CN103512903A - Method and system for automatically measuring surface clearness of heliostat - Google Patents

Abstract

The invention provides a method for automatically measuring surface clearness of a heliostat. The method includes the following steps: establishing a mathematical model of the surface clearness of a to-be-measured heliostat; extracting a light spot image of a standard heliostat projected on a receiving surface, removing the standard heliostat, extracting the background image on the receiving surface; applying the obtained light spot image and the background image of the standard heliostat and the light spot image and the background image of the to-be-measured heliostat into the mathematical model to obtain the surface clearness of the to-be-measured heliostat. The method provided by the invention can be used for measuring the surface clearness of thousands of heliostats in a large-scale heliostat field in the field of solar thermal power generation, and is highly practical. Meanwhile, the method has low cost and high efficiency, and is suitable for a large scale heliostat field.

Description

A kind of method and system of automatic measurement heliostat surface clearness

Technical field

This patent relates to tower type solar photo-thermal power generation field, relates in particular to a kind of method and system of automatic measurement heliostat surface clearness.

Background technology

In tower type solar photo-thermal power generation field, adopt a large amount of heliostats that sunshine is gathered to the heat dump on heat absorption tower, heating working medium, produces high temperature and high pressure steam, the generating of driving steam turbine genset.The heliostat field that wherein a large amount of heliostats form, is the important component part of tower type solar solar-thermal generating system, for by the solar radiation collection of dispersion and project heat dump, thereby realizes the photo-thermal conversion of solar power tower.

At present, the tower power station of the demonstration of having built up in the world and business all has large-scale heliostat field, as PS20 has 624 121m ²heliostat, the total reflective surface area 75000m of Jing Chang ²; SEDC has 1640 7.3m ²heliostat, the total reflective surface area 12000m of Jing Chang ²; ESolar has 12180 1.14m ²heliostat, the total reflective surface area 13836m of Jing Chang ²; GemaSolar has 2650 120m ²heliostat, the total reflective surface area 318000m of Jing Chang ².Above-mentioned large-scale heliostat field, normal operation along with power station, the cleanliness on heliostat surface can be more and more lower, directly affect the energy that whole mirror place provides, and then affect the whole generated energy of tower type solar solar-thermal generating system, therefore, need to measure mirror field heliostat surface clearness, when heliostat mirror surface cleaning degree is during lower than certain value, will implement cleaning to heliostat, the energy that guarantees that with this heliostat mirror place can provide meets specified generating requirement.

In document " Final Test and Evaluation Results from the Solar Two Project ", mention with hand-held device SMS Micro-Scan and measure heliostat surface clearness, measurement result is directly subject to the impact of sampling location and quantity, cost is high and measurement efficiency is low, the measurement of inapplicable extensive mirror field heliostat surface clearness.

Summary of the invention

A kind of method that the invention provides automatic measurement heliostat surface clearness, is characterized in that,

Set up the mathematical model of solar eyepiece surface clearness to be determined;

Extraction standard mirror projects the light spot image on receiving plane, removes after standard mirror, extracts the background image on receiving plane now;

Extract mirror to be measured and project the light spot image on receiving plane, remove after mirror to be measured, extract the background image on receiving plane now;

Light spot image, the background image of light spot image, background image and the mirror to be measured of the standard mirror obtaining are applied to described mathematical model, obtain solar eyepiece surface clearness to be determined.

Preferably, the light spot image of described standard mirror, background image comprise standard mirror project the light spot image on receiving plane gray scale and

and while removing standard mirror the background image on receiving plane gray scale and

; The light spot image of described mirror to be measured, background image comprise mirror to be measured project the light spot image on receiving plane gray scale and

and while removing mirror to be measured background image on receiving plane gray scale and

.

Preferably, described mathematical model is

${\mathrm{\η}}_{\mathrm{clr}2}=\frac{({\mathrm{spot}}_{{\mathrm{sum}}_2}-{\mathrm{bg}}_{{\mathrm{sum}}_2})*{\mathrm{\η}}_{{\mathrm{sb}}_1}}{({\mathrm{spot}}_{{\mathrm{sum}}_1}-{\mathrm{bg}}_{{\mathrm{sum}}_1})*{\mathrm{\η}}_{{\mathrm{sb}}_2}},$

Wherein, described η _clr2: solar eyepiece surface clearness to be determined;

η _sb1: the shade of standard mirror blocks efficiency;

η _sb2: the shade of mirror to be measured blocks efficiency;

Wherein

in the light spot image of light spot image, background image and the mirror to be measured of standard mirror, background image, extract,

by theory, calculated or emulation testing obtains.

Preferably, the process of establishing of the mathematical model of described mensuration solar eyepiece surface clearness is:

Set up the mathematical model of heliostat surface clearness

Standard heliostat surface clearness is $1=\frac{{\mathrm{Gray}}_{{\mathrm{sum}}_1}*C}{{\mathrm{DNI}}_1*S_h*{\mathrm{\η}}_{{\mathrm{eff}}_1}*{\mathrm{\η}}_{\mathrm{ref}}},$

Solar eyepiece surface clearness to be determined is ${\mathrm{\η}}_{\mathrm{cl}{r}_2}=\frac{{\mathrm{Gray}}_{{\mathrm{sum}}_2}*C}{{\mathrm{DNI}}_2*S_h*{\mathrm{\η}}_{{\mathrm{eff}}_2}*{\mathrm{\η}}_{\mathrm{ref}}},$

Comprehensive two formulas obtain ${\mathrm{\η}}_{{\mathrm{clr}}_2}=\frac{{\mathrm{Gray}}_{{\mathrm{sum}}_2}*{\mathrm{\η}}_{{\mathrm{sb}}_1}}{{\mathrm{Gray}}_{{\mathrm{sum}}_1}*{\mathrm{\η}}_{{\mathrm{sb}}_2}},$

$\left\{\begin{array}{c}{\mathrm{Gray}}_{{\mathrm{sum}}_1}={\mathrm{spot}}_{{\mathrm{sum}}_1}-{\mathrm{bg}}_{{\mathrm{sum}}_1}\\ {\mathrm{Gray}}_{{\mathrm{sum}}_2}={\mathrm{spot}}_{{\mathrm{sum}}_2}-{\mathrm{bg}}_{{\mathrm{sum}}_2}\end{array}\right.,$

The expression formula that finally obtains mirror surface clearness to be measured is

${\mathrm{\η}}_{{\mathrm{clr}}_2}=\frac{({\mathrm{spot}}_{{\mathrm{sum}}_2}-{\mathrm{bg}}_{{\mathrm{sum}}_2})*{\mathrm{\η}}_{{\mathrm{sb}}_1}}{({\mathrm{spot}}_{{\mathrm{sum}}_1}-{\mathrm{bg}}_{{\mathrm{sum}}_1})*{\mathrm{\η}}_{{\mathrm{sb}}_2}}.$

Preferably, described certain camera is CCD camera.

The present invention also provides a kind of system of automatic measurement heliostat surface clearness, comprises standard mirror and receiving plane, and it also comprises

Image receiving unit: project the light spot image on receiving plane for extracting standard mirror, remove after standard mirror, extract the background image on receiving plane now; Extract mirror to be measured and project the light spot image on receiving plane, remove after mirror to be measured, extract the background image on receiving plane now;

Calculation processing unit: receive light spot image, the background image of light spot image, background image and the mirror to be measured of the standard mirror obtaining, the mathematical model that the light spot image of the light spot image of described standard mirror, background image and mirror to be measured, background image is applied to built-in solar eyepiece surface clearness to be determined obtains solar eyepiece surface clearness to be determined.

Preferably, the light spot image of described standard mirror, background image comprise standard mirror project the light spot image on receiving plane gray scale and

and while removing standard mirror the background image on receiving plane gray scale and

the light spot image of described mirror to be measured, background image comprise mirror to be measured project the light spot image on receiving plane gray scale and

and while removing mirror to be measured background image on receiving plane gray scale and

Preferably, described mathematical model is

${\mathrm{\η}}_{\mathrm{clr}2}=\frac{({\mathrm{spot}}_{{\mathrm{sum}}_2}-{\mathrm{bg}}_{{\mathrm{sum}}_2})*{\mathrm{\η}}_{{\mathrm{sb}}_1}}{({\mathrm{spot}}_{{\mathrm{sum}}_1}-{\mathrm{bg}}_{{\mathrm{sum}}_1})*{\mathrm{\η}}_{{\mathrm{sb}}_2}},$

Wherein, described η _clr2: solar eyepiece surface clearness to be determined;

η _sb1: the shade of standard mirror blocks efficiency;

η _sb2: the shade of mirror to be measured blocks efficiency;

Wherein

in the light spot image of light spot image, background image and the mirror to be measured of standard mirror, background image, extract

can also can test acquisition by theoretical simulation.

Preferably, the process of establishing of the mathematical model of described mensuration solar eyepiece surface clearness is:

Set up the mathematical model of heliostat surface clearness

Standard heliostat surface clearness is $1=\frac{{\mathrm{Gray}}_{{\mathrm{sum}}_1}*C}{{\mathrm{DNI}}_1*S_h*{\mathrm{\η}}_{{\mathrm{eff}}_1}*{\mathrm{\η}}_{\mathrm{ref}}},$

Solar eyepiece surface clearness to be determined is ${\mathrm{\η}}_{\mathrm{cl}{r}_2}=\frac{{\mathrm{Gray}}_{{\mathrm{sum}}_2}*C}{{\mathrm{DNI}}_2*S_h*{\mathrm{\η}}_{{\mathrm{eff}}_2}*{\mathrm{\η}}_{\mathrm{ref}}},$

Comprehensive two formulas obtain ${\mathrm{\η}}_{{\mathrm{clr}}_2}=\frac{{\mathrm{Gray}}_{{\mathrm{sum}}_2}*{\mathrm{\η}}_{{\mathrm{sb}}_1}}{{\mathrm{Gray}}_{{\mathrm{sum}}_1}*{\mathrm{\η}}_{{\mathrm{sb}}_2}},$

$\left\{\begin{array}{c}{\mathrm{Gray}}_{{\mathrm{sum}}_1}={\mathrm{spot}}_{{\mathrm{sum}}_1}-{\mathrm{bg}}_{{\mathrm{sum}}_1}\\ {\mathrm{Gray}}_{{\mathrm{sum}}_2}={\mathrm{spot}}_{{\mathrm{sum}}_2}-{\mathrm{bg}}_{{\mathrm{sum}}_2}\end{array}\right.,$

The expression formula that finally obtains mirror surface clearness to be measured is

${\mathrm{\η}}_{{\mathrm{clr}}_2}=\frac{({\mathrm{spot}}_{{\mathrm{sum}}_2}-{\mathrm{bg}}_{{\mathrm{sum}}_2})*{\mathrm{\η}}_{{\mathrm{sb}}_1}}{({\mathrm{spot}}_{{\mathrm{sum}}_1}-{\mathrm{bg}}_{{\mathrm{sum}}_1})*{\mathrm{\η}}_{{\mathrm{sb}}_2}}$

Preferably, described certain camera is CCD camera.

The invention has the beneficial effects as follows:

(1) this method can realize automatic measurement heliostat surface clearness, has solved the measurement of the thousands of heliostat surface clearnesses in the extensive heliostat mirror field in tower type solar photo-thermal power generation field, has very strong practicality;

(2) this method is low for measuring heliostat surface clearness cost, and efficiency is high, is suitable for extensive heliostat Jing Chang.

Certainly, implement arbitrary product of the present invention and might not need to reach above-described all advantages simultaneously.

Accompanying drawing explanation

The process schematic diagram that Fig. 1 measures for the heliostat surface clearness that the embodiment of the present invention provides;

The mirror to be measured that Fig. 2 provides for the embodiment of the present invention is at the light spot image of receiving plane;

The mirror to be measured that Fig. 3 provides for the embodiment of the present invention is at the background image of receiving plane;

The standard mirror that Fig. 4 provides for the embodiment of the present invention is at the light spot image of receiving plane;

The standard mirror that Fig. 5 provides for the embodiment of the present invention is at the background image of receiving plane.

Specific embodiment

A kind of method that the invention provides automatic measurement heliostat surface clearness, it comprises the steps:

Set up the mathematical model of solar eyepiece surface clearness to be determined;

Extraction standard mirror projects the light spot image on receiving plane, removes after standard mirror, extracts the background image on receiving plane now;

Extract mirror to be measured and project the light spot image on receiving plane, remove after mirror to be measured, extract the background image on receiving plane now;

Light spot image, the background image of light spot image, background image and the mirror to be measured of the standard mirror obtaining are applied to described mathematical model, obtain solar eyepiece surface clearness to be determined.

Wherein said mathematical model is

${\mathrm{\η}}_{\mathrm{clr}2}=\frac{({\mathrm{spot}}_{{\mathrm{sum}}_2}-{\mathrm{bg}}_{{\mathrm{sum}}_2})*{\mathrm{\η}}_{{\mathrm{sb}}_1}}{({\mathrm{spot}}_{{\mathrm{sum}}_1}-{\mathrm{bg}}_{\mathrm{su}{m}_1})*{\mathrm{\η}}_{s{b}_2}},$

Wherein, described η _clr2: solar eyepiece surface clearness to be determined;

η _sb1: the shade of standard mirror blocks efficiency;

η _sb2: the shade of mirror to be measured blocks efficiency;

Wherein

in the light spot image of light spot image, background image and the mirror to be measured of standard mirror, background image, extract,

can also can test acquisition by theoretical simulation.

The light spot image of described standard mirror, background image comprise standard mirror project the light spot image on receiving plane gray scale and

and while removing standard mirror the background image on receiving plane gray scale and

the light spot image of described mirror to be measured, background image comprise mirror to be measured project the light spot image on receiving plane gray scale and

and while removing mirror to be measured background image on receiving plane gray scale and

The present invention also provides a kind of system of automatic measurement heliostat surface clearness, and it comprises

Image receiving unit: project the light spot image on receiving plane for extracting standard mirror, remove after standard mirror, extract the background image on receiving plane now; Extract mirror to be measured and project the light spot image on receiving plane, remove after mirror to be measured, extract the background image on receiving plane now;

Calculation processing unit: receive light spot image, the background image of light spot image, background image and the mirror to be measured of the standard mirror obtaining, the mathematical model that the light spot image of the light spot image of described standard mirror, background image and mirror to be measured, background image is applied to built-in solar eyepiece surface clearness to be determined obtains solar eyepiece surface clearness to be determined.

Wherein, the light spot image of described standard mirror, background image comprise standard mirror project the light spot image on receiving plane gray scale and

and while removing standard mirror the background image on receiving plane gray scale and

the light spot image of described mirror to be measured, background image comprise mirror to be measured project the light spot image on receiving plane gray scale and

and while removing mirror to be measured background image on receiving plane gray scale and

described mathematical model is

${\mathrm{\η}}_{\mathrm{clr}2}=\frac{({\mathrm{spot}}_{{\mathrm{sum}}_2}-{\mathrm{bg}}_{{\mathrm{sum}}_2})*{\mathrm{\η}}_{{\mathrm{sb}}_1}}{({\mathrm{spot}}_{{\mathrm{sum}}_1}-{\mathrm{bg}}_{{\mathrm{sum}}_1})*{\mathrm{\η}}_{{\mathrm{sb}}_2}},$

Wherein, described η _clr2: solar eyepiece surface clearness to be determined;

η _sb1: the shade of standard mirror blocks efficiency;

η _sb2: the shade of mirror to be measured blocks efficiency;

Wherein

in the light spot image of light spot image, background image and the mirror to be measured of standard mirror, background image, extract,

can also can test acquisition by theoretical simulation.

Embodiment

The image receiving unit that the present embodiment provides is CCD camera, the precondition of the present embodiment be the electroresponse of CCD camera light be linear and measure during DNI stable, receiving plane surface is perfect reflecting diffuser.

As Fig. 1, by controlling the angle of heliostat, make dot projection to receiving plane, CCD camera is taken light spot image simultaneously.When receiving loss of prestige spot, CCD camera is taken background image now.

The mathematical model process of the measurement heliostat surface clearness of setting up is as follows:

The gray-scale value (Gray) of the final output image of CCD camera is affected by the factors such as incident light radiance, optical system, CCD opto-electronic conversion and electronic system.Incident light is through optical filter, the optical lens of optical system and be irradiated to behind the door soon on CCD chip, the radiation energy Q at CCD image planes place _e(λ) be:

$Q_e\left(\mathrm{\λ}\right)=\frac{\mathrm{\π}*A_d*L\left(\mathrm{\λ}\right)*{\text{\τ}}_0*t}{{4F}^2}---\left(1\right)$

Wherein: A _d: ccd detector area;

F: the relative aperture number of camera;

τ ₀: transmissivity of optical system;

L (λ): the radiance of incident light;

T: time shutter.

If the spectral response functions of CCD is R _ccd, the simulating signal of CCD output is:

V=Q _e(λ)*R _ccd (2)

Consider that CCD chip inevitably exists each noise like in photoelectric conversion process,, after CCD driving and treatment circuit, the gray-scale value of the final output image of CCD can be expressed as:

$\mathrm{Gray}=\frac{\mathrm{\π}*A_d*L\left(\mathrm{\λ}\right)*{\text{\τ}}_0*t}{{4F}^2}{R}_{\mathrm{ccd}}*G{+N}_1{+N}_2{+N}_3---\left(3\right)$

Wherein: G: gain amplification coefficient;

N ₁: the dark current noise in CCD photoelectric conversion process;

N ₂: the noise irrelevant with incident radiation brightness comprises reading noise and quantizing noise etc.;

N ₃: the noise relevant with incident radiation brightness, comprises photon shot noise etc.

In our application, noise effect is very little, can ignore, and the photoelectric response function of CCD camera is linear, and (3) formula can be reduced to:

$\mathrm{Gray}=\frac{\mathrm{\π}*A_d{\text{*\τ}}_0*t}{{4F}^2}{R}_{\mathrm{ccd}}*G*L\left(\mathrm{\λ}\right)---\left(4\right)$

When a timing such as time shutter, camera position, detection area, relative aperture number, in (4) formula

be a constant, can obtain the gray-scale value of the final output image of CCD camera and the radiance value of incident light is linear.The radiance of CCD camera incident light and the energy on photographic subjects surface are also linear relationships.Therefore, when control heliostat projects receiving plane, image when CCD camera shooting receiving plane has hot spot, be designated as light spot image, after shooting completes, control hot spot and remove from receiving plane, CCD camera is taken receiving plane without the image of hot spot simultaneously, be designated as both gray scales of background image and difference and the energy that provides of heliostat can represent by following relation:

$\frac{E_h}{\mathrm{Gra}{y}_{\mathrm{sum}}}=C---\left(5\right)$

Wherein, E _h: the energy that heliostat provides;

Gray _sum: the gray scale of spot area light spot image and background image and poor in CCD photographic images;

C: constant.

The energy that heliostat provides can represent with following formula:

E _h=DNI*S _h*η _eff*η _ref*η _clr (6)

Wherein, E _h: the energy that heliostat provides;

DNI: direct solar radiation;

η _eff: the efficiency of heliostat;

S _h: heliostat area;

μ _ref: heliostat surface reflectivity;

η _clr: heliostat surface clearness.

Therefore,

${\mathrm{\η}}_{\mathrm{clr}}=\frac{{\mathrm{Gray}}_{\mathrm{sum}}*C}{\mathrm{DNI}*S_h*{\mathrm{\η}}_{\mathrm{eff}}*{\mathrm{\η}}_{\mathrm{ref}}}---\left(7\right)$

Therefore, in the time need to measuring the cleanliness (being designated as mirror to be measured) on certain face heliostat surface, can be by its adjacent heliostat surface clean clean (being designated as standard mirror), cleanliness η _clrcan be designated as 1, utilize the gray scale of spot area in CCD photographic images and be designated as

direct solar radiation is designated as DNI ₁, heliostat efficiency is at that time designated as

(7) formula can be written as

$1=\frac{{\mathrm{Gray}}_{{\mathrm{sum}}_1}*C}{{\mathrm{DNI}}_1*S_h*{\mathrm{\η}}_{{\mathrm{eff}}_1}*{\mathrm{\η}}_{\mathrm{ref}}}---\left(8\right)$

For mirror to be measured, cleanliness are designated as

utilize spot area in CCD photographic images gray scale and direct solar radiation is designated as DNI ₂, heliostat efficiency is at that time designated as

(7) formula can be written as

${\mathrm{\η}}_{{\mathrm{clr}}_2}=\frac{{\mathrm{Gray}}_{{\mathrm{sum}}_2}*C}{{\mathrm{DNI}}_2*S_h*{\mathrm{\η}}_{{\mathrm{eff}}_2}*{\mathrm{\η}}_{\mathrm{ref}}}---\left(9\right)$

(9) mirror heliostat surface clearness to be measured can be tried to achieve in/(8):

${\mathrm{\η}}_{{\mathrm{clr}}_2}=\frac{{\mathrm{Gray}}_{{\mathrm{sum}}_2}*{\mathrm{DNI}}_1*{\mathrm{\η}}_{{\mathrm{eff}}_1}}{{\mathrm{Gray}}_{{\mathrm{sum}}_1}*{\mathrm{DNI}}_2*{\mathrm{\η}}_{{\mathrm{eff}}_2}}---\left(10\right)$

Because DNI during measuring is stable, and be adjacent heliostat, the shade removing between mirror in heliostat efficiency blocks efficiency eta _sboutward, other efficiency are makeed an appointment as cosine efficiency can adopt approximate relation:

Therefore, (10) formula can be changed into

${\mathrm{\η}}_{{\mathrm{clr}}_2}=\frac{{\mathrm{Gray}}_{{\mathrm{sum}}_2}*{\mathrm{\η}}_{{\mathrm{sb}}_1}}{{\mathrm{Gray}}_{{\mathrm{sum}}_1}*{\mathrm{\η}}_{{\mathrm{sb}}_2}}---\left(11\right)$

The flow process of measuring mirror surface clearness to be measured is as follows:

Issue control command 1. to mirror to be measured, make its dot projection to receiving plane, image when CCD camera is taken and had mirror hot spot to be measured on receiving plane, is shown in Fig. 2, the gray scale of image and being designated as

Issue control command 2. to mirror to be measured, its hot spot is removed from receiving plane, background image when CCD camera is taken on receiving plane without mirror hot spot to be measured, is shown in Fig. 3, the gray scale of image be designated as

Issue control command 3. to standard mirror, make its dot projection to receiving plane, image when CCD camera is taken and had standard mirror hot spot on receiving plane, is shown in Fig. 4, the gray scale of image and being designated as

Issue control command 4. to standard mirror, its hot spot is removed from receiving plane, background image when CCD camera is taken on receiving plane without standard mirror hot spot, is shown in Fig. 5, the gray scale of image and being designated as

There is following relation

$\left\{\begin{array}{c}{\mathrm{Gray}}_{{\mathrm{sum}}_1}={\mathrm{spot}}_{{\mathrm{sum}}_1}-{\mathrm{bg}}_{{\mathrm{sum}}_1}\\ {\mathrm{Gray}}_{{\mathrm{sum}}_2}={\mathrm{spot}}_{{\mathrm{sum}}_2}-{\mathrm{bg}}_{{\mathrm{sum}}_2}\end{array}\right.---\left(14\right)$

Therefore, the expression formula of mirror surface clearness to be measured is

${\mathrm{\η}}_{{\mathrm{clr}}_2}=\frac{({\mathrm{spot}}_{{\mathrm{sum}}_2}-{\mathrm{bg}}_{{\mathrm{sum}}_2})*{\mathrm{\η}}_{{\mathrm{sb}}_1}}{({\mathrm{spot}}_{{\mathrm{sum}}_1}-{\mathrm{bg}}_{{\mathrm{sum}}_1})*{\mathrm{\η}}_{{\mathrm{sb}}_2}}---\left(15\right)$

Wherein,

can also can test acquisition by theoretical simulation.

Above testing process is carried out to programmed control realization, can robotization realize the cleanliness of measuring heliostat surface.

In order to verify the accuracy of the method measurement heliostat surface clearness, spy carries out following test:

In certain tower type solar item eyepiece field, choose adjacent 6 heliostats of certain row, numbering in order is 1～6, all cleans up, and by the method for above statement, measures its surperficial cleanliness, and concrete measurement result is as follows:

Heliostat 1～6 is all the heliostats after cleaning, and can be used as standard mirror, and its theoretical cleanliness approximate 1, utilize the average 1.00385 of the method measurement result, variance 0.0114.Consider that when actual heliostat dispatches from the factory, reflectivity itself exists fluctuation among a small circle, can think that the result of the method measurement heliostat surface clearness is accurately.

The invention has the beneficial effects as follows:

(3) this method can realize automatic measurement heliostat surface clearness, has solved the measurement of the thousands of heliostat surface clearnesses in the extensive heliostat mirror field in tower type solar photo-thermal power generation field, has very strong practicality.

(4) this method is low for measuring heliostat surface clearness cost, and efficiency is high, is suitable for extensive heliostat Jing Chang.For example, certain tower type solar photo-thermal power generation project, Jing Chang has 5000 multiaspect 10m ²heliostat, the cleanliness of sampling measurement 500 heliostats, while adopting the method to measure, after cleaning mirror has cleaned, only need to open Survey Software, can automatically complete measurement, and whole process only needs to complete for 0.5 hour.And use other mirror surface cleaning degree testers to carry out cleanliness while measuring to heliostat surface, and need the above common cooperation manual measurement of 3 people, spend 6 hours just can complete above, and measurement result is also directly subject to sampling location and number affects.Both compare, and have fully demonstrated the method in the superiority of measuring in efficiency.

The disclosed preferred embodiment of the present invention is just for helping to set forth the present invention above.Preferred embodiment does not have all details of detailed descriptionthe, and also not limiting this invention is only described embodiment.Obviously, according to the content of this instructions, can make many modifications and variations.These embodiment are chosen and specifically described to this instructions, is in order to explain better principle of the present invention and practical application, thereby under making, technical field technician can understand and utilize the present invention well.The present invention is only subject to the restriction of claims and four corner and equivalent.

Claims (10)

1. automatically measure a method for heliostat surface clearness, it is characterized in that,

Set up the mathematical model of solar eyepiece surface clearness to be determined;

Extraction standard mirror projects the light spot image on receiving plane, removes after standard mirror, extracts the background image on receiving plane now;

Extract mirror to be measured and project the light spot image on receiving plane, remove after mirror to be measured, extract the background image on receiving plane now;

Light spot image, the background image of light spot image, background image and the mirror to be measured of the standard mirror obtaining are applied to described mathematical model, obtain solar eyepiece surface clearness to be determined.

2. the method for automatic measurement heliostat surface clearness as claimed in claim 1, is characterized in that, the light spot image of described standard mirror, background image comprise standard mirror project the light spot image on receiving plane gray scale and

and while removing standard mirror the background image on receiving plane gray scale and

the light spot image of described mirror to be measured, background image comprise mirror to be measured project the light spot image on receiving plane gray scale and and while removing mirror to be measured background image on receiving plane gray scale and

3. the method for automatic measurement heliostat surface clearness as claimed in claim 2, is characterized in that, described mathematical model is

Wherein, described in

solar eyepiece surface clearness to be determined;

the shade of standard mirror blocks efficiency;

the shade of mirror to be measured blocks efficiency;

Wherein

in the light spot image of light spot image, background image and the mirror to be measured of standard mirror, background image, extract,

by theory, calculated or emulation testing obtains.

4. the method for automatic measurement heliostat surface clearness as claimed in claim 3, is characterized in that, the process of establishing of the mathematical model of described mensuration solar eyepiece surface clearness is:

Set up the mathematical model of heliostat surface clearness

Standard heliostat surface clearness is

Solar eyepiece surface clearness to be determined is

Comprehensive two formulas obtain

The expression formula that finally obtains mirror surface clearness to be measured is

5. the method for automatic measurement heliostat surface clearness as claimed in claim 1, is characterized in that, described certain camera is CCD camera.

6. automatically measure a system for heliostat surface clearness, comprise standard mirror and receiving plane, it is characterized in that, also comprise

Image receiving unit: project the light spot image on receiving plane for extracting standard mirror, remove after standard mirror, extract the background image on receiving plane now; Extract mirror to be measured and project the light spot image on receiving plane, remove after mirror to be measured, extract the background image on receiving plane now;

Calculation processing unit: receive light spot image, the background image of light spot image, background image and the mirror to be measured of the standard mirror obtaining, the mathematical model that the light spot image of the light spot image of described standard mirror, background image and mirror to be measured, background image is applied to built-in solar eyepiece surface clearness to be determined obtains solar eyepiece surface clearness to be determined.

7. the system of automatic measurement heliostat surface clearness as claimed in claim 6, is characterized in that, the light spot image of described standard mirror, background image comprise standard mirror project the light spot image on receiving plane gray scale and and while removing standard mirror the background image on receiving plane gray scale and

the light spot image of described mirror to be measured, background image comprise mirror to be measured project the light spot image on receiving plane gray scale and

and while removing mirror to be measured background image on receiving plane gray scale and

8. the system of automatic measurement heliostat surface clearness as claimed in claim 7, is characterized in that, described mathematical model is

Wherein, described η _clr2: solar eyepiece surface clearness to be determined;

η _sb1: the shade of standard mirror blocks efficiency;

η _sb2: the shade of mirror to be measured blocks efficiency;

Wherein

in the light spot image of light spot image, background image and the mirror to be measured of standard mirror, background image, extract,

can also can test acquisition by theoretical simulation.

9. the system of automatic measurement heliostat surface clearness as claimed in claim 8, its feature is, the process of establishing of the mathematical model of described mensuration solar eyepiece surface clearness is:

Set up the mathematical model of heliostat surface clearness

Standard heliostat surface clearness is

Solar eyepiece surface clearness to be determined is

Comprehensive two formulas obtain

The expression formula that finally obtains mirror surface clearness to be measured is

。

10. the system of automatic measurement heliostat surface clearness as claimed in claim 1, is characterized in that, described certain camera is CCD camera.

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