CN106872226A - By making the method that the imitative body of solid is corrected to agricultural product optical characteristics detection means by oneself - Google Patents

Abstract

The invention discloses a kind of by making the method that the imitative body of solid is corrected to agricultural product optical characteristics detection means by oneself.Make the imitative body of the solid with different optical property parameters, and the reference value of its optical property parameter is obtained according to standard method and theoretical formula method, detected under visible near-infrared wave band by agricultural product optical property parameter detection means, obtain the measured value of the optical property parameter under different wave length, measured value relation corresponding with reference value according to imitative optical property parameter of the body under each wavelength of different solids is fitted acquisition fitting parameter, after actual sample is measured by agricultural product optical property parameter detection means, the measured value of the optical property parameter obtained to measurement with fitting parameter is modified.Die module low cost of the invention, the making solid imitative body time is short, and the imitative body of fixed solid of making can be preserved for a long time, complete the correction to detection means, improve the accuracy of detection of agricultural product optical characteristics.

Description

Method for calibrating the optical characteristic detection device of agricultural products by self-made solid phantom

technical field

The invention relates to a method for calibrating a device, in particular to a method for calibrating an optical characteristic detection device of agricultural products by self-made solid phantom.

Background technique

The detection technology of the optical properties of biological tissue has been widely studied and applied in the quality detection of food and agricultural products. Since Norris used near-infrared spectroscopy in the detection of agricultural products in 1964, most of the traditional research on near-infrared spectroscopy has focused on the non-destructive testing of chemical components in agricultural products.

However, there are two main forms of light propagation and attenuation in biological tissues: absorption and scattering, which can be characterized by the absorption coefficient and the reduced scattering coefficient. The absorption coefficient in the visible-near-infrared band is related to some important chemical components (such as: SSC) in agricultural products, and the scattering is usually related to its microscopic physical structure. Therefore, for the quality inspection of agricultural products, it is of great significance to measure these two parameters.

In the field of agricultural product detection, there are some existing researches: time-resolved reflectance spectroscopy; spatially resolved spectroscopy; spatially resolved method based on hyperspectral; spatial frequency domain imaging method and integrating sphere method. Before these methods are used in actual detection, it is necessary to use standard substances to calibrate and verify the accuracy of these spectral or imaging devices and instruments as well as the corresponding algorithms. These reference materials are called solid analogues. The optical characteristic parameters of the solid phantom should include the range of the optical characteristic parameters of agricultural products, so that the correction of the larger optical characteristic parameters of different detection systems can be realized.

At present, there are two types of solid phantoms in research: solid and liquid, but solid phantoms can be stored for a long time and can be made into different shapes, which can better meet the actual situation of agricultural product testing. At present, the production of solid phantoms for agricultural products is still blank in China, and there are commercial solid phantoms abroad, but the cost is relatively high. Since different agricultural product optical characteristic parameter detection devices require a large number of solid phantoms of different shapes and sizes, it is necessary to develop a set of low-cost and easy-to-manufacture solid phantom manufacturing methods and corresponding calibration methods.

Contents of the invention

In order to solve the problems in the background technology, the object of the present invention is to provide a method for calibrating the optical characteristic detection device of agricultural products by self-made solid phantom.

Technical scheme of the present invention has the following steps:

1) Make solid phantoms with different optical characteristic parameters, and calculate the reference values of their optical characteristic parameters according to standard methods and theoretical formulas;

2) For the solid phantom made in step 1), the optical characteristic parameter detection device of agricultural products is used for detection in the visible-near-infrared band, and the measured values of optical characteristic parameters (absorption coefficient and reduced scattering coefficient) at different wavelengths are obtained ;

3) According to the one-to-one correspondence relationship between the measured values of the optical characteristic parameters of different solid phantoms at each wavelength and the reference value, the fitting parameters are obtained by fitting;

4) After the actual sample is measured by the agricultural product optical characteristic parameter detection device, the measured value of the optical characteristic parameter obtained by the measurement is corrected by the fitting parameters obtained in step 3).

The optical characteristic parameters include absorption coefficient and reduced scattering coefficient.

Described step 3) and step 4) specifically are:

First make n solid phantoms with the same reduced scattering coefficient and different absorption coefficients for correcting the absorption coefficient of the detection device, and at the same time make m solid bodies with the same absorption coefficient and different reduced scattering coefficients for correcting the reduced scattering coefficient of the detection device Mimic body;

Then, according to the measured values and reference values of absorption coefficients and reduced scattering coefficients of different solid phantoms at the same wavelength, the following formula is used to calculate the average value k(μ _a ) _λ and the average value k(μ' _s ) _λ of the ratio of the reference value and the measured value of the reduced scattering coefficient of m solid phantoms as the fitting parameter:

Among them, λ represents the wavelength, μ _a (i) _ref and μ _a (i) _mea respectively represent the reference value and measurement value of the absorption coefficient of the i-th solid phantom in all n solid phantoms, μ' _s (j) _ref and μ' _s (j) _mea respectively represent the reference value and measured value of the reduced scattering coefficient of j solid phantoms among all m solid phantoms;

Finally, for this wavelength, the absorption coefficient and reduced scattering coefficient obtained by measuring the actual sample through the optical characteristic parameter detection device of agricultural products are linearly corrected by the following formula, that is, the absorption coefficient and reduced scattering coefficient measured by the detection device are respectively multiplied by their fitting Parameters k(μ _a ) _λ and k(μ' _s ) _λ :

μ _a (i) _calibrated = k(μ _a ) _λ * μ _a (i) _mea

μ' _s (j) _calibrated = k(μ' _s ) _λ *μ' _s (j) _mea

Among them, μ _a (i) _calibrated and μ _a (i) _mea respectively represent the corrected value and measured value of the absorption coefficient of the i-th solid phantom among all n solid phantoms, μ' _s (j) _ref and μ ' _s (j) _mea represents the corrected value and the measured value of the reduced scattering coefficient of the jth solid phantom among all m solid phantoms, respectively.

The solid phantom is made by using India Ink as an absorber, titanium dioxide (TiO ₂ ) as a scatterer, and polyurethane AB material as a base material, using different molds to form solid phantoms of different shapes.

The concrete steps of making described solid analog body are:

1.1) According to the range of the absorption coefficient and the reduced scattering coefficient value of the optical characteristic parameter value of the agricultural product and the size of the solid phantom to be made, determine the quality of India ink, titanium dioxide and polyurethane AB material in the solid phantom, the three are respectively a part, b part, c part;

1.2) Mix 0.5a part of Indian ink into 0.5c part of polyurethane material A to obtain mixed solution I, and mix b part of TiO2 and 0.5a part of Indian ink into 0.5c part of polyurethane material B to obtain mixed solution II;

1.3) Put the mixed solution I and the mixed solution II in an ultrasonic cleaning machine to vibrate and stir with a glass rod to make them evenly mixed to obtain the mixed solution III;

1.4) Put the mixture III in a vacuum drying oven to vacuum for 10-15 minutes, take it out every 1 minute, put it in an ultrasonic cleaner to vibrate and stir once with a glass rod;

1.5) Inject the vacuumized mixture III into the mold, and place it at room temperature until it solidifies to obtain a solid analog.

From the mixed solution I that described step 1.3) is made, get a part and put into cuvette, measure its absorbance and the thickness of cuvette by using the temperature control cuvette support of QUANTUMNORTHWEST company, according to the absorbance and cuvette The reference value of the absorption coefficient μ _a is obtained by calculating the thickness through Lambert-Beer's law, and the reference value of the reduced scattering coefficient μ _'s is obtained through the calculation of the Mie theory.

Described cuvette is to adopt the temperature control cuvette of QUANTUM NORTHWEST company.

For the correction requirements of different platforms and methods, the mold includes three kinds of molds for different usage requirements, namely, a mold for making a thin flat solid phantom, a mold for making a thick flat solid phantom, and a mold for making a thick flat solid phantom. It is used to make a mold with a hemispherical thick plate solid imitation body. The mold is built by modular components; the modular components include a base plate, a thin middle plate, a syringe, a thick middle plate, a beaker and a hemispherical plate, a thin The middle plate is an annular structure with a through groove in the middle. The side wall of the annular structure is opened with a radial channel for injecting liquid. The base plate is a flat plate structure. The hemispherical plate is a flat plate structure with a boss in the center of one end. A hemispherical hole is opened in the center of the non-boss end face.

The mold for making a thin flat solid phantom is mainly composed of two base plates and a thin middle plate between the two base plates, and the mixed liquid in the syringe is injected through the radial channel of the side wall of the thin middle plate.

The mold for making a thick plate-shaped solid body is mainly composed of a base plate and a thick middle plate placed on the base plate. The mixed solution in the beaker is poured into the through groove in the middle of the thick middle plate and the base plate forms In the cavity.

The mold for making a thick plate-shaped solid body with a hemisphere is mainly composed of a hemispherical plate and a thick middle plate placed on the non-bossed end face of the hemispherical plate. In the cavity formed by the groove and the hemispherical plate.

According to the correction requirements of different detection devices, the present invention specially designs and manufactures the above-mentioned molds to make solid phantoms of different shapes and sizes. For the integrating sphere system, it is required to measure the reflectance and transmittance of the sample, so the sample should not be too thick. Therefore, the present invention specially adopts a thin plate solid imitation mold with a thickness of about 10mm. For time-resolved spectroscopy systems, spatially resolved spectroscopy systems, and hyperspectral-based spatially resolved systems, the spatial frequency domain imaging system requires the sample to be a semi-infinite medium, so the present invention particularly uses a thick plate-type solid phantom mold with a thickness of about 50mm . In addition, for the imaging system, since many agricultural products are not flat, a solid phantom with a hemispherical shape is designed to correct the accuracy of the imaging system for detecting curved surface samples. mold.

The beneficial effects of the present invention are:

The mold of the invention adopts a modular design, has low cost, and takes a short time to manufacture the solid analog body, and the manufactured fixed solid analog body can be preserved for a long time.

The invention can complete the calibration of the detection device under the premise of satisfying the range of the optical characteristic parameters of the agricultural products, and improve the detection accuracy of the optical characteristics of the agricultural products.

Description of drawings

Fig. 1 is the mold structure schematic diagram of thin plate type solid imitation body;

Fig. 2 is the mold structure schematic diagram of thick plate type solid imitation body;

Fig. 3 is the mold structure schematic diagram of band hemispherical thick plate type solid imitation body;

Fig. 4 is the structural representation of base plate;

Fig. 5 is a front view of a hemispherical plate;

Figure 6 is a top view of the hemispherical plate;

Fig. 7 is a sectional view of a hemispherical plate;

Fig. 8 is a schematic diagram of a thin middle plate;

Figure 9 is a schematic diagram of a thick middle plate.

Fig. 10 is a flowchart of an embodiment of the present invention.

In the figure: 1. Base plate, 2. Thin middle plate, 4. Syringe, 5. Thick middle plate, 6. Beaker, 7. Hemispherical plate.

detailed description

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

Embodiments of the present invention are as follows, and the process is as shown in Figure 10:

1) Solid body imitation production:

The materials selected for making the solid phantom in this embodiment include: base material, absorbing material and scattering material. Among them, the base material is polyurethane AB material (water clear) (WC-781, BJB, USA), the absorbing material is Indian ink (Talens, Netherlands), the scattering material is titanium dioxide (T105415, Aladdin, China), and its particle size range is 0.2 -0.4um.

1.1) Determine the required range of optical characteristic parameters according to the type of sample to be measured, and then determine the required volume fraction of _TiO2 and India ink according to the range of optical characteristic parameters. Here the volume fraction of _TiO2 was determined to be 0.02%, 0.03%, 0.05%, and that of India ink was 0.04%, 0.07%, 0.1%. According to the volume fraction of TiO ₂ , calculate the required volume of TiO ₂ , and then calculate the required weight of TiO ₂ according to the density of TiO ₂ as ρ _TiO2 =4g/cm ³ . According to the volume fraction of India ink, calculate the volume of required India ink.

1.2) According to the calibrated platform and method, three different solid phantoms are made. The mold is built by modular components. The modular components specifically include the base plate 1, the thin middle plate 2, the syringe 4, the thick middle plate 5, and the beaker 6 and the hemispherical plate 7, the thin middle plate 2 and the thick middle plate 5 are all annular structures with a through groove in the middle, and radial channels for injecting liquid are opened on the side walls of the annular structure, as shown in Figure 8 and Figure 9 respectively The base plate 1 is a flat plate structure as shown in Figure 4; the hemispherical plate 7 is a flat plate structure with a boss in the center of one end, and the center of the non-bossed end surface of the hemispherical plate 7 has a hemispherical hole, as shown in Figure 5-7. The corresponding molds are:

(1) 10mm thick thin flat solid phantom (used to correct the integrating sphere system and IAD method), the corresponding mold is shown in Figure 1, mainly composed of two base plates 1 and a thin middle plate 2 between the two base plates 1 Composition, the mixed solution in the syringe 4 is injected through the radial channel of the side wall of the thin middle plate 2;

(2) 50mm thick thick plate solid phantom (used to correct the spatial frequency domain imaging system, spatial resolution diffuse reflectance spectroscopy system and other systems that require the sample to be a semi-infinite medium), the corresponding mold is shown in Figure 2, mainly composed of a base plate 1 and a thick middle plate 5 placed on the base plate 1, the mixed solution in the beaker 6 is poured into the cavity formed by the through groove in the middle of the thick middle plate 5 and the base plate 1;

(3) 50mm thick hemispherical thick plate type solid imitation body (for contour correction), the corresponding mold is shown in Figure 3, which mainly consists of a hemispherical plate 7 and a thick middle plate 5 placed on the non-bossed end surface of the hemispherical plate 7 The mixed solution in the beaker 6 is poured into the cavity formed by the through groove in the middle of the thick middle plate 5 and the hemispherical plate 7 .

1.3) Among them, to make solid analogs of type (1), the required polyurethane materials A and B are 75mL and 75mL respectively; series 1: the content of Indian ink is the same, but the content of TiO ₂ is different. Weigh 0.128g, 0.192g, 0.320g of _TiO2 into 3 parts of material B with an electronic balance, and put 52.5uL of Indian ink into 3 parts of material A and the above material B with a pipette gun, respectively. Mixed solutions Ⅰ and Ⅱ were obtained respectively; series 2: same content of TiO ₂ , different content of India ink. Use an electronic balance to weigh 0.192g of TiO ₂ and put them into 3 parts of material B, and use a pipette gun to measure 30uL, 52.5uL, and 75uL of Indian ink respectively and put them into 3 parts of material A and the above-mentioned 3 parts of material B. Mixtures I and II were obtained respectively.

To make solid analogs of categories (2) and (3), the required polyurethane materials A and B are 200mL and 200mL respectively; series 1: the content of Indian ink is the same, but the content of TiO ₂ is different. Weigh 0.341g, 0.512g, and 0.853g of _TiO with an electronic balance respectively and put them into 3 parts of material B, and use a pipette gun to measure 140uL of Indian ink respectively and put them into 3 parts of material A and the above-mentioned material B respectively. Mixtures I and II were obtained; series ₂ : same content of TiO2, different content of India ink. Use an electronic balance to weigh 0.512g of TiO ₂ into 3 parts of material B, and use a pipette gun to measure 80uL, 140uL, and 200uL of Indian ink respectively into 3 parts of material A and the above-mentioned material B to obtain a mixture Liquid I and II.

1.4) Calculation of absorption coefficient and reference value of reduced scattering coefficient

For the series 2 of the three types of solid phantoms, take a part of the mixture I into the cuvette, and use the temperature-controlled sample cell holder (CUV-qpot-ABSKIT, QUANTUM NORTHWEST, USA) and the tungsten-halogen lamp (model HL -2000-FHSA, Ocean Optics, USA), QE 65Pro spectrometer (Ocean Optics, USA) and two optical fibers (modelP1000-2-VIS-NIR, Ocean Optics, USA), measured the absorbance of the mixture Ⅰ, and then according to the Calculated by Berber's law.

The mathematical expression of Lambert-Beer's law: A=lg(1/T)=Kbc, wherein A is the absorbance, T is the transmittance, K molar absorption coefficient, c is the concentration of the light-absorbing substance, and b is the thickness of the absorbing layer, which is The thickness of the sample layer. Absorption coefficient μ _a =Kc=A/b, as long as the absorbance of the solution and the thickness of the cuvette (here 10mm) are known, μ _a can be calculated.

The reference value of the reduced scattering coefficient is obtained through the Mie algorithm (Christian "MATLAB Functions for Mie Scattering and Absorption.", 2002). The parameters that need to be input are the refractive index of polyurethane: 1.50, the refractive index of TiO ₂ at 527nm: 2.6738, the diameter of TiO ₂ : the median value here is 0.3um, and the volume fraction of TiO ₂ : 0.02%, 0.03%, and 0.05%.

1.5) Put the mixed solution I and the mixed solution II in an ultrasonic cleaning machine to vibrate for 15 minutes and stir with a glass rod to make them evenly mixed to obtain the mixed solution III. Put the mixed solution III into a vacuum drying oven for vacuuming at 0.1 MPa for 10-15 minutes.

1.6) For the solid analog of category (1), inject the mixed solution III into the mold combination 1 shown in FIG. 1 through the syringe 4 . For (2) (3) type solid analogs, pour directly through the beaker 6 into the mold combinations 2 and 3 as shown in FIGS. 2 and 3 . Place it at room temperature until it solidifies into a solid.

The finished type (1) solid phantom has a little gap in the 4 corners, but it does not affect the use of calibration measurement. The finished (3) solid phantom has a complete shape and no defects. The solid phantom of category (2) is similar to the solid phantom of category (3), except that there is no hemisphere.

For the completed first type (1) (3) solid analogs, the corresponding solid analogs of the same sample number have the same component content, and the component content of each block is shown in the following table:

Table 1

2) Calibration of the spatial frequency domain imaging system

The three solid phantoms in series 1 (same absorption coefficient but different reduced scattering coefficients) in the third type of solid phantoms made by making are used to correct the reduced scattering coefficient of the detection device, and the three solid phantoms in series 2 Volumes (same reduced scattering coefficient, different absorption coefficient) are used to correct the absorption coefficient of the detection device.

In the process of making the above-mentioned solid phantom, the reference values of the absorption coefficient and the reduced scattering coefficient have been obtained. At a wavelength of 527nm, the absorption coefficient and reduced scattering coefficient of each solid phantom are obtained through the detection of the spatial frequency domain imaging system.

The absorption coefficient and the reduced scattering coefficient are linearly corrected respectively, that is, the absorption coefficient and the reduced scattering coefficient measured by the spatial frequency domain imaging system are multiplied by a coefficient: k(μ _a ) _λ and k(μ' _s ) _λ . k(μ _a ) _λ is the mean value of the ratio of the reference value to the measured value of the absorption coefficient of the three solid phantoms in series 2, and k(μ' _s ) _λ is the reference value of the reduced scattering coefficient of the three solid phantoms in series 1 The mean of the ratios to the measured values.

Among them, μ _a (i) _ref and μ _a (i) _mea represent the reference value and measured value of the absorption coefficient of the i-th solid phantom among the three solid phantoms in series 2, respectively. μ' _s (j) _ref and μ' _s (j) _mea respectively represent the reference value and measured value of the reduced scattering coefficient of the jth solid phantom among the three solid phantoms in series 1, and the value of λ is: 527nm.

The corrected test results are shown in Table 2 below:

Table 2

The maximum relative error in the detection of the reduced scattering coefficient is 2.39%, and the maximum relative error in the detection of the absorption coefficient is 13.48%, and the correction process of the system is completed. It can be seen that the method of the present invention can correct the optical characteristic detection device for agricultural products and improve the optical characteristics of agricultural products. detection accuracy.

In addition, the cost of the present invention is 20 times lower than that of commercially purchased solid phantoms, and the production of molds and solid phantoms as well as system calibration can be realized with about RMB 3,000.

Claims (7)

1. it is a kind of by making the method that the imitative body of solid is corrected to agricultural product optical characteristics detection means by oneself, it is characterised in that method Step is：

1) the imitative body of the solid with different optical property parameters is made, and its light is obtained according to standard method and theoretical formula method Learn the reference value of characterisitic parameter；

2) for step 1) in the imitative body of the solid that is fabricated to, by agricultural product optical property parameter detection means visible-near red Detected under wave section, obtained the measured value of the optical property parameter under different wave length；

3) the measured value relation corresponding with reference value according to imitative optical property parameter of the body under each wavelength of different solids is carried out Fitting obtains fitting parameter；

4) by agricultural product optical property parameter detection means measure actual sample after, by step 3) obtain fitting parameter The measured value of the optical property parameter obtained to measurement is modified.

2. a kind of by making what the imitative body of solid was corrected to agricultural product optical characteristics detection means by oneself according to claims 1 Method, it is characterised in that：Described optical property parameter is to include absorption coefficient and reduced scattering coefficient.

3. a kind of by making what the imitative body of solid was corrected to agricultural product optical characteristics detection means by oneself according to claims 1 Method, it is characterised in that：Described step 3) and step 4) be specifically：

The solid that n reduced scattering coefficient is identical and absorption coefficient is different for correcting detection means absorption coefficient is first made to imitate Body, while making for correcting, m absorption coefficient of detection means reduced scattering coefficient is identical and reduced scattering coefficient is different Solid imitates body；

Then according to imitative absorption coefficient of the body under Same Wavelength of different solids and the measured value and reference value of reduced scattering coefficient Using below equation calculate the average k (μ of the reference value with measured value ratio that obtain absorption coefficient_a)_λAnd reduced scattering coefficient Reference value and measured value ratio average k (μ '_s)_λAs fitting parameter：

$k{\left({\mathrm{\μ}}_a\right)}_{\mathrm{\λ}}=\underset{i=1}{\overset{n}{\Σ}}\frac{{\mathrm{\μ}}_a{\left(i\right)}_{ref}/{\mathrm{\μ}}_a{\left(i\right)}_{mea}}{n}$

$k{\left({{\mathrm{\μ}}^{\′}}_s\right)}_{\mathrm{\λ}}=\underset{j=1}{\overset{m}{\Σ}}\frac{{{\mathrm{\μ}}^{\′}}_s{\left(j\right)}_{ref}/{{\mathrm{\μ}}^{\′}}_s{\left(j\right)}_{mea}}{m}$

Wherein, λ represents wavelength, μ_a(i)_refWith μ_a(i)_meaI-th suction of the imitative body of solid in the imitative body of all n solids is represented respectively Receive the reference value and measured value of coefficient, μ '_s(j)_refWith μ '_s(j)_meaThe j imitative body of solid in the imitative body of all m solids is represented respectively Reduced scattering coefficient reference value and measured value；

Under finally for the wavelength, the absorption coefficient that actual sample is obtained is measured by agricultural product optical property parameter detection means Linearly corrected using below equation with reduced scattering coefficient：

μ_a(i)_calibrated=k (μ_a)_λ*μ_a(i)_mea

μ'_s(j)_calibrated=k (μ '_s)_λ*μ'_s(j)_mea

Wherein, μ_a(i)_calibratedWith μ_a(i)_meaI-th absorption coefficient of the imitative body of solid in the imitative body of all n solids is represented respectively Correction after value and measured value, μ '_s(j)_refWith μ '_s(j)_meaJ-th solid imitates body in representing the imitative body of all m solids respectively Value and measured value after the correction of reduced scattering coefficient.

4. a kind of by making what the imitative body of solid was corrected to agricultural product optical characteristics detection means by oneself according to claims 1 Method, it is characterised in that：

The making of the imitative body of described solid is as absorption, with titanium dioxide (TiO using india ink (India Ink)₂) conduct Scattering is sub, use different Mold Makings to form the imitative body of solid of different shapes as base material using polyurethane AB material.

5. a kind of by making what the imitative body of solid was corrected to agricultural product optical characteristics detection means by oneself according to claims 4 Method, it is characterised in that：

The making of the imitative body of described solid is concretely comprised the following steps：

1.1) scope of the absorption coefficient according to agricultural product optical property parameter value and reduced scattering coefficient value and required making The size of the imitative body of solid, determines the quality of india ink, titanium dioxide and polyurethane AB material in the imitative body of solid, and three is respectively a Part, b parts, c parts；

1.2) 0.5a parts of india ink is mixed into 0.5c parts of polyurethane A material and obtains mixed liquor I, by b parts of TiO2 and 0.5a Part india ink obtains mixed liquor II in being mixed together in 0.5c parts of polyurethane B material；

1.3) mixed liquor I and mixed liquor II are put into ultrasound cleaner vibrator to swing and stirred using glass bar, make its uniform mixing, Obtain mixed liquor III；

1.4) mixed liquor III is put into vacuum drying chamber to vacuumize 10-15 minutes, taking-up in every 5 minutes is put into ultrasound cleaner vibrator Swing and use glass bar to stir once；

1.5) mixed liquor III after vacuumizing is injected into mould, treats that its solidifies under placement normal temperature, obtains the imitative body of solid.

6. a kind of by making what the imitative body of solid was corrected to agricultural product optical characteristics detection means by oneself according to claims 5 Method, it is characterised in that：

From the step 1.3) part is taken in the mixed liquor I that is made is put into cuvette, by using QUANTUM The temperature control cuvette support of NORTHWEST companies surveys the thickness of its absorbance and cuvette, according to absorbance and the thickness of cuvette Degree is calculated by langbobier law and obtains absorption coefficient μ_aReference value, by Mie theory calculate obtain reduced scattering coefficient μ’_sReference value.

7. a kind of by making what the imitative body of solid was corrected to agricultural product optical characteristics detection means by oneself according to claims 5 Method, it is characterised in that：Described mould includes three kinds of moulds for different use demands, namely for making thin flat plate Type solid imitates the mould of body, the mould for making the imitative body of thick flat-plate-type solid and for making the imitative body of band hemisphere thick plate type solid Mould, mould built by modular assembly；Modular assembly specifically includes bedplate (1), thin intermediate plate (2), note Emitter (4), thick intermediate plate (5), beaker (6) and hemisphere plate (7), thin intermediate plate (2) and thickness intermediate plate (5) be in the middle part of be provided with it is logical The loop configuration of groove, the side wall of loop configuration is provided with the radial passage for injecting liquid, and bedplate (1) is one flat plate knot Structure, hemisphere plate (7) is slab construction of one end center with boss, and the non-raised head face center of hemisphere plate (7) is provided with hemispherical-shaped aperture；

Described is main by two pieces of bedplates (1) and two pieces of bedplates (1) for making the mould of the imitative body of Boping template solid Between thin intermediate plate (2) constitute, mixed liquor in syringe (4) is injected by the radial passage of thin intermediate plate (2) side wall；

The described mould for making the imitative body of thick flat-plate-type solid mainly by one piece of bedplate (1) and is placed in bedplate (1) Thick intermediate plate (5) constitute, what the groove and bedplate (1) that the mixed liquor in beaker (6) is poured into the middle of thick intermediate plate (5) were formed In cavity volume；

It is described that for making, the mould with the imitative body of hemisphere thick plate type solid is main by one piece of hemisphere plate (7) and to be placed in hemisphere plate (7) thick intermediate plate (5) on non-raised head face is constituted, groove that the mixed liquor in beaker (6) is poured into the middle of thick intermediate plate (5) and In the cavity volume that hemisphere plate (7) is formed.