CN103115687B - Hartmann sensor is to the detection method of great dynamic range light wave top rake - Google Patents

Abstract

The invention belongs to air adaptive optical technique field, is that a kind of Hartmann sensor that utilizes is to the detection method of great dynamic range light wave top rake.The present invention only uses a Hartmann sensor in the ADAPTIVE OPTICS SYSTEMS of docking with telescope, angle of inclination before several calibration cycle incident light waves of system starts exceedes the dynamic range of Hartmann sensor, therefore small light spot array Hartmann collected regards a large spot as, the center-of-mass coordinate and the side-play amount thereof that calculate large spot draw the integral inclined of wavefront, by this data feedback to galvanometer to correct the inclination of wavefront, so repeat this process 5 ~ 10 times, within the integral inclined dynamic range being reduced to Hartmann sensor that can make wavefront, now system control program will provide " order " recover Hartmann sensor probing wave before normal function, ADAPTIVE OPTICS SYSTEMS is run well.The present invention can make the dynamic range expansion at least 15 times of Hartmann sensor, as shown in the figure.<!--1-->

Description

Hartmann sensor is to the detection method of great dynamic range light wave top rake

Technical field

The invention belongs to air adaptive optical technique field, that a kind of Hartmann sensor that utilizes is to the detection method of great dynamic range light wave top rake, significantly can improve the detectivity of Hartmann sensor, save special wavefront tilt sensing device, reduce the energy loss of the ADAPTIVE OPTICS SYSTEMS of docking with telescope.

Background technology

Adaptively correcting system before light wave in air adaptive optical technique field, its function carries out real-Time Compensation correction, to obtain desirable real-time optical imaging to continuous incident telescopical target light distorted wavefront.

The ADAPTIVE OPTICS SYSTEMS of usually docking with telescope completes wavefront correction based on two correctors in thick school and smart school, inclination before the oscillating mirror wherein doing thick school also claims galvanometer only to correct incident light wave, and the high-order distortion after slant correction completes correction by wave-front corrector.Corresponding thick school and these two correctors of smart school need have two wave front detectors: 1) probing wave top rake: general employing CCD is wavefront tilt sensing device, to the target hot spot received, calculate the side-play amount of its barycenter in x-y plane coordinate system, thus resolve wavefront in three-dimensional inclination, the advantage of ccd detector is that the dynamic range of tilt detection is large, and shortcoming is only limited to probing wave top rake, 2) the high-order distortion before probing wave beyond surface thereof: high-order distortion before general employing Hartmann sensor probing wave, Hartmann sensor is made up of microlens array plate and high-sensitive CCD, before incident wavefront is divided into wavelet one by one by microlens array, because lenticule number is abundant, for only having the plane wave front of inclination before wavelet, can degree of tilt be relied on by the small light spot focused on after lenticule on the CCD of back and depart from the center corresponding to normal incidence plane wave, by strictly calculating each small light spot barycenter departure degree in the x and y direction, the vergence direction before each wavelet and degree of tilt can be drawn, before going these wavelets of matching with a set of Zernike mode function again, just can reconstruct tested high-order distorted wavefront.The principle of work of Hartmann sensor has detailed description on [FrancoisRoddier, Adaptiveopticsinastronomy, CambridgeUniversityPress, 1999, Parttwo, pp99].

Consider M × M lenticule microlens array plate with lattice-array arrangement, CCD panel has P × P pixel, corresponding each lenticular subregion has n × n pixel, wherein n=P/M.The parallel beam of normal incidence microlens array plate forms incircle on CCD panel, is uniformly distributed Q the small light spot that microlens array focuses on out in circle, and the region outside circle is without spot area.Generally, the dynamic range of Hartmann sensor is determined by the pixel count on the lenticule number of microlens array, small light spot diameter and CCD panel.Small light spot cannot cover pixels all on subregion, must leave certain leeway, when small light spot edge arrives subzone boundaries, just reaches the maximum measurement range of Hartmann sensor, i.e. dynamic range.

Facula mass center coordinate (c _x, c _y) computation also according to [FrancoisRoddier, Adaptiveopticsinastronomy, CambridgeUniversityPress, 1999, Parttwo, pp99]:

The pixel panel of back CCD sets up rectangular coordinate system, is in units of initial point, pixel usually by the upper left corner, if transverse axis is from left to right x-axis, the longitudinal axis is from top to bottom y-axis, and in spot array, the center-of-mass coordinate of any one small light spot is:

$c_x=\frac{{\&Sigma;}_{i,j}{x}_{i,j}{I}_{i,j}}{{\&Sigma;}_{i,j}{I}_{i,j}},c_y=\frac{{\&Sigma;}_{i,j}{y}_{i,j}{I}_{i,j}}{{\&Sigma;}_{i,j}{I}_{i,j}}---\left(1\right)$

Wherein i, j be CCD pixel coordinate fasten x-axis and y-axis pixel sequence number, be positive integer from 0, x _i,jwith y _i,jbe respectively two coordinate components of (i, j) pixel center point, I _i,jfor the light intensity of (i, j) pixel, range of summation is all pixels on subregion.If the small light spot center-of-mass coordinate corresponding to normal incidence plane wave is (c _x0, c _y0), the inclination before wavelet in x-axis and y-axis is respectively k _x, k _y, then have:

$k_x=\frac{c_x-c_{x0}}{f},k_y=\frac{c_y-c_{y0}}{f}---\left(2\right)$

Wherein f is lenticular focal length.

The advantage of Hartmann sensor is that Wavefront detecting speed is fast, method is simple, but because data reading rate request limited dynamic range can not be too large, namely the subregion on CCD panel is less, when group wavetilt is serious, small light spot can cross limited subregion, and enter the subregion of adjacent small light spot, and the luminous energy in subregion is only considered in order to the centroid calculation of the usual small light spot of high speed data processing, cause small light spot centroid calculation mistake.Therefore, integral inclined before the usual first probing wave of adaptive system, makes the dynamic range of incident light significantly reduce, and then use Hartmann sensor by galvanometer after being corrected, can correct detection wavefront distortion, and is mainly high-order distortion.

In fact, every luminous energy entering detector is all consumed in detector, can not be used for target imaging, and therefore in ADAPTIVE OPTICS SYSTEMS, the loss of detector more luminous energy is larger.

Summary of the invention

In order to eliminate the energy loss of wavefront tilt sensing device, the present invention only uses a Hartmann sensor, not only the integral inclined but also detection high-order distortion before probing wave, for thick, essence two corrector feedback wave front datas, object is to provide the detection method of a kind of Hartmann sensor to great dynamic range light wave top rake, simultaneously simplified self-adaptive optical system structure.

Basic thought of the present invention is: several calibration cycles of starting working in adaptive system, angle of inclination before incident light wave is very large, exceed Hartmann sensor dynamic range and measurement range, now, the small light spot array that Hartmann sensor must be collected regards an an entirety i.e. large spot as, the center-of-mass coordinate of large spot is calculated according to the way of a calculating facula mass center, the integral inclined of wavefront is drawn according to the side-play amount of barycenter, by this data feedback to galvanometer to correct the inclination of wavefront, but not give wave-front corrector feedback data; The incident light come next, its wavetilt can significantly reduce due to the correction of galvanometer, repeats to such high-frequency process above; Because wavefront chattering frequency is far below the emending frequency of galvanometer, incident light after galvanometer corrects for several times, within the integral inclined dynamic range that will be reduced to Hartmann sensor of its wavefront, the inclination of wavefront and high-order distortion can simultaneously by correct detections, now system control program will provide " order " recover Hartmann sensor probing wave before normal procedure, ADAPTIVE OPTICS SYSTEMS is run well.

For a better understanding of the present invention, optical design of the present invention and control procedure are described in detail in detail below.

ADAPTIVE OPTICS SYSTEMS schematic diagram of the present invention is as Fig. 1, wherein 1 is telescopical emergent light focus, 1 ' is Halogen lamp LED pointolite, measure response curve to use when system initialization, 2 is collimation lenses, 3 is galvanometers, and 4 is color separation films, and 5 is polaroids, 6 and 7 is the first contracting bundle lens and the second contracting bundle lens respectively, 8 is Hartmann sensor, and 9 and 10 is the 3rd contracting bundle lens and the 4th contracting bundle lens respectively, and 11 is wave-front correctors, 12 is catoptrons, 13 and 14 composition imaging lens group, 15 is CCD, and 16 is computing machines.Have self-adaptation wavefront correction control program in computing machine 16, and wavetilt emending frequency 5 ~ 10 times is greater than wavefront chattering frequency, computing machine 16 is connected with CCD15 with Hartmann sensor 8, galvanometer 3, wave-front corrector 11; Color separation film 4 is high-pass filtering sheets, make wavelength be greater than the light transmission of 700nm, and the light that wavelength is less than 700nm is reflected; Galvanometer 3 and Hartmann sensor 8 are in the light path of closed-loop control, and the residual tilt that what namely Hartmann sensor 8 detected is after galvanometer 3 corrects, can reduce the demand to Hartmann sensor 8 dynamic range like this; Wave-front corrector 11 and Hartmann sensor 8 are then in open loop light path, because the light only entered before wave-front corrector 11 that Hartmann sensor 8 receives, wavetilt is herein corrected by galvanometer 3 substantially, and the dynamic range required by high-order distortion is that Hartmann sensor 8 can meet; The optical axis of the 4th contracting bundle lens 10 moves 5mm ± 0.2mm vertically upward relative to the optical axis of the 3rd contracting bundle lens 9, light beam is made to incide on wave-front corrector 11 by having a down dip with 1.5 ° of angles after the 4th contracting bundle lens 10, then the light beam reflected from wave-front corrector 11 is separated with incident beam optical axis and again arrives the 4th and contract and restraint lens 10 and focus on, realize being separated with entrance focus, catoptron 12 is set herein, folded light beam focus is made to be positioned on catoptron 12, and by folding bundle 90 °, enter CCD15 imaging by imaging lens group 13 and 14.

Hartmann sensor 8 has M × M lenticule of lattice-array arrangement, the CCD of P × P pixel, and corresponding each lenticular subregion has n × n pixel, wherein n=P/M.The parallel beam of normal incidence microlens array plate forms incircle on CCD panel, and as shown in Figure 2, in circle, black roundlet spot represents Q the small light spot that microlens array focuses on out, and the region outside circle is without spot area.

The back CCD pixel panel of Hartmann sensor 8 sets up rectangular coordinate system, is in units of initial point, pixel by the lower left corner, and transverse axis is from left to right x-axis, and the longitudinal axis is from top to bottom y-axis; Then compose sequence number for the subregion array in CCD pixel panel corresponding to microlens array, represent subregion sequence number in the x and y direction respectively with s and t, the two is all be the positive integer 0 of starting point from 0,1,2,3, M, wherein M is the subregion number in the length of side of lattice-array arrangement; Two pairs of drivers orthogonal on galvanometer 3 are parallel to x-axis and y-axis respectively, and are called A axle and the B axle of galvanometer 3; Using the initial point center-of-mass coordinate (c of the geometric center of every sub regions as Q small light spot _{(s, t) x0}, c _{(s, t) y0}); According to the drive voltage range that galvanometer 3 can apply, A, B two axles of galvanometer 3 all apply the half value of maximum voltage, and the position adjusted after galvanometer 3 response, ensure Hartmann sensor 8 is still Q by the lenticule number that normal incidence light beam covers, now the two pairs of drivers can from initial point clockwise or rotate counterclockwise galvanometer 3; Barycenter (the c of arbitrarily small hot spot _{(s, t) x}, c _{(s, t) y}) algorithm is:

$c_{(s,t)x}=\frac{\underset{i=sn}{\overset{(s+1)n-1}{\&Sigma;}}\underset{j=tn}{\overset{(t+1)n-1}{\&Sigma;}}{x}_{i,j}{I}_{i,j}}{\underset{i=sn}{\overset{(s+1)n-1}{\&Sigma;}}\underset{j=tn}{\overset{(t+1)n-1}{\&Sigma;}}{I}_{i,j}},c_{(s,t)y}=\frac{\underset{i=sn}{\overset{(s+1)n-1}{\&Sigma;}}\underset{j=tn}{\overset{(t+1)n-1}{\&Sigma;}}{y}_{i,j}{I}_{i,j}}{\underset{i=sn}{\overset{(s+1)n-1}{\&Sigma;}}\underset{j=m}{\overset{(t+1)n-1}{\&Sigma;}}{I}_{i,j}}---\left(3\right)$

(3) formula shows, the subregion be only limited in the incircle territory of light beam covering just can calculate small light spot center-of-mass coordinate, because light beam footprint just has be greater than noise I ₀brightness, therefore make I _i,j≤ 2I ₀the center-of-mass coordinate of subregion small light spot be constantly equal to its initial point center-of-mass coordinate (c _{(s, t) x0}, c _{(s, t) y0}).Utilize the small light spot center-of-mass coordinate after driving and initial point center-of-mass coordinate (c _{(s, t) x0}, c _{(s, t) y0}) difference, then small light spot barycenter side-play amount in the x-direction and side-play amount in the y-direction are just easy to calculate, in the incircle territory cover light beam, the centroid offset of all small light spots and Q small light spot is averaging the inclination that just can obtain overall wavefront, and the data in fact used are barycenter side-play amount A in x-axis and y-axis of overall wavefront _xand A _y:

$A_x=\frac{1}{Q}\underset{s=0}{\overset{M}{\&Sigma;}}\underset{t=0}{\overset{M}{\&Sigma;}}\left(c_{(s,t)x}-c_{(s,t)x0}\right),A_y=\frac{1}{Q}\underset{s=0}{\overset{M}{\&Sigma;}}\underset{t=0}{\overset{M}{\&Sigma;}}\left(c_{(s,t)y}-c_{(s,t)y0}\right)---\left(4\right)$

Use A respectively _xand A _yrelative drive voltages V does curve, can obtain the A axle of galvanometer 3 and the response curve of B axle.A on the A axle of parallel x-axis _x-V _xresponse curve schematic diagram, as Fig. 3, wherein increases voltage course and is respectively solid line and dotted line with reduction voltage course; As shown in Figure 3, due to the echo effect of tilting mirror, increase voltage and reduce the side-play amount that voltage course measurement obtains and do not overlap, at positive and negative large side-play amount place two, curve intersects respectively, and side-play amount corresponding to two point of crossing is exactly the maximum positive and negative side-play amount A of Hartmann sensor 8 normal response _x,pwith A _x,n; A in so corresponding y-axis _y-V _yresponse snapback, can produce the maximum positive and negative side-play amount A of normal response equally _y,pwith A _y,n, need at A _x,pwith A _y,pwith | A _x,n| with | A _y,n| in find out smaller value A respectively _pwith | A _n|, side-play amount is at [A _p, A _n] Hartmann sensor 8 can provide normal response, therefore [A in scope _p, A _n] be the dynamic range of Hartmann sensor 8.

When adaptive system is started working, usually the tilt quantity being detected wavefront is larger, exceeding Hartmann sensor 8 can the dynamic range of normal response, namely part or all of small light spot exceeds the subregion belonging to self, now need spot array to be regarded as a large spot, according to the center-of-mass coordinate algorithm of (1) formula, the center-of-mass coordinate (C of overall large spot _b,x, C _b,y) be:

$C_{B,x}=\frac{\underset{i=0}{\overset{P}{\&Sigma;}}\underset{j=0}{\overset{P}{\&Sigma;}}{x}_{i,j}{I}_{i,j}}{\underset{i=0}{\overset{P}{\&Sigma;}}\underset{j=0}{\overset{P}{\&Sigma;}}{I}_{i,j}},C_{B,y}=\frac{\underset{i=0}{\overset{P}{\&Sigma;}}\underset{j=0}{\overset{P}{\&Sigma;}}{y}_{i,j}{I}_{i,j}}{\underset{i=0}{\overset{P}{\&Sigma;}}\underset{j=0}{\overset{P}{\&Sigma;}}{I}_{i,j}}---\left(5\right)$

Wherein range of summation is all pixels and P × P pixel on CCD panel.Due to the interference of turbulent flow, on CCD panel, the Luminance Distribution of small light spot is uneven, so the usual error of large spot center-of-mass coordinate obtained is larger, be only suitable for using when wavetilt amount is larger, once wavetilt amount enter Hartmann sensor 8 can the dynamic range of normal response, then revert to employing (3), method that (4) formula calculates wavetilt.

The origin of large spot barycenter can utilize incident beam to cover the geometric center of CCD panel zone simply, is expressed as (C _{b, x0}, C _{b, y0}), so the side-play amount of large spot barycenter is:

A _Bx＝C _B,x-C _B,x0,A _By＝C _B,y-C _B,y0(6)。

Before adaptive system is started working, first to measure the response matrix of Hartmann sensor 8 pairs of galvanometers 3 and wave-front corrector 11, the present invention only need describe the response matrix measuring method to galvanometer 3: blocked before focus 1 by the telescope emergent light shown in Fig. 1, and dispose into a Halogen lamp LED pointolite 1 ' in telescopical focus 1, the light beam of pointolite 1 ', by not only parallel but also diameter is identical with the diameter of telescope receiving beam after collimation lens 2, ensures that the lenticule number that Hartmann sensor 8 is covered by normal incidence light beam is still for Q is individual.

In the present invention, the response matrix of Hartmann sensor 8 pairs of galvanometers 3 has two, and one is the response matrix of dynamic range, and two is response matrixs of normal dynamic range.

First measure the response matrix of dynamic range, A axle orthogonal on galvanometer 3 and B axle are parallel to x-axis and y-axis respectively, successively measure the response of A, B diaxon of Hartmann sensor 8 pairs of galvanometers 3.

The response curve A of A axle _bx-V _bxmeasurement: the half value applying maximum voltage on the B axle of galvanometer 3, progressively be added to maximum voltage with certain voltage step-length from minimum value to the A axle driver being parallel to x-axis to drive, then progressively ramp voltage gets back to minimum amount of voltage that, and Hartmann sensor 8 records the small light spot array distribution data after each making alive; Computing machine 16 is made to calculate center-of-mass coordinate and the side-play amount A of overall large spot respectively according to (5), (6) formula _bx; Use A _bxand A _byrelative drive voltages V does curve, can obtain the dynamic range response curve A of galvanometer 3 diaxon _bx-V _bx.

The response curve A of B axle _by-V _bymeasurement: the half value applying maximum voltage on the A axle of galvanometer 3, in kind measure and be parallel to the B axle actuator response characteristic of y-axis, draw side-play amount A _bywith dynamic range response curve A _by-V _by.

Response curve as the normal dynamic range in Fig. 3 is similar, due to the echo effect of tilting mirror, the side-play amount that increase voltage and the measurement of reduction voltage course obtain does not overlap, at positive and negative large side-play amount place two, curve intersects respectively, and side-play amount corresponding to two point of crossing is exactly the maximum positive and negative side-play amount A of Hartmann sensor 8 over range response _{bx, p}with A _{bx, n}; A in so corresponding y-axis _by-V _byresponse snapback, can produce maximum positive and negative side-play amount A equally _{by, p}with A _{by, n}, need at A _{bx, p}with A _{by, p}with | A _{bx, n}| with | A _{by, n}| in find out smaller value A respectively _bpwith | A _bn|, side-play amount is at [A _bp, A _bn] small light spot can exceed the subregion belonging to self in scope, Hartmann sensor 8 can provide the response of large spot, therefore [A _bp, A _bn] being the extraordinary dynamic range of Hartmann sensor 8, corresponding drive voltage range is close to the maximum drive scope reaching galvanometer 3; Try to achieve the median profile of A axle and B axle two pairs of snapbacks, and two median profile are all limited to [A _bp, A _bn] in scope, the two corresponding drive voltage range is divided into 40 ~ 100 scale division values respectively, and on two median profile, obtains corresponding offset value respectively, makes two two-dimensional matrixs, i.e. dynamic range response matrix A _bx(V _bx), A _by(V _by); By dynamic range response matrix A _bx(V _bx), A _by(V _by) be input in the internal memory of computing machine 16.

Next step measures the normal dynamic range response matrix of A, B axle.Parameter according to Hartmann sensor 8: subregion n × n-pixel, small light spot diameter m pixel, and m<n, therefore small light spot barycenter is ± (n-m)/2 pixel at the maximum offset of normal dynamic range; According to the dynamic range response matrix A that previous step obtains _bx(V _bx), the side-play amount finding overall large spot barycenter 2 times of scopes namely ± a pair driving voltage corresponding to (n-m) pixel place, in this drive voltage range, measure the normal dynamic range response matrix of A, B axle.

First measure the normal dynamic range response curve of A axle: constantly apply voltage to A axle according to the method described above, with less step-length, relatively each magnitude of voltage computing machine 16 reads spot array signal from Hartmann sensor 8; Computing machine 16 is made to calculate the mean deviation amount of small light spot barycenter array respectively according to (3), (4) formula; Obtain the response curve A of A axle normal dynamic range _x-V _x, draw the side-play amount A that on response snapback, two intersection points are corresponding _x,pand A _x,n.

In kind measure the normal dynamic range response curve A of B axle _y-V _y, also obtain B axle and return the maximum positive and negative side-play amount A that on stagnant response curve, two intersection points are corresponding _y,p, A _y,n.

At A _x,pwith A _y,pwith | A _x,n| with | A _y,n| in find out smaller value A respectively _pand A _n, obtain side-play amount at [A _p, A _n] Hartmann sensor 8 can provide normal response, [A in scope _p, A _n] be " dynamic range " of the usual institute appellation of Hartmann sensor 8; Try to achieve the median profile of A axle and B axle two pairs of snapbacks respectively, and two median profile are all limited to [A _p, A _n] in scope; The two corresponding drive voltage range is divided into 40 ~ 100 scale division values respectively, and on two median profile, obtains corresponding offset value respectively, makes two two-dimensional matrixs, i.e. normal dynamic range response matrix A _x(V _x) and A _y(V _y); By normal dynamic range response matrix A _x(V _x), A _y(V _y) be input in the internal memory of computing machine 16.

In fact, in time using the adaptive system shown in Fig. 1 to do overall correction to wavefront, because initial wavetilt all several times can exceed the normal measurement range of Hartmann sensor 8 usually, therefore the self-adaptation wavefront correction control program that computing machine 16 stores is first according to the signal that Hartmann sensor 8 provides, utilization (5), (6) formula calculate the A of large spot _bxand A _byvalue, the dynamic range response matrix A then stored _bx(V _bx), A _by(V _by) in search corresponding driving voltage V _bx, V _by, apply V _bx, V _bywavetilt correction is carried out in galvanometer 3; Carry out the A of next cycle Wavefront detecting, large spot again _bxand A _byvalue calculates, So repeat 5 ~ 10 cycles, repetition frequency and wavetilt emending frequency are 5 ~ 10 times of wavefront chattering frequency, to ensure side-play amount A _xand A _ybe rapidly reduced to [A _n, A _p] in scope, namely tested wavetilt is within the scope of the normal response of Hartmann sensor 8; From then on the method degree of precision ground adaptively correcting wavetilt of employing (3), (4) formula calculating small light spot barycenter mean deviation amount is reverted to, utilize the high-order of small light spot centroid calculation wavefront to distort simultaneously, drive the high-order distortion on wave-front corrector 11 adaptively correcting wavefront, the light beam after correction enters CCD imaging.

Accompanying drawing explanation

Fig. 1 is ADAPTIVE OPTICS SYSTEMS light path principle figure of the present invention.Wherein 1 is telescopical emergent light focus, 1 ' is Halogen lamp LED pointolite, measure response curve to use when system initialization, 2 is collimation lenses, 3 is galvanometers, 4 are color separation films, make wavelength be greater than the light transmission of 700nm, and the light that wavelength is less than 700nm is reflected, 5 is polaroids, 6 and 7 is the first contracting bundle lens and the second contracting bundle lens respectively, 8 is Hartmann sensor, and 9 and 10 is the 3rd contracting bundle lens and the 4th contracting bundle lens respectively, and 11 is wave-front correctors, 12 is catoptrons, 13 and 14 composition imaging lens group, 15 is CCD, and 16 is computing machines.

Fig. 2 is the incircle schematic diagram that the parallel beam of normal incidence Hartmann sensor 8 covers on the CCD panel of back.Wherein the interior black roundlet spot of circle represents Q the small light spot that microlens array focuses on out, and outer circle domain is without spot area, and solid line lattice represents CCD pixel, and dotted line block plaid represents the subregion at small light spot place, and "+" represents the center of subregion.The dynamic range of Hartmann sensor 8 is determined by the length of side of small light spot diameter and CCD panel sub-zones, when small light spot edge arrives subzone boundaries, just reaches the maximum measurement range of Hartmann sensor 8.

Fig. 3 is the response snapback A of Hartmann sensor 8 pairs of galvanometers 3 _x-V _xschematic diagram.Wherein V _xwith A _xbe respectively the x-axis driving voltage of galvanometer 3 and the small light spot barycenter of the Hartmann sensor 8 mean deviation amount in x-axis, solid line is for increasing voltage course, dotted line for reducing voltage course, A _x,pwith A _x,nbe respectively the maximum positive and negative side-play amount to x-axis inclination energy normal response.

Fig. 4 is the adaptively correcting light path specifically implementing the inclination of wavefront great dynamic range.Wherein 1 ' is pointolite, and 2 is collimation lenses, and 3 is galvanometers, 4 are color separation films, make wavelength be greater than the light transmission of 700nm, and the light that wavelength is less than 700nm is reflected, 6 and 7 is the first contracting bundle lens and the second contracting bundle lens respectively, 8 is Hartmann sensor, and 16 is computing machines.

Fig. 5 is the adaptively correcting process flow diagram controlling galvanometer 3.The first five cycle after representation program starts, adopt the centroid offset computing method of overall large spot to carry out the adaptively correcting of wavetilt, then revert to the wavetilt adaptively correcting adopting the computing method of small light spot barycenter mean deviation amount to carry out degree of precision.

Fig. 6 is the concrete response curve implementing to measure.Wherein being exaggerated partial trace is the response curve A adopting the mean deviation of small light spot barycenter to measure _x-V _x, other parts are the response curve A adopting the centroid offset of overall large spot to record _bx-V _bx, V _bxwith A _bxthe overall large spot barycenter of the x-axis being respectively galvanometer 3 driving voltage and Hartmann sensor 8 is on a large scale in the side-play amount of x-axis, and solid line is for increasing voltage course, dotted line for reducing voltage course.

Fig. 7 is the spot array that galvanometer 3 that in concrete enforcement, Hartmann sensor 8 records tilts in x direction: the large inclination of (a) dynamic range; Little inclination within (b) dynamic range; Spot array c () inclination is corrected by degree of precision after.

Embodiment:

Telescope focus 1 in Fig. 1 light path pointolite 1 ' is replaced, remove polaroid 5, third and fourth contracting bundle lens 9 and 10, wave-front corrector 11, catoptron 12, imaging lens group 13 and 14, CCD15, be built into the simplification light path of great dynamic range light wave top rake adaptively correcting as shown in Figure 4, be only made up of pointolite 1 ', collimation lens 2, galvanometer 3, color separation film 4, first and second contracting bundle lens 6 and 7, Hartmann sensor 8 and computing machine 16.Galvanometer 3 is connected with computing machine 16 respectively with Hartmann sensor 8, wavetilt adaptively correcting program is had in computing machine 16, its emending frequency is 15 ~ 20 times of wavefront chattering frequency in usual atmospheric conditions, aligning step as shown in Figure 5, the first five cycle started, adopt the centroid offset computing method of overall large spot to carry out the adaptively correcting of wavetilt, then revert to the wavetilt adaptively correcting adopting the computing method of small light spot barycenter mean deviation amount to carry out degree of precision.

The focus that in light path, pointolite 1 ' is positioned at collimation lens 2 sending spherical wave, by becoming the directional light that diameter is slightly less than galvanometer 3 bore after collimation lens 2, after being reflected by galvanometer 3, entering color separation film 4; The light of 400nm ~ 700nm wave band reflects by color separation film 4, it restraints lens 7 through the first contracting bundle lens 6 with the second contracting makes beam diameter mate and the parallel Hartmann sensor 8 that enters with Hartmann sensor 8, the horizontal direction of Hartmann sensor 8 is x-axis, the normal of galvanometer 3 becomes 45 degree and places with incident light axis, and its A axle is parallel with x-axis.

In light path, the model of each element and technical parameter are:

1) the pointolite 1 ' GCI-0601 type direct current voltage reulation optical fiber source that is company of Daheng, is a kind of white light source, uses diaphragm to be controlled to be 200 microns by bore;

2) collimation lens 2, first contracting bundle lens 6 and the second contracting bundle lens 7 are cemented doublet, and focal length is respectively 50mm, 100mm, 100mm, and bore is respectively 12mm, 25mm, 25mm;

3) galvanometer 3 is the S334 type of German PI Corp., bore 10mm, has vertical each other A, B two axles to control, and input voltage range is all 0 to 10V, continuously adjustabe, when galvanometer 3 is positioned at initial position, its A, B two axles all apply 5.00V voltage, response frequency is 700Hz;

4) color separation film 4 is high-pass filtering sheets, make wavelength be greater than the light transmission of 700nm, and the light that wavelength is less than 700nm is reflected;

5) the back CCD of Hartmann sensor 8 adopts AndorDU860, use valid pixel number 40 × 40, subregion n × n=4 × 4 pixel, small light spot diameter about 2.5 pixel, microlens array M × M=10 × 10 are Q=80 by the lenticule number that normal incidence light beam covers; Shown in Fig. 2, the back CCD pixel panel of Hartmann sensor 8 sets up rectangular coordinate system, is in units of initial point, pixel by the lower left corner, and transverse axis is from left to right x-axis, and the longitudinal axis is from top to bottom y-axis; Then compose sequence number for the subregion array in the CCD pixel panel of correspondence, represent subregion sequence number in the x and y direction respectively with s and t, the two is all be the positive integer of starting point from 0 is 0,1,2,3 ... M, wherein M=10;

6) computing machine 16 is DELLT5500 workstation, windowsXP operating system, and double-core CPUX9650 dominant frequency is respectively 3.00GHz and 2.99GHz, inside saves as 3.00GB.

Utilize above-mentioned light path system, first measure the response matrix of A, B axle of Hartmann sensor 8 pairs of galvanometers 3:

A. the dynamic range response matrix of A, B axle is measured

First measure the dynamic range response curve of A axle: first the voltage of B axle is set to 5.00V; Then from 0V to 10V, with the increasing velocity of step-length 0.15V, constantly voltage is applied to A axle, relatively each magnitude of voltage computing machine 16 reads spot array signal from Hartmann sensor 8, last spot array signal is obtained when voltage is increased to 9.00V, when increasing voltage again, hot spot array signal entirety exceeds Hartmann sensor 8 Receiver aperture, terminates to increase alive measurement; Do again from 9.00V to 0.00V, the inverse process of the voltage grading of step-length 0.15V measures; Make computing machine 16 calculate A shaft voltage respectively according to (5), (6) formula and increase progressively the side-play amount with overall large spot barycenter inverse process from 0.00V to 9.00V; The dynamic range response curve of A axle is obtained, as crossed over two A of [0V, 9V] in Fig. 6 according to the curve plotting method of Fig. 3 _bx-V _bxsnapback, wherein solid line and dotted line are respectively increases voltage course and reduces voltage course, the maximum offset of two intersection point corresponding A axle dynamic ranges on snapback, is respectively 11.8 pixels and-12.3 pixels;

Measure the dynamic range response curve of B axle: the voltage of A axle is set to 5.00V; Then same steps is adopted to measure the dynamic range response curve A of B axle _by-V _by; The maximum offset of two intersection points corresponding B axle dynamic range on the snapback obtained, is respectively 13.0 pixels and-12.8 pixels;

Maximum offset relatively on A, B axle, obtains dynamic range side-play amount limited range [A _bp, A _bn]=[11.8 pixel ,-12.3 pixels];

Try to achieve the median profile of A axle and B axle two pairs of snapbacks, and two median profile are all limited to [11.8 pixels,-12.3 pixels] in scope, the two corresponding drive voltage range is [0V, 9V], [1V, 8V], these two drive voltage range are divided into 60 scale division values respectively, and on two median profile, obtain corresponding offset value respectively, make two two-dimensional matrixs, thus obtain the dynamic range response matrix A of A axle and B axle _bx(V _bx), A _by(V _by);

By dynamic range response matrix A _bx(V _bx), A _by(V _by) be input in the internal memory of computing machine 16.

B. the normal dynamic range response matrix of A, B axle is measured

Parameter according to Hartmann sensor 8: subregion 4x4 pixel, small light spot diameter about 2.5 pixel, therefore small light spot barycenter is about ± 0.75 pixel at the maximum offset of normal dynamic range; According to the dynamic range response matrix A that previous step obtains _bx(V _bx), the side-play amount finding overall large spot barycenter is [4.5V, 5.5V] in 2 times of scopes drive voltage range that namely ± 2 pixels are corresponding, measures the normal dynamic range response matrix of A, B axle in this drive voltage range;

First measure the normal dynamic range response curve of A axle: equally the voltage of B axle is set to 5.00V; Then from 4.50V to 5.50V, with the increasing velocity of step-length 0.02V, constantly apply voltage to A axle, relatively each magnitude of voltage computing machine 16 reads spot array signal from Hartmann sensor 8; Do again from 5.50V to 4.50V, the inverse process of the voltage grading of step-length 0.02V measures; Computing machine 16 is made to calculate according to (3), (4) formula A axle to increase progressively the medium and small facula mass center with decrementing procedure mean deviation amount at this voltage respectively; The response curve of A axle normal dynamic range is obtained, as being contained in two A in dynamic range response snapback in Fig. 6 according to the curve plotting method of Fig. 3 _x-V _xcurve, the top right plot of Fig. 6 is its enlarged drawing, and wherein solid line and dotted line are respectively increases voltage course and reduces voltage course, draws the side-play amount A that two intersection points of two curve intersections are corresponding _x,p=0.78 pixel, A _x,n=-0.81 pixel;

Measure the normal dynamic range response curve of B axle: the voltage of A axle is set to 5.00V; Then same steps is adopted to measure the normal dynamic range response curve A of B axle _y-V _y, B axle returns the side-play amount A that on stagnant response curve, two intersection points are corresponding _y,p=0.54 pixel, A _y,n=-0.76 pixel;

At A _x,pwith A _y,pwith | A _x,n| with | A _y,n| in find out smaller value respectively, obtain side-play amount at [A _p, A _n]=[0.54 pixel ,-0.76 pixel] Hartmann sensor 8 can provide normal response in scope;

Try to achieve the median profile of A axle and B axle two pairs of snapbacks respectively, and two median profile are all limited to [0.54 pixel,-0.76 pixel] in scope, the two corresponding drive voltage range is [4.34V, 5.38V], [4.62V, 5.30V], these two drive voltage range are divided into 60 scale division values respectively, and on two median profile, obtain corresponding offset value respectively, make two two-dimensional matrixs, thus obtain the normal dynamic range response matrix A of A axle and B axle _x(V _x) and A _y(V _y);

By normal dynamic range response matrix A _x(V _x), A _y(V _y) be input in the internal memory of computing machine 16.

The adaptively correcting experiment that before coming into effect primary wave below, dynamic range tilts.The condition of initial dynamic range light wave top rake is produced by galvanometer 3; The A axle of galvanometer 3 is parallel with the x-axis in Hartmann sensor 8, only does the experiment of x direction dynamic range wavetilt:

I) on the A axle of galvanometer 3,0V voltage is applied, B axle applies 5.00V voltage, to produce the large wavetilt exceeding Hartmann sensor 8 dynamic range in the direction of the x axis, then the spot array figure in Hartmann sensor 8 is recorded, as Fig. 7 (a), utilization (5), (6) formula calculate the A of large spot _bxand A _byvalue is respectively 11.5 pixels and 0.5 pixel, illustrates that inclination in x-axis is enough large, and inclination in y-axis is very little, within normal dynamic range;

Ii) in wavetilt adaptively correcting program as shown in Figure 5, add one instruction, stop after making program only carry out 5 calibration cycles, then start this program;

Iii) the spot array figure obtained after carrying out 5 calibration cycles, as Fig. 7 (b), calculates the A of the method acquisition of barycenter with large spot _bxand A _byvalue is respectively 0.03 pixel and 0.48 pixel, proves tested wavetilt in the normal response scope [0.54 pixel ,-0.76 pixel] of Hartmann sensor 8;

Iv) initial dynamic range light wave top rake is regenerated, namely apply 0V voltage, B axle apply 5.00V voltage on the A axle of galvanometer 3, in the program shown in Fig. 5, also rejoin one instruction, stop after making program carry out 10 calibration cycles, then start this program;

V) the spot array figure obtained after carrying out 10 calibration cycles, as Fig. 7 (c), adopts the A that small light spot barycenter mean deviation amount obtains _xand A _yvalue is respectively 0.07 pixel and 0.01 pixel, proves to adopt the method precision of small light spot centroid calculation mean deviation amount very high.

The normal dynamic range of contrast implementation process and the maximum offset of dynamic range response, prove that the responding range of Hartmann sensor is expanded more than 15 times by the present invention, make self-adaptation wavefront correction system that a Hartmann sensor is only set without the need to arranging special wavefront tilt sensing device and just can normally work.

Claims (2)

1. the detection method of a great dynamic range light wave top rake, it is characterized in that several calibration cycles of starting working in adaptive system, when the angle of inclination before incident light wave is very large, exceed Hartmann sensor dynamic range and measurement range, the small light spot array collected by Hartmann sensor regards an an entirety i.e. large spot as, calculates the center-of-mass coordinate of large spot according to the way of a calculating facula mass center; Draw the integral inclined of wavefront according to the side-play amount of barycenter, by this data feedback to galvanometer to correct the inclination of wavefront, but not give wave-front corrector feedback data; The incident light come next, its wavetilt can significantly reduce due to the correction of galvanometer, repeats to such high-frequency process above; Because wavefront chattering frequency is far below the emending frequency of galvanometer, incident light after galvanometer corrects for several times, within the integral inclined dynamic range that will be reduced to Hartmann sensor of its wavefront, the inclination of wavefront and high-order distortion are simultaneously by correct detection, now system control program will provide " order " recover Hartmann sensor probing wave before normal procedure, adaptive system is run well;

A wave front detector is only had in adaptive system used, by collimation lens (2), galvanometer (3), color separation film (4), polaroid (5), first contracting bundle lens (6) and the second contracting bundle lens (7), Hartmann sensor (8), 3rd contracting bundle lens (9) and the 4th contracting bundle lens (10), wave-front corrector (11), catoptron (12), the first imaging len (13) and the second imaging len (14), CCD (15), computing machine (16) is formed, self-adaptation wavefront correction control program is had in computing machine (16), computing machine (16) is connected with CCD (15) with Hartmann sensor (8), galvanometer (3), wave-front corrector (11), color separation film (4) is high-pass filtering sheet, make wavelength be greater than the light transmission of 700nm, and the light that wavelength is less than 700nm is reflected, galvanometer (3) and Hartmann sensor (8) are in the light path of closed-loop control, and wave-front corrector (11) and Hartmann sensor (8) are then in open loop light path, the optical axis of the 4th contracting bundle lens (10) moves 5mm ± 0.2mm vertically upward relative to the optical axis of the 3rd contracting bundle lens (9), light beam is made to incide on wave-front corrector (11) by having a down dip with 1.5 ° of angles after the 4th contracting bundle lens (10), then the light beam reflected from wave-front corrector (11) is separated with incident beam optical axis and again arrives the 4th and contract and restraint lens (10) and focus on, realize being separated with entrance focus, catoptron (12) is set herein, folded light beam focus is made to be positioned on catoptron (12), and by folding bundle 90 °, CCD (15) imaging is entered by the first imaging len (13) and the second imaging len (14),

The detection method of described great dynamic range light wave top rake, is characterized in that the response matrix of Hartmann sensor (8) to galvanometer (3) has two, and one is the response matrix of normal dynamic range, and two is response matrixs of dynamic range; The response matrix measuring method of dynamic range is: blocked focus (1) is front by telescope emergent light, and dispose into a Halogen lamp LED pointolite (1 ') in telescopical focus (1), forms response matrix measuring system; The back CCD pixel panel of Hartmann sensor (8) sets up rectangular coordinate system, is in units of initial point, pixel by the lower left corner, and transverse axis is from left to right x-axis, and the longitudinal axis is from top to bottom y-axis; When starting to measure, regard the spot array that Hartmann sensor (8) provides as a large spot, the center-of-mass coordinate (C of overall large spot _b,x, C _b,y) be calculated as follows:

$C_{B,x}=\frac{\underset{i=0}{\overset{P}{\&Sigma;}}\underset{j=0}{\overset{P}{\&Sigma;}}{x}_{i,j}{I}_{i,j}}{\underset{i=0}{\overset{P}{\&Sigma;}}\underset{j=0}{\overset{P}{\&Sigma;}}{I}_{i,j}},C_{B,y}=\frac{\underset{i=0}{\overset{P}{\&Sigma;}}\underset{j=0}{\overset{P}{\&Sigma;}}{y}_{i,j}{I}_{i,j}}{\underset{i=0}{\overset{P}{\&Sigma;}}\underset{j=0}{\overset{P}{\&Sigma;}}{I}_{i,j}}$

Wherein x, y represent x-axis, y-axis respectively, C _b,x, C _b,yrepresent the coordinate components of barycenter in x-axis and the coordinate components of y-axis of overall large spot respectively, i, j be CCD pixel coordinate fasten x-axis and y-axis pixel sequence number, be positive integer from 0, x _i,jwith y _i,jbe respectively x-axis coordinate components and the y-axis coordinate components of (i, j) pixel center point, I _i,jfor the light intensity of (i, j) pixel, range of summation is all pixels and P × P pixel on CCD panel;

The origin of large spot barycenter is the geometric center that incident beam covers CCD panel zone, is expressed as (C _{b, x0}, C _{b, y0}), so the side-play amount of large spot barycenter is: A _bx=C _b,x-C _{b, x0}, A _by=C _b,y-C _{b, y0};

Utilize and calculate large spot centroid offset A _bxand A _bymethod measure Hartmann sensor (8) dynamic range response snapback, obtain maximum positive and negative side-play amount A from two intersection points of snapback _{bx, p}with A _{bx, n}, A _{by, p}with A _{by, n}, at A _{bx, p}with A _{by, p}with | A _{bx, n}| with | A _{by, n}| in find out smaller value A respectively _bpwith | A _bn|, [A _bp, A _bn] be the extraordinary dynamic range of Hartmann sensor (8); Try to achieve the median profile of A axle and B axle two pairs of snapbacks, and two median profile are all limited to [A _bp, A _bn] in scope, the two corresponding drive voltage range is divided into 50 ~ 100 scale division values respectively, and on two median profile, obtains corresponding offset value respectively, makes two two-dimensional matrixs, i.e. dynamic range response matrix A _bx(V _bx), A _by(V _by); By dynamic range response matrix A _bx(V _bx), A _by(V _by) be input in the internal memory of computing machine (16);

The signal that first the self-adaptation wavefront correction control program that computing machine (16) stores provides according to Hartmann sensor (8) calculates the A of large spot _bxand A _byvalue, the dynamic range response matrix A then stored _bx(V _bx), A _by(V _by) in search corresponding driving voltage V _bx, V _by, apply V _bx, V _bywavetilt correction is carried out in galvanometer (3); Carry out the A of next cycle Wavefront detecting, large spot again _bxand A _bythe dynamic range response matrix A that value calculates, then storing _bx(V _bx), A _by(V _by) in search corresponding driving voltage V _bx, V _by, apply V _bx, V _bywavetilt correction is carried out in galvanometer (3); So repeat 5 ~ 10 cycles, repetition frequency and wavetilt emending frequency are 5 ~ 10 times of wavefront chattering frequency, to ensure side-play amount A _xand A _ybe rapidly reduced to [A _n, A _p] in scope, namely tested wavetilt is within the scope of the normal response of Hartmann sensor (8); From then on the self-adaptation wavefront correction program adopting Hartmann sensor (8) normal dynamic range is reverted to, calculate small light spot barycenter mean deviation amount thus the adaptively correcting wavetilt of degree of precision ground, utilize the high-order of small light spot centroid calculation wavefront to distort simultaneously, drive the high-order distortion on wave-front corrector (11) adaptively correcting wavefront, the light beam after correction enters CCD imaging.

2. the detection method of great dynamic range light wave top rake according to claim 1, is characterized in that in described adaptive system:

1) pointolite (1 ') is a kind of white light source, is the GCI-0601 type direct current voltage reulation optical fiber source of company of Daheng, and it is 200 microns that bore controls;

2) collimation lens (2), the first contracting bundle lens (6) and the second contracting bundle lens (7) are cemented doublet, and focal length is respectively 50mm, 100mm, 100mm, and bore is respectively 12mm, 25mm, 25mm;

3) galvanometer (3) the S334 type product that is German PI Corp., bore 10mm, vertical each other A, B two axles are had to control, input voltage range is all 0 to 10V, continuously adjustabe, when galvanometer (3) is positioned at initial position, its A, B two axles all apply 5.00V voltage, response frequency is 700Hz;

4) color separation film (4) is high-pass filtering sheet, make wavelength be greater than the light transmission of 700nm, and the light that wavelength is less than 700nm is reflected;

5) the back CCD of Hartmann sensor (8) adopts AndorDU860, valid pixel number is used to be 40 × 40, subregion n × n=4 × 4 pixel, small light spot diameter is 2.5 pixels, microlens array M × M=10 × 10 lenticule is Q=80 by the lenticule number that normal incidence light beam covers;

6) computing machine (16) is DELLT5500 workstation, windowsXP operating system, and double-core CPUX9650 dominant frequency is respectively 3.00GHz and 2.99GHz, inside saves as 3.00GB; Have self-adaptation wavefront correction control program in computing machine (16), the emending frequency of wherein wavetilt is 300Hz; The first five calibration cycle started, adopt the centroid offset computing method of overall large spot to carry out the adaptively correcting of wavetilt, then revert to the wavetilt adaptively correcting adopting the computing method of small light spot barycenter mean deviation amount to carry out degree of precision;

In system, the dynamic range offset ranges of Hartmann sensor (8) reaches [11.8 pixels ,-12.3 pixels], than normal dynamic range side-play amount expansion at least 15 times.