed optical switch are selected the optical fiber one at least two detection fiber, be transferred to incidence hole two, the first high-speed optical switches on the collimated light integrating sphere and select the light intensity If that comes out from the diffuse reflection of optical fiber one position from the testing sample two that described collimated light integrating sphere measured hole transmits
1(λ
i);
S03, second high-speed optical switch are selected the optical fiber two at least two detection fiber, be transferred to incidence hole two, the first high-speed optical switches on the collimated light integrating sphere and select the light intensity If that comes out from the diffuse reflection of optical fiber two positions from the testing sample two that described collimated light integrating sphere measured hole transmits
2(λ
i);
S04, described controller obtain diffuse reflectance Rf
1(λ i)=If
1(λ
i)/I0 (λ
i), diffuse reflectance Rf
2(λ
i)=If
2(λ
i)/I0 (λ
i);
S05, according to theoretical diffusion rate formula:
R＝EXP(-rμeff)/[(μa+μs’)r
2]
μ eff=[3 μ a in the formula (μ a+ μ s ')]
1/2, under each wavelength, 2 detections of corresponding optical fiber are apart from the theoretical diffuse reflectance R at r1 and r2 place
1(λ
i) and R
2(λ
i):
R
1(λ
i)＝EXP(-r1μeff)/[(μa+μs’)r1
2]
R
2(λ
i)＝EXP(-r2μeff)/[(μa+μs’)r2
2]
The structure objective function,
F(λ
i)＝[R
1(λ
i)-Rf
1(λ
i)]
2+[R
2(λ
i)-Rf
2(λ
i)
]2
Adopt the nonlinear fitting algorithm, try to achieve the wavelength X that F (λ i) is reached hour
iμ a (the λ at place
i) and μ s ' (λ
i), wavelength points is calculated and can be obtained net result absorption coefficient spectrum μ a (λ) and reduced scattering coefficient is composed μ s ' (λ) so one by one.
9, the quantivative approach of elimination diffuse transmission influence as claimed in claim 8, it is characterized in that, described quantivative approach is used to measure the chemical composition content to be measured of muddy liquid system testing sample, or the chemical composition content to be measured of blade, powdered substance, fresh meat section, cube meat and live body testing sample is measured.
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| CN104406693B (en) * | 2014-11-13 | 2017-01-11 | 浙江大学 | Device and method for collecting visible and near infrared spectrum of fruits in field |
| CN106770050B (en) * | 2016-12-31 | 2023-08-11 | 上海复展智能科技股份有限公司 | Liquid spectrum transmission and scattering coefficient measuring device based on integrating sphere |
| CN109632651B (en) * | 2018-06-06 | 2021-02-19 | 湖南理工学院 | Multi-parameter spectrum measurement method and system for turbid medium |
| CN110082349B (en) * | 2019-02-01 | 2021-11-02 | 南京师范大学 | Remote sensing estimation method for inland eutrophication lake water body blue-green algae biomass ratio based on OLCI |
| JP7371905B2 (en) * | 2019-12-20 | 2023-10-31 | マイクロコントロールシステムズ株式会社 | Analyzer that performs analysis using collimated light |
| CN112033939B (en) * | 2020-09-17 | 2021-05-04 | 上海海关机电产品检测技术中心 | Film absorptivity test method for ultraviolet ray tracing simulation |
| CN112285124B (en) * | 2020-11-09 | 2023-03-31 | 南京财经大学 | Method and device for judging aflatoxin B1 pollution degree in vegetable oil and optical judging device |
| CN112683851A (en) * | 2021-03-22 | 2021-04-20 | 宁波普瑞柏生物技术股份有限公司 | Protein concentration detection and analysis method, device and application thereof |
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