CN105572051A - Polarized water turbidity measurement device, system and method - Google Patents

Abstract

The invention discloses a polarized water turbidity measurement device, system and method. The polarized water turbidity measurement device is characterized by comprising a light source (1) which is used for emitting monochromatic light I to a first lens (2), wherein the monochromatic light I sequentially penetrates through the first lens (2) and a first polarizing film (5) and is split into incident light Ia and scattered light Ib by a light splitting mirror (8), the included angle between the incident light Ia and the scattered light Ib is 90 degrees, the scattered light Ib enters a first photoelectric detector (7), 90-degree surface scattered light I<a1> formed after the incident light Ia enters a measurement groove (3) sequentially penetrates through a second polarizing film (6) and a second lens (4) and enters a second photoelectric detector (9); a temperature measurement sensor is arranged in the measurement groove (3). According to the device, the system and the method, by virtue of a data processing manner of a least square support vector machine, the temperature is compensated, the measuring error is eliminated, and the measurement accuracy is improved.

Description

A kind of measurement mechanism of polarization type water turbidity, measuring system and measuring method

Technical field

The present invention relates to a kind of measurement mechanism of polarization type water turbidity, measuring system and measuring method, belong to liquid turbidity field of measuring technique.

Background technology

The turbidity of water is a kind of optical effect in water sample, refers to that the solid particulate matter and impurity that suspend in water sample are to the degree of the water sample transparency change caused by the scattering of light and absorption.The concentration, optical property etc. of its turbidity size and impurity have relation.In recent years, water pollution event happens occasionally, and threatens the life and health of broad masses of the people, causes the popular care to water quality monitoring.Photovoltaic measurement due to its fast and accurately characteristic be widely used among the fields of measurement of turbidity.

According to turbidimetry international standard ISO7027, the measurement of turbidity measures scattered light on 90 ° of directions, this measuring method has good linear relationship in low turbidity region, but result in measuring error because scattered light creates Multiple Scattering in high concentrtion region, it is measured range and receives huge restriction, among the detection that cannot be widely used in chemical industry turbidity.And on the other hand, in actual measurement, because the parasitic light in bias light and incident liquid inevitably enters among detector, affect the measuring accuracy of whole turbidimeter.

In Chinese invention (CN1087425) disclosed in, inventor have employed the incident liquid level of single light source, incident detector after the surface scattering light scioptics accepting 90 ° converge, although inventor have employed the device of automatically cleaning, to solve due to stained and error that is that cause.But because this measuring method have employed a detector, therefore cannot solve because light source shakes the measuring error caused.Its light without polarization selected is measured simultaneously, and detector does not have selectivity to various light source, cannot remove the impact of bias light and Multiple Scattering light.For above two kinds of problems, the turbidimeter measuring instrument of this Patent design, by utilizing the characteristic of polarized light, eliminates the impact of most of bias light and interference of stray light.The design of double light path simultaneously greatly can remove the impact of the light intensity shake that light source ages causes.Compare with transmission beam method and 90 ° of scattering methods, light path is shorter, and Multiple Scattering is less, therefore it is larger to measure range.Laying temperature sensor simultaneously, the temperature in measurement mechanism.This device adopts the data regression disposal route of least square method supporting vector machine (LS-SVM), data fitting is carried out to temperature, scattered light intensity, former light intensity, light intensity ratio simultaneously, compared to the approximating method of common least square method, the method has better linear in few sample, non-linear, high-dimensional problem, solve the impact of temperature on turbidity, improve precision.

Summary of the invention

Technical matters to be solved by this invention is, provides a kind of measurement mechanism and measuring system of polarization type water turbidity of single light source double light path polarized light; Further, the invention provides the error of the turbidimetry that a kind of solution causes due to flashing, and eliminate the impact that bias light and Multiple Scattering parasitic light cause, adopt the data processing method of least square method supporting vector machine simultaneously, temperature is compensated, eliminate measuring error, improve the measuring method of the polarization type water turbidity of measuring accuracy.

For solving the problems of the technologies described above, the technical solution used in the present invention is:

A kind of measurement mechanism of polarization type water turbidity, it is characterized in that, comprise: for launching the light source of a monochromic beam I to the first lens, described monochromatic light I becomes incident light I in 90 ° angles with after the first polaroid by spectroscope light splitting through described first lens successively _awith scattered light I _b, described scattered light I _benter the first photodetector, described incident light I _aenter 90 ° of surface scattering light I after measuring flume _a1successively by entering the second photodetector after the second polaroid and the second lens; Sensor for measuring temperature is provided with in described measuring flume.

Described measuring flume comprises U-type groove, described U-type groove comprises two vertically disposed intake chamber and effluent troughs, described intake chamber is communicated with by transverse groove with the bottom of effluent trough, the surrounding of described intake chamber and effluent trough is provided with overflow groove, be positioned at described intake chamber and effluent trough opposite side two described in isopipe root be connected; The top of described intake chamber is higher than the top of described effluent trough; The inwall of described intake chamber is provided with at least one pair of baffle.

The angle of described baffle and intake chamber inwall is 45 ~ 75 °.

The top of described intake chamber exceeds at least 2 centimetres, the top of described effluent trough, and the cross-sectional area of described intake chamber is greater than the cross-sectional area of described effluent trough.

Described light source is the near infrared light of 860nm; Described spectroscope is raster pattern spectroscope; Described first photodetector and the second photodetector are phototriode; Described sensor for measuring temperature is DHT22 sensor.

A measuring system for polarization type water turbidity, is characterized in that: comprise above-mentioned measurement mechanism, signal processing module, display module and baffle controls circuit; Described signal processing module comprises the amplifying circuit, filtering circuit, the A/D convertor circuit that connect successively; Described amplifying circuit is connected with described first photodetector and the second photodetector respectively, and described display module is connected with baffle controls circuit; Described signal processing module is connected with described display module.

A measuring method for the measurement mechanism of polarization type water turbidity, is characterized in that: comprise the following steps:

Utilize the equation of linear regression group of least square vector support machine:

y＝W ^TΦ(x)+b(1)

$\min J(W,e)=\frac{1}{2}{W}^{T}W+C\underset{k=1}{\overset{n}{\&Sigma;}}{e}_k^2---\left(2\right)$

s.t.y(x _k)＝W ^TΦ(x _k)+b+e _k,k＝1,....n(3)

In formula (1), Φ (x) represents the water turbidity factor of influence of each input to the influence function of turbidity value; W represents the function coefficients matrix of each water turbidity factor of influence; Y represents water turbidity;

Formula (2) carries out the matching of least square vector, the e Representative errors in formula (2) to formula (1); e _krepresent the error of each water turbidity factor of influence; T represents the compute mode of matrix; C representative is used for the regulatory factor of departure proportion; J (W, e) represents constraint condition, selects the minimum value of W and e;

Formula (1), (2) are carried out to about fasciculation and obtained formula (3), and s.t. is the affined meaning; Formula (2) and formula (3) composition system of equations;

Lagrange's equation is set up by formula (3):

$L(W,b,e,\mathrm{\&alpha;})=J(W,e)-\underset{i}{\overset{N}{\&Sigma;}}{\mathrm{\&alpha;}}_i\left(W^T\mathrm{\&Phi;}\right(x_i)+b-y(x_i\left)\right)---\left(4\right)$

In formula (4), α represents Lagrange multiplier; α _irepresent the Lagrange multiplier of each water turbidity factor of influence; I=1 ~ N;

According to KKT condition, to the W in formula (4), e, α, b ask local derviation to obtain:

$\frac{\&part;L}{\&part;W}=0\&RightArrow;\underset{i=1}{\overset{N}{\&Sigma;}}{\mathrm{\&alpha;}}_i\mathrm{\&Phi;}\left(x_i\right)---\left(5\right)$

$\frac{\&part;L}{\&part;b}=0\&RightArrow;\underset{i=1}{\overset{N}{\&Sigma;}}{\mathrm{\&alpha;}}_i=0---\left(6\right)$

$\frac{\&part;L}{\&part;e}=0\&RightArrow;{\mathrm{\&alpha;}}_i={\mathrm{Ce}}_k---\left(7\right)$

$\frac{\&part;L}{\&part;{\mathrm{\&alpha;}}_i}=0\&RightArrow;W^T\mathrm{\&Phi;}\left(x_i\right)+b+e_k-y\left(x_i\right)---\left(8\right)$

Solved b and α by formula (5) ~ formula (8), obtained least square method supporting vector machine model:

$f\left(x\right)=\underset{i=1}{\overset{N}{\&Sigma;}}{\mathrm{\&alpha;}}_{i}k(x,x_i)+b---\left(9\right)$

In formula (9), f (x) represents water turbidity; K (x, x _i) represent the radial basis function of each water turbidity factor of influence;

$k(x,x_i)=\exp \left\{\frac{-\left|\right|x-x_i|{|}^2}{{\mathrm{\&sigma;}}^2}\right\}---\left(10\right)$

In formula (10), x represents the value when pre-test of each water turbidity factor of influence; x _ithe trained values of each water turbidity factor of influence before representative; σ represents kernel function width;

Bring formula (10) into formula (9):

$f\left(x\right)=\underset{i=1}{\overset{N}{\&Sigma;}}{\mathrm{\&alpha;}}_i\exp \left\{\frac{-\left|\right|x-x_i|{|}^2}{{\mathrm{\&sigma;}}^2}\right\}+b---\left(11\right)$

Bring in formula (11) using each water turbidity factor of influence as input value, regulate regulatory factor C and kernel function width cs, output valve f (x) is turbidity value; Output valve f (x) and standard turbidity solution are demarcated.

Described water turbidity factor of influence comprises temperature, scattered light intensity, reference light intensity and light intensity ratio; Described scattered light intensity is scattered light I _blight intensity, described with reference to light intensity be Ia ₁light intensity, described light intensity ratio is I _b/ I _a1.

The preparation method of described standard turbidity solution is: be filled with in described measuring flume successively by the formal hydrazine solution of several different water turbidity, and record its corresponding magnitude of voltage respectively, described magnitude of voltage comprises I _band I _a1.

The water turbidity computing method of described standard turbidity solution are: calculate light intensity ratio I according to magnitude of voltage _b/ I _a1, using the water turbidity y of standard turbidity solution and light intensity ratio x as horizontal, ordinate, linear fit, obtains linear equation, y=k ₁x+b ₁, k ₁and b ₁for definite value, will measure and the light intensity ratio calculated substitution y=k ₁x+b ₁the size of water turbidity is just obtained in equation.

The special above technical scheme of the present invention compared with prior art, has following technique effect:

1, measurement mechanism of the present invention and measuring system, proposes a kind of turbidimetry scheme of single light source double light path, measures scattered light and reference light, effectively can reduce the stained measuring error caused of flashing and detector.

2, measurement mechanism of the present invention and measuring system, adopts polarizer generation, analyzer detection polarized light, greatly can reduce the impact of bias light and parasitic light, improve precision.

3, measurement mechanism of the present invention and measuring system, designed measuring flume, utilizes gravitational difference water filling, and liquid, through baffle, ensures sluggish flow and tested liquid level.

4, measurement mechanism of the present invention and measuring system, improves systems axiol-ogy sensitivity, simplifies whole measuring system, and has higher level of integrated system, more compact structure, realizes the on-line quick detection of water turbidity under complicated environmental condition.

5, the present invention adopts the data processing method of least square method supporting vector machine, compensates temperature, eliminates measuring error, improves measuring accuracy.

The measurement mechanism of a kind of polarization type water turbidity provided by the invention, measuring system and measuring method, propose a kind of turbidimetry scheme of double light path of single light source double detector, measure the light signal of 90 ° of scattered lights and light source itself, effectively reduce the measuring error that flashing causes.Owing to have employed polarized light detection, the error that greatly can reduce background stray light and cause through the light that Multiple Scattering is strayed into detector, precision is higher, and antijamming capability is strong.Meanwhile, utilize the principle of surface scattering compared with traditional transmission beam method and 90 ° of scattering methods, light path is shorter, and Multiple Scattering is less, therefore it is larger to measure range.Laying temperature sensor simultaneously, the temperature in measurement mechanism.This device adopts the data regression disposal route of least square method supporting vector machine (LS-SVM), data fitting is carried out to temperature, scattered light intensity, former light intensity, light intensity ratio simultaneously, compared to the approximating method of common least square method, the method has better linear in few sample, non-linear, high-dimensional problem, solve the impact of temperature on turbidity, improve precision.

Figure of description

Fig. 1 is process flow diagram of the present invention;

Fig. 2 is the structural representation of measuring flume in the present invention.

Embodiment

Below in conjunction with accompanying drawing, the present invention is further described.

As shown in Fig. 1 ~ Fig. 2, a kind of measurement mechanism of polarization type water turbidity, it is characterized in that, comprise: for launching the light source 1 of a monochromic beam I to the first lens 2, described monochromatic light I becomes incident light I in 90 ° angles with after the first polaroid 5 by spectroscope 8 light splitting through described first lens 2 successively _awith scattered light I _b, described scattered light I _benter the first photodetector 7, described incident light I _aenter 90 ° of surface scattering light I after measuring flume 3 _a1successively by entering the second photodetector 9 after the second polaroid 6 and the second lens 4; Sensor for measuring temperature is provided with in described measuring flume 3.

Described measuring flume 3 comprises U-type groove, described U-type groove comprises two vertically disposed intake chamber 12 and effluent troughs 10, described intake chamber 12 is communicated with by transverse groove 13 with the bottom of effluent trough 10, the surrounding of described intake chamber 12 and effluent trough 10 is provided with overflow groove 14, be positioned at described intake chamber 12 and effluent trough 10 opposite side two described in be connected bottom overflow groove 14; The top of described intake chamber 12 is higher than the top of described effluent trough 10; The inwall of described intake chamber 12 is provided with at least one pair of baffle 11.

Overflow water body and flow into recovery pond through gathering-device, so that later use.

Described baffle 11 is 45 ~ 75 ° with the angle of intake chamber 12 inwall.

The top of described intake chamber 12 exceeds at least 2 centimetres, the top of described effluent trough 10, and the cross-sectional area of described intake chamber 12 is greater than the cross-sectional area of described effluent trough 10.

Described light source 1 is the near infrared light of 860nm; Described spectroscope 8 is raster pattern spectroscope; Described first photodetector 7 and the second photodetector 9 are phototriode; Described sensor for measuring temperature is DHT22 sensor.

A measuring system for polarization type water turbidity, is characterized in that: comprise above-mentioned measurement mechanism, signal processing module, display module and baffle controls circuit; Described signal processing module comprises the amplifying circuit, filtering circuit, the A/D convertor circuit that connect successively; Described amplifying circuit is connected with described first photodetector 7 and the second photodetector 9 respectively, and described display module is connected with baffle controls circuit; Described signal processing module is connected with described display module.

Light source 1 adopts the near infrared light of 860nm, can reduce the impact of colourity for turbidimetry of water sample to greatest extent; Spectroscope 8 adopts raster pattern spectroscope, and the monochromatic light sent by light source is divided into the light of two bundle same frequencys of known light intensity proportionate relationship, and it is roughly equal that raster pattern spectroscope produces the assorted district of spectrum, and red light district resolution is higher than lens type; Photodetector is a phototriode, and phototriode sensitivity is higher, and volume is little; Measuring flume 3 water inlet is on a left side, water delivering orifice is on the right side, the difference in height of both utilizations carries out water flood operations, to reduce the flow velocity of water, avoid the generation of bubble, and keep the level of tested liquid level and the design of groove inwall employing baffle 11, the bubble in water body is adhered to, avoids bubble on the impact of turbidimetry.

Light path detailed path of the present invention is as follows: light beam I is produced by light source 1, after the first lens 2 and the polarizer 5 (i.e. the first polaroid), to become 30 ° of incidences with tested liquid level, creates light beam I by spectroscope 8 _awith light beam I _b, light beam I _bdirect incident first photoelectric detector 7.Light beam I _aincident measuring flume 3, rear scattered light I _a1be incident to the second polaroid 6, after be incident to the second photoelectric detector 9 through the convergence effect of the second lens 4, need during measurement to ensure above-mentioned all devices all at grade, and the polarization direction of polaroid and the incident direction of light and shake the plane being perpendicular in direction.

The present invention utilizes the transmission beam method mode of light to measure the turbidity of testing liquid, and its principle is as follows:

The light I that the special light source of the present invention sends, after the polarizer, is incident to spectroscope 8, I after decaying to original half I ' according to Malus law _a1i _athrough the light of spectroscope 8.I _b1i _bthrough surface scattering and incident light direction light in 90 °.Both business d and currently treat that the turbidity of sample measuring liquid has certain funtcional relationship, derives as follows:

$d=\frac{I_{b1}}{I_{a1}}$

Wherein: I _a1and I _b1magnitude of voltage after the first photodetector and the second photodetector carry out opto-electronic conversion, I _b1=I _b;

According to Bill's Lambert law and mile scattering theorem, by I _b1=β ₁i _bkT, I _a1=β ₂i _abring into and can obtain:

$d=\frac{{\mathrm{\&beta;}}_1{I}_{b}KT}{{\mathrm{\&beta;}}_2{I}_a}$

Wherein: β ₁with β ₂be a point backscatter extinction logarithmic ratio, composition, the character of K and testing liquid are relevant, and T is the turbidity value of testing liquid; β ₁, β ₂be constant with K, use β _1*k/ β ₂=D represents,

Can obtain, $d=\frac{{\mathrm{\&beta;}}_1{I}_{b}KT}{{\mathrm{\&beta;}}_2{I}_b}=\frac{{\mathrm{\&beta;}}_{1}KT}{{\mathrm{\&beta;}}_2}$

Above formula abbreviation can be obtained, $d=\frac{{\mathrm{\&beta;}}_{1}KT}{{\mathrm{\&beta;}}_2}=DT$

Be directly proportional by known d and the T of above formula, then can pass through I _a1with I _b1ratio d try to achieve the turbidity value T of testing liquid.Due to when low turbidity, surface scattering light light intensity is less, is difficult to be detected error larger.At different temperature, liquid Brownian movement can be different simultaneously, and scattered light light intensity also can be different, therefore compensate calculating to measuring tempeature etc. below.

A measuring method for the measurement mechanism of polarization type water turbidity, is characterized in that: comprise the following steps:

Utilize the equation of linear regression group of least square vector support machine:

y＝W ^TΦ(x)+b(1)

$\min J(W,e)=\frac{1}{2}{W}^{T}W+C\underset{k=1}{\overset{n}{\&Sigma;}}{e}_k^2---\left(2\right)$

s.t.y(x _k)＝W ^TΦ(x _k)+b+e _k,k＝1,....n(3)

In formula (1), Φ (x) represents the water turbidity factor of influence of each input to the influence function of turbidity value; W represents the function coefficients matrix of each water turbidity factor of influence; Y represents water turbidity;

Formula (2) carries out the matching of least square vector, the e Representative errors in formula (2) to formula (1); e _krepresent the error of each water turbidity factor of influence; T represents the compute mode of matrix; C representative is used for the regulatory factor of departure proportion; J (W, e) represents constraint condition, selects the minimum value of W and e;

W=[W1, W2, W3, W4] be temperature, scattered light intensity, with reference to light intensity and light intensity ratio to the set of four of turbidity influence function coefficients, a namely matrix of coefficients;

Formula (1), (2) are carried out to about fasciculation and obtained formula (3), and s.t. is the abbreviation of subjectto, is the affined meaning; Formula (2) and formula (3) composition system of equations;

Formula (2), compared with traditional linear regression method, adds the quadratic sum item of error, requires that error sum of squares is minimum, prevent extremum dominate.Meanwhile, linear programming problem, compared with traditional method, is improved to the problem solving system of linear equations by least square method supporting vector machine, thus improves computational accuracy, and responsive to exceptional value.Because this problem is unconstrained problem, be difficult to process.Set up Lagrange's equation, become constrained problem.

Lagrange's equation is set up by formula (3):

$L(W,b,e,\mathrm{\&alpha;})=J(W,e)-\underset{i}{\overset{N}{\&Sigma;}}{\mathrm{\&alpha;}}_i\left(W^T\mathrm{\&Phi;}\right(x_i)+b-y(x_i\left)\right)---\left(4\right)$

In formula (4), α represents Lagrange multiplier; α _irepresent the Lagrange multiplier of each water turbidity factor of influence; I=1 ~ N;

According to KKT condition, to the W in formula (4), e, α, b ask local derviation to obtain:

$\frac{\&part;L}{\&part;W}=0\&RightArrow;\underset{i=1}{\overset{N}{\&Sigma;}}{\mathrm{\&alpha;}}_i\mathrm{\&Phi;}\left(x_i\right)---\left(5\right)$

$\frac{\&part;L}{\&part;b}=0\&RightArrow;\underset{i=1}{\overset{N}{\&Sigma;}}{\mathrm{\&alpha;}}_i=0---\left(6\right)$

$\frac{\&part;L}{\&part;e}=0\&RightArrow;{\mathrm{\&alpha;}}_i={\mathrm{Ce}}_k---\left(7\right)$

$\frac{\&part;L}{\&part;{\mathrm{\&alpha;}}_i}=0\&RightArrow;W^T\mathrm{\&Phi;}\left(x_i\right)+b+e_k-y\left(x_i\right)---\left(8\right)$

Solved b and α by formula (5) ~ formula (8), obtained least square method supporting vector machine model:

$f\left(x\right)=\underset{i=1}{\overset{N}{\&Sigma;}}{\mathrm{\&alpha;}}_{i}k(x,x_i)+b---\left(9\right)$

In formula (9), f (x) represents water turbidity; K (x, x _i) represent the radial basis function of each water turbidity factor of influence; Wherein k (x, x _i) be radial basis function, linear kernel function, S type kernel function, polynomial type kernel function, generally get gaussian kernel function;

$k(x,x_i)=\exp \left\{\frac{-\left|\right|x-x_i|{|}^2}{{\mathrm{\&sigma;}}^2}\right\}---\left(10\right)$

In formula (10), x represents the value when pre-test of each water turbidity factor of influence; x _ithe trained values of each water turbidity factor of influence before representative; σ represents kernel function width;

Bring formula (10) into formula (9):

$f\left(x\right)=\underset{i=1}{\overset{N}{\&Sigma;}}{\mathrm{\&alpha;}}_i\exp \left\{\frac{-\left|\right|x-x_i|{|}^2}{{\mathrm{\&sigma;}}^2}\right\}+b---\left(11\right)$

Bring in formula (11) using each water turbidity factor of influence as input value, regulate regulatory factor C and kernel function width cs, output valve f (x) is turbidity value; Output valve f (x) and standard turbidity solution are demarcated.

Described water turbidity factor of influence comprises temperature, scattered light intensity, reference light intensity and light intensity ratio; Described scattered light intensity is scattered light I _blight intensity, described with reference to light intensity be Ia ₁light intensity, described light intensity ratio is I _b/ I _a1.

The preparation method of described standard turbidity solution is: be filled with successively in described measuring flume 3 by the formal hydrazine solution of several different water turbidity, and record its corresponding magnitude of voltage respectively, described magnitude of voltage comprises I _band I _a1.

The water turbidity computing method of described standard turbidity solution are: calculate light intensity ratio I according to magnitude of voltage _b/ I _a1, using the water turbidity y of standard turbidity solution and light intensity ratio x as horizontal, ordinate, linear fit, obtains linear equation, y=k ₁x+b ₁, k ₁and b ₁for definite value, will measure and the light intensity ratio calculated substitution y=k ₁x+b ₁the size of water turbidity is just obtained in equation.

Implementation step of the present invention is as follows:

1, open water inlet valve and water outlet valve, in measuring flume 3, be slowly charged into testing liquid.Unnecessary liquid overflows from water inlet.

2, control circuit is by sending instruction to photodetector, makes photodetector first carry out preheating before measuring, after the temperature stabilization of photodetector, measures.

3, light source exports corresponding frequencies light beam after the polarizer, two-beam is created after spectroscope 8, enter measuring system, scattered light is after analyzer, the light received carries out converging and sending photodetector to by lens, and the light signal received separately is converted to electric signal and sends signal processing module to by photodetector.The analyzing direction of analyzer can be regulated, maximum to ensure the light intensity that the second photodetector obtains.

4, the amplifying circuit in signal processing module, filtering circuit and A/D convertor circuit amplify electric signal successively, filtering, AD conversion, generate digital signal and send control circuit to and process, the magnitude of voltage after demodulation is obtained by control circuit, and obtain ratio d by formula, by ratio d, reference light intensity I _b, scattered light intensity Ia ₁, and temperature value T brings in least square method supporting vector machine as input variable Xi, the result y obtained carries out through MatLab tool box obtaining b and α after data training, after carrying out data fitting, demarcation, finally sends display module display to.

The above is only the preferred embodiment of the present invention; be noted that for those skilled in the art; under the premise without departing from the principles of the invention, can also make some improvements and modifications, these improvements and modifications also should be considered as protection scope of the present invention.

Claims (10)

1. the measurement mechanism of a polarization type water turbidity, it is characterized in that, comprise: for launching the light source (1) of a monochromic beam I to the first lens (2), described monochromatic light I becomes incident light I in 90 ° angles with after the first polaroid (5) by spectroscope (8) light splitting through described first lens (2) successively _awith scattered light I _b, described scattered light I _benter the first photodetector (7), described incident light I _aenter 90 ° of surface scattering light I after measuring flume (3) _a1successively by entering the second photodetector (9) after the second polaroid (6) and the second lens (4); Described measuring flume is provided with sensor for measuring temperature in (3).

2. the measurement mechanism of a kind of polarization type water turbidity according to claim 1, it is characterized in that: described measuring flume (3) comprises U-type groove, described U-type groove comprises two vertically disposed intake chambers (12) and effluent trough (10), described intake chamber (12) is communicated with by transverse groove (13) with the bottom of effluent trough (10), the surrounding of described intake chamber (12) and effluent trough (10) is provided with overflow groove (14), be positioned at described intake chamber (12) and effluent trough (10) opposite side two described in overflow groove (14) bottom be connected, the top of described intake chamber (12) is higher than the top of described effluent trough (10), the inwall of described intake chamber (12) is provided with at least one pair of baffle (11).

3. the measurement mechanism of a kind of polarization type water turbidity according to claim 2, is characterized in that: described baffle (11) is 45 ~ 75 ° with the angle of intake chamber (12) inwall.

4. the measurement mechanism of a kind of polarization type water turbidity according to claim 2, it is characterized in that: the top of described intake chamber (12) exceeds at least 2 centimetres, the top of described effluent trough (10), the cross-sectional area of described intake chamber (12) is greater than the cross-sectional area of described effluent trough (10).

5. the measurement mechanism of a kind of polarization type water turbidity according to claim 1, is characterized in that: the near infrared light that described light source (1) is 860nm; Described spectroscope (8) is raster pattern spectroscope; Described first photodetector (7) and the second photodetector (9) are phototriode; Described sensor for measuring temperature is DHT22 sensor.

6. a measuring system for polarization type water turbidity, is characterized in that: comprise the measurement mechanism as described in any one of Claims 1 to 5, signal processing module, display module and baffle controls circuit; Described signal processing module comprises the amplifying circuit, filtering circuit, the A/D convertor circuit that connect successively; Described amplifying circuit is connected with described first photodetector (7) and the second photodetector (9) respectively, and described display module is connected with baffle controls circuit; Described signal processing module is connected with described display module.

7. the measuring method of the measurement mechanism of a kind of polarization type water turbidity according to any one of Claims 1 to 5, is characterized in that: comprise the following steps:

Utilize the equation of linear regression group of least square vector support machine:

y＝W ^TΦ(x)+b(1)

$\min J(W,e)=\frac{1}{2}{W}^{T}W+C\underset{k=1}{\overset{n}{\&Sigma;}}{e}_k^2---\left(2\right)$

s.t.y(x _k)＝W ^TΦ(x _k)+b+e _k,k＝1,....n(3)

In formula (1), Φ (x) represents the water turbidity factor of influence of each input to the influence function of turbidity value; W represents the function coefficients matrix of each water turbidity factor of influence; Y represents water turbidity;

Formula (2) carries out the matching of least square vector, the e Representative errors in formula (2) to formula (1); e _krepresent the error of each water turbidity factor of influence; T represents the compute mode of matrix; C representative is used for the regulatory factor of departure proportion; J (W, e) represents constraint condition, selects the minimum value of W and e;

Formula (1), (2) are carried out to about fasciculation and obtained formula (3), and s.t. is the affined meaning; Formula (2) and formula (3) composition system of equations;

Lagrange's equation is set up by formula (3):

$L(W,b,e,\mathrm{\&alpha;})=J(W,e)-\underset{i}{\overset{N}{\&Sigma;}}{\mathrm{\&alpha;}}_i\left(W^T\mathrm{\&Phi;}\right(x_i)+b-y(x_i\left)\right)---\left(4\right)$

In formula (4), α represents Lagrange multiplier; α _irepresent the Lagrange multiplier of each water turbidity factor of influence; I=1 ~ N;

According to KKT condition, to the W in formula (4), e, α, b ask local derviation to obtain:

$\frac{\&part;L}{\&part;W}=0\&RightArrow;\underset{i=1}{\overset{N}{\&Sigma;}}{\mathrm{\&alpha;}}_i\mathrm{\&Phi;}\left(x_i\right)---\left(5\right)$

$\frac{\&part;L}{\&part;b}=0\&RightArrow;\underset{i=1}{\overset{N}{\&Sigma;}}{\mathrm{\&alpha;}}_i=0---\left(6\right)$

$\frac{\&part;L}{\&part;e}=0\&RightArrow;{\mathrm{\&alpha;}}_i={\mathrm{Ce}}_k---\left(7\right)$

$\frac{\&part;L}{\&part;{\mathrm{\&alpha;}}_i}=0\&RightArrow;W^T\mathrm{\&Phi;}\left(x_i\right)+b+e_k-y\left(x_i\right)---\left(8\right)$

Solved b and α by formula (5) ~ formula (8), obtained least square method supporting vector machine model:

$f\left(x\right)=\underset{i=1}{\overset{N}{\&Sigma;}}{\mathrm{\&alpha;}}_{i}k(x,x_i)+b---\left(9\right)$

In formula (9), f (x) represents water turbidity; K (x, x _i) represent the radial basis function of each water turbidity factor of influence;

$k(x,x_i)=\exp \left\{\frac{-\left|\right|x-x_i|{|}^2}{{\mathrm{\&sigma;}}^2}\right\}---\left(10\right)$

In formula (10), x represents the value when pre-test of each water turbidity factor of influence; x _ithe trained values of each water turbidity factor of influence before representative; σ represents kernel function width;

Bring formula (10) into formula (9):

$f\left(x\right)=\underset{j=1}{\overset{N}{\&Sigma;}}{\mathrm{\&alpha;}}_i\exp \left\{\frac{-\left|\right|x-x_i|{|}^2}{{\mathrm{\&sigma;}}^2}\right\}+b---\left(11\right)$

Bring in formula (11) using each water turbidity factor of influence as input value, regulate regulatory factor C and kernel function width cs, output valve f (x) is turbidity value; Output valve f (x) and standard turbidity solution are demarcated.

8. the measuring method of a kind of polarization type water turbidity according to claim 7, is characterized in that: described water turbidity factor of influence comprises temperature, scattered light intensity, reference light intensity and light intensity ratio; Described scattered light intensity is scattered light I _blight intensity, described with reference to light intensity be Ia ₁light intensity, described light intensity ratio is I _b/ I _a1.

9. the measuring method of a kind of polarization type water turbidity according to claim 7, it is characterized in that: the preparation method of described standard turbidity solution is: the formal hydrazine solution of several different water turbidity is filled with successively in described measuring flume (3), record its corresponding magnitude of voltage respectively, described magnitude of voltage comprises I _band I _a1.

10. the measuring method of a kind of polarization type water turbidity according to claim 8, is characterized in that: the water turbidity computing method of described standard turbidity solution are: calculate light intensity ratio I according to magnitude of voltage _b/ I _a1, using the water turbidity y of standard turbidity solution and light intensity ratio x as horizontal, ordinate, linear fit, obtains linear equation, y=k ₁x+b ₁, k ₁and b ₁for definite value, will measure and the light intensity ratio calculated substitution y=k ₁x+b ₁the size of water turbidity is just obtained in equation.