CN103047998B - Space Optical System detectivity detection method - Google Patents

Abstract

The present invention relates to a kind of Space Optical System detectivity detecting system and detection method, this detecting system includes light-source system, colimated light system, punctate opacity of the cornea unit, spectra collection unit, master control system, data processing unit and display unit；Colimated light system and spectra collection unit are separately positioned on the emitting light path of light source；Punctate opacity of the cornea unit is arranged between light-source system and colimated light system and is on the focal plane of light-source system；Space Optical System to be measured is arranged on the emitting light path after collimated system；Data processing unit is connected with display unit and Space Optical System to be measured respectively；Master control system is connected with Space Optical System to be measured, light-source system and spectra collection unit respectively.The invention provides a kind of can reliably and accurately acquisition and detect data and Space Optical System detectivity detecting system convenient to operate and detection method.

Description

Space Optical System detectivity detection method

Technical field

The invention belongs to field of optical detection, relate to a kind of Space Optical System detectivity detecting system and detection method, particularly relate to a kind of detecting system that Space Optical System detection limit and the big index of encircled energy two are tested and detection method.

Background technology

Extraterrestrial target is detected by Space Optical System, and its detectivity determines the practicality of system.In order to fully verify the detectivity of optical system, need its detectivity is tested comprehensively.Detection limit, the test of encircled energy, it is sufficient to than more comprehensively the detectivity of optical system being evaluated.On the one hand, the test of detection limit may determine that the limit of weak signal target is responded by optical system.On the other hand, the test of encircled energy it will be seen that optical system is to the Energy distribution after target imaging.For the space orientations such as star sensor, navigation optical system, encircled energy then directly affects its spatial attitude certainty of measurement.Encircled energy is the highest, and detection limit is the highest, but attitude measurement accuracy tends to reducing；Encircled energy is the lowest, then cannot detect relatively weak signal target, and gesture stability is not the most just known where to begin.So detection limit conditions each other with encircled energy two indices, only both work in coordination, and could play the detectivity of optical system to greatest extent.Therefore, to the research in terms of Space Optical System detectivity test in laboratory, just seem the most necessary.

The most domestic have corresponding visible ray and ultraviolet magnitude simulator, but all cannot complete the automatic measurement to detection limit and encircled energy.Herein propose a kind of Space Optical System detectivity detecting system, the test of the two index can be covered.

Summary of the invention

In order to solve above-mentioned technical problem present in background technology, the invention provides and a kind of can reliably and accurately obtain detection data and Space Optical System detectivity detecting system convenient to operate and detection method.

The technical solution of the present invention is: the invention provides a kind of Space Optical System detectivity detecting system, it is characterised in that: described Space Optical System detectivity detecting system includes light-source system, colimated light system, punctate opacity of the cornea unit, spectra collection unit, master control system, data processing unit and display unit；Described colimated light system and spectra collection unit are separately positioned on the emitting light path of light source；Described punctate opacity of the cornea unit is arranged between light-source system and colimated light system and is on the focal plane of light-source system；Space Optical System to be measured is arranged on the emitting light path after collimated system；Described data processing unit is connected with display unit and Space Optical System to be measured respectively；Described master control system is connected with Space Optical System to be measured, light-source system and spectra collection unit respectively.

Above-mentioned colimated light system is off-axis reflection optical system；Described off-axis reflection optical system includes off axis paraboloid mirror primary mirror, the first folding axle mirror, the second folding axle mirror and iris；Described first folding axle mirror, the second folding axle mirror and off axis paraboloid mirror primary mirror are successively set on light-source system emitting light path after punctate opacity of the cornea unit；Described Space Optical System to be measured is arranged on the emitting light path after off axis paraboloid mirror primary mirror reflects；Described iris is arranged between off axis paraboloid mirror primary mirror and Space Optical System to be measured；Described iris is the veiling glare diaphragm that disappears；Described off-axis reflection optical system is the off-axis reflection optical system that bore is Φ 500mm and focal length is 5000mm.

Above-mentioned light-source system includes canonical product bulb separation, halogen tungsten lamp, xenon lamp and adjustable power supply；Described halogen tungsten lamp and xenon lamp are arranged on the inwall of canonical product bulb separation；Described master control system is connected with halogen tungsten lamp and xenon lamp respectively by adjustable power supply.

Above-mentioned punctate opacity of the cornea unit is punctate opacity of the cornea target target plate；Described spectra collection unit is spectral radiant emittance meter.

A kind of detection method based on Space Optical System detectivity detecting system as above, it is characterized in that and said method comprising the steps of:

1) TV star detecting Space Optical System to be measured is equivalent, and gathers the image of TV star's equivalent time；

2) according to step 1) image that collected calculates the encircled energy of Space Optical System to be measured.

Above-mentioned steps 1) specific implementation be:

1.1.1) light light-source system；

1.1.2) by spectra collection unit, the spectral information of light-source system is acquired；

1.1.3) calculate accordingly by the data processing unit spectroscopic data to being gathered and feed back to master control system；

1.1.4) the power supply output during master control system controls light-source system；

1.1.5) being calculated TV star's equivalence and calculated TV star equivalence is compared with the TV star's equivalence requiring index, if meeting the requirements index, then carrying out step 1.1.6)；If undesirable index, then return step 1.1.4)；Described TV star's equivalence is system detection limit；

1.1.6) Space Optical System to be measured moved to the light-emitting window of colimated light system and gather image；

1.1.7) by data processing unit, the image obtained is calculated, obtain target signal to noise ratio.

Above-mentioned steps 1.1.3) specific implementation be:

1.1.3.1) spectroscopic data collected being carried out associated quad calculating, obtain spectral irradiance E (λ) value at colimated light system light-emitting window, its computing formula is:

$E\left(\mathrm{\λ}\right)=\frac{\mathrm{\π}}{4}\·{\left(\frac{d}{f^{\′}}\right)}^2\·L\left(\mathrm{\λ}\right)\·\mathrm{\τ}$

Wherein:

D is punctate opacity of the cornea element diameter；

F ' is colimated light system focal length；

L (λ) is spoke brightness value；

τ is the transmitance of colimated light system；

1.1.3.2) by step 1.1.3.1) obtained by spectral irradiance E (λ) value be calculated illuminance value E at colimated light system light-emitting window_Illuminance, its computing formula is:

Wherein:

K_mIt is human eye correspondence vision improvement maximum spectral luminous efficacy constant, described K_mTake 683lm/W；

V (λ) is human eye vision improvement function；

Described step 1.1.5) in the equivalent concrete calculating process of the TV star be:

By step 1.1.3.1) obtained by illuminance value E_IlluminanceCarrying out being calculated apparent magnitude m value, its computing formula is:

lgE_Illuminance-lgE₀=0.4 (m-0)

Wherein:

E₀It is the illuminance that zero star such as grade is corresponding, described E₀It is 2.648 × 10^-6lx；

Described step 1.1.7) calculating process carry out according to equation below:

$SNR=\frac{S_E}{N_E}=\frac{S_C}{\sqrt{\frac{S_C}{g}+\frac{B_C}{g}+N^2}}$

Wherein:

S_CIt it is target DN value sum in 3 × 3 pixels；

S_EIt it is the signal represented with electron number；

B_CIt it is dark background meansigma methods；

N_EIt it is the background signal represented with electron number；

N is the standard deviation of dark background；

G is the gain of CCD.

Above-mentioned steps 1) specific implementation it may also is that

1.2.1) light light-source system；

1.2.2) Space Optical System to be measured is moved to the light-emitting window of colimated light system collection image；

1.2.3) data processing unit calculates obtaining image, obtains target signal to noise ratio；

1.2.4) judge signal to noise ratio size, the setting value if target signal to noise ratio meets the requirements, then carry out step 1.2.5)；If the undesirable setting value of target signal to noise ratio, then adjust the output of light source power supply power supply, until signal to noise ratio carries out step 1.2.5 after reaching setting value again)；

1.2.5) gathering the spectral information of spectra collection unit, carry out corresponding data process, obtain spectral irradiance E (λ) value, described spectral irradiance E (λ) value is system detection limit value；

1.2.6) image during acquisition system detection limit value.

Above-mentioned steps 1.2.3) in the calculation of signal to noise ratio be:

$SNR=\frac{S_E}{N_E}=\frac{S_C}{\sqrt{\frac{S_C}{g}+\frac{B_C}{g}+N^2}}$

Wherein:

S_CIt it is target DN value sum in 3 × 3 pixels；

S_EIt it is the signal represented with electron number；

B_CIt it is dark background meansigma methods；

N_EIt it is the background signal represented with electron number；

N is the standard deviation of dark background；

G is the gain of CCD；

Described step 1.2.5) in the concrete calculation of spectral irradiance E (λ) value be:

$E\left(\mathrm{\λ}\right)=\frac{\mathrm{\π}}{4}\·{\left(\frac{d}{f^{\′}}\right)}^2\·L\left(\mathrm{\λ}\right)\·\mathrm{\τ}$

Wherein:

D is punctate opacity of the cornea element diameter；

F ' is colimated light system focal length；

L (λ) is spoke brightness value；

τ is the transmitance of colimated light system.

Above-mentioned steps 2) specific implementation be: according to step 1) image that collected calculates the encircled energy of Space Optical System to be measured by Theravada's Gauss curve fitting method.

The invention have the advantage that

The present invention utilizes least square Gauss curve fitting method first, calculates Space Optical System disc of confusion diameter, and is evaluated encircled energy with this.The limitation of beyond tradition " number pixel " method, in the most reasonable a kind of, the data process of fitting treatment mode of science, it is thus achieved that detect data reliably, accurately.

The present invention uses a kind of new signal to noise ratio formula, calculates signal to noise ratio during Space Optical System limit detection, also falls within pioneering at home.

The present invention passes through two kinds of feedback systems, controls colimated light system light-emitting window spoke brightness value.One is by spectral radiant emittance measurement amount colimated light system light-emitting window spoke brightness value, calculates real time data and feeds back to master control system control light source power supply power supply output.Two is by being calculated signal noise ratio (snr) of image, and master control system controls the output of light source power supply power supply in real time according to gained snr value.So can obtain two groups of data: one is the target signal to noise ratio under specifying apparent magnitude energy；Two is the limit detection energy (i.e. apparent magnitude illuminance) under specifying signal to noise ratio.

The Space Optical System detectivity detecting system of the present invention, light source is selected integrating sphere light source, is improve the stability of test.

The Space Optical System detectivity detecting system of the present invention, light source selects halogen tungsten lamp, xenon lamp reciprocally incorporated lamp, it is possible to achieve broadband spectral energy proportioning and multiple color temperatures combination.

The Space Optical System detectivity detecting system of the present invention, punctate opacity of the cornea unit is selected the standard punctate opacity of the cornea of higher circularity, can be improved the precision of test.

The Space Optical System detectivity detecting system of the present invention, colimated light system is selected the off-axis three antiparallel light pipes of 5000mm, is introduced aberration hardly, be greatly improved measuring accuracy.Select this collimator, the faintest starlight target (limiting apparent magnitude 16Mv) can be simulated, improve the test scope of native system.

The Space Optical System detectivity detecting system of the present invention, spectra collection unit selects high accuracy spectral radiant emittance meter, and the canonical product bulb separation traced to the source by NIST has carried out standard transmission, can obtain test result the most accurately.

The Space Optical System detectivity detecting system of the present invention, is provided with iris at colimated light system exit window, can adjust the bore of colimated light system outgoing beam according to the clear aperture size of different spaces camera, to meet the needs of different cameral test.

The Space Optical System detectivity detecting system of the present invention, is provided with iris at colimated light system exit window, can effectively block veiling glare, improves measuring accuracy.

Accompanying drawing explanation

Fig. 1 is the structural representation of Space Optical System detectivity detecting system provided by the present invention；

Fig. 2 is Gauss curve fitting design sketch；

Fig. 3 is the Gauss distribution figure of whole disc of confusion；

Fig. 4 is 80% energy surrounded cone Gauss distribution figure；

Wherein:

1-light-source system；2-punctate opacity of the cornea unit；3-off axis paraboloid mirror primary mirror；4-the first folding axle mirror；5-the second folding axle mirror；6-iris；7-Space Optical System to be measured；8-spectral radiant emittance meter；9-electronic control translation stage；The automatically controlled turntable of 10-；11-master control system；12-data processing unit；13-display unit；14-colimated light system.

Detailed description of the invention

See Fig. 1, the invention provides a kind of Space Optical System detectivity detecting system, this Space Optical System detectivity detecting system includes light-source system 1, colimated light system 14, punctate opacity of the cornea unit 2, spectra collection unit, master control system 11, data processing unit 12 and display unit 13；Colimated light system 14 and spectra collection unit are separately positioned on the emitting light path of light source；Punctate opacity of the cornea unit 2 is arranged between light-source system 1 and colimated light system 14 and is on the focal plane of light-source system 1；Space Optical System 7 to be measured is arranged on the emitting light path after collimated system 14；Data processing unit 12 is connected with display unit 13 and Space Optical System to be measured 7 respectively；Master control system 11 is connected with Space Optical System 7 to be measured, light-source system 1 and spectra collection unit respectively.

Colimated light system 14 is off-axis reflection optical system；Off-axis reflection optical system includes off axis paraboloid mirror primary mirror the 3, first folding axle mirror the 4, second folding axle mirror 5 and iris 6；First folding axle mirror the 4, second folding axle mirror 5 and off axis paraboloid mirror primary mirror 3 are successively set on the light-source system 1 emitting light path after punctate opacity of the cornea unit 2；Space Optical System 7 to be measured is arranged on the emitting light path after off axis paraboloid mirror primary mirror 3 reflects；Iris 6 is arranged between off axis paraboloid mirror primary mirror 3 and Space Optical System to be measured 7；Iris 6 is the veiling glare diaphragm that disappears；Off-axis reflection optical system is the off-axis reflection optical system that bore is Φ 500mm and focal length is 5000mm.

Light-source system 1 includes canonical product bulb separation, halogen tungsten lamp, xenon lamp and adjustable power supply；Halogen tungsten lamp and xenon lamp are arranged on the inwall of canonical product bulb separation；Master control system 11 is connected with halogen tungsten lamp and xenon lamp respectively by adjustable power supply.Canonical product bulb separation can be with uniform light；Halogen tungsten lamp, xenon lamp reciprocally incorporated lamp can mutual proportioning, obtain the simulated solar spectrum of corresponding colour temperature；Adjustable power supply can be by the control and regulation light-source brightness of master control system 11.

Punctate opacity of the cornea unit 2 is punctate opacity of the cornea target target plate；Spectra collection unit is spectral radiant emittance meter 8.Spectral radiant emittance meter 8 is arranged at colimated light system 14 light-emitting window, and is carried on the translation stage that control unit is controlled.

Main control unit is power supply controller, automatically controlled turntable 10 controller and controllor for step-by-step motor, power supply controller adjusts light-source brightness, automatically controlled turntable 10 controller adjusts light source direction, and controllor for step-by-step motor controls translation stage motion at colimated light system 14 light-emitting window.Automatically controlled turntable 10 carries integrating sphere light source and rotates, and electronic control translation stage 9 carries Space Optical System 7 to be measured and can be allowed at colimated light system 14 light-emitting window move.

Data processing unit 12 includes that receiving spectral radiant emittance meter 8 data is integrated computing, the conversion of irradiance to the apparent magnitude, target signal to noise ratio calculates and utilizes the software that target energy concentration degree is calculated by least square Gauss curve fitting method, belonging to self-developed software, concrete irradiance integration, the conversion of irradiance to the apparent magnitude, signal to noise ratio, disc of confusion diameter (encircled energy) algorithm packaging are wherein.

Disc of confusion diameter algorithm is to aim at encircled energy to measure the New Algorithm developed.

Spoke brightness, to the process of conversion between the apparent magnitude, is the human eye vision photopic vision function issued with reference to CIE and apparent magnitude definition is calculated.

Automatically controlled turntable 10 controls via master control system 11, rotation is carried on the integrating sphere light source 1 above turntable and turns to spectral radiant emittance meter 8 institute in the face of direction, spectral radiant emittance meter 8 gathers real-time spoke brightness value at light-emitting window, and submit to data processing unit 12, after calculating integration spoke brightness value, compare with setting value, and then control the output of integrating sphere light source power supply power supply, during until obtaining identical with setting spoke brightness value, stop the change to power supply；Integrating sphere light source is rotated so that it is the light sent is radiated on punctate opacity of the cornea 2；Punctate opacity of the cornea 2 is positioned on the focal plane of colimated light system 14, through the light of punctate opacity of the cornea by the first folding axle mirror 4 and 5 dozens, the second folding axle mirror on the primary mirror 3 of colimated light system, with collimated light beam from colimated light system outgoing；At exit window, it is provided with iris 6, both veiling glare can be suppressed, moreover it can be used to control the bore of collimated light beam；Master control system 11 moves electronic control translation stage 7 and moves, and Space Optical System 7 is moved to colimated light system 14 light-emitting window, stores image after punctate opacity of the cornea unit 2 carries out imaging；According to image, utilize respective algorithms, carry out the measurement of detection limit and encircled energy.

Meanwhile, present invention also offers a kind of detection method based on Space Optical System detectivity detecting system as above, the method comprises the following steps:

1) TV star detecting Space Optical System to be measured is equivalent, and gathers the image of TV star's equivalent time；

Step 1) specific implementation be:

When light source igniting, light source is first turned to spectral radiant emittance meter direction by master control system, carries out spectral information collection.The spectroscopic data gathered is calculated by data processing unit accordingly, feeds back to master control system.Master control system, by the control flow arranged in advance, actively controls the power supply output in light-source system, until reaching required, stable test condition, the TV star's equivalence obtained now by conversion is system detection limit.Space Optical System to be measured is moved to collimator light-emitting window collection image by then master control system control electronic control translation stage.Data processing unit calculates obtaining image, obtains target signal to noise ratio, specifically:

1.1.1) light light-source system；

1.1.2) by spectra collection unit, the spectral information of light-source system is acquired；

1.1.3) calculate accordingly by the data processing unit spectroscopic data to being gathered and feed back to master control system；

1.1.3.1) spectroscopic data collected being carried out associated quad calculating, obtain spectral irradiance E (λ) value at colimated light system light-emitting window, its computing formula is:

$E\left(\mathrm{\λ}\right)=\frac{\mathrm{\π}}{4}\·{\left(\frac{d}{f^{\′}}\right)}^2\·L\left(\mathrm{\λ}\right)\·\mathrm{\τ}$

Wherein:

D is punctate opacity of the cornea element diameter；

F ' is colimated light system focal length；

L (λ) is spoke brightness value；

τ is the transmitance of colimated light system；

1.1.3.2) by step 1.1.3.1) obtained by spectral irradiance E (λ) value be calculated illuminance value E at colimated light system light-emitting window_Illuminance, its computing formula is:

Wherein:

K_mIt is human eye correspondence vision improvement maximum spectral luminous efficacy constant, described K_mTake 683lm/W；

V (λ) is human eye vision improvement function；

1.1.4) the power supply output during master control system controls light-source system；

1.1.5) being calculated TV star's equivalence and calculated TV star equivalence is compared with the TV star's equivalence requiring index, if meeting the requirements index, then carrying out step 1.1.6)；If undesirable index, then return step 1.1.4)；Described TV star's equivalence is system detection limit；

By step 1.1.3.1) obtained by illuminance value E_IlluminanceCarrying out being calculated apparent magnitude m value, its computing formula is:

lgE_Illuminance-lgE₀=0.4 (m-0)

Wherein:

E₀It is the illuminance that zero star such as grade is corresponding, described E₀It is 2.648 × 10^-6lx；

Described step 1.1.7) calculating process carry out according to equation below:

$SNR=\frac{S_E}{N_E}=\frac{S_C}{\sqrt{\frac{S_C}{g}+\frac{B_C}{g}+N^2}}$

Wherein:

S_CIt it is target DN value sum in 3 × 3 pixels；

S_EIt it is the signal represented with electron number；

B_CIt it is dark background meansigma methods；

N_EIt it is the background signal represented with electron number；

N is the standard deviation of dark background；

G is the gain of CCD.

1.1.6) Space Optical System to be measured moved to the light-emitting window of colimated light system and gather image；

1.1.7) by data processing unit, the image obtained is calculated, obtain target signal to noise ratio.

It addition, the step 1 mentioned by the present invention) specific implementation can also be in the following way:

When light source illuminates punctate opacity of the cornea target, master control system controls electronic control translation stage and Space Optical System to be measured moves to collimator light-emitting window collection image, and data processing unit calculates obtaining image, obtains target signal to noise ratio.Judge signal to noise ratio size and adjust the output of light source power supply power supply, until signal to noise ratio reaches setting value with this.Then master control system control light source turns to spectral radiant emittance meter direction, gathers spectral information, carries out corresponding data process, obtain system detection limit value.Gather now image, calculate system capacity concentration degree, specifically:

1.2.1) light light-source system；

1.2.2) Space Optical System to be measured is moved to the light-emitting window of colimated light system collection image；

1.2.3) data processing unit calculates according to equation below obtaining image, obtains target signal to noise ratio；

$SNR=\frac{S_E}{N_E}=\frac{S_C}{\sqrt{\frac{S_C}{g}+\frac{B_C}{g}+N^2}}$

Wherein:

S_CIt it is target DN value sum in 3 × 3 pixels；

S_EIt it is the signal represented with electron number；

B_CIt it is dark background meansigma methods；

N_EIt it is the background signal represented with electron number；

N is the standard deviation of dark background；

G is the gain of CCD；

1.2.4) judge signal to noise ratio size, the setting value if target signal to noise ratio meets the requirements, then carry out step 1.2.5)；If the undesirable setting value of target signal to noise ratio, then adjust the output of light source power supply power supply, until signal to noise ratio carries out step 1.2.5 after reaching setting value again):

The concrete calculation of spectral irradiance E (λ) value is:

$E\left(\mathrm{\λ}\right)=\frac{\mathrm{\π}}{4}\·{\left(\frac{d}{f^{\′}}\right)}^2\·L\left(\mathrm{\λ}\right)\·\mathrm{\τ}$

Wherein:

D is punctate opacity of the cornea element diameter；

F ' is colimated light system focal length；

L (λ) is spoke brightness value；

τ is the transmitance of colimated light system.

1.2.5) gathering the spectral information of spectra collection unit, carry out corresponding data process, obtain spectral irradiance E (λ) value, described spectral irradiance E (λ) value is system detection limit value；

1.2.6) image during acquisition system detection limit value.

Both the above control mode can meet the different spaces optical system needs to detection limit index test.On the one hand, directly instruct master control system to carry out magnitude simulation with charter specific targets, finally by calculating signal to noise ratio, pass judgment on optical system limit detection index；On the other hand, by a series of calculating and adjustment, enabling record under fixing signal to noise ratio, the weak signal target magnitude that optical system can detect.Both modes, based on master control system, by spectral radiant emittance meter and the cooperation of Space Optical System, complete automatically determining of detection limit, improve whole testing efficiency, detected detection limit more comprehensively.

2) according to step 1) image that collected calculates the encircled energy of Space Optical System to be measured.

Bore D according to optical system and the punctate opacity of the cornea of the focal distance f selection suitable diameter d of colimated light system, Space Optical System is placed at colimated light system light-emitting window, regulation light-source brightness, make punctate opacity of the cornea picture in the picture close to saturated, gather image, calculate system capacity concentration degree by least square Gauss curve fitting method.

The mensuration of encircled energy

The focal distance f of bore D according to optical system and colimated light system selects the punctate opacity of the cornea of suitable diameter d, sees formula:

$d\≤\frac{1.22\mathrm{\λ}}{D}\·f---\left(5\right)$

Space Optical System is placed at colimated light system light-emitting window, regulates light-source brightness so that punctate opacity of the cornea picture, in the picture close to saturated, gather image, calculates according to the following steps:

The punctate opacity of the cornea figure of shooting is gone background, and background value is B:

B=A_pixel+5·σ_pixel(6)

When disperse unit bright image unit DN value is more than this threshold value of B, just can be detected.

A_pixelThe average gray value of signal pattern view picture figure during for clapping star；

σ_pixelFor dark background noise figure.

Centered by disperse unit gray scale peak, taking 9 × 9 pixels is region C, be enough to comprise in this region

Whole energy of disc of confusion.

Disperse unit center position (x is tried to achieve with centroid method in selected areas C_i,y_i), see formula (7), (8):

$x_0=\frac{\underset{i=1}{\overset{N}{\Σ}}i\×f(i,j)}{\underset{i=1}{\overset{N}{\Σ}}\underset{j=1}{\overset{N}{\Σ}}f(i,j)}---\left(7\right)$

$y_0=\frac{\underset{j=1}{\overset{N}{\Σ}}j\×f(i,j)}{\underset{i=1}{\overset{N}{\Σ}}\underset{j=1}{\overset{N}{\Σ}}f(i,j)}---\left(8\right)$

To the gray value f of pixel, (i, j) is normalized, and obtains f₁(i,j)。

To with pixel each in the C of region to (x₀,y₀) distance be x-axis, with the gray value f of each pixel₁(i, j) is y-axis, and these values are carried out Gauss curve fitting, and fit equation isMethod therefor is least square Gauss curve fitting method, based on iteration theorem, sees Fig. 2, is Gauss curve fitting design sketch.

Coefficient a, b in the one-dimensional Gauss equation that will be tried to achieve substitutes in dimensional Gaussian equation (polar coordinate system),

It is shown below:

$T(\mathrm{\ρ},\mathrm{\θ})=a\·e^{-\frac{{\mathrm{\ρ}}^2}{b}}---\left(9\right)$

ρ is the footpath, pole of polar coordinate system；

θ is the polar angle of polar coordinate system.

Equation (4) is utilized to calculate,

$\frac{\underset{0}{\overset{2\mathrm{\π}}{\∫}}\underset{0}{\overset{d}{\∫}}T(\mathrm{\ρ},\mathrm{\θ})\·\mathrm{\ρ}d\mathrm{\ρ}d\mathrm{\θ}}{\underset{0}{\overset{2\mathrm{\π}}{\∫}}\underset{0}{\overset{\mathrm{\∞}}{\∫}}T(\mathrm{\ρ},\mathrm{\θ})\·\mathrm{\ρ}d\mathrm{\ρ}d\mathrm{\θ}}=0.8---\left(10\right)$

Seeing Fig. 3 and Fig. 4, it can be seen that draw circle with d for radius, account for the 80% of whole dimensional Gaussian distribution cone volume with the volume of dimensional Gaussian distribution the surrounded circular cone of envelope, namely encircled energy is the bottom surface radius of circle corresponding to 80%.

Calculated d value is multiplied by 2, is i.e. disc of confusion diameter, the namely encircled energy of punctate opacity of the cornea target.

The Space Optical System detectivity detecting system of the present invention, possesses and setting detection limit is carried out automatic standard adjustment, and can pass through another automatic control mode, and setting signal to noise ratio carries out the mensuration of detection limit.

The method has the advantage such as automatic feedback measurement mechanism, automatic light source brightness regulation relative to the magnitude simulator of traditional sense, saving labour force that can be the biggest, improves testing efficiency.And propose to utilize setting signal to noise ratio, directly measure the Space Optical System actual detection limit.It is possible not only to the test conventional to detection limit, and the limit detection level of optical system can have been tested out, provide important science data for engineer applied.In the calculating of magnitude simulation, introduce human eye vision improvement Efficiency Function, can the most accurately simulating stellar magnitude be calculated.The spectral radiant emittance meter traced to the source from NIST can be the whole data calculating and providing accurate, stable.By the relative spectral radiant energy flux curve data of the sun, the formula of magnitude simulation is verified, calculated that obtaining the starlight illumination such as internationally recognized zero is 2.65 × 10 smoothly^-6Lx, thus proves that this kind of method is to stand deliberation completely in theory.

The Space Optical System detectivity detecting system of the present invention, the disc of confusion diameter of energy Accurate Determining Space Optical System, the mensuration mode of beyond tradition " number pixel ", with the most reasonable a kind of, the data processing method of science, is accurately determined this index.During Space Optical System disc of confusion measuring diameter, being distributed only between 3 × 3 to 5 × 5 pixels mainly due to disc of confusion energy, the information data obtained during test is the most rare, if using traditional method, the result of mensuration will be introduced into the biggest error.And by after disc of confusion least square Gauss curve fitting method, measuring accuracy can be improved a magnitude.This has meaning free from worldly cares for the evaluation of Space Optical System encircled energy, and this index will directly affect the positioning precision of space star sensor, gesture stability, is all widely used on the aerospace flight vehicles such as satellite, intercontinental strategic missile, spacecraft.

Claims (5)

1. a detection method based on Space Optical System detectivity detecting system, described Space Optical System detectivity detecting system includes light-source system, colimated light system, punctate opacity of the cornea unit, spectra collection unit, master control system, data processing unit and display unit；Described colimated light system and spectra collection unit are separately positioned on the emitting light path of light source；Described punctate opacity of the cornea unit is arranged between light-source system and colimated light system and is on the focal plane of light-source system；Space Optical System to be measured is arranged on the emitting light path after collimated system；Described data processing unit is connected with display unit and Space Optical System to be measured respectively；Described master control system is connected with Space Optical System to be measured, light-source system and spectra collection unit respectively；

Described colimated light system is off-axis reflection optical system；Described off-axis reflection optical system includes off axis paraboloid mirror primary mirror, the first folding axle mirror, the second folding axle mirror and iris；Described first folding axle mirror, the second folding axle mirror and off axis paraboloid mirror primary mirror are successively set on light-source system emitting light path after punctate opacity of the cornea unit；Described Space Optical System to be measured is arranged on the emitting light path after off axis paraboloid mirror primary mirror reflects；Described iris is arranged between off axis paraboloid mirror primary mirror and Space Optical System to be measured；Described iris is the veiling glare diaphragm that disappears；Described off-axis reflection optical system is the off-axis reflection optical system that bore is Φ 500mm and focal length is 5000mm；

Described light-source system includes canonical product bulb separation, halogen tungsten lamp, xenon lamp and adjustable power supply；Described halogen tungsten lamp and xenon lamp are arranged on the inwall of canonical product bulb separation；Described master control system is connected with halogen tungsten lamp and xenon lamp respectively by adjustable power supply；

Described punctate opacity of the cornea unit is punctate opacity of the cornea target target plate；Described spectra collection unit is spectral radiant emittance meter；

It is characterized in that: said method comprising the steps of:

1) TV star detecting Space Optical System to be measured is equivalent, and gathers the image of TV star's equivalent time:

1.1.1) light light-source system；

1.1.2) by spectra collection unit, the spectral information of light-source system is acquired；

1.1.3) calculate accordingly by the data processing unit spectroscopic data to being gathered and feed back to master control system；

1.1.4) the power supply output during master control system controls light-source system；

1.1.5) being calculated TV star's equivalence and calculated TV star equivalence is compared with the TV star's equivalence requiring index, if meeting the requirements index, then carrying out step 1.1.6)；If undesirable index, then return step 1.1.4)；Described TV star's equivalence is system detection limit；

1.1.6) Space Optical System to be measured moved to the light-emitting window of colimated light system and gather image；

1.1.7) by data processing unit, the image obtained is calculated, obtain target signal to noise ratio；

2) according to step 1) image that collected calculates the encircled energy of Space Optical System to be measured.

Method the most according to claim 1, it is characterised in that:

Described step 1.1.3) specific implementation be:

1.1.3.1) spectroscopic data collected being carried out associated quad calculating, obtain spectral irradiance E (λ) value at colimated light system light-emitting window, its computing formula is:

Wherein:

D is punctate opacity of the cornea element diameter；

F ' is colimated light system focal length；

L (λ) is spoke brightness value；

τ is the transmitance of colimated light system；

1.1.3.2) by step 1.1.3.1) obtained by spectral irradiance E (λ) value be calculated illuminance value E at colimated light system light-emitting window_Illuminance, its computing formula is:

Wherein:

K_mIt is human eye correspondence vision improvement maximum spectral luminous efficacy constant, described K_mTake 683lm/W；

V (λ) is human eye vision improvement function；

Described step 1.1.5) in the equivalent concrete calculating process of the TV star be:

By step 1.1.3.1) obtained by illuminance value E_IlluminanceCarrying out being calculated apparent magnitude m value, its computing formula is:

lgE_Illuminance-lg E₀=0.4 (m-0)

Wherein:

E₀It is the illuminance that zero star such as grade is corresponding, described E₀It is 2.648 × 10^-6lx；

Described step 1.1.7) calculating process carry out according to equation below:

Wherein:

S_CIt it is target DN value sum in 3 × 3 pixels；

S_EIt it is the signal represented with electron number；

B_CIt it is dark background meansigma methods；

N_EIt it is the background signal represented with electron number；

N is the standard deviation of dark background；

G is the gain of CCD.

3. a detection method based on Space Optical System detectivity detecting system, described Space Optical System detectivity detecting system includes light-source system, colimated light system, punctate opacity of the cornea unit, spectra collection unit, master control system, data processing unit and display unit；Described colimated light system and spectra collection unit are separately positioned on the emitting light path of light source；Described punctate opacity of the cornea unit is arranged between light-source system and colimated light system and is on the focal plane of light-source system；Space Optical System to be measured is arranged on the emitting light path after collimated system；Described data processing unit is connected with display unit and Space Optical System to be measured respectively；Described master control system is connected with Space Optical System to be measured, light-source system and spectra collection unit respectively；

Described colimated light system is off-axis reflection optical system；Described off-axis reflection optical system includes off axis paraboloid mirror primary mirror, the first folding axle mirror, the second folding axle mirror and iris；Described first folding axle mirror, the second folding axle mirror and off axis paraboloid mirror primary mirror are successively set on light-source system emitting light path after punctate opacity of the cornea unit；Described Space Optical System to be measured is arranged on the emitting light path after off axis paraboloid mirror primary mirror reflects；Described iris is arranged between off axis paraboloid mirror primary mirror and Space Optical System to be measured；Described iris is the veiling glare diaphragm that disappears；Described off-axis reflection optical system is the off-axis reflection optical system that bore is Φ 500mm and focal length is 5000mm；

Described light-source system includes canonical product bulb separation, halogen tungsten lamp, xenon lamp and adjustable power supply；Described halogen tungsten lamp and xenon lamp are arranged on the inwall of canonical product bulb separation；Described master control system is connected with halogen tungsten lamp and xenon lamp respectively by adjustable power supply；

Described punctate opacity of the cornea unit is punctate opacity of the cornea target target plate；Described spectra collection unit is spectral radiant emittance meter；

It is characterized in that: said method comprising the steps of:

1) TV star detecting Space Optical System to be measured is equivalent, and gathers the image of TV star's equivalent time:

1.2.1) light light-source system；

1.2.2) Space Optical System to be measured is moved to the light-emitting window of colimated light system collection image；

1.2.3) data processing unit calculates obtaining image, obtains target signal to noise ratio；

1.2.4) judge signal to noise ratio size, the setting value if target signal to noise ratio meets the requirements, then carry out step 1.2.5)；If the undesirable setting value of target signal to noise ratio, then adjust the output of light source power supply power supply, until signal to noise ratio carries out step 1.2.5 after reaching setting value again)；

1.2.5) gathering the spectral information of spectra collection unit, carry out corresponding data process, obtain spectral irradiance E (λ) value, described spectral irradiance E (λ) value is system detection limit value；

1.2.6) image during acquisition system detection limit value；

2) according to step 1) image that collected calculates the encircled energy of Space Optical System to be measured.

Method the most according to claim 3, it is characterised in that:

Described step 1.2.3) in the calculation of signal to noise ratio be:

Wherein:

S_CIt it is target DN value sum in 3 × 3 pixels；

S_EIt it is the signal represented with electron number；

B_CIt it is dark background meansigma methods；

N_EIt it is the background signal represented with electron number；

N is the standard deviation of dark background；

G is the gain of CCD；

Described step 1.2.5) in the concrete calculation of spectral irradiance E (λ) value be:

Wherein:

D is punctate opacity of the cornea element diameter；

F ' is colimated light system focal length；

L (λ) is spoke brightness value；

τ is the transmitance of colimated light system.

5. according to the method described in claim 2 or 4, it is characterised in that: described step 2) specific implementation be:

According to step 1) image that collected calculates the encircled energy of Space Optical System to be measured by Theravada's Gauss curve fitting method.