CN101571386A - Calculation method and device of sunbeam incidence angles - Google Patents

Abstract

The invention relates to a calculation method and a device of sunbeam incidence angles. The steps are as follows: 1) a standard template image when the sunbeam rays vertically is obtained in a laboratory, the positions of origin centroids of imaging points are calculated by the centroid algorithm, the positions of the origin centroids are pre-set in a processor; 2) the calculation of the sunbeam incidence angles in the environment is carried out: i) when arriving time t, images at the imaging points are obtained, the positions of the centroids are calculated through the centroid algorithm; ii) the position difference of the origin centroid of each imaging point is calculated; iii) the average value of the position differences of the imaging points is calculated; iv) the position average difference of each imaging point is calculated; v) the filtration is carried out on the position average difference of each imaging point, a new imaging point set is constituted by the imaging points which meet the filtration conditions; vi) the position difference of the origin centroid of each imaging point after the filtration is calculated; and vii) the sunbeam incidence angles of alpha t and beta t at the t time are calculated. The invention is widely used in a posture measurement and control system on a spacecraft and can solve the problem that the device can not work normally due to inaccurate calculation of a single hole of a light introducer.

Description

A kind of computing method of angle of incidence of sunlight and device

Technical field

The present invention relates to a kind of attitude sensor field, particularly about a kind of computing method and device that is used for the angle of incidence of sunlight of attitude measurement control system on the spacecraft.

Background technology

Sun sensor is the important devices of carrying out attitude measurement on the spacecraft, has been widely used in space industry now, comprises space shuttle, earth satellite and deep space probe etc.In recent years,, spacecraft with respect to the attitude measurement accuracy of the sun with to measure the requirement of reliability more and more higher, is especially needed the system of high precision imaging, comprise investigation satellite, resource and astronomical sight satellite and telstar along with the requirement of space mission.High-precision angle of incidence of sunlight degree measure can realize the spacecraft solar array accurately to day, obtain with the ceiling capacity that guarantees satellite.Simultaneously, based on the angle of incidence of sunlight degree measure to day stable mode also be a kind of originate mode and the safe mode of most satellites.

The photosensitive detecting element of traditional analog sun sensor adopts the solar battery sheet based on photovoltaic property, and analog quantity output, and ratio of precision is lower, and anti-interference is not strong yet, can not satisfy the big visual field and the high-precision requirement of spacecraft attitude control.(Charge Couple Device, the CCD) development of technology have obtained widespread use based on the digital sun sensor of linear CCD technology in aerospace engineering along with charge coupled device.This sun sensor has the high and strong characteristics of antijamming capability of precision with respect to analog sun sensor, can replace star sensor to use in some specific occasions.

As shown in Figure 1, in the analysis of digital sun sensor, the imaging model with sun sensor is approximately the pinhole imaging system model usually, is coordinate center O (x with sun sensor at the central point of sunshine zero angle ₀, y ₀) on array image sensor 2 planes, set up coordinate system xoy, being the z coordinate perpendicular to array image sensor 2 directions.A certain moment t, sunshine obtains unique imaging point coordinate (x through light introducer 1 imaging on array image sensor 2 of sun sensor _t, y _t).The focal length of supposing sun sensor simultaneously is f, then obtains the inertia vector v of the sun _tVector w in the coordinate system of sun sensor _tFor:

$w_t=\frac{1}{\sqrt{{(x_t-x_0)}^2+{(y_t-y_0)}^2+f^2}}\left[\begin{array}{c}(x_t-x_0)\\ -(y_t-y_0)\\ f\end{array}\right]$

With t x axle angle of incidence of sunlight α constantly _tWith y axle angle of incidence of sunlight β _tBe expressed as respectively:

${\mathrm{\α}}_t={\tan }^{-1}\left(\frac{-(x_t-x_0)}{f}\right)---\left(1\right)$

${\mathrm{\β}}_t={\tan }^{-1}\left(\frac{-(y_t-y_0)}{f}\right)---\left(2\right)$

In equation (1) and the equation (2), f, x ₀, y ₀Be system constants, so x axle and y axle angle of incidence of sunlight (α _t, β _t) precision depend mainly on (x _t, y _t) computational accuracy.Existing digital sun sensor generally adopts single hole or single seam formula light introducer 1, and the occupied pixel of the imaging point on array image sensor 2 can reach 25, compares with traditional linear array sensor, and precision increases.But because monotrysian type light introducer 1 only can obtain a picture point (x on array image sensor 2 _t, y _t), the extraction of its imaging point image, identification, processing and computing are all relative simple, and the imagery exploitation rate is low, so the precision of sun sensor only depends on the computational accuracy of single hole.Stopped up by the space material when the light hole 3 of monotrysian type light introducer 1 is interfered, perhaps any variation takes place in the pattern of light hole 3, all can cause the precision of sun sensor to descend fast, even causes sun sensor to lose efficacy.And when array image sensor 2 because environmental problems such as space irradiation cause small number of pixels to be damaged, or the imaging point of monotrysian type sun sensor is when appearing at failure area, also can cause the sun sensor can not operate as normal.

Summary of the invention

At the problems referred to above, the purpose of this invention is to provide a kind of computing method and device that solves the angle of incidence of sunlight of the whole APS sun sensor cisco unity malfunction problem that causes by the single hole computational accuracy misalignment of light introducer.

For achieving the above object, the present invention takes following technical scheme: a kind of computing method of angle of incidence of sunlight, its step comprises: the standard form image when 1) obtaining the sunray vertical incidence in the laboratory is calculated to be the initial point centroid position (x of picture point by centroid algorithm _0k, y _0k), k=1 ..., p, p are the imaging point number; With described initial point centroid position (x _0k, y _0k) be preset in the processor; 2) calculating of angle of incidence of sunlight in the running environment; I) when moment t, obtain the imaging point image, calculate centroid position (x by described centroid algorithm _Tk, y _Tk); Ii) calculate poor (the Δ x of initial point centroid position of each imaging point _Tk, Δ y _Tk)

$\left\{\begin{array}{c}\mathrm{\Δ}{x}_{\mathrm{tk}}=x_{\mathrm{tk}}-x_{0k}\\ \mathrm{\Δ}{y}_{\mathrm{tk}}=y_{\mathrm{tk}}-y_{0k}\end{array}\right.;$

Iii) calculate alternate position spike average (the Δ x of described imaging point image _t, Δ y _t)

$\left\{\begin{array}{c}\mathrm{\Δ}{\stackrel{\‾}{x}}_t=\frac{1}{p}\underset{k=1}{\overset{p}{\mathrm{\Σ}}}\mathrm{\Δ}{x}_{\mathrm{tk}}\\ \mathrm{\Δ}{\stackrel{\‾}{y}}_t=\frac{1}{p}\underset{k=1}{\overset{p}{\mathrm{\Σ}}}\mathrm{\Δ}{y}_{\mathrm{tk}}\end{array}\right.;$

Vi) calculate position mean difference (the Δ x of each described imaging point _Tk, Δ y _Tk)

Δx _tk＝Δx _tk-Δx _t

；

Δy _tk＝Δy _tk-Δy _t

V) to position mean difference (the Δ x of each described imaging point _Tk, Δ y _Tk) carry out filtering, establishing filtering threshold is ξ, and the imaging point that satisfies filtering condition is constituted new imaging point set; Described filtering condition is:

$\left\{\begin{array}{c}-\mathrm{\&xi;}<\mathrm{\&Delta;}{\stackrel{\&OverBar;}{x}}_{\mathrm{tk}}<\mathrm{\&xi;}\\ -\mathrm{\&xi;}<\mathrm{\&Delta;}{\stackrel{\&OverBar;}{y}}_{\mathrm{tk}}<\mathrm{\&xi;}\end{array},k=1,...,m\right.$

M is an imaging point number in the described new imaging point set;

Vi) initial point centroid position difference is (Δ x, Δ y) after the calculation of filtered

$\left\{\begin{array}{c}\mathrm{\&Delta;}\stackrel{\&OverBar;}{x}=\frac{1}{m}\underset{k=1}{\overset{m}{\mathrm{\&Sigma;}}}\mathrm{\&Delta;}{x}_{\mathrm{tk}}\\ \mathrm{\&Delta;}\stackrel{\&OverBar;}{y}=\frac{1}{m}\underset{k=1}{\overset{m}{\mathrm{\&Sigma;}}}\mathrm{\&Delta;}{y}_{\mathrm{tk}}\end{array}\right.$

Vii) calculate t angle of incidence of sunlight α constantly _tAnd β _t:

$\left\{\begin{array}{c}{\mathrm{\&alpha;}}_t={\tan }^{-1}\left(\frac{-\mathrm{\&Delta;}\stackrel{\&OverBar;}{x}}{f}\right)\\ {\mathrm{\&beta;}}_t={\tan }^{-1}\left(\frac{-\mathrm{\&Delta;}\stackrel{\&OverBar;}{y}}{f}\right)\end{array}\right.$

F is a focal length.

In the described centroid algorithm, k imaging point comprises n * n pixel in the described imaging point image, then centroid position (the x of described imaging point _k, y _k),

$x_k=\frac{\underset{i,j}{\overset{n}{\mathrm{\&Sigma;}}}{x}_{\mathrm{ij}}{I}_{\mathrm{ij}}}{\underset{i,j}{\overset{n}{\mathrm{\&Sigma;}}}{I}_{\mathrm{ij}}};$ $y_k=\frac{\underset{i,j}{\overset{n}{\mathrm{\&Sigma;}}}{y}_{\mathrm{ij}}{I}_{\mathrm{ij}}}{\underset{i,j}{\overset{n}{\mathrm{\&Sigma;}}}{I}_{\mathrm{ij}}}$

Wherein, x _Ij=i, y _Ij=j is pixel (i, the j) position in described imaging point image, I _IjBe described pixel (i, gray-scale value j).

A kind of calculation element of angle of incidence of sunlight is characterized in that: it comprises light introducer, array image sensor, processor and interface circuit, and described smooth introducer comprises a plurality of light holes; Described processor calculates angle of incidence of sunlight according to the gray-scale value of the imaging point pixel of described area array sensor output; The result of calculation of described angle of incidence of sunlight is transferred in the host computer by described interface circuit.

Described processor is a flush bonding processor.

Described smooth introducer comprises p light hole, and the arrangement of light hole is arbitrarily.

The present invention is owing to take above technical scheme, it has the following advantages: 1, the light introducer of sun sensor of the present invention includes a plurality of light holes, therefore can produce than the more imaging point of single hole sun sensor, simultaneously because the present invention carries out the calculating of angle of incidence of sunlight in the initial point centroid position difference that is chosen to picture point, adopted the method for the average and threshold filter of porous, degree of accuracy is than single imaging point method raising several times.2, because sun sensor of the present invention adopts the light introducer of face battle array APS imageing sensor and a plurality of light holes, the influence that therefore can effectively avoid imageing sensor top pixel damage etc. to cause improves the reliability and stability of sun sensor.APS sun sensor of the present invention can be widely used in attitude measurement control system on the spacecraft.

Description of drawings

Fig. 1 is the image-forming principle synoptic diagram of monotrysian type sun sensor

Fig. 2 is a smooth introducer structural representation of the present invention

Fig. 3 is the imaging point image of array image sensor of the present invention

Embodiment

Below in conjunction with drawings and Examples the present invention is described in detail.

As shown in Figure 2, (it comprises light introducer 1, array image sensor 2, flush bonding processor 3 and interface circuit 4 for Actel Pixels Sensor, APS) sun sensor to the present invention is based on porous array type active pixel sensor.Wherein light introducer 1 includes p light hole 3, is used for sunshine and produces image on array image sensor 2.Array image sensor 2 is the APS cmos image sensor that has certain distance with light introducer 1, array image sensor 2 has big face battle array, be used to export the gray-scale value of each pixel of imaging point of image, wherein the light hole 3 of light introducer 1 becomes corresponding relation with imaging point on the image.The gray-scale value of the imaging point pixel of 3 pairs of imageing sensors of flush bonding processor, 2 outputs calculates and analyzes, and obtains the exact position of imaging point.Afterwards according to the accurate position calculation t of imaging point x axle angle of incidence of sunlight α constantly _tWith y axle angle of incidence of sunlight β _t, at last result of calculation is transferred to host computer by interface circuit 4.

In the flush bonding processor 3, the calculation procedure of angle of incidence of sunlight is as follows:

Standard form image when 1, obtaining the sunray vertical incidence

This step real running environment to sun sensor in the laboratory is simulated, and major equipment comprises solar simulator, electronic theodolite, two-axle rotating table and sun sensor.At first, use electronic theodolite that solar simulator is measured, guarantee solar simulator and electronic theodolite point-blank.Secondly, sun sensor is installed on the two-axle rotating table, rotates two-axle rotating table, make sun sensor, solar simulator and electronic theodolite point-blank, make simulated solar irradiation vertically inject light introducer 1, guaranteed the incident angle α of simulated solar irradiation ₀=0, β ₀=0, wherein, α ₀, β ₀X axle angle of incidence of sunlight when being expressed as the sun sensor vertical incidence respectively and y axle angle of incidence of sunlight.When sunshine projects on the array image sensor 2 by light introducer 1, the gray-scale value of each effective imaging point pixel in the array image sensor 2 outputting standard template images.

As shown in Figure 3, in the embodiments of the invention, the light introducer 1 of sun sensor comprises p=36 the light hole of arranging arbitrarily 3, and then the image on array image sensor 2 comprises the imaging point of 36 correspondences.Use centroid algorithm that each imaging point is carried out centroid calculation, obtain the initial point centroid position (x of p imaging point _0k, y _0k), k=1 ..., p.Wherein, centroid algorithm be the pixel grey scale single order apart from method, suppose that the picture position of k imaging point comprises n * n pixel, then initial point centroid position (x _0k, y _0k) be:

$x_{0k}=\frac{\underset{i,j}{\overset{n}{\mathrm{\&Sigma;}}}{x}_{\mathrm{ij}}{I}_{\mathrm{ij}}}{\underset{i,j}{\overset{n}{\mathrm{\&Sigma;}}}{I}_{\mathrm{ij}}}$ $;y_{0k}=\frac{\underset{i,j}{\overset{n}{\mathrm{\&Sigma;}}}{y}_{\mathrm{ij}}{I}_{\mathrm{ij}}}{\underset{i,j}{\overset{n}{\mathrm{\&Sigma;}}}{I}_{\mathrm{ij}}}---\left(3\right)$

Wherein, x _Ij=i, y _Ij=j is pixel (i, j) horizontal ordinate and the ordinate in imaging point image coordinate system xoy, the I that imaging point k is comprised _IjBe pixel (i, gray-scale value j).Initial point centroid position (the x of imaging point during afterwards with the sunshine vertical incidence _0k, y _0k), k=1 ..., p is preset in the flush bonding processor 3.

2, the computation process of angle of incidence of sunlight in the running environment

1) when sun sensor orbits with satellite, for any one t constantly, when in the field angle scope of angle of incidence of sunlight at sun sensor, on array image sensor 2, can obtain the imaging point image, the imaging point image comprises p imaging point.According to the gray-scale value of pixel that imaging point comprises, calculate the centroid position (x of each imaging point by the centroid algorithm of equation (3) _Tk, y _Tk), k=1 ..., p.

2) calculate poor (the Δ x of initial point centroid position of each imaging point _Tk, Δ y _Tk).Imaging point position (x to moment t _Tk, y _Tk) the initial point centroid position (x of imaging point when being preset at sunshine vertical incidence in the flush bonding processor 3 _0k, y _0k) poor, obtain poor (the Δ x of initial point centroid position _Tk, Δ y _Tk), k=1 ..., p.Wherein:

$\left\{\begin{array}{c}\mathrm{\&Delta;}{x}_{\mathrm{tk}}=x_{\mathrm{tk}}-x_{0k}\\ \mathrm{\&Delta;}{y}_{\mathrm{tk}}=y_{\mathrm{tk}}-y_{0k}\end{array}\right.,$ k＝1，…，p

3) be calculated to be alternate position spike average (the Δ x of picture point image _t, Δ y _t).Obtain p poor (the Δ x of initial point centroid position _Tk, Δ y _Tk) alternate position spike average (Δ x _t, Δ y _t), i.e. the barycenter of the imaging point image that obtains constantly of t, wherein:

$\left\{\begin{array}{c}\mathrm{\&Delta;}{\stackrel{\&OverBar;}{x}}_t=\frac{1}{p}\underset{k=1}{\overset{p}{\mathrm{\&Sigma;}}}\mathrm{\&Delta;}{x}_{\mathrm{tk}}\\ \mathrm{\&Delta;}{\stackrel{\&OverBar;}{y}}_t=\frac{1}{p}\underset{k=1}{\overset{p}{\mathrm{\&Sigma;}}}\mathrm{\&Delta;}{y}_{\mathrm{tk}}\end{array}\right.$

4) calculate position mean difference (the Δ x of each imaging point _Tk, Δ y _Tk).Under theoretical situation, according to the directional light image-forming principle, the change in location amplitude of each imaging point all equates, that is: Δ x _t=Δ x _Tk, Δ y _t=Δ y _Tk, k=1 ... p.And in practice, owing to be subjected to that the error of calculation etc. is calculated or the influence of other disturbing factors, the relative position between the different imaging points has certain error, and the grade of error is very little, under the normal condition approximately less than 0.2 pixel.For whether p imaging point in the discrimination imaging point image exists undesired signal, we at first calculate t p imaging point alternate position spike (Δ x constantly _Tk, Δ y _Tk) respectively with alternate position spike average (Δ x _t, Δ y _t) difference, obtain position mean difference (Δ x _Tk, Δ y _Tk),

Δx _tk＝Δx _tk-Δx _t

，k＝1，…，p

Δy _tk＝Δy _tk-Δy _t

5) to position mean difference (the Δ x of each imaging point _Tk, Δ y _Tk) carry out filtering.Consider the influence of indivedual undesired signals, the present invention is to position mean difference (the Δ x of each imaging point _Tk, Δ y _Tk) carry out filtering.In the embodiments of the invention, establish fixing filtering threshold ξ=0.5 pixel, promptly from p position mean difference (Δ x _Tk, Δ y _Tk), k=1 ..., find out all position mean difference (Δ x among the p _Tk, Δ y _Tk) less than the imaging point of filtering threshold ξ=0.5, constitute new imaging point set M, supposing has m imaging point to satisfy filtering condition:

$\left\{\begin{array}{c}-0.5<\mathrm{\&Delta;}{\stackrel{\&OverBar;}{x}}_{\mathrm{tk}}<0.5\\ -0.5<\mathrm{\&Delta;}{\stackrel{\&OverBar;}{y}}_{\mathrm{tk}}<0.5\end{array}\right.,$ k＝1，…，m

Imaging point k=1 among the imaging point set M ..., poor (the Δ x of the initial point centroid position of m correspondence _Tk, Δ y _Tk), k=1 ..., m.

6) the initial point centroid position difference with imaging point among the t new imaging point set M constantly is (Δ x _Tk, Δ y _Tk) average, the initial point centroid position difference that obtains filtered t moment imaging point is (Δ x, Δ y);

$\left\{\begin{array}{c}\mathrm{\&Delta;}\stackrel{\&OverBar;}{x}=\frac{1}{m}\underset{k=1}{\overset{m}{\mathrm{\&Sigma;}}}\mathrm{\&Delta;}{x}_{\mathrm{tk}}\\ \mathrm{\&Delta;}\stackrel{\&OverBar;}{y}=\frac{1}{m}\underset{k=1}{\overset{m}{\mathrm{\&Sigma;}}}\mathrm{\&Delta;}{y}_{\mathrm{tk}}\end{array}\right.;$

7) calculate any time tx axle angle of incidence of sunlight α _tWith y axle angle of incidence of sunlight β _t:

$\left\{\begin{array}{c}{\mathrm{\&alpha;}}_t={\tan }^{-1}\left(\frac{-\mathrm{\&Delta;}\stackrel{\&OverBar;}{x}}{f}\right)\\ {\mathrm{\&beta;}}_t={\tan }^{-1}\left(\frac{-\mathrm{\&Delta;}\stackrel{\&OverBar;}{y}}{f}\right)\end{array}\right.$

Wherein, f is the focal length of described sun sensor.

The present invention has adopted the method to the filtering of m imaging point weighted mean to guarantee accuracy of measurement system, supposes that the error of calculation noise equivalent angle of single imaging point is σ ₀, and x axle angle of incidence of sunlight α _tWith y axle angle of incidence of sunlight β _tPrecision directly be decided by σ ₀When adopting m imaging point, suppose that equally the error of calculation noise equivalent angle of each picture point is σ ₀, be about through filtered error of calculation noise equivalent angle σ:

$\mathrm{\&sigma;}=\frac{{\mathrm{\&sigma;}}_0}{\sqrt{m}}$

Therefore the angle of incidence of sunlight degree of accuracy of porous sun sensor has improved than single imaging point method

Doubly.

The present invention adopts the method for fixed threshold filtering in step 5), with the threshold value of 0.5 pixel as filtering, simultaneously to poor (the Δ x of initial point centroid position of t each imaging point constantly _Tk, Δ y _Tk), k=1 ..., p, and calculated its average will think an external interference with the imaging point that average differs by more than 0.5 pixel, with its filtering.The kind method has realized the rejecting to undesired signal like this, has realized the high reliability and the high precision of sun sensor.

Claims (6)

1, a kind of computing method of angle of incidence of sunlight, its step comprises:

Standard form image when 1) obtaining the sunray vertical incidence in the laboratory is calculated to be the initial point centroid position (x of picture point by centroid algorithm _0k, y _0k), k=1 ..., p, p are the imaging point number; With described initial point centroid position (x _0k, y _0k) be preset in the processor;

2) calculating of angle of incidence of sunlight in the running environment

I) when moment t, obtain the imaging point image, calculate centroid position (x by described centroid algorithm _Tk, y _Tk);

Ii) calculate poor (the Δ x of initial point centroid position of each imaging point _Tk, Δ y _Tk)

$\left\{\begin{array}{c}{\mathrm{\&Delta;x}}_{\mathrm{tk}}=x_{\mathrm{tk}}-x_{0k}\\ {\mathrm{\&Delta;y}}_{\mathrm{tk}}=y_{\mathrm{tk}}-y_{0k}\end{array}\right.;$

Iii) calculate alternate position spike average (the Δ x of described imaging point image _t, Δ y _t)

$\left\{\begin{array}{c}\mathrm{\&Delta;}{\stackrel{\&OverBar;}{x}}_t=\frac{1}{p}\underset{k=1}{\overset{p}{\mathrm{\&Sigma;}}}{\mathrm{\&Delta;x}}_{\mathrm{tk}}\\ \mathrm{\&Delta;}{\stackrel{\&OverBar;}{y}}_t=\frac{1}{p}\underset{k=1}{\overset{p}{\mathrm{\&Sigma;}}}{\mathrm{\&Delta;y}}_{\mathrm{tk}}\end{array}\right.;$

Vi) calculate position mean difference (the Δ x of each described imaging point _Tk, Δ y _Tk)

Δx _tk＝Δx _tk-Δx _t

；

Δy _tk＝Δy _tk-Δy _t

V) to position mean difference (the Δ x of each described imaging point _Tk, Δ y _Tk) carry out filtering, establishing filtering threshold is ξ, and the imaging point that satisfies filtering condition is constituted new imaging point set; Described filtering condition is:

$\left\{\begin{array}{c}-\mathrm{\&xi;}<\mathrm{\&Delta;}{\stackrel{\&OverBar;}{x}}_{\mathrm{tk}}<\mathrm{\&xi;}\\ -\mathrm{\&xi;}<{\mathrm{\&Delta;}\stackrel{\&OverBar;}{y}}_{\mathrm{tk}}<\mathrm{\&xi;}\end{array}\right.k=1,\&CenterDot;\&CenterDot;\&CenterDot;,m$

M is an imaging point number in the described new imaging point set;

Vi) initial point centroid position difference is (Δ x, Δ y) after the calculation of filtered

$\left\{\begin{array}{c}\mathrm{\&Delta;}\stackrel{\&OverBar;}{x}=\frac{1}{m}\underset{k=1}{\overset{m}{\mathrm{\&Sigma;}}}{\mathrm{\&Delta;x}}_{\mathrm{tk}}\\ \mathrm{\&Delta;}\stackrel{\&OverBar;}{y}=\frac{1}{m}\underset{k=1}{\overset{m}{\mathrm{\&Sigma;}}}{\mathrm{\&Delta;y}}_{\mathrm{tk}}\end{array}\right.;$

Vii) calculate t angle of incidence of sunlight α constantly _tAnd β _i:

$\left\{\begin{array}{c}{\mathrm{\&alpha;}}_t={\tan }^{-1}\left(\frac{-\mathrm{\&Delta;}\stackrel{\&OverBar;}{x}}{f}\right)\\ {\mathrm{\&beta;}}_t={\tan }^{-1}\left(\frac{-\mathrm{\&Delta;}\stackrel{\&OverBar;}{y}}{f}\right)\end{array}\right.$

F is a focal length.

2, the computing method of a kind of angle of incidence of sunlight as claimed in claim 1 is characterized in that: in the described centroid algorithm, k imaging point comprises n * n pixel in the described imaging point image, then centroid position (the x of described imaging point _k, y _k),

$x_k=\frac{\underset{i,j}{\overset{n}{\mathrm{\&Sigma;}}}{x}_{\mathrm{ij}}{I}_{\mathrm{ij}}}{\underset{i,j}{\overset{n}{\mathrm{\&Sigma;}}}{I}_{\mathrm{ij}}};$ $y_k=\frac{\underset{i,j}{\overset{n}{\mathrm{\&Sigma;}}}{y}_{\mathrm{ij}}{I}_{\mathrm{ij}}}{\underset{i,j}{\overset{n}{\mathrm{\&Sigma;}}}{I}_{\mathrm{ij}}}$

Wherein, x _Ij=i, y _Ij=j is pixel (i, the j) position in described imaging point image, I _IjBe described pixel (i, gray-scale value j).

3, a kind of calculation element of the angle of incidence of sunlight of method as claimed in claim 1 or 2 of realizing, it is characterized in that: it comprises light introducer, array image sensor, processor and interface circuit, described smooth introducer comprises a plurality of light holes; Described processor calculates angle of incidence of sunlight according to the gray-scale value of the imaging point pixel of described area array sensor output; The result of calculation of described angle of incidence of sunlight is transferred in the host computer by described interface circuit.

4, the calculation element of a kind of angle of incidence of sunlight as claimed in claim 3 is characterized in that: described processor is a flush bonding processor.

5, the calculation element of a kind of angle of incidence of sunlight as claimed in claim 3 is characterized in that: described smooth introducer comprises p light hole, and the arrangement of light hole is arbitrarily.

6, the calculation element of a kind of angle of incidence of sunlight as claimed in claim 4 is characterized in that: described smooth introducer comprises p light hole, and the arrangement of light hole is arbitrarily.

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