CN1333231C - Method for measuring light-beam central position by array CCD - Google Patents

Abstract

The present invention provides a method for measuring the center position of light beams by a linear array CCD and relates to a photoelectric measurement method for measuring the center position of the light beams irradiating on the surface of the linear array CCD and a specific method for applying the method to measure displacement and angular displacement. The present invention makes the radiation power density of faculae on the surface of the CCD distribute in a Gaussian distribution mode or a quasi-Gaussian distribution mode, the limit of error of digital signals outputted is determined by the CCD, the characteristics of associated circuits, etc., and truncated threshold value is also selected. The estimated value of the center position of the light beams is obtained by calculating effective digital signals distributed in a truncation quasi-Gaussian distribution mode by a weighted regression method, and the range of the width of the light beams is determined by using a Monte Carlo method numerical simulation error distribution method. The method of the present invention can decrease the effective resolution and the precision of the center position of the light beams measured by the linear array CCD from about 1W to below 0.03W, wherein the W means picture element distance. Thus, the measurements of submicron precision displacement and 1 second effective resolution angle measurement are realized, and the present invention can be applied to the measurement field of other relevant measurements of the tilting mirror and angle of a ballistic galvanometer, the wavelength of line spectra, etc.

Description

A kind of method with line array CCD measuring beam center

Technical field

The present invention relates to a kind of measurement and incide the new photoelectric measurement method of the beam center position on line array CCD surface, reach the concrete grammar that this method of utilization is measured displacement of the lines, length and angular displacement, angle etc., belong to the technical field of geometric measurement method and instrument; Also can be applicable to be convertible into displacement and the measured measurement of angle metric other type, for example pass through ballistic galvanometer tilting mirror deflection angular measurement magnetic flux density, survey line wavelength etc. by the position on the spectrum face of tested spectral line.

Background technology

In the measuring technique of in the past utilization line array CCD, corresponding 1 pixel of most effective resolutions is W at interval, the report of indivedual inferior pixel resolution techniques also can only be reduced to the effective resolution value about 0.5W, if any document in realize that with the two row CCD of the 0.5W that staggers inferior pixel measures.Though the indivedual bibliographical informations of resolution below 0.1 pixel are also arranged, do not see the description of indexs such as non-linear standard deviation or uncertainty are arranged in this class document, thereby can not regard as with certain measurement range in the effective resolution that interrelates of measurement standard difference.

Usually require in the prior art that width of light beam preferably is too narrow to 2W～3W on the CCD surface below 5W; Usually require beam distribution even as far as possible, the general least square regression method under supposing such as " center of gravity " determining method or the power of grade that adopts.Can prove with regression theory: when the dependent variable that waits power to return had the same error eigenwert, the error of the marginal date that value is less was wanted remarkable influence greater than the data of middle part error to result's influence; And accurate Gaussian lineshape parameter dependent variable y when returning _j=lnV _DjWeight factor direct ratio and value V again _DjSquare, the error character value of line style edge dependent variable is big, power is little.Prior art also will fully keep the effective information that obtains, and data is rejected taked careful attitude.

In the prior art, range of displacement measurement reaches about 35mm, resolution reaches sub-micron mainly contains grating technology and laser interferometry, but the measurement nonlinearity erron of grating technology limit is in micron dimension.Measurement of angle resolution and accuracy mainly contain photoelectric encoder etc. than the device of 0.5 ' difference in the prior art, and measurement of angle resolution and accuracy are better than 2 " round grating technology arranged.The measurement of angle accuracy is 3～6 ", effective resolution reaches 1 " digital automation measurement mechanism application demand is wide, realizes relatively difficulty with the method beyond the circle grating technology..

CCD spectrometer in the prior art mostly with pixel at interval W be definite foundation of wavelength resolution, the accuracy that guarantees wavelength measurement with the stability and the repeatability of optical-mechanical system.

Summary of the invention

The objective of the invention is for improving effective resolution and the precision of existing line array CCD the beam center position measurement, a kind of method with line array CCD measuring beam center is provided, make it reach 0.03W following (W is the pixel spacing), reach 1 with the displacement that realizes sub-micron precision or measurement of length method, effective resolution " angular displacement or the measuring method of angle, and make it can be applied to the fields of measurement of other related physical quantity.

Technical scheme of the present invention is as follows:

A kind of method with line array CCD measuring beam center is characterized in that:

1) makes the width of cloth of the hot spot battle array along the line direction on ccd detector surface penetrate the power line density and be Gaussian distribution or accurate Gaussian distribution;

2) obtain the truncation threshold value: establishing j centre coordinate of ccd detector is x _jThe significant figure signal of pixel be output as V _Dj, described V _DjIntegral multiple for LSB; According to ccd detector and dependent circuit characteristics, output bit number N and noise amplitude, with formula ± U _Vj=± (a+c%V _j) express V _DjThe limits of error, a is positive constant in the formula, c% is the direct proportion coefficient; With (a+c% * 2 ^N) to 2 ^NA certain integer between/20 is made truncation threshold value V _Th, be not less than threshold value V after making truncation _ThThe significant figure output signal V of pixel _DjBe the accurate Gaussian distribution of truncation;

3) be x to centre coordinate _jThe accurate Gaussian distribution output signal of the truncation V of pixel _Dj, adopt the regression equation model $y_j=b_0+b_1{x}_j+b_2{x}_{\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="C20051001206600181.png"\; state="\{\{state\}\}">j</figure-callout>}}^2,$ Respectively with x _jAnd x _j ²For independent variable, with y _j=ln (V _Dj) be dependent variable, as weight factor be $w_{y_j}={(V_{\mathrm{Dj}}/U_{V_j})}^2$ Weighted regression ask b1 _Withb ₂, calculate the beam center location estimate again ${\hat{x}}_c=-b_1/\left({2b}_2\right);$

4) make the width of light beam scope with Monte Carlo method numerical simulation error profile, its concrete steps are:

A). when pixel interval W is known, for beam center position x _c, penetrate the Gaussian distribution E of power line density by the width of cloth _l(x _c, x)=E _LmExp ((x-x _c) ²/ (2 σ ²)), under the value of a certain distribution standard deviation σ, to fixed sampling time at interval and the location variable x integration in the pixel to calculate centre coordinate be x _jThe simulating signal V of j pixel _j=V _j(x _j, x _c), as the photoelectric measurement signal initial value before the analog to digital conversion; V _jBe relative value, choose proportionality constant during integration and make V _jPeak value be 0.8 * 2 ^N

B). be limited to according to error $\&PlusMinus;U_{V_j}=\&PlusMinus;(a+c\%V_j)$ One group of stochastic error of rule numerical simulation distribute ${\mathrm{\&epsiv;}}_{V_j}=r_{\mathrm{aj}}+r_{\mathrm{cj}}\%V_j,$ Here r _AjAnd r _CjBe respectively error be limited to ± a and ± uniform random number of c; Get (V _j+ ε _Vj) the digital signal output V of integral part after as analog to digital conversion _Dj

C). intercepting V _Dj〉=V _ThThe significant figure signal;

D). to equation $y_j=\ln \left(V_{\mathrm{Dj}}\right)=b_0+b_1{x}_j+b_2{x}_{\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="C20051001206600181.png"\; state="\{\{state\}\}">j</figure-callout>}}^2$ As weight factor be $w_{y_j}={(V_{\mathrm{Dj}}/U_{V_j})}^2$ Weighted regression, obtain ${\hat{x}}_c=-b_1/\left({2b}_2\right),$ And calculate error ${\mathrm{\&epsiv;}}_{\mathrm{xc}}={\hat{x}}_c-x_c$ Come;

E). the simulation error distribution of many groups of identical rules is calculated the error ε of each group respectively _Xc, and then the standard deviation s that calculates error _Xc, this promptly marks the corresponding beam center position x of difference σ with beam distribution _cMeasurement standard poor;

F). different σ values is repeated above-mentioned A calculate corresponding standard deviation s to the step of E _Xc, draw s _XcRelation curve between/W and the σ/W, and then find out and make s _Xc/ W is not more than the span of beam distribution parameter σ/W of 0.08.

In above-mentioned method, it is characterized in that: be not less than threshold value V after making truncation _ThThe significant figure output signal V of pixel _DjNumber, promptly the effective pixel number in the width of light beam is between 5～50.

The invention provides the method for utilizing said method to measure the tilting mirror corner, it is characterized in that this method comprises the steps:

1) be 10mm≤F with focal length ₁First convex lens of '≤50mm, the slit that light source is illuminated form the reduced and bright easily slit real image of width adjusting of an equivalent width, and the light that this slit real image sends is focal length 50mm≤f through focal length after the tilting mirror reflection again ₂Second convex lens of '≤300mm form width of light beam on the ccd detector surface; Make the effective output signal V of pixel after the truncation _DjNumber, promptly the effective pixel number in the width of light beam is between 5～50;

2) utilize the computing machine of ccd detector and signals collecting and processing, according to above-mentioned with line array CCD detector measurement beam center position x _eMethod, obtain the truncation threshold value, to the significant figure signal of the accurate Gaussian distribution of truncation output V _DjWeighted regression provides the beam center position in real time;

3) utilize the angle of deflection of tilting mirror and ccd detector surface beam center position x _cSide-play amount (x _c-x _C0) between the first approximation relational expression: (x _c-x _C0)=(k ₂D) sin (2 α) can try to achieve the single order valuation of tilting mirror corner α, k in the formula ₂Be the lateral magnification of second lens, d is slit real image Q ₁To the distance of tilting mirror rotating shaft O, x _C0Be that tilting mirror corner α=0 o'clock beam center is positioned at the coordinate at the intersection point place of the ccd detector surface and second lens axis; After installing and adjust, measurement mechanism obtains angle of deflection and ccd detector surface beam center position x by fixed degree _cBetween degree of the deciding measured data of relation, and then obtain the modified value data of single order valuation.

The invention provides a kind of utilization said method and measure the dynamic deflection angle method of ballistic galvanometer tilting mirror, it is characterized in that this method comprises the steps:

1) be 10mm≤f with focal length ₁First convex lens of '≤50mm, the slit that light source is illuminated form the reduced and width adjusting of equivalent width slit real image easily, and the light that this slit real image sends is 50mm≤f through focal length after the reflection of ballistic galvanometer tilting mirror again ₂Second convex lens of '≤300mm form accurate Gaussian distribution hot spot on the ccd detector surface; Ballistic galvanometer and described parts are fixed on the same rigid plate that is added with earthquake counter measure;

2) select pixel sum N for use _p〉=7400, the line array CCD detector of pixel spacing W=4.7 μ m, signal output bit number N=8, V _DjLimits of error formula $\&PlusMinus;U_{V_j}\&ap;\&PlusMinus;(1.5+1.5\%V_{\mathrm{Dj}})$ Truncation threshold value V is chosen in expression _Th=6LSBs;

3) regulate lateral magnification k and slit real image Q ₁To tilting mirror rotating shaft O order apart from d, make ccd detector effective width N _pThe impact quantity of electric charge that W and ballistic galvanometer need be surveyed or the range of electric current are corresponding; Regulate the distance of slit simultaneously, make the interior effective pixel number of ccd detector surface light beam width between 10～30 to first lens;

4) regulate the brightness of light source or the circuit gain in signals collecting and the computing parts, make the digital signal maximal value (V of pixel after the truncation _Dj) _Max≈ 200LSB, the dependent variable y when the truncation rear weight returns _j=ln (V _Dj) weight factor use $w_{y_i}={(V_{\mathrm{Dj}}/U_{V_j})}^2$ Formula is calculated, and calculates beam center position x _cValuation after so that the dynamic deflection angle of calculating the galvanometer tilting mirror come.

The present invention also provides a kind of utilization described with line array CCD measuring beam center x _cMethod method that displacement or length are measured, this method comprises the steps:

1) utilize signals collecting and computing parts, ccd detector and optical module to realize measuring, described ccd detector adopts pixel sum N _p〉=5000 and the pixel line array CCD detector of W≤7 μ m at interval; Described optical module is made up of semiconductor laser and lens, and it is with a tight waist that the quasi-parallel semiconductor laser beam forms accurate Gaussian distribution through lens on the ccd detector surface; Described optical module or form by light emitting diode, slit or aperture, lens, lens will converge at the ccd detector surface through the light of slit or aperture;

2) the effective pixel number of light beam in ccd detector surface light beam width of described optical module institute outgoing is between 10～30, but ccd detector and optical module are installed in respectively on the movable member of stationary parts and moving linearly, the orientation of ccd detector pixel is parallel with movable member direction of motion, in when, between beam axis or spot center position and the ccd detector relative displacement taking place when, weighted regression result's value

Change thereupon,, realize displacement or measurement of length with direct reflection displacement or position change.

The invention provides a kind of described measuring method of using method realization 0～360 degree angle of line array CCD detector measurement beam center position of using, it is characterized in that:

1) make quasi-parallel semiconductor laser beam that diameter is not less than 3mm by arbitrary direct reflection of the positive n face of rotatable metal body, the sequence number of establishing this mirror surface is i, and folded light beam is not less than through the angle, effective aperture ± and the object lens of 360 °/n converge in pixel sum N _p〉=5000 and the pixel surface of the linear array of W≤7 μ m at interval, described objective focal length is

Objective lens optical axis is perpendicular to the ccd detector surface;

2) focusing makes the effective pixel number of light beam in ccd detector surface light beam width between 10～30, and output adopts truncation processing and weighted regression to obtain beam center coordinate x to the ccd detector digital signal _cValuation;

3) the position angle φ of described positive n face body is by mirror surface sequence number i and beam center coordinate x _cValuation Determine, $\mathrm{\&phi;}=\frac{360}{n}i+\arctan \left(\frac{{\hat{x}}_c-x_{c0}}{{f_3}^{\&prime;}}\right)+\mathrm{\&epsiv;}({\hat{x}}_c,i)+{\mathrm{\&phi;}}_0,$ X in the formula _C0Be the optical axis of lens 9 and the coordinate of ccd detector surface intersection point, φ ₀Be the constant item, Be the angle modification item of determining by fixed degree, directly export or show the position angle φ of positive n face body by signals collecting and calculating unit.

It is described with line array CCD detector measurement beam center position x to the invention provides a kind of utilization _cMethod realize to measure the method for wire visible spectrum wavelength, it is characterized in that this method comprises the steps:

1) make the quasi-parallel light beam of the different wave length that every millimeter grating dispersion element that is no less than 1200 lines sends be not less than the lens or concave mirror of 150mm through a focal length with different diffraction angle after, image in the line array CCD detector surface, described ccd detector pixel sum N _p〉=5000 and pixel W≤7 μ m at interval;

2) focusing makes effective pixel number in ccd detector surface light beam width between 5～15 to described lens or concave mirror;

3) by digital signal output truncation processing and weighted regression, calculate wire spectral line λ to be measured to the ccd detector pixel _xThe coordinate valuation at center

Again simultaneously or alternately measure some the known wavelength λ that wavelength is positioned near the He-Ne discharge tube the spectral line to be measured _iThe valuation of reference spectral line centre coordinate

Obtain local linear dispersion equation with least square line match or quadratic regression ${\hat{x}}_{\mathrm{ci}}=f\left({\mathrm{\&lambda;}}_i\right),$ At last will The substitution dispersion equation is obtained unknown spectral line wavelength X _xCome.

The present invention compared with prior art has the following advantages and the high-lighting progress:

The present invention passes through to adopt the beam distribution of accurate Gaussian distribution to improve the detection sensitivity of beam center position; By of the influence of suitable raising truncation threshold value with the reduction interference noise; By the influence " randomization " in the overall measurement useful signal of uncertain systematic error components such as suitably adding the angle pencil of ray effective width and make the response characteristic of each pixel inhomogeneous, non-linear, again by considering that the weighted regression after the pixel substantial measurement errors characteristic improves the accuracy of beam center position measurement.The present invention can be reduced to effective resolution and the standard deviation with line array CCD detector measurement beam center position below the 0.03W, reduces 1～2 order of magnitude than prior art.Therefore, use the standard deviation that displacement measurement method of the present invention measures when W ≈ 4.7 μ m and can work as N less than 0.25 μ m _p≈ 7400 non-linear hour standard deviations can reach 1 * 10 of measurement range ^-5Below; Use angle measurement method of the present invention also can effectively improve the precision of measurement.

The present invention require hot spot become accurate Gaussian distribution this than the distribution that is easier to realize.The present invention emphasizes to adopt dependent variable not wait the weighted regression method of precision, with the influence of effective minimizing edge of distributed partial data error.Can prove with regression theory: when the dependent variable that waits power to return had the same error eigenwert, the error of the marginal date that value is less was to result-b ₁/ (2b ₂) influence want significantly influence greater than the data of middle part error; And accurate Gaussian lineshape parameter dependent variable y when returning _j=lnV _DjWeight factor direct ratio and value V again _DjSquare, the error character value of line style edge dependent variable is big, power is little.

Description of drawings

Fig. 1 is an apparatus structure synoptic diagram of measuring the tilting mirror corner according to method of the present invention.

Fig. 2 is the synoptic diagram of the primary structure of the angle measurement method of measurement 0～360 degree.

Embodiment

Below to of the present invention with line array CCD measuring beam center method and according to this method carry out the tilting mirror outer corner measurement, impact the dynamic deflection angle measurement of circuit meter tilting mirror, displacement measurement, 0～360 degree measurement of angle and the wavelength measurement of wire visible spectrum specify as follows:

One, uses the assay method of line array CCD measuring beam center

1.1 adopt the light beam radiation power density distribution of accurate Gaussian distribution

Gaussian distribution is that the common beam cross section width of cloth is penetrated the more approaching distribution of power density distribution, also is to be easier to the approximate distribution that realizes.If ccd detector adjacent picture elements center distance is W (pixel at interval).If it is Gaussian distribution that the width of cloth on the receiving plane is penetrated the power line density

E _l(x _c，x)＝E _lmexp(-(x-x _c) ²/(2σ ²))(1)

X in the formula _cBe the beam center coordinate, σ is a distribution standard deviation. half maximum value half width is approximately σ (the half value half width equals 1.177 σ), and therefore available σ or relative value σ/W characterize width of light beam feature on the ccd detector receiving plane.

Centre coordinate for ccd detector is x _jJ pixel (pixel is W=x at interval _j-x _J-1), the simulating signal V of pixel transmission _j(x _j, x _c) be proportional to the radiation energy on the pixel, promptly be proportional to the width of cloth and penetrate power line density E _lIntegration to location variable x in sampling time dt and the effective pixel width of x direction

$V_j=V_j(x_j,x_c)=S\&Integral;\left({\&Integral;}_{x_{1j}}^{x_{\mathrm{rj}}}{E}_l(x_c,x)\mathrm{dx}\right)\mathrm{dt}---\left(2\right)$

X in the formula ₁, x _rBe the coordinate on border, the pixel left and right sides, pixel effective width (x _Rj-x _1j) be slightly less than W.Coefficient S is the opto-electronic conversion factor. the digital signal output V of j pixel _DjIt is the pairing value of bigit of Nbit.V _DjThe pairing value note in position, end " 1 " is made LSB.Other respective amount is a unit with LSB also.

$V_{\mathrm{Dj}}=\mathrm{int}\left(\frac{V_j\left(x_c\right)}{V_{\mathrm{LSB}}}\right)---\left(3\right)$

For certain width parameters σ, the output of an only limited adjacent picture elements is non-vanishing.As beam center x _cWhen changing continuously, the output V of limited adjacent picture elements _DjCan only get discrete round values, V _DjSubstantially be proportional to the radiation energy that receives.

V _Dj-ε _j＝A _mexp(-(x _j-x _c) ²/(2σ ²))(4)

A in the following formula _mBe proportionality constant, ε _jBe the error that departs from strict Gaussian distribution line style, ε _jConcentrated expression the error effect of beam distribution to the interval factor such as discontinuous of inhomogeneous and non-linear, the round-off error of AD conversion, the energy integral of the departing from of Gaussian distribution, ccd detector responsiveness. taken the logarithm and can get in the following formula both sides

$\ln (V_{\mathrm{Dj}}-{\mathrm{\&epsiv;}}_j)=\ln A_m-\frac{1}{{2\mathrm{\&sigma;}}^2}{(x_j-x_c)}^2---\left(5\right)$

Centre coordinate x with j pixel _jAnd x _j ²Be independent variable, with y _j=ln (V _Dj) be dependent variable, the regression model that adopts following formula to represent

y _j＝b ₀+b ₁x _j+b ₂x _j ²(6)

Can obtain each coefficient b in principle ₀, b ₁And b ₂, and then can get beam center position x _cValuation

${\hat{x}}_c=-\frac{{\mathrm{<figure-callout\; id="1"\; label="b"\; filenames="C20051001206600181.png"\; state="\{\{state\}\}">b</figure-callout>}}_1}{{2b}_2}---\left(7\right)$

1.2 the accurate Gaussian distribution of truncation

x _cPixel digital signal output V near the interval _DjBe accurate Gaussian distribution.Because the influence of diffraction effect, bias light and interference noise makes some pixel outside this interval export also non-zero, establishing its maximal value is V _N, its representative value is 1LSB.For reducing noise and other interference, choose and be a bit larger tham V the influence of regression result _NTruncation threshold value V _ThOr other higher truncation threshold, only keep V _Dj〉=V _ThThe accurate gaussian distribution data of truncation make regression Calculation.Roughly determining V _DjThe limits of error ± U _VjAfterwards, selected greater than (U _Vj) _Max, less than 2 ^NA certain integer between/20 is made truncation threshold value V _Th

1.3 weighted regression is to reduce to have the error component influence of randomness

| ε _j|＜V _DjThe time (5) formula left side can be rewritten as

$\ln (V_{\mathrm{Dj}}-{\mathrm{\&epsiv;}}_j)=\ln \left(V_{\mathrm{Dj}}(1-\frac{{\mathrm{\&epsiv;}}_j}{V_{\mathrm{Dj}}})\right)=\ln V_{\mathrm{Dj}}-\frac{{\mathrm{\&epsiv;}}_j}{V_{\mathrm{Dj}}}+\&CenterDot;\&CenterDot;\&CenterDot;---\left(8\right)$

Can find out from following formula: even ε _jStandard deviation be constant, V _DjEtc. precision, dependent variable y _j=ln (V _Dj) the error approximate value be ε _j/ V _Dj, y _iPrecision do not wait V yet _DjHour y _jPrecision is low, V _DjY when big _jThe precision height.Therefore need with following weighted regression method:

If V _DjError be limited to ± U _Vj, dependent variable y _j=ln (V _Dj) relative weight factor be $w_{\mathrm{yj}}={\left(U_{\mathrm{yj}}\right)}^{-2}\&ap;{(V_{\mathrm{Dj}}/{U_V}_j)}^2.$ To equation

(6) can be transformed to the constant item shown in (9) formula be " waiting power " regression problem of zero to the weighted regression of formula

${\hat{y}}_j^{*}=b_0{x}_{0j}^{*}+b_1{x}_{1j}^{*}+b_2{x}_{2j}^{*}---\left(9\right)$

Dependent variable and independent variable are respectively during recurrence

$\left\{\begin{array}{c}{y_j}^{*}=\sqrt{w_{y_j}}{y}_j=\ln \left(V_{\mathrm{Dj}}\right)V_j/U_{V_{\mathrm{Dj}}}\\ {x_{0j}}^{*}=\sqrt{w_{y_j}}=V_{\mathrm{Dj}}/U_{V_j};{x_{1j}}^{*}=x_j\sqrt{w_{y_j}};{x_{2j}}^{*}={x_j}^2\sqrt{w_{y_j}}\end{array}\right.---\left(10\right)$

The valuation of beam center position still uses (7) formula to calculate, promptly ${\hat{x}}_c=-{\mathrm{<figure-callout\; id="1"\; label="b"\; filenames="C20051001206600181.png"\; state="\{\{state\}\}">b</figure-callout>}}_1/\left(2b_2\right).$

Estimate V according to ccd detector and dependent circuit characteristics, output bit number N, noise amplitude etc. _DjUsefulness $\&PlusMinus;U_{V_j}=\&PlusMinus;(a+c\%V_{\mathrm{Dj}})$ The limits of error that form is represented, a is positive constant here, c% is the direct proportion coefficient, U during bit number N=8 _VjRepresentative value is taken as (1.5+1.5%V _Dj).

1.4 make the width of light beam scope with Monte Carlo method numerical simulation error profile

A). Gaussian distribution hypothesis lower integral is asked the relative output of each pixel

When pixel interval W is known, for beam center coordinate x _c, according to Gaussian distribution (1) formula that the width of cloth is penetrated the power line density, calculating centre coordinate at the value lower integral of a certain distribution standard deviation σ is x _jThe simulating signal V of j pixel _j=V _j(x _j, x _c), as the preceding photoelectric measurement signal initial value of analog to digital conversion (ADC); V _jBe relative value, choose fixing proportionality constant during with (2) formula integration and make V _jPeak value be about 0.8 * 2 ^N

B). be limited to according to error $\&PlusMinus;U_{V_j}=\&PlusMinus;(a+c\%V_j)$ One group of stochastic error of rule numerical simulation distribute ${\mathrm{\&epsiv;}}_{V_j}=r_{\mathrm{aj}}+r_{\mathrm{cj}}\%V_j,$ Here r _AjAnd r _CjBe respectively error be limited to ± a and ± uniform random number of c; Get (V _j+ ε _Vj) the digital signal output V of integral part after as ADC _Dj

C). adopt from (2 ^N* c%+a) to 2 ^NA certain integer between/20 is made truncation threshold value V _Th, intercepting V _Dj〉=V _ThThe significant figure signal.

D). to equation $y_j=\ln \left(V_{\mathrm{Dj}}\right)=b_0+b_1{x}_j+b_2{\mathrm{<figure-callout\; id="2"\; label="x\; j"\; filenames="C20051001206600181.png"\; state="\{\{state\}\}">x</figure-callout>}}_j^{}$ As weight factor be $w_{y_j}={(V_{\mathrm{Dj}}/U_{V_j})}^2$ Weighted regression, obtain ${\hat{x}}_c=-{\mathrm{<figure-callout\; id="1"\; label="b"\; filenames="C20051001206600181.png"\; state="\{\{state\}\}">b</figure-callout>}}_1/\left({2b}_2\right),$ And calculate error ${\mathrm{\&epsiv;}}_{\mathrm{xc}}={\hat{x}}_c-x_c$ Come.

E). the simulation error distribution of many groups of identical rules is calculated the error ε of each group respectively _Xc, and then the standard deviation s that calculates error _Xc, the beam center position x that this is promptly corresponding with the beam distribution standard deviation sigma _cMeasurement standard poor.

F). different σ values is repeated above-mentioned A calculate corresponding standard deviation s to the step of E _Xc, draw s _XcRelation curve between/W and the σ/W, and then find out and make s _Xc/ W is not more than the span of beam distribution parameter σ/W of 0.08.A large amount of calculating shows: x _cValue to s _XcThe influence of the relation curve between/W and the σ/W is very little.

Typical consequence with the Monte Carlo method numerical evaluation has: for the line array CCD detector of 8bit, be limited to zero even suppose measuring error, only consider the influence of analog-to-digital randomness round-off error, the truncation gaussian distribution data is done power recurrence such as least square method, when σ/W=1.8, can get the error that round-off error causes and be limited to 0.06W; During σ/W=1.8 the truncation gaussian distribution data is made weight factor w _Yj∝ V _Dj ²Weighted least-squares method return, can get the error that round-off error causes and be limited to 0.006W, reduce an order of magnitude than recurrence such as the power of grade.

Another advantage of weighted regression is, to the continuous V that participates in returning _DjThe truncation threshold value choose insensitive.

Table 1CCD pixel sequence number and output signal measured value tables of data

Pixel sequence number j	501	502	503	504	505	506	507	508	509	510
											V Dj	12	37	87	152	200	193	137	70	27	6

For example for the data shown in the table 1, first row of table 1 is the pixel sequence number, and second row is 10 measured value V that typically contain error _DjHandling if distributed data is done different truncation, comprise pixel number after the 504th～507 these 4 pixels, the truncation and be no less than 6 possible truncation mode and have 8 kinds (degree of freedom is respectively 6～3), is 7 former array together with degree of freedom, has 9 kinds.These 9 kinds different data truncation results are made weighted regression, can get

Mean value be 505.366.9 results' standard deviation only is 0.0035, and visible different truncation threshold value is very little to result's influence.Even degree of freedom only is 3, also influence is little.In the actual measurement, the influence of diffraction, scattering and other noise and error component will make some should be output as zero pixel output non-zero.Insensitive permission improves the truncation threshold value to weighted regression to the truncation mode, has created condition for cutting down noise effect.To the line array CCD detector of 8bit output, adopt ${\left(V_{D_j}\right)}_{\max }\&ap;200\mathrm{LSBs}$ And truncation threshold value V _Th(typical data of getting when the threshold value here is calculating is got the more threshold value V of insurance to=4 value _Th=6 also can calculate to such an extent that similarly the result is next) and $U_{V_{\mathrm{Aj}}}=1.5\mathrm{LSBs}+1.5\%V_{\mathrm{Dj}}$ The error profile model, to the situation of radiation power line density Gaussian distribution, calculated s with Monte Carlo method _XcCorresponding relation between/W and the σ/W. 0.005＜s when 0.7≤σ/W≤18 _Xc/ W＜0.045, and s _XcBecome approximate linear relation between/W and the σ/W.Make s _XcThe span that/W is not more than beam distribution parameter σ/W of 0.08 is about 0.7～25.

With ccd detector pixel sum N _p≈ 7400 and pixel be the device of W=4.7 μ m at interval, make ccd detector surface width parameters σ/W ≈ 2.5～5 o'clock (corresponding truncation threshold value is 4, peak value be 200 o'clock truncation after full duration be about that 14W～28W), a large amount of measured datas show: the standard deviation to same beam center position duplicate measurements is not more than 0.04W; To the grouping duplicate measurements, the inferior time interval of adjacent survey is 0.5ms～100ms in every group, the standard deviation of every cell mean is not more than 0.02W, maximum deviation between each cell mean also is not more than 0.02W, thereby proved that effective resolution of the present invention can reach 0.02W, promptly pixel at interval 1/50

Make s _Xc/ W is not more than 0.08 beam distribution parameter and examines/and the span of W is bigger, and the error during actual measurement is usually little than the limits of error that estimates.The middle body of accurate Gaussian distribution is rendered as substantially and changes little flat-head type when σ/W is big.Be not less than threshold value V after the actual truncation of choosing _ThThe significant figure output signal V of pixel _DjNumber, promptly the effective pixel number in the width of light beam is between 5～50.

Two, measure the method for tilting mirror corner

Fig. 1 is an apparatus structure synoptic diagram of measuring the tilting mirror corner according to method of the present invention.This device comprises light source 3, slit 4, first convex lens 1, tilting mirror 5, second convex lens 2 and ccd detector 6; With focal length is 10mm≤f ₁First convex lens, 1 feasible slit 4 Q below the tested tilting mirror 5 of diagram that is illuminated by light source 3 of '≤50mm ₁Point place forms the reduced and width adjusting of equivalent width slit real image easily, and the light that this real image sends is through tilting mirror 5 reflection backs, the process focal length is 50mm≤f again ₂Second convex lens 2 of '≤300mm are at the surperficial Q of ccd detector 6 ₂The point place forms the accurate Gaussian distribution hot spot of effective pixel number between 5～50 in the width of light beam;

With ccd detector 6 and signals collecting and computing parts 7 realization truncation processing and weighted regressions, provide beam center position x in real time _cValuation; Utilize the angle of deflection and the ccd detector surface beam center position x of tilting mirror 5 _cSide-play amount (x _c-x _C0) between the first approximation relational expression be (x _c-x _C0)=(k ₂D) sin (2 α) can try to achieve the single order valuation of tilting mirror corner α, k in the formula ₂Be the lateral magnification of lens 2, d is slit real image Q ₁To the distance of tilting mirror rotating shaft O, x _C0Be that tilting mirror corner α=beam center was positioned at ccd detector surface and lens 2 optical axis P in 0 o'clock ₂₀Q ₂₀Intersection point Q ₂₀The beam center coordinate at place.After installing and adjust, measurement mechanism obtains angle of deflection and ccd detector surface beam center position x by fixed degree _cBetween degree of the deciding measured data of relation, and then obtain the modified value data of single order valuation.

The relevant calculation of light path and supplementary notes

If width is w ₀Accurate slit 4 be f to focal length ₁The distance of the object space principal point of ' lens 1 is l ₁The real image center is at Q ₁The equivalent light source slit width at place is w ₁, Q ₁Is l to lens 1 as the distance of square principal point ₁', can get

${\mathrm{<figure-callout\; id="1"\; label="w"\; filenames="C20051001206600181.png"\; state="\{\{state\}\}">w</figure-callout>}}_1=w_0\frac{{l^{\&prime;}}_1}{{\mathrm{<figure-callout\; id="1"\; label="l"\; filenames="C20051001206600181.png"\; state="\{\{state\}\}">l</figure-callout>}}_1}=w_0\frac{1}{l_1}{(\frac{1}{{f^{\&prime;}}_1}-\frac{1}{l_1})}^{-1}=w_0\frac{1}{({\mathrm{<figure-callout\; id="1"\; label="l"\; filenames="C20051001206600181.png"\; state="\{\{state\}\}">l</figure-callout>}}_1/{{\mathrm{<figure-callout\; id="1"\; label="f"\; filenames="C20051001206600181.png"\; state="\{\{state\}\}">f</figure-callout>}}_1}^{\&prime;})-1}---\left(11\right)$

If the optical axis of lens 1 is through the rotating shaft O point of plane tilting mirror 5, the optical axis of lens 2 also passes through the O point.In the tilting mirror reference position, lens 1 and 2 optical axis are with respect to the normal symmetry of plane tilting mirror 5.Q ₁With virtual image P in its level crossing ₂₀Symmetrical plane be minute surface.If line segment OQ ₁With OP ₂₀Length be d.When tilting mirror turns over low-angle α, establish new virtual image mid point at P ₂The place, line O P ₂With O P ₂₀Between angle be 2 α.P ₂Vertical range to optical axis is dsin (2 α).Virtual image mid point P ₂Be imaged on Q on the ccd detector surface through lens 2 ₂Point, Q ₂Distance (x to optical axis _c-x _C0) be

$x_{\mathrm{\&alpha;}}=x_c-x_{c0}=l_{Q_{2\mathrm{<figure-callout\; id="2"\; label="x\; Q"\; filenames="C20051001206600181.png"\; state="\{\{state\}\}">x</figure-callout>}}{Q}_{}{}_2}=k_2\left(d\tan 2\mathrm{\&alpha;}\right)---\left(15\right)$

K in the formula ₂It is the lateral magnification of lens 2.Only consider the standard deviation s that ccd detector is surveyed truncation Gaussian distribution beam center _XcThe time, system is to the measurement standard difference s of corner α _αThe approximate s that is proportional to _Xc, be inversely proportional to d and k ₂, s _α≈ s _Xc/ (2dk ₂).

Three, the line array CCD photoelectric measurement method of the dynamic deflection angle of impact galvanometer tilting mirror of Shi Xianing

Adopt device as described in Figure 1, ballistic galvanometer main frame and described device are installed on the same rigid plate that is added with earthquake counter measure, the tilting mirror 5 among Fig. 1 is exactly the tilting mirror of ballistic galvanometer, and the surperficial hot spot of ccd detector 6 is accurate Gaussian distribution; 1) be 10mm≤f with focal length ₁First convex lens (1) of '≤50mm make slit (4) that light source (3) illuminates form the reduced and width adjusting of equivalent width slit real image easily, and the light that this slit real image sends is 50mm≤f through focal length after ballistic galvanometer tilting mirror (5) reflection again ₂Second convex lens (2) of '≤300mm form accurate Gaussian distribution hot spot on ccd detector (6) surface; Ballistic galvanometer and described parts are fixed on the same rigid plate that is added with earthquake counter measure;

2) select pixel sum N for use _p〉=7400, the line array CCD detector of pixel spacing W=4.7 μ m, signal output bit number N=8, V _DjLimits of error formula $\&PlusMinus;U_{V_j}\&ap;\&PlusMinus;(1.5+1.5\%V_{\mathrm{Dj}})$ Truncation threshold value V is chosen in expression _Th=6LSBs;

3) regulate lateral magnification k and slit real image Q ₁To tilting mirror rotating shaft O order apart from d, make ccd detector effective width N _pThe impact quantity of electric charge that W and ballistic galvanometer need be surveyed or the range of electric current are corresponding; Regulate the distance of slit (4) simultaneously, make the interior effective pixel number of ccd detector surface light beam width between 10～30 to first lens (1);

4) regulate the brightness of light source (3) or the circuit gain in signals collecting and the computing parts (7), make the digital signal maximal value (V of pixel after the truncation _Dj) _Max≈ 200LSB, the dependent variable y when the truncation rear weight returns _j=ln (V _Dj) weight factor use $w_{y_j}={(V_{\mathrm{Dj}}/U_{V_j})}^2$ Formula is calculated, and calculates beam center position x _cValuation after so that the dynamic deflection angle of calculating the galvanometer tilting mirror come.

Ballistic galvanometer adopts the AC43 type among the embodiment, selects pixel sum N for use _pThe line array CCD detector of ≈ 7400, pixel spacing W=4.7 μ m, signal output bit number N=8, V _DjLimits of error formula $U_{V_j}\&ap;1.5+1.5\%V_{\mathrm{Dj}}$ Expression, the truncation threshold value V that chooses _Th=6LSBs.Regulate lateral magnification k ₂With slit real image Q ₁To tilting mirror rotating shaft O order apart from d, make ccd detector effective width N _pW is roughly corresponding with the range of the impact quantity of electric charge (or electric current) that ballistic galvanometer need be surveyed; Regulate the distance of slit 4 simultaneously, make the interior effective pixel number of ccd detector surface light beam width between 8～18 to lens 1; Regulate to adopt the brightness of light source of light emitting diode or the circuit gain in signals collecting and the computing parts to make the digital signal maximal value (V of pixel after the truncation _Dj) _Max≈ 200LSB, dependent variable y during the censored data weighted regression _j=ln (V _Dj) weight factor use $w_{y_j}={(V_{\mathrm{Dj}}/U_{V_j})}^2$ Formula is calculated, and calculates beam center position x _cValuation after so that the dynamic amount of deflection of calculating the galvanometer tilting mirror come.

Light path design adopts parameter to be: tilting mirror rotating shaft O is to the spacing L=560mm on ccd detector surface, the focal distance f of second convex lens 2 ₂'=150mm, slit real image Q ₁Focal distance f to tilting mirror rotating shaft O apart from d=110mm, first convex lens 1 ₁'=35mm.Calculate the lateral magnification k of second convex lens 2 ₂=1.96, x under the low-angle _α≈ 216tan (2 α), unit is mm.The pairing corner of pixel spacing IW=4.7 μ m is 0.01mrad.Do not pursue the minimal value of theoretical resolution during parameter selection, main consider it is influence for uncertain systematic error components such as the response characteristic that makes each pixel are inhomogeneous, non-linear in the overall measurement useful signal fully " randomization ", also for make the device compactness, easy to adjust, take into account measurement range.The effective resolution of traditional ballistic galvanometer tilting mirror deflection angle is $\frac{0.2\mathrm{<figure-callout\; id="2"\; label="mm"\; filenames="C20051001206600181.png"\; state="\{\{state\}\}">mm</figure-callout>}}{2\&times;1000\mathrm{mm}}\&ap;1\&times;{10}^{-4}\mathrm{rad}=0.1\mathrm{mrad}.$

Adopt the device of the inventive method, work as s _xCan to reach the former AC4/3 type of about 0.001mrad ballistic galvanometer electric current scale division value when light source scale spacing is 1.3m be 8 * 10 to the effective resolution of corner during ≈ 0.1W～0.47 μ m ^-10A/mm.Adopt the electric current " scale division value " of the single pixel correspondence of new measuring system of line array CCD detector to reach 24pA, the standard deviation of measuring little electric current has reached s _I≈ 4pA.For between 200～60000pA by the micrometer electric current, the part measurement data is as shown in table 2.Beam center deflection reading x on the ccd detector _αBecome proportional relation preferably with electric current I, ${\hat{I}}_i=b_1{x}_{\mathrm{\&alpha;i}},$ The electric current residual error v of fitting a straight line gained _Ii=I _i-b ₁x _{α i}Absolute value | v _Ii|≤3.6pA+0.25%I _iConventional ballistic galvanometer effective resolution only is about 0.1% of range, the about 0.1mrad of corner resolution, and in the present embodiment, the pairing corner standard deviation of 3.6pA can be reduced to below the 0.002mrad.Compare with the rod reading device of original AC4/3 type ballistic galvanometer, the precision of the current measurement of embodiment and corner resolution have all improved two orders of magnitude.

Table 2 is measured the measurement data of ballistic galvanometer deflection angle with line array CCD

Electric current I/pA	232.4	473.2	940.8	1877.9	3766.9	7515.3	14914.3	60561.2
									Deflection x α/W	9.64	19.66	39.45	78.26	157.41	314.55	623.48	2541.62
Residual error (x α-41.86081)/W	-0.09	-0.15	0.07	-0.35	-0.28	-0.04	-0.85	6.48

Four, realize the method for displacement or linear measure longimetry

1) utilize signals collecting and computing parts, ccd detector and optical module to realize measuring, described ccd detector adopts pixel sum N _p〉=5000 and the pixel line array CCD detector of W≤7 μ m at interval; Described optical module is made up of semiconductor laser and lens, and it is with a tight waist that the quasi-parallel semiconductor laser beam forms accurate Gaussian distribution through lens on the ccd detector surface; Described optical module or form by light emitting diode, slit or aperture, lens, lens will converge at the ccd detector surface through the light of slit or aperture;

2) the effective pixel number of light beam in ccd detector surface light beam width of described optical module institute outgoing is between 10～30, but ccd detector and optical module are installed in respectively on the movable member of stationary parts and moving linearly, the orientation of ccd detector pixel is parallel with movable member direction of motion, in when, between beam axis or spot center position and the ccd detector relative displacement taking place when, weighted regression result's value

Change thereupon,, realize displacement or measurement of length with direct reflection displacement or position change.

Among the embodiment, adopt pixel sum N _p≈ 7400 and pixel be the line array CCD detector of W=4.7 μ m at interval; What adopt is LED source is converged at the ccd detector surface by lens through the principal maximum segment beam of slit diffraction method.

A kind of displacement measuring device experiment of implementing, optical module maintains static, and ccd detector is installed on the translation platform of Abbe comparator.During the ccd detector translation, the reading value of Abbe comparator, beam center position are that the regressand value of unit, the residual values that measurement point departs from regression straight line etc. are listed in the table 3 respectively with pixel interval W.The residual error standard deviation of the data of 19 groups of continuous coverage positions is 0.67 μ m.The uncertainty of Abbe comparator is 1.5 μ m.Every group of mean value that the ccd detector measured value is 20 scanning measured values of ccd detector on the same position in the table 3, the standard deviation of every cell mean all is not more than 0.02W.

Table 3 is surveyed the data of Abbe comparator worktable displacement with line array CCD

Comparator reading value/mm	3.0000	4.0000	5.0000	6.0000	8.0000	10.0000	12.0000	14.0000	16.0000	18.0000
											CCD measured value/W	714.95	927.45	1139.83	1352.09	1776.69	2201.52	2626.01	3050.46	3475.02	3899.90
Residual error/the mm of off-straight	0.0010	0.0001	-0.0003	-0.0001	-0.0001	-0.0011	-0.0006	0.0002	0.0004	-0.0009
											Comparator reading value/mm	20.0000	22.0000	24.0000	26.0000	28.0000	30.0000	31.0000	32.0000	33.0000
CCD measured value/W	4324.35	4748.81	5173.30	5598.01	6022.55	6447.33	6659.72	6872.16	7084.44
											Residual error/the mm of off-straight	-0.0001	0.0005	0.0011	0.0007	0.0010	0.0001	-0.0003	-0.0009	-0.0008

Show according to analysis, the standard deviation of the reading error of indication of Abbe comparator itself is about 0.6 μ m, the error synthesis of it and apparatus of the present invention together, standard deviation has been not more than 0.7 μ m, and this has illustrated that the inventive method non-linear relative standard deviation in the measurement range of 30mm is not more than $\frac{0.67\&times;0.001}{30}\&ap;2.3\&times;{10}^{-5}.$

Second kind of displacement measuring device realizing tested, and the ccd detector box is fixed in by the elastic deformation principle makes on little actuating platform continuous 22 groups of little actuating platform drum reading z and ccd detector beam center position x _cMeasured value List in the table 4.Fitting a straight line is ${\hat{x}}_c=b_0+b_{1}z,$ The dependent variable standard deviation $s_{x_c}\&ap;0.039W~0.18\mathrm{\&mu;m},$ Maximum non-linear residual error is 0.45 μ m, and standard deviation here and residual error have also comprised the influence (this error effect is not seen calibrating and reference statement) of the nonlinearity erron between little actuating playscript with stage directions body displacement and the drum reading.Data in the table 4 show: to being not less than the tested displacement of pixel quasi-continuous variation at interval, non-linear standard deviation has been not more than 0.20 μ m.

Table 4 activates the data of platform displacement with the line array CCD micrometer

Measure sequence number	1	2	3	4	5	6	7	8	9	10	11
												Little actuating platform reading z/ lattice	2	4	6	8	10.2	12	14	16	19.2	22	24.2
Beam center position x c/W	7.095	7.179	7.191	7.203	7.226	7.308	7.307	7.357	7.514	7.504	7.645

Beam center position x c/μm	33.35	33.74	33.80	33.85	33.96	34.35	34.34	34.58	35.32	35.27	35.93
												Residual error/μ m	0.12	0.30	0.13	-0.04	-0.17	0.01	-0.22	-0.20	0.18	-0.18	0.24
Measure sequence number	12	13	14	15	16	17	18	19	20	21	22
												Little actuating platform reading z/ lattice	26	28.2	30.2	32.2	34	36	38	40	42	44	46
Beam center position x c/W	7.619	7.675	7.64	7.803	7.802	7.887	7.918	7.968	8.045	8.103	8.124
												Beam center position x c/μm	35.81	36.07	35.91	36.67	36.67	37.07	37.21	37.45	37.81	38.08	38.18
Residual error/μ m	-0.08	-0.06	-0.45	0.09	-0.11	0.06	-0.01	0.00	0.14	0.19	0.07

Five, realize the measuring method of 0～360 degree angle

Fig. 2 is the synoptic diagram of the primary structure of the angle measurement method of measurement 0～360 degree.Diameter is not less than the quasi-parallel semiconductor laser beam of 3mm by arbitrary direct reflection of the positive n face of rotatable metal body 8, and when n=24 wherein, a face of positive 24 bodies rotated ± 180 °/n=± 7.5 °, folded light beam turned over ± and 15 °.Folded light beam is not less than through the angle, effective aperture ± and 15 ° lens 9 converge in pixel sum N _p≈ 7400 and pixel be the surface of the line array CCD detector 6 of W=4.7 μ m at interval, and the focal length of lens 9 is

Make objective lens optical axis perpendicular to the ccd detector surface; Focusing makes effective pixel number in the accurate Gaussian distribution width of light beam that the ccd detector surface converges between 8～18, adopts truncation processing and weighted regression to obtain the valuation of beam center coordinate xc to the digital signal output of ccd detector pixel.The position angle φ of positive 24 bodies 8 is by mirror surface sequence number i and beam center coordinate x _cValuation

Determine, $\mathrm{\&phi;}=15i+\arctan$ $\left(\frac{{\hat{x}}_c-x_{c0}}{{f_3}^{\&prime;}}\right)$ $+\mathrm{\&epsiv;}$ $({\hat{x}}_c,i)+{\mathrm{\&phi;}}_0,$ X in the formula _C0Be the optical axis of lens 9 and the coordinate of ccd detector surface intersection point, φ ₀Be the constant item, Be to come definite angle modification item, φ by fixed degree ₀And ε (x _c, i) be fixed among the calculation procedure.The position angle φ of positive 24 bodies 8 is directly exported or shown to signals collecting and computing parts.

It is that 120mm, grade of errors are 2 that metal adopts nominal diameters apart from 24 bodies " approved product.The actual lens of selecting for use 9 are relative aperture f ₃'/D=1.4, focal distance f ₃The photographic field lens of '=50mm.

Six, the method for the measurement wire visible spectrum wavelength of Shi Xianing

1) make the quasi-parallel light beam of the different wave length that every millimeter grating dispersion element that is no less than 1200 lines sends be not less than the lens or concave mirror of 150mm through a focal length with different diffraction angle after, image in the line array CCD detector surface, described ccd detector pixel sum N _p〉=5000 and pixel W≤7 μ m at interval;

2) focusing makes effective pixel number in ccd detector surface light beam width between 5～15 to described lens or concave mirror;

3) by digital signal output truncation processing and weighted regression, calculate wire spectral line λ to be measured to the ccd detector pixel _xThe coordinate valuation at center Again simultaneously or alternately measure some the known wavelength λ that wavelength is positioned near the He-Ne discharge tube the spectral line to be measured _iThe valuation of reference spectral line centre coordinate Obtain local linear dispersion equation with least square line match or quadratic regression ${\hat{x}}_{\mathrm{ci}}=f\left({\mathrm{\&lambda;}}_i\right),$ At last will The substitution dispersion equation is obtained unknown spectral line wavelength X _xCome.

In an embodiment, grating is every millimeter 1200 line, and the quasi-parallel light beam is that the object lens of 150mm image in the line array CCD detector surface through a focal length, ccd detector pixel sum N _p≈ 7400 and pixel be W=4.7 μ m at interval.Focusing makes the ccd detector surface form the spectral line of the accurate Gaussian distribution of effective pixel number between 5～10 in the width of light beam to object lens; Measure two the wavelength difference of blue light 483nm in H and the D spectrum at a distance of the spectral line of about 0.13nm with this method, make the interior effective pixel number of ccd detector surface light beam width between 5～10, the spectrometer order of diffraction of existing band CCD is inferior to be fixed as 1, the pairing position resolution of effective resolution is generally 1W, implement to measure that example selects that the order of diffraction of blue light time is 3, incident angle is greater than 75 degree, be the about 0.100mm of blue light spectral line center distance that observes H and D on the focal plane of lens of 150mm with micrometer eyepiece at focal length, be about 20W.Because the effective resolution of line array CCD of the present invention is can reach below the 0.03W usefulness, the effective resolution that wavelength difference is measured improves about two orders of magnitude.The relative standard deviation who adopts truncation processing and weighted regression that the blue light spectral line wavelength difference of H and D is measured is not more than 0.3%.

To line wavelength λ to be measured _xWhen measuring, accurately known spectral line of nearly 60 wavelength is arranged in the side spectrum of the He-Ne discharge tube of glow discharge.Select near 5～7 known wavelength λ of spectral line to be measured _iSpectral line measure.Ask local linear dispersion equation with fitting a straight line or quadratic regression, mainly according to the standard deviation size of the different model dependent variables in match (recurrence) back, the obvious little model of general selection standard difference; If the standard deviation of two kinds of models is more or less the same, then should select straight line model for use.General grating spectrograph realizes that by the repeatability of mechanical system the accuracy of wavelength measurement is about 0.2nm.Because the wavelength uncertainty with reference to spectral line in the present embodiment is generally less than 0.005nm, this method is a kind of method that compares and measures in essence, so can realize the accuracy of measurement of higher line-spectra wavelength.

Claims (7)

1. method with line array CCD measuring beam center is characterized in that:

1) makes the width of cloth of the hot spot battle array along the line direction on ccd detector surface penetrate the power line density and be Gaussian distribution or accurate Gaussian distribution;

2) obtain the truncation threshold value: establishing j centre coordinate of ccd detector is x _jThe digital signal of pixel be output as V _Dj, described V _DjIntegral multiple for LSB; According to ccd detector and dependent circuit characteristics, output bit number N and noise amplitude, use formula $\&PlusMinus;U_{V_j}=\&PlusMinus;(a+c\%V_j)$ Express V _DjThe limits of error, a is positive constant in the formula, c% is following scale-up factor; With (a+c% * 2 ^N) to 2 ^NA certain integer between/20 is made truncation threshold value V _Th, be not less than threshold value V after making truncation _ThThe significant figure output signal V of pixel _DjBe the accurate Gaussian distribution of truncation;

3) be x to centre coordinate _jThe significant figure signal output V of the accurate Gaussian distribution of truncation of pixel _Dj, adopt the regression equation model $y_j=b_0+b_1{x}_j+b_2{x}_j^2$ , respectively with x _jAnd x _j ²For independent variable, with y _j=ln (V _Dj) be dependent variable, as weight factor be $w_{\mathrm{yj}}={(V_{\mathrm{Dj}}/U_{v_j})}^2$ Weighted regression ask b ₁And b ₂, calculate the beam center location estimate again ${\hat{x}}_c=-b_1/\left({2b}_2\right)$ ;

4) make the width of light beam scope with Monte Carlo method numerical simulation error profile, its concrete steps are:

A). when pixel interval W is known, for beam center position x _c, penetrate the Gaussian distribution E of power line density by the width of cloth _l(x _c, x)=E _LmExp ((x-x _c) ²/ (2 σ ²)), under the value of a certain distribution standard deviation σ, to fixed sampling time at interval and the location variable x integration in the pixel to calculate centre coordinate be x _jThe simulating signal V of j pixel _j=V _j(x _j, x _c), as the photoelectric measurement signal initial value before the analog to digital conversion; V _jBe relative value, choose proportionality constant during integration and make V _jPeak value be 0.8 * 2 ^N

B). be limited to according to error $\&PlusMinus;U_{V_j}\&PlusMinus;(a+c\%V_j)$ One group of stochastic error of rule numerical simulation distribute ${\mathrm{\&epsiv;}}_{V_j}=r_{\mathrm{aj}}+r_{\mathrm{cj}}\%V_j$ , this is r early _AjAnd r _CjBe respectively error be limited to ± a and ± uniform random number of c; Get (V _j+ ε _Vj) the digital signal output V of integral part after as analog to digital conversion _Dj

C). intercepting V _Dj〉=V _ThThe significant figure signal;

D). to equation $y_j=1n\left(V_{\mathrm{Dj}}\right)=b_0+b_1{x}_j+b_2{x}_j^2$ As weight factor be $w_{\mathrm{yj}}={(V_{\mathrm{Dj}}/U_{v_j})}^2$ Weighted regression, obtain ${\hat{x}}_c=-b_1/\left(2b_2\right),$ And calculate error ${\mathrm{\&epsiv;}}_{\mathrm{xc}}={\hat{x}}_c-x_c$ Come;

E). the simulation error distribution of many groups of identical rules is calculated the error ε of each group respectively _Xc, and then the standard deviation s that calculates error _Xc, this promptly marks the corresponding beam center position x of difference σ with beam distribution _cMeasurement standard poor;

F). different σ values is repeated above-mentioned A calculate corresponding standard deviation s to the step of E _Xc, draw s _XcRelation curve between/W and the σ/W, and then find out and make s _Xc/ W is not more than the span of beam distribution parameter σ/W of 0.08.

2. it is characterized in that in accordance with the method for claim 1: be not less than threshold value V after the truncation _ThThe significant figure output signal V of pixel _DjNumber, promptly the effective pixel number in the width of light beam is between 5～50.

3. a method of using the described method of claim 1 to measure the tilting mirror corner is characterized in that this method comprises the steps:

1) be 10mm≤f with focal length ₁First convex lens (1) of '≤50mm make slit (4) that light source (3) illuminates form the reduced and width adjusting of equivalent width slit real image easily, and the light that this slit real image sends is 50mm≤f through focal length after tilting mirror (5) reflection again ₂Second convex lens (2) of '≤300mm, the hot spot of effective pixel number between 5～50 in ccd detector (6) surface formation width of light beam;

2) utilize ccd detector (6), signals collecting and computing parts (7), according to step 2 in the claim 1) and 3) method, to the accurate Gaussian distribution output signal of truncation V _DjWeighted regression provides beam center position x in real time _cValuation;

3) utilize the angle of deflection of tilting mirror (5) and ccd detector surface beam center position x _cSide-play amount (x _c-x _C0) between the first approximation relational expression: (x _c-x _C0)=(κ ₂D) sin (2 α) can try to achieve the single order valuation of tilting mirror corner α, κ in the formula ₂Be the lateral magnification of second convex lens, d is slit real image Q ₁To the distance of tilting mirror rotating shaft O, x _C0Be that tilting mirror corner α=0 o'clock beam center is positioned at the coordinate at the intersection point place of the ccd detector surface and the second convex lens optical axis; After installing and adjust, measurement mechanism obtains angle of deflection and ccd detector surface beam center position x by fixed degree _cBetween degree of the deciding measured data of relation, and then obtain Value Data under the repairing of single order valuation.

4. a method of using claim 1 or 3 described methods to measure the dynamic deflection angle of tilting mirror of ballistic galvanometer is characterized in that this method comprises the steps:

1) be 10mm≤f with focal length ₁First convex lens (1) of '≤50mm, make slit (4) that light source (3) illuminates form the reduced and width adjusting of equivalent width slit real image easily, the light that this slit real image sends is 50mm≤f through focal length after tilting mirror (5) reflection of ballistic galvanometer again ₂Second convex lens (2) of '≤300mm form accurate Gaussian distribution hot spot on ccd detector (6) surface: ballistic galvanometer and described first convex lens, light source, slit, second convex lens and ccd detector are fixed on the same rigid plate that is added with earthquake counter measure;

2) select pixel sum N for use _p〉=7400, the line array CCD detector device of pixel spacing W=4.7 μ m, signal output bit number N=8, V _DjLimits of error formula $\&PlusMinus;U_{V_j}\&ap;\&PlusMinus;(1.5+1.5\%V_{\mathrm{Dj}})$ Truncation threshold value V is chosen in expression _Th=6LSBs;

3) regulate lateral magnification κ and slit real image Q ₁To tilting mirror rotating shaft O order apart from d, make ccd detector effective width N _pThe impact quantity of electric charge that W and ballistic galvanometer need be surveyed or the range of electric current are corresponding; Regulate the distance of slit (4) simultaneously, make the interior effective pixel number of ccd detector surface light beam width between 10～30 to first convex lens (1);

4) regulate the brightness of light source (3) or the circuit gain in signals collecting and the computing parts (7), make the digital signal maximal value (V of pixel after the truncation _Dj) _Max≈ 200LSB, the dependent variable y when the truncation rear weight returns _j=ln (V _Dj) weight factor use $w_{y_j}={(V_{\mathrm{Dj}}/U_{V_j})}^2$ Formula is calculated, and calculates beam center position x _cValuation after so that the dynamic deflection angle of calculating the galvanometer tilting mirror come.

5. method of using the described method of claim 1 that displacement or length are measured, this method comprises the steps:

1) utilize signals collecting and computing parts, ccd detector and optical module to realize measuring, described ccd detector adopts pixel sum N _p〉=5000 and the pixel line array CCD detector of W≤7 μ m at interval; Described optical module is made up of semiconductor laser and lens, and it is with a tight waist that the quasi-parallel semiconductor laser beam forms accurate Gaussian distribution through lens on the ccd detector surface; Described optical module or form by light emitting diode, slit or aperture, lens, lens will converge at the ccd detector surface through the light of slit or aperture;

2) the effective pixel number of light beam in ccd detector surface light beam width of described optical module institute outgoing is between 10～30, but ccd detector and optical module are installed in respectively on the movable member of stationary parts and moving linearly, the orientation of ccd detector pixel is parallel with movable member direction of motion, in when, between beam axis or spot center position and the ccd detector relative displacement taking place when, weighted regression result's value

Change thereupon,, realize displacement or measurement of length with direct reflection displacement or position change.

6. one kind is used the described method of claim 1 to realize 0～360 angle measurement method of spending, and it is characterized in that:

1) make quasi-parallel semiconductor laser beam that diameter is not less than 3mm by arbitrary direct reflection of the positive n face of rotatable metal body (8), the sequence number of establishing this mirror surface is i, and folded light beam is not less than through the angle, effective aperture ± and the object lens (9) of 360 °/n converge in pixel sum N _p〉=5000 and the pixel surface of the line array CCD detector (6) of W≤7 μ m at interval, described objective focal length is Objective lens optical axis is perpendicular to the ccd detector surface;

2) focusing makes the effective pixel number of light beam in ccd detector surface light beam width between 10～30, adopts truncation processing and weighted regression to obtain beam center coordinate x to the digital signal output of ccd detector pixel _cValuation;

3) the position angle φ of described positive n face body (8) is by mirror surface sequence number i and beam center coordinate x _cValuation

Determine, $\mathrm{\&phi;}=\frac{260}{n}i+\arctan \left(\frac{{\hat{x}}_c-x_{c0}}{f_3^{\&prime;}}\right)\mathrm{\&epsiv;}({\hat{x}}_c,i)+{\mathrm{\&phi;}}_0,$ X in the formula _C0Be the optical axis of lens 9 and the coordinate of ccd detector surface intersection point, φ ₀Be the constant item,

Be the angle modification item of determining by fixed degree, directly export or show the position angle φ of positive n face body (8) by signals collecting and calculating unit.

7. a method of using the measurement wire visible spectrum wavelength of the described method realization of claim 1 is characterized in that this method comprises the steps:

1) make the quasi-parallel light beam of the different wave length that every millimeter grating dispersion element that is no less than 1200 lines sends be not less than the lens or concave mirror of 150mm through a focal length with different diffraction angle after, image in the line array CCD detector surface, described ccd detector pixel sum N _p〉=5000 and pixel W≤7 μ m at interval;

2) focusing makes effective pixel number in ccd detector surface light beam width between 5～15 to described lens or concave mirror;

3) by digital signal output truncation processing and weighted regression to the ccd detector pixel, calculating wavelength is λ _xThe coordinate valuation of wire core to be measured Again simultaneously or alternately measure some the known wavelength λ that wavelength is positioned near the He-Ne discharge tube the spectral line to be measured _iThe valuation of reference spectral line centre coordinate Obtain local linear dispersion equation with least square line match or quadratic regression ${\hat{x}}_{\mathrm{ci}}=f\left({\mathrm{\&lambda;}}_i\right),$ At last will

The substitution dispersion equation is obtained unknown spectral line wavelength X _xCome.

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