CN103968945A

CN103968945A - Ultra-sensitive spectral imaging astronomical telescope based on second-order compressed sensing and method

Info

Publication number: CN103968945A
Application number: CN201410231481.7A
Authority: CN
Inventors: 刘雪峰; 翟光杰; 王超; 俞文凯; 姚旭日
Original assignee: National Space Science Center of CAS
Current assignee: National Space Science Center of CAS
Priority date: 2014-05-28
Filing date: 2014-05-28
Publication date: 2014-08-06
Anticipated expiration: 2034-05-28
Also published as: CN103968945B

Abstract

The invention relates to an ultra-sensitive spectral imaging astronomical telescope based on second-order compressed sensing, which comprises an optical unit and an electric unit, wherein the optical unit comprises an astronomical telescope lens, a first spatial light modulator, a collimation part, a spectrometric part, a spectral convergence part, a second spatial light modulator and a collection part; the electric unit comprises a single-photon point detector, a counter, a random number generator, a control module, a data packet memory and a compressed sensing module; a celestial image is collected through the astronomical telescope lens, and is imaged to the first spatial light modulator; a randomly modulated light beam is collimated into parallel light, and the parallel light forms a spectral band through the spectrometric part; the spectral band is secondarily randomly modulated through the second spatial light modulator, and is finally collected in the single-photon point detector; and a compressed sensing algorithm is used for obtaining an astronomical target spectral image according to a photon count value and two groups of random matrixes.

Description

Hypersensitive light spectrum image-forming astronomical telescope and method based on second order compressed sensing

Technical field

The present invention relates to optics and uranology field, particularly a kind of hypersensitive light spectrum image-forming astronomical telescope and method based on second order compressed sensing.

Background technology

Astronomical telescope is the important tool of observation celestial body, can not say large there is no telescopical birth and development, just there is no modern astronomy.Along with telescope improving of performance in every respect, uranology is also just experiencing huge leap, is advancing rapidly the understanding of the mankind to universe.

Press the difference of service band, astronomical telescope can be divided into optical telescope and radio telescope.Wherein optical telescope, mainly taking visible ray as service band, according to the difference of place to use, can be divided into ground based astronomy telescope and space solar telescope.Due to the difference of optical system, can be divided into again the types such as reflecting telescope, refracting telescope, catadioptric telescope; Radio telescope is mainly taking radiowave as service band.At present the celestial body (fixed star etc.) of the ground observation overwhelming majority in condensed state is still observed Main Means with optical region, this be due to: the tyemperature of celestial body scopes such as most of fixed stars are from thousands of degree to tens thousand of degree, and radiation concentrates on optical region; Carry the spectral line of a large amount of astrophysics information, mainly concentrate on visible range; Atmosphere has good transmission in visible range.

In astronomical sight, obtaining of spectral information has great importance, and this is because a large amount of information can show with the form of spectrum in uranology.The first, to the research of universe and galaxy.The advanced problems such as the birth in universe, the formation of galaxy are all based upon on the Research foundation of galaxy physics.Research large scale structure of the universe depends on the work of galaxy redshift survey.The spectrum that obtains galaxy just can obtain the red shift of galaxy, and then know its distance, obtain thus the distributed in three dimensions of galaxy, so just can understand the structure in whole cosmic space, can study large scale structure of the universe and galaxy physics including formation, the evolution of galaxy simultaneously.The spectrum that obtains galaxy is to carry out the most basic needs of this work.The second, the research of the architectural feature to fixed star and the Galactic System.Due to the different elements spectral line that takes on a different character, by the spectrum of a fixed star, can analyze that its element forms and the chemical composition such as content, can analyze the physical conditions such as its density, temperature, can also measure its movement velocity and running orbit etc.Study the distribution of different types of fixed star, can work out the structure in the Galactic System and the formation in the Galactic System.The 3rd, to the research of extraterrestrial life.By the spectrum of fixed star or planet, can study the content of its surface moisture and oxygen, to determine whether to exist biological possibility.Therefore, in uranology, the research of spectrum is had to important and irreplaceable effect.

But astronomical telescope wants to obtain astronomic graph picture and astronomical spectral information is very difficult simultaneously, wherein topmost difficulty is the problem of dimension.The total three-dimensional information of the astronomic graph picture of two dimension and the spectral information of one dimension, according to traditional acquisition of information mode, need to have the detector of three dimensions, and this obviously cannot realize at present, therefore existing a large amount of astronomical telescope can only obtain respectively astronomical image information or astronomical spectral information, and cannot obtain the information of two aspects simultaneously.A kind of solution is to obtain image information by two-dimensional detector on common astronomical telescope, the light signal that leaches a certain interested wave band by modes such as optical filters again carries out imaging, can obtain like this light spectrum image-forming of single wave band, can only carry out duplicate measurements by changing filter system and will obtain multiband or full wave light spectrum image-forming, and obtain the image of different-waveband.The mode of this light spectrum image-forming need to realize by scanning optical spectrum, obtain high-resolution spectrum, will inevitably bring huge time cost, and obtains when still cannot realizing astronomical image information and astronomical spectral information in essence.

Sensitivity is the very important index of astronomical telescope, because astronomical telescope sensitivity improves, just can see darker farther celestial body, this equates and can see more early stage universe, the basic problem that the mankind such as this origin for research universe are concerned about is significant.In astronomical spectrographic detection, owing to only obtaining the information of single wave band, during with all band imaging compared with the intensity of light signal greatly weaken, therefore higher to the requirement of sensitivity.The sensitivity of astronomical solar spectral telescope improves, and the wavelength just can be by spectral measurement time is got thinner, obtains higher spectral resolution.Therefore the more highly sensitive astronomical telescope of the development need of astronomical imaging and astronomical light spectrum image-forming.

The raising of astronomical telescope sensitivity at present mainly realizes by the increase of bore, and telescopical bore is larger, and light collecting light ability is stronger, and sensitivity also can be higher, and therefore the telescopical bore of Modern Astronomical is made increasing.But along with the increase of telescope bore, a series of technical matters is comed one after another.For example, the Hale telescope that bore is 5 meters was once maximum in the world astronomical telescope, and its camera lens is from weighing 14.5 tons, and the weight of moving part is 530 tons, and 6 meters of bore astronomical telescopes that built up afterwards weigh 800 tons especially.On the one hand, the telescopical conference of conducting oneself with dignity makes len distortion quite obvious, and on the other hand, mirror temperature inequality also makes minute surface produce distortion, and then affects image quality.From manufacture view, classic method manufacture telescopical expense almost to bore square or cube be directly proportional, be all extremely restricted in performance and expense so manufacture more bigbore telescope.

Another key factor that affects astronomical telescope sensitivity is the performance of optical detector, and highly sensitive detector must effectively improve the sensitivity of astronomical telescope.Avalanche photodide (APD) based on Geiger mode of operation can detect the energy of single photon, is the highest detector of sensitivity in theory, also referred to as single-photon detector.Other highly-sensitive detectors also comprise photomultiplier (PMT), and its sensitivity can reach several or tens photons.Present stage, China only had the APD detector of single-point, the ability of also not producing array APD due to the restriction of manufacture craft; In the world can with array APD maximum pixel also only have 128 × 128, do not reach the demand that obtains high resolving power astronomic graph picture far away.In addition, PMT is because the reason of working mechanism does not have detector array yet.To the solution of the not enough problem of highly-sensitive detector pixel count, a kind of way is to use point probe to scan to be embodied as picture, the problem of bringing is like this that scan detector can expend a large amount of time, greatly reduce image acquisition speed, the information detection time of image diverse location produces difference simultaneously, and the image shift meeting of scan period causes the decline of imaging resolution.Another kind of way is a large amount of point probes to be combined into array survey, but obtain enough resolution, need the extremely huge single-point detector of quantity, as the image that will obtain 1024 × 768 pixels needs about 800,000 point probe, cause high cost, and point probe splicing can exist serious dutycycle problem, causes the decline of light harvesting effect, and then affect telescopical sensitivity.Therefore, utilize these highly sensitive detectors of prior art all cannot solve the problem of the detection dimension of light spectrum image-forming astronomical telescope existence, cannot obtain astronomic graph picture and astronomical spectral information simultaneously.

In sum, existing light spectrum image-forming astronomical telescope exists that image and spectrographic detection Information Dimension are spent greatly, the problem of detector dimension deficiency, and cannot realize highly sensitive detection.Due to the limitation of principle of work, there is restriction in traditional light spectrum image-forming astronomical telescope in the approach that realizes multidimensional detection and raising detection sensitivity, and the higher light spectrum image-forming astronomical telescope of sensitivity is needed in astrophysical development badly.

Summary of the invention

The object of the invention is to taking second order compressed sensing as basis, overcome the deficiency of light spectrum image-forming astronomical telescope of the prior art in multidimensional detection and sensitivity, thereby a kind of hypersensitive light spectrum image-forming astronomical telescope based on second order compressed sensing is provided.

To achieve these goals, the invention provides a kind of hypersensitive light spectrum image-forming astronomical telescope based on second order compressed sensing, comprise optical unit I and electrical units II; Wherein, optical unit I comprises astronomical telescope camera lens 1, the first spatial light modulator 2, collimating components 3, spectrum light splitting part 4, spectrum convergence parts 5, second space photomodulator 6, collecting part 7; Electrical units II comprises single photon point probe 8, counter 9, randomizer 10, control module 11, packet memory 12 and compressed sensing module 13; Wherein, described collimating components 3 comprises collecting lens 3_1, diaphragm 3_2, collimation lens 3_3; Described randomizer 10 comprises the first randomizer 10_1, the second randomizer 10_2;

Described in the optical signals of the single photon level of coming from celestial body propagation, astronomical telescope camera lens 1 is collected, and is imaged onto in described the first spatial light modulator 2; Described the first spatial light modulator 2 looks like to carry out Stochastic Modulation to being imaged on its surperficial astronomic graph, with random chance, the light of diverse location on image is reflexed to described collimating components 3 directions; First the light of described the first spatial light modulator 2 random reflected converge to described diaphragm 3_2 by described collecting lens 3_1, limited spot size, form approximate pointolite, then form directional light through described collimation lens 3_3 collimation, be radiated on described spectrum light splitting part 4; Described spectrum light splitting part 4 by the light of different wave length to different directions outgoing; After described spectrum is assembled parts 5, the light of different wave length converges to described spectrum and assembles diverse location on parts 5 focal planes, forms band; Described second space photomodulator 6 is placed on the focal plane position of described spectrum convergence parts 5, and its surperficial band is carried out to Stochastic Modulation, with random chance, the light of diverse location on band is reflexed to described collecting part 7 directions; Described collecting part 7 is collected the light signal that described second space photomodulator 6 reflects and come, and is surveyed by single photon point probe 8 in described electrical units II;

Described the first randomizer 10_1 produces random number and is used for controlling described the first spatial light modulator 2, described the second randomizer 10_2 generation random number for controlling described second space photomodulator 6; Described the first spatial light modulator 2 and described second space photomodulator 6 are realized the Stochastic Modulation to light signal according to this random number; Described single photon point probe 8 is surveyed the single photon in the utmost point low light level to be measured, exports after the single photon signal collecting being converted to the electric signal of impulse form; Described counter 9 records the electric pulse number of the representative single photon number that described single photon point probe 8 sends; Described control module 11 is controlled coordination to whole hypersensitive light spectrum image-forming astronomical telescope, comprise job control and the transmitting of synchronizing pulse trigger pip to each parts, guarantee described counter 9, described the first spatial light modulator 2 and described second space photomodulator 6 synchronous workings; The stochastic matrix that the single photon number that described counter 9 records and described the first randomizer 10_1, described the second randomizer 10_2 generate all deposits in described packet memory 12; Described compressed sensing module 13 is utilized single photon number and the corresponding stochastic matrix in described packet memory 12, and chooses sparse base astronomical spectrum picture is rebuild, and obtains the astronomical spectrum picture of utmost point low light level level.

In technique scheme, described the first randomizer 10_1, the second randomizer 10_2 are for generating the speckle of two-value Bernoulli Jacob distribution or the speckle of two-value non-uniform Distribution, and two-value forms by 0 and 1; Wherein, in the time that the second randomizer 10_2 generates the speckle that two-value Bernoulli Jacob distributes, need make the speckle of the first frame complete 1, and Bernoulli Jacob distribute and is obtained by Walsh or Hadamard or noiselet conversion; In the time that the second randomizer 10_2 generates the speckle of two-value non-uniform Distribution, in every frame speckle, 1 number need be much smaller than 0 number, and 1 is random in the space distribution of every frame speckle; The speckle that the first randomizer 10_1 generates does not limit.

In technique scheme, described astronomical telescope camera lens 1 adopts the camera lens of following any one astronomical telescope type: reflective astronomical telescope, comprises Newtonian, Cassegrain's formula, Ge Lishi; Refraction type astronomical telescope, comprises Galileo telescope, Kepler telescope; Refracting-reflecting astronomical telescope, comprises Schmidt-Cassegrain formula, Maksutov-Cassegrain formula; Multi mirror telescope; Binoculars; Also comprise the space solar telescope being applied on satellite, space station.

In technique scheme, described the first spatial light modulator 2 or second space photomodulator 6 adopt Digital Micromirror Device to realize.

In technique scheme, the collecting lens 3_1 in described collimating components 3, collimation lens 3_3 scioptics or concave mirror are realized; Diaphragm 3_2 realizes by slit or aperture.

In technique scheme, described spectrum light splitting part 4 comprises the dispersion light splitting part for the light of different wave length is separated, and described dispersion light splitting part adopts the device with light splitting ability including grating, prism to realize.

In technique scheme, described spectrum light splitting part 4 also comprises the pre-filter part that does not carry out the light of the wavelength of light spectrum image-forming for filtering, and described pre-filter part is realized by optical filter.

In technique scheme, described spectrum is assembled parts 5 and is realized by lens or concave mirror; Described spectrum is assembled parts 5 light of different wave length is transmitted in the different pixels of described second space photomodulator 6 from small to large successively by wavelength.

In technique scheme, when described the first spatial light modulator 2 is stable in the Stochastic Modulation time each time, described second space photomodulator 6 carries out several times Stochastic Modulation.

In technique scheme, described collecting part 7 is realized by lens or concave mirror.

In technique scheme, described single photon point probe 8 adopts Geiger mode angular position digitizer avalanche diode or photomultiplier to realize.

In technique scheme, described control module 11 guarantees that between described counter 9 and described the first spatial light modulator 2, described second space photomodulator 6, synchronous working comprises: described the first spatial light modulator 2 carries out several times Stochastic Modulation; When described the first spatial light modulator 2 was stable in the Stochastic Modulation time each time, described second space photomodulator 6 carries out several times Stochastic Modulation; Described second space photomodulator 6 often carries out Stochastic Modulation one time, described counter 9 is accumulated respectively the electric pulse number of the representative single photon number that described single photon point probe 8 sends, until described second space photomodulator 6 carries out Stochastic Modulation next time, described counter 9 is stable at a photon counting in the Stochastic Modulation time by described second space photomodulator 6 and transfers to packet memory 12, and will count zero clearing, start counting next time.

In technique scheme, described compressed sensing module 13 adopts any one in following algorithm to realize compressed sensing: coupling track algorithm MP, orthogonal coupling track algorithm OMP, base track algorithm BP, greedy reconstruction algorithm, LASSO, LARS, GPSR, Bayesian Estimation algorithm, magic, IST, TV, StOMP, CoSaMP, LBI, SP, l1_ls, smp algorithm, SpaRSA algorithm, TwIST algorithm, l ₀reconstruction algorithm, l ₁reconstruction algorithm, l ₂reconstruction algorithm; Sparse base adopts any one in dct basis, wavelet basis, Fourier transform base, gradient base, gabor transform-based; In the time that institute's observation texts and pictures picture itself has good sparse property,, by the variation of sparse base, directly original signal is not rebuild.

The astronomical spectrum picture acquisition methods that the present invention also provides the hypersensitive light spectrum image-forming astronomical telescope based on second order compressed sensing to realize, comprising:

Step 1) step obtained of light signal:

Step 2) optical modulation and single photon detection, the counting step of synchronousing working;

Described the first randomizer 10_1 produces random number and is used for controlling described the first spatial light modulator 2, described the second randomizer 10_2 generation random number for controlling described second space photomodulator 6; Described the first spatial light modulator 2 realizes the Stochastic Modulation to light signal in image dimension according to random number, described second space photomodulator 6 is realized the Stochastic Modulation to light signal in spectrum dimension according to random number; Described single photon point probe 8 is surveyed the single photon in the utmost point low light level to be measured, exports after the single photon signal collecting being converted to the electric signal of impulse form; Described counter 9 records the electric pulse number of the representative single photon number that described single photon point probe 8 sends; Described control module 11 is controlled coordination to whole hypersensitive light spectrum image-forming astronomical telescope, comprise job control and the transmitting of synchronizing pulse trigger pip to each parts, guarantee described counter 9, described the first spatial light modulator 2 and described second space photomodulator 6 synchronous workings;

Step 3) single photon number and the pretreated step of stochastic matrix;

The corresponding stochastic matrix of the first randomizer 10_1 is not done to pre-service;

In the time that the second randomizer 10_2 generates the speckle of two-value Bernoulli Jacob distribution, if the 1st frame is complete 1, by all column vector y of single photon number composition in a pixel of corresponding certain wavelength on counter 9, dimension is m × 1, m is total measurement number, and the stochastic matrix on second space photomodulator 6 is denoted as to A, and dimension is m × n, n is total signal length, and making the corresponding single photon number of the first frame is y ₁, make 2y-y ₁as new single photon number, 2A-1 is as new stochastic matrix;

In the time that the second randomizer 10_2 generates the speckle of two-value non-uniform Distribution, skip this step 3);

Step 4) compressed sensing spectrum picture recover step;

The stochastic matrix that the single photon number that described counter 9 records and described the first randomizer 10_1, described the second randomizer 10_2 generate all deposits in described packet memory 12; The stochastic matrix that first described compressed sensing module 13 utilizes single photon number in described packet memory 12 and corresponding described the second randomizer 10_2 to generate carries out the reconstruction of compressed sensing algorithm, obtains the curve of spectrum under 2 each Stochastic Modulation of described the first spatial light modulator; Then utilize and in each the curve of spectrum, represent that the photon numerical value of a certain wavelength carries out the reconstruction of compressed sensing algorithm with the stochastic matrix that corresponding described the first randomizer 10_1 generates, and obtains the astronomic graph picture of a certain wavelength; Respectively the astronomic graph of different wave length is looked like to rebuild, obtain the astronomical spectrum picture of utmost point low light level level.

In technique scheme, in step 1) also comprise before the step to each pixel corresponding wavelength is demarcated on described second space photomodulator 6; This step comprises:

Choose several specific wavelengths laser instrument transmitting specific wavelength light or leach the light of some specific wavelength from wide spectrum light source with optical filter, then the light of these special wavelength is irradiated into optical system from astronomical telescope camera lens, by the modulation condition of described second space photomodulator 6 is controlled, utilize described single photon point probe 8 to measure the photon number of each pixel on described second space photomodulator 6, photon number corresponding these specific wavelengths of peaked location of pixels that distribute; The wavelength that other location of pixels are corresponding can calculate according to linear distribution.

In technique scheme, in step 1) also comprise before the step that reduces noise of instrument; This step comprises: instrument is carried out to enclosed package, or the transmitance of raising optics, or the cleanliness of raising instrument internal, or the efficiency of raising spectrum beam splitting system 4, or the parameter including detection efficiency, dark counting of raising single photon point probe 8, or improve stability of instrument.

In technique scheme, in step 1) also comprise that before employing active optics or adaptive optics improve the step of signal noise ratio (snr) of image; Wherein, described active optics initiatively changes the shape of primary mirror minute surface by actuator, revises the impact that the deformation of the minute surface causing due to gravity, temperature and wind-force itself brings imaging, reduces consequent optical distortion; First described adaptive optics need to detect wavefront distortion situation, then by the small-sized variable shape minute surface that carries actuator that is arranged on telescope focal plane rear, wavefront is corrected in real time, thereby is repaired the distortions of factor to light wave wavefront such as atmospheric turbulence.

The invention has the advantages that:

1, the present invention has utilized up-to-date Mathematics Research achievement---compressive sensing theory, only need single photon point probe can obtain one dimension spectrum, two dimensional image three-dimensional information altogether, realize high-resolution astronomical spectrum picture observation, solve Information Dimension in present stage high sensitivity spectrum imaging and spent height, the problem of detector dimension deficiency;

2, in astronomical spectrum picture acquisition process, single photon point probe position can be fixed holding position, neither needs image to scan, and does not also need spectrum to scan, and has reduced the error that Mechanical Moving produces; Measuring process single photon point probe all can obtain the information of astronomic graph as overall region and spectrum entire scope each time, has ensured the homogeneity of the acquisition of information of image diverse location and different wave length;

3, each light signal of measuring in spatial light modulator (image) 2 and spatial light modulator (spectrum) 6 respectively has half to collect single photon point probe, therefore measure single photon point probe at every turn and all can obtain 1/4 of entire image all wavelengths light signal, the light signal strength of single measurement when image being scanned or spectrum is scanned, the equally light signal strength in single pixel when using single photon linear array or detector array to carry out image and spectrographic detection, it is a kind of high flux, the metering system of high s/n ratio, while allowing light spectrum image-forming thus, obtain more image information and the spectral information of small scale, can realize high image resolution, the high sensitivity spectrum picture of high spectral resolution is surveyed,

4, compressive sensing theory allows the hits of sub-sampling, in the present invention, all utilize compressive sensing theory in image detection and two stages of spectrographic detection, all realized sub-sampling in two stages, the measurement number of times that measurement number of times is realized image detection and spectrographic detection much smaller than single photon point probe scan pattern can utilize the shorter time to obtain astronomical spectrum picture;

5, the present invention utilizes single photon point probe to realize the sensitivity far above existing astronomical telescope, fundamentally solved in the past and improved the mode of astronomical telescope sensitivity from the approach that improves telescope bore, do not need the telescope lens of super large caliber can realize highly sensitive astronomical image detection, the telescope bore of appropriate size can improve the homogeneity of camera lens and optics, mechanical property, improves imaging precision and resolution;

6, the hypersensitive light spectrum image-forming astronomical telescope based on second order compressed sensing in the present invention can be widely used in the astronomical telescope under the condition of work such as ground, space, plays an important role for the development in the fields such as uranology, cosmology, astrophysics.

Brief description of the drawings

Fig. 1 is the structural representation of hypersensitive astronomical telescope of the present invention;

Drawing explanation

I optical unit

1 astronomical telescope camera lens 2 spatial light modulators (image)

3 collimating components 3_1 collecting lenses

3_2 diaphragm 3_3 collimation lens

4 spectrum light splitting part 5 spectrum are assembled parts

6 spatial light modulators (spectrum), 7 collecting parts

II electrical units

8 single photon point probe 9 counters

10 randomizer 10_1 randomizers (image)

10_2 randomizer (spectrum) 11 control modules

12 packet memory 13 compressed sensing modules

Fig. 2 is the reflex mechanism description figure of single micro mirror in Digital Micromirror Device.

Fig. 3 utilizes the photon number of different pixels on single photon linear array detector to realize the schematic diagram of light spectrum image-forming;

Drawing explanation

6 single photon linear array detector 7 counters

8 randomizers

Embodiment

Now the invention will be further described by reference to the accompanying drawings.

Hypersensitive light spectrum image-forming astronomical telescope based on second order compressed sensing of the present invention has utilized compressed sensing (Compressive Sensing, be called for short CS) principle, described compressed sensing principle is the brand-new mathematical theory being proposed by people such as Donoho, Tao and Candes.According to compressed sensing, by signal being carried out to the mode of stochastic sampling, can utilize the hits requiring far below Nyquist/Shannon's sampling theorem to realize the sampling to signal message, and ideally recover original signal by mathematical algorithm, and there is very high robustness.Compressed sensing is mainly divided into three steps: compression sampling, sparse conversion and algorithm are rebuild; Wherein, compression sampling, refers to be less than the process y=Ax that the measurement number of number of signals is sampled to signal, and wherein x is measured signal, and A is for measuring matrix, and y is measured value.Can compress surveying dimension the linear random sampling of signal simultaneously, only need to can obtain lower than original signal dimension detector the linear superposition information of signal.Described sparse conversion is to choose suitable sparse base Ψ, and making x is sparse through Ψ effect income value x ', and x can sparse expression under Ψ framework; It is at known measurements y that described algorithm is rebuild, measure the process that solves y=A Ψ x'+e under the condition of matrix A and sparse base Ψ, finally again by be finally inversed by x.

With reference to figure 1, the hypersensitive light spectrum image-forming astronomical telescope based on compressed sensing principle of the present invention comprises optical unit I and electrical units II; Wherein, optical unit I comprises astronomical telescope camera lens 1, the first spatial light modulator 2, collimating components 3, spectrum light splitting part 4, spectrum convergence parts 5, second space photomodulator 6, collecting part 7; Electrical units II comprises single photon point probe 8, counter 9, randomizer 10, control module 11, packet memory 12 and compressed sensing module 13;

In optical unit I, the optical signals astronomical telescope camera lens 1 of the single photon level of coming from celestial body propagation is collected, and be imaged onto in the first spatial light modulator 2, the imaging surface size of astronomical telescope camera lens should be suitable with the useful area of the first spatial light modulator 2, make on the useful area of the first spatial light modulator 2 overlay image information completely, astronomical telescope image that camera lens becomes can not exceed outside the useful area of the first spatial light modulator 2 simultaneously; The first spatial light modulator 2 looks like to carry out Stochastic Modulation to being imaged on its surperficial astronomic graph, with random chance, the light of diverse location on image is reflexed to collimating components 3 directions; Collimating components 3 comprises collecting lens 3_1, diaphragm 3_2, collimation lens 3_3; First the light of the first spatial light modulator 2 random reflected converge to diaphragm 3_2 by collecting lens 3_1, and limited spot size forms approximate pointolite, then forms directional light through collimation lens 3_3 collimation, is radiated on spectrum light splitting part 4; Spectrum light splitting part 4 by the light of different wave length to different directions outgoing; After spectrum is assembled parts 5, the light of different wave length converges to spectrum and assembles the diverse location on parts 5 focal planes, forms band; Second space photomodulator 6 is placed on the focal plane position of spectrum convergence parts 5, and its surperficial band is carried out to Stochastic Modulation, with random chance, the light of diverse location on band is reflexed to collecting part 7 directions; Collecting part 7 is collected the light signal that second space photomodulator 6 reflects and come, and is surveyed by single photon point probe 8 in electrical units II;

In electrical units II, described randomizer 10 comprises the first randomizer 10_1, and the second randomizer 10_2 produces respectively random number for controlling described the first spatial light modulator 2 and described second space photomodulator 6; Described the first spatial light modulator 2 realizes the Stochastic Modulation to light signal in image dimension according to random number, described second space photomodulator 6 is realized the Stochastic Modulation to light signal in spectrum dimension according to this random number; Described single photon point probe 8 is surveyed the single photon in the utmost point low light level to be measured, exports after the single photon signal collecting being converted to the electric signal of impulse form; Described counter 9 records the electric pulse number of the representative single photon number that described single photon point probe 8 sends; Described control module 11 is controlled coordination to whole hypersensitive light spectrum image-forming astronomical telescope, comprise job control and the transmitting of synchronizing pulse trigger pip to each parts, guarantee described counter 9, described the first spatial light modulator 2 and described second space photomodulator 6 synchronous workings; The stochastic matrix that the single photon number that described counter 9 records and described the first randomizer 10_1, described the second randomizer 10_2 generate all deposits in described packet memory 12; Described compressed sensing module 13 is utilized single photon number and the corresponding stochastic matrix in described packet memory 12, and chooses suitable sparse base astronomical spectrum picture is rebuild, and obtains the astronomical spectrum picture of utmost point low light level level.

Be more than the description of the general structure to the hypersensitive light spectrum image-forming astronomical telescope based on second order compressed sensing of the present invention, below the specific implementation of all parts in the hypersensitive light spectrum image-forming astronomical telescope based on second order compressed sensing be further described.

Described astronomical telescope camera lens 1 is for collecting the photon signal of launching and propagate into position of telescope from celestial body, and celestial body is carried out to imaging.The picture quality such as imaging resolution and aberration, aberration of astronomical telescope is mainly determined by astronomical telescope camera lens.The structure of astronomical telescope camera lens can adopt the camera lens of following any one astronomical telescope type: reflective astronomical telescope, comprises Newtonian, Cassegrain's formula, Ge Lishi etc.; Refraction type astronomical telescope, comprises Galileo telescope, Kepler telescope etc.; Refracting-reflecting astronomical telescope, comprises Schmidt-Cassegrain formula, Maksutov-Cassegrain formula etc.; Multi mirror telescope; Binoculars; Also comprise the space solar telescope being applied on satellite, space station.

Described the first spatial light modulator 2 and described second space photomodulator 6 all belong to spatial light modulator (SLM), and it can load on information in the light field of one dimension or bidimensional.This class device can be under the control of time dependent electric drive signal or other signals, change photodistributed amplitude or intensity, phase place, polarization state and wavelength on space, or incoherent light is changed into coherent light, it is the Primary Component in the contemporary optics fields such as real-time optical information processing, optical computing, optical neural network and adaptive optics, its kind has a variety of, mainly contain Digital Micromirror Device (Digital Micro-mirror Device is called for short DMD), liquid crystal light valve, frosted glass etc.In the present embodiment, described SLM is Digital Micromirror Device, comprises micro mirror array and integrated circuit part.In other embodiments, can be also the SLM of other type.The device that the first spatial light modulator 2 and described second space photomodulator 6 can be same types, as all adopted DMD, can be also dissimilar device, and as the first spatial light modulator 2 adopts DMD, second space photomodulator 6 adopts liquid crystal light valve.

The DMD adopting in the present embodiment includes the array (DMD of main flow is made up of 1024 × 768 array) that is arranged in a large number the micro mirror on hinge, each eyeglass is of a size of 14 μ m × 14 μ m, and can realize independent control to the light in each pixel.Carry out electronic addressing by the storage unit under each eyeglass with binary signal, just can allow each eyeglass (in the present embodiment, be+12 ° and-12 °) to 10～12 ° of left and right of both sides upsets under electrostatic interaction, this two states is designated as to 1 and 0, respectively corresponding " opening " and " pass ", in the time that eyeglass is not worked, they are in " berthing " state of 0 °.

In Fig. 2, the reflex mechanism of the single micro mirror in DMD is described.In figure, rectangle represents DMD micro mirror, and 0 ° of position is micro mirror initial position.In figure, mark the normal direction of micro mirror in the time of initial position, and light incident, exit direction.When micro mirror is during in+12 ° of rollover states, micro mirror turns clockwise+12 °, and normal direction is+12 ° of rotations thereupon also.According to reflection law, reflected light will turn clockwise 24 °; In like manner, when micro mirror is during in-12 ° of rollover states, reflected light will be rotated counterclockwise 24 °.Therefore, the reflected light of both direction becomes 48 ° of angles.When collimating components 3 or collecting part 7 are during in+12 ° or-12 ° of reflection directions, can not collect to the photon of another direction reflection, can realize at random the light of the upper diverse location of DMD is collected into light path.

Described collimating components 3, for collimating the light of the first spatial light modulator 2 Stochastic Modulation, becomes directional light and offers described spectrum light splitting part 4, and the depth of parallelism of light is higher, and the resolution of spectrum light splitting is higher.Described collecting lens 3_1 converges light to described diaphragm 3_2, and limited spot size forms approximate pointolite, then forms directional light through described collimation lens 3_3 collimation.Described collecting lens 3_1, described collimation lens 3_3 scioptics or concave mirror are realized; Described diaphragm 3_2 realizes by slit or aperture.

Described spectrum light splitting part 4 comprises dispersion light splitting part and pre-filter part.Dispersion light splitting part is for separating the light of different wave length.Directional light impinges upon after dispersion light splitting part, and the light of different wave length can be with different angles transmission or reflection.The device that dispersion light splitting part adopts grating, prism etc. to have light splitting ability is realized, and in the present embodiment, dispersion light splitting part adopts blazed grating to realize.Pre-filter part is for first leach the light that needs the wavelength of surveying before spectrum light splitter part at irradiation, and other do not carry out the light of the wavelength of light spectrum image-forming filtering, can reduce the noise in light path.Pre-filter part is realized by optical filter.As the optional implementation of one, described spectrum light splitting part 4 only comprises dispersion light splitting part, does not comprise pre-filter part.

Described spectrum is assembled parts 5 for assembling the light after described spectrum light splitting part 4 dispersions.The light that incides described spectrum convergence parts 5 with equidirectional converges to point identical on its focal plane, the light of different directions incident converges to described spectrum and assembles different point on parts 5 focal planes, and therefore described spectrum convergence parts 5 are sequentially arranged in the light of different wave length on focal plane from small to large by wavelength.Described spectrum is assembled parts 5 and is realized by lens or concave mirror.In the present embodiment, described spectrum is assembled parts 5 and is realized by lens.

Described second space photomodulator 6 is placed on described spectrum and assembles on the focal plane of parts 5, and therefore the light of different wave length is sequentially arranged on described second space photomodulator 6 in different pixels from small to large by wavelength.The orientation of wavelength can be parallel with Pixel arrangement direction on described second space photomodulator 6, also can be along cornerwise direction, and other become direction at any angle with Pixel arrangement direction on described second space photomodulator 6.In the present embodiment, the orientation of wavelength is parallel with Pixel arrangement direction on described second space photomodulator 6.

When described the first spatial light modulator 2 is stable in the Stochastic Modulation time each time, described second space photomodulator 6 carries out several times Stochastic Modulation.Described the first spatial light modulator 2 is in the time of different random modulation condition, and the Stochastic Modulation sequence of described second space photomodulator 6 can be same or different.In the present embodiment, described the first spatial light modulator 2 is in the time of Stochastic Modulation state each time, and the Stochastic Modulation sequence of described second space photomodulator 6 is all identical.For example, the Stochastic Modulation of spatial light modulator 2 is 1010, and when spatial light modulator 2 is during in 1 state, spatial light modulator 6 is repeatedly modulated, as 110011; Spatial light modulator 2 is in the time of 0 state, and spatial light modulator 6 still modulates 110011.

Described collecting part 7 is realized by lens or concave mirror.In the present embodiment, described collecting part 7 adopts lens to realize.

Described single photon point probe 8 adopts Geiger mode angular position digitizer avalanche diode or photomultiplier to realize.In the present embodiment, described single photon point probe 8 adopts Geiger mode angular position digitizer avalanche diode to realize.

Described control module 11 realizes job control and the trigger pulse control to each parts, guarantees that between described counter 9 and described the first spatial light modulator 2, described second space photomodulator 6, synchronous working comprises: described the first spatial light modulator 2 carries out several times Stochastic Modulation; In the time that described the first spatial light modulator 2 is stable in the Stochastic Modulation time each time, described second space photomodulator 6 carries out several times Stochastic Modulation; Described second space photomodulator 6 often carries out Stochastic Modulation one time, described counter 9 is accumulated respectively the electric pulse number of the representative single photon number that described single photon point probe 8 sends, until described second space photomodulator 6 carries out Stochastic Modulation next time, described counter 9 is stable at a photon counting in the Stochastic Modulation time by described second space photomodulator 6 again and transfers to packet memory 12, and will count zero clearing, start counting next time.

Described compressed sensing module 13 is utilized single photon number in described packet memory 12 and corresponding stochastic matrix, and chooses suitable sparse base the astronomic graph of different wave length is looked like to rebuild, and obtains the astronomical spectrum picture of utmost point low light level level.This module only needs a small amount of linear random projection of astronomic graph picture and band under each wavelength just can reconstruct astronomical spectrum picture, and can utilize matrix fill-in theory to make up the loss of learning in astronomical spectrum picture.Wherein, described sparse conversion is to choose suitable Ψ, make astronomic graph as x can be under Ψ framework sparse expression.Compressed sensing module 13 adopts any one in following algorithm to realize compressed sensing: coupling track algorithm MP, orthogonal coupling track algorithm OMP, base track algorithm BP, greedy reconstruction algorithm, LASSO, LARS, GPSR, Bayesian Estimation algorithm, magic, IST, TV, StOMP, CoSaMP, LBI, SP, l1_ls, smp algorithm, SpaRSA algorithm, TwIST algorithm, l ₀reconstruction algorithm, l ₁reconstruction algorithm, l ₂reconstruction algorithm.Sparse base adopts any one in dct basis, wavelet basis, Fourier transform base, gradient base, gabor transform-based.In the time that institute's observation texts and pictures picture itself has good sparse property, can, not by the variation of sparse base, directly original signal be rebuild.

Fig. 3 has described stochastic matrix on the photon number utilizing single photon point probe 8 to survey to obtain and the first spatial light modulator 2, second space photomodulator 6 and has realized the process of light spectrum image-forming.In figure 2 represents the first spatial light modulator, and 6 represent second space photomodulator, and 8 represent single photon point probe, and 9 represent counter.

The first spatial light modulator 2 carries out N time Stochastic Modulation altogether, corresponding N stochastic matrix n ₁, n ₂n _n, within the Stochastic Modulation time of the first spatial light modulator 2, second space photomodulator 6 carries out Stochastic Modulation M time, corresponding M stochastic matrix m ₁, m ₂m _m.Second space photomodulator 6 was fixed in each Stochastic Modulation time, and the photon number that single photon point probe 8 detects is by counter 9 records.In the first spatial light modulator 2 Stochastic Modulation time each time, corresponding M the count value of M Stochastic Modulation of second space photomodulator 6, obtains a light intensity curve I.The corresponding N bar of N the Stochastic Modulation light intensity curve I of the first spatial light modulator 2 ₁, I ₂i _n.

When spectrum picture is rebuild, utilize first respectively M photon count value of 1 light intensity curve and M stochastic matrix m of second space photomodulator 6 ₁, m ₂m _mcarry out compressed sensing calculating, when obtaining the first spatial light modulator 2 and being fixed on a Stochastic Modulation, light distribution on second space photomodulator 6, due to each pixel corresponding wavelength light signal from small to large on second space photomodulator 6, obtained a curve of spectrum, its spectrum segment number equates with the pixel count K of second space photomodulator 6 lastrows.Can obtain the N bar curve of spectrum by N bar light intensity curve, corresponding with N Stochastic Modulation in the first spatial light modulator 2.

The light intensity of getting a certain same position on the N bar curve of spectrum, obtains representing a certain wavelength X _kthe intensity level N of light signal, N Stochastic Modulation in corresponding the first spatial light modulator 2 respectively.Utilize this N photon count value and N stochastic matrix n1, n2 ... nN carries out compressed sensing calculating, can obtain this wavelength X _kimage.Utilize the light intensity of each position on the N bar curve of spectrum, with N stochastic matrix n in the first spatial light modulator 2 ₁, n ₂n _ncarry out compressed sensing calculating, can obtain the image of each wavelength, realize the light spectrum image-forming to astronomical target.

It is more than the structure explanation to the hypersensitive light spectrum image-forming astronomical telescope based on second order compressed sensing of the present invention.Below the course of work of this light spectrum image-forming astronomical telescope is described.

Hypersensitive light spectrum image-forming astronomical telescope based on second order compressed sensing of the present invention comprises the following steps in the time of work:

Step 1) step obtained of light signal:

Described in the optical signals of the single photon level of coming from celestial body propagation, astronomical telescope camera lens 1 is collected, and is imaged onto in described the first spatial light modulator 2; Described the first spatial light modulator 2 looks like to carry out Stochastic Modulation to being imaged on its surperficial astronomic graph, with random chance, the light of diverse location on image is reflexed to described collimating components 3 directions; Described collimating components 3 comprises collecting lens 3_1, diaphragm 3_2, collimation lens 3_3; First the light of described the first spatial light modulator 2 random reflected converge to described diaphragm 3_2 by described collecting lens 3_1, limited spot size, form approximate pointolite, then form directional light through described collimation lens 3_3 collimation, be radiated on described spectrum light splitting part 4; Described spectrum light splitting part 4 by the light of different wave length to different directions outgoing; After described spectrum is assembled parts 5, the light of different wave length converges to described spectrum and assembles diverse location on parts 5 focal planes, forms band; Described second space photomodulator 6 is placed on the focal plane position of described spectrum convergence parts 5, and its surperficial band is carried out to Stochastic Modulation, with random chance, the light of diverse location on band is reflexed to described collecting part 7 directions; Described collecting part 7 is collected the light signal that described second space photomodulator 6 reflects and come, and is surveyed by single photon point probe 8 in described electrical units II;

Described randomizer 10 comprises the first randomizer 10_1, and the second randomizer 10_2 produces respectively random number for controlling described the first spatial light modulator 2 and described second space photomodulator 6; Described the first spatial light modulator 2 realizes the Stochastic Modulation to light signal in image dimension according to random number, described second space photomodulator 6 is realized the Stochastic Modulation to light signal in spectrum dimension according to this random number; Described single photon point probe 8 is surveyed the single photon in the utmost point low light level to be measured, exports after the single photon signal collecting being converted to the electric signal of impulse form; Described counter 9 records the electric pulse number of the representative single photon number that described single photon point probe 8 sends; Described control module 11 is controlled coordination to whole hypersensitive light spectrum image-forming astronomical telescope, comprise job control and the transmitting of synchronizing pulse trigger pip to each parts, guarantee described counter 9, described the first spatial light modulator 2 and described second space photomodulator 6 synchronous workings;

Step 3) single photon number and the pretreated step of stochastic matrix;

The corresponding stochastic matrix of the first randomizer (10_1) is not done to pre-service;

In the time that the second randomizer (10_2) generates the speckle of two-value Bernoulli Jacob distribution, if the 1st frame is complete 1, by all column vector y of single photon number composition in a pixel of upper corresponding certain wavelength of counter (9), dimension is m × 1, m is total measurement number, and the stochastic matrix on second space photomodulator (6) is denoted as to A, and dimension is m × n, n is total signal length, and making the corresponding single photon number of the first frame is y ₁, make 2y-y ₁as new single photon number, 2A-1 is as new stochastic matrix;

In the time that the second randomizer (10_2) generates the speckle of two-value non-uniform Distribution, skip this step 3);

Step 4) compressed sensing spectrum picture recover step;

As the preferred implementation of one, in another embodiment, in step 1) also comprise before the operation to each pixel corresponding wavelength is demarcated on described second space photomodulator 6.At timing signal, first choose the laser instrument of several specific wavelengths, or leach the light of some specific wavelength from wide spectrum light source with optical filter, then respectively the light of special wavelength is irradiated into optical system from astronomical telescope camera lens, by the modulation condition control to described second space photomodulator 6, utilize described single photon point probe 8 to measure the photon number of each pixel on described second space photomodulator 6, photon number i.e. corresponding these specific wavelengths of peaked location of pixels that distribute.The wavelength that other location of pixels are corresponding can calculate according to linear distribution.

As the preferred implementation of one, In yet another embodiment, in step 1) also include before the operation that reduces noise of instrument.Noise of instrument source comprises neighbourhood noise, optical noise, electrical noise etc.In compressed sensing sampling, information is present in the fluctuation of probe value, if the fluctuation of signal has been flooded in the fluctuation of noise of instrument, compressed sensing algorithm lost efficacy; If the fluctuation of noise of instrument is less than or much smaller than the fluctuation of signal, can be better perfect reconstruction image even.Therefore, reduce noise of instrument and contribute to improve image quality.The mode of minimizing noise of instrument has multiple, as instrument is carried out to enclosed package, enters optical system and detection system to block external environment condition light signal; Improve the transmitance of optics, improve the cleanliness of instrument internal, reduce decay and the scattering of light signal; Improve the efficiency of spectrum light splitting part 4; Improve the parameter such as detection efficiency, dark counting of single photon point probe 8; Improve stability of instrument, reduce instrument and shake the impact on imaging resolution.

As the preferred implementation of one, In yet another embodiment, in step 1) also include before the operation that utilizes active optics, adaptive optics to improve light spectrum image-forming signal to noise ratio (S/N ratio).Active optics is a kind of Wavefront Rectification technology adopting for eliminating distortion that telescopical optical system and support affect by gravity, temperature, wind-force etc. to cause.Initiatively change the shape of primary mirror minute surface by actuator, can revise the impact that the deformation of the minute surface causing due to gravity, temperature and wind-force itself brings imaging, reduce consequent optical distortion.Adaptive optics is the technology of wavefront distortion in the imaging process that caused by atmospheric turbulence or other factors of a kind of compensation.First adaptive optics need to detect wavefront distortion situation, then by the small-sized variable shape minute surface that carries actuator that is arranged on telescope focal plane rear, wavefront is corrected in real time, thereby is repaired the distortions of factor to light wave wavefront such as atmospheric turbulence.Astronomical telescope camera lens 1 is designed according to the requirement of active optics or adaptive optics, can effectively improve the image quality of astronomical telescope camera lens 1, and then improve the astronomic graph image quality that hypersensitive light spectrum image-forming astronomical telescope obtains.

It should be noted last that, above embodiment is only unrestricted in order to technical scheme of the present invention to be described.Although the present invention is had been described in detail with reference to embodiment, those of ordinary skill in the art is to be understood that, technical scheme of the present invention is modified or is equal to replacement, do not depart from the spirit and scope of technical solution of the present invention, it all should be encompassed in the middle of claim scope of the present invention.

Claims

1. the hypersensitive light spectrum image-forming astronomical telescope based on second order compressed sensing, is characterized in that, comprises optical unit (I) and electrical units (II); Wherein, optical unit (I) comprises astronomical telescope camera lens (1), the first spatial light modulator (2), collimating components (3), spectrum light splitting part (4), spectrum convergence parts (5), second space photomodulator (6), collecting part (7); Electrical units (II) comprises single photon point probe (8), counter (9), randomizer (10), control module (11), packet memory (12) and compressed sensing module (13); Wherein, described collimating components (3) comprises collecting lens (3_1), diaphragm (3_2), collimation lens (3_3); Described randomizer (10) comprises the first randomizer (10_1), the second randomizer (10_2);

Described in the optical signals of the single photon level of coming from celestial body propagation, astronomical telescope camera lens (1) is collected, and is imaged onto in described the first spatial light modulator (2); Described the first spatial light modulator (2) looks like to carry out Stochastic Modulation to being imaged on its surperficial astronomic graph, with random chance, the light of diverse location on image is reflexed to described collimating components (3) direction; First the light of described the first spatial light modulator (2) random reflected converge to described diaphragm (3_2) by described collecting lens (3_1), limited spot size, form approximate pointolite, then pass through described collimation lens (3_3) collimation and form directional light, be radiated on described spectrum light splitting part (4); Described spectrum light splitting part (4) by the light of different wave length to different directions outgoing; After described spectrum is assembled parts (5), the light of different wave length converges to described spectrum and assembles diverse location on parts (5) focal plane, forms band; Described second space photomodulator (6) is placed on the focal plane position of described spectrum convergence parts (5), its surperficial band is carried out to Stochastic Modulation, with random chance, the light of diverse location on band is reflexed to described collecting part (7) direction; Described collecting part (7) is collected described second space photomodulator (6) reflection and next light signal, by single photon point probe (8) detection in described electrical units (II);

Described the first randomizer (10_1) generation random number is used for controlling described the first spatial light modulator (2), described the second randomizer (10_2) produces random number and is used for controlling described second space photomodulator (6); Described the first spatial light modulator (2) and described second space photomodulator (6) are realized the Stochastic Modulation to light signal according to this random number; Described single photon point probe (8) is surveyed the single photon in the utmost point low light level to be measured, exports after the single photon signal collecting being converted to the electric signal of impulse form; Described counter (9) records the electric pulse number of the representative single photon number that described single photon point probe (8) sends; Described control module (11) is controlled coordination to whole hypersensitive light spectrum image-forming astronomical telescope, comprise job control and the transmitting of synchronizing pulse trigger pip to each parts, guarantee described counter (9), described the first spatial light modulator (2) and described second space photomodulator (6) synchronous working; The stochastic matrix that the single photon number that described counter (9) records and described the first randomizer (10_1), described the second randomizer (10_2) generate all deposits in described packet memory (12); Described compressed sensing module (13) is utilized single photon number and the corresponding stochastic matrix in described packet memory (12), and choose sparse base astronomical spectrum picture is rebuild, obtain the astronomical spectrum picture of utmost point low light level level.

2. the hypersensitive light spectrum image-forming astronomical telescope based on second order compressed sensing according to claim 1, it is characterized in that, described the first randomizer (10_1), the second randomizer (10_2) are for generating the speckle of two-value Bernoulli Jacob distribution or the speckle of two-value non-uniform Distribution, and two-value forms by 0 and 1; Wherein, in the time that the second randomizer (10_2) generates the speckle that two-value Bernoulli Jacob distributes, need make the speckle of the first frame complete 1, and Bernoulli Jacob distribute and is obtained by Walsh or Hadamard or noiselet conversion; In the time that the second randomizer (10_2) generates the speckle of two-value non-uniform Distribution, in every frame speckle, 1 number need be much smaller than 0 number, and 1 is random in the space distribution of every frame speckle; The speckle that the first randomizer (10_1) generates does not limit.

3. the hypersensitive light spectrum image-forming astronomical telescope based on second order compressed sensing according to claim 1, it is characterized in that, described astronomical telescope camera lens (1) adopts the camera lens of following any one astronomical telescope type: reflective astronomical telescope, comprises Newtonian, Cassegrain's formula, Ge Lishi; Refraction type astronomical telescope, comprises Galileo telescope, Kepler telescope; Refracting-reflecting astronomical telescope, comprises Schmidt-Cassegrain formula, Maksutov-Cassegrain formula; Multi mirror telescope; Binoculars; Also comprise the space solar telescope being applied on satellite, space station.

4. the hypersensitive light spectrum image-forming astronomical telescope based on second order compressed sensing according to claim 1, is characterized in that, described the first spatial light modulator (2) or second space photomodulator (6) adopt Digital Micromirror Device to realize.

5. the hypersensitive light spectrum image-forming astronomical telescope based on second order compressed sensing according to claim 1, it is characterized in that, collecting lens (3_1) in described collimating components (3), collimation lens (3_3) scioptics or concave mirror are realized; Diaphragm (3_2) is realized by slit or aperture.

6. the hypersensitive light spectrum image-forming astronomical telescope based on second order compressed sensing according to claim 1, it is characterized in that, described spectrum light splitting part (4) comprises the dispersion light splitting part for the light of different wave length is separated, and described dispersion light splitting part adopts the device with light splitting ability including grating, prism to realize.

7. the hypersensitive light spectrum image-forming astronomical telescope based on second order compressed sensing according to claim 6, it is characterized in that, described spectrum light splitting part (4) also comprises the pre-filter part that does not carry out the light of the wavelength of light spectrum image-forming for filtering, and described pre-filter part is realized by optical filter.

8. the hypersensitive light spectrum image-forming astronomical telescope based on second order compressed sensing according to claim 1, is characterized in that, described spectrum is assembled parts (5) and realized by lens or concave mirror; Described spectrum is assembled parts (5) light of different wave length is transmitted in the different pixels of described second space photomodulator (6) from small to large successively by wavelength.

9. the hypersensitive light spectrum image-forming astronomical telescope based on second order compressed sensing according to claim 1, it is characterized in that, when described the first spatial light modulator (2) is stable in the Stochastic Modulation time each time, described second space photomodulator (6) carries out several times Stochastic Modulation.

10. the hypersensitive light spectrum image-forming astronomical telescope based on second order compressed sensing according to claim 1, is characterized in that, described collecting part (7) is realized by lens or concave mirror.

The 11. hypersensitive light spectrum image-forming astronomical telescopes based on second order compressed sensing according to claim 1, is characterized in that, described single photon point probe (8) adopts Geiger mode angular position digitizer avalanche diode or photomultiplier to realize.

The 12. hypersensitive light spectrum image-forming astronomical telescopes based on second order compressed sensing according to claim 1, it is characterized in that, described control module (11) guarantees that between described counter (9) and described the first spatial light modulator (2), described second space photomodulator (6), synchronous working comprises: described the first spatial light modulator (2) carries out several times Stochastic Modulation; When described the first spatial light modulator (2) was stable in the Stochastic Modulation time each time, described second space photomodulator (6) carries out several times Stochastic Modulation; Described second space photomodulator (6) often carries out Stochastic Modulation one time, described counter (9) is accumulated respectively the electric pulse number of the representative single photon number that described single photon point probe (8) sends, until described second space photomodulator (6) carries out Stochastic Modulation next time, described counter (9) is stable at a photon counting in the Stochastic Modulation time by described second space photomodulator (6) and transfers to packet memory (12), and will count zero clearing, start counting next time.

The 13. hypersensitive light spectrum image-forming astronomical telescopes based on second order compressed sensing according to claim 1, it is characterized in that, described compressed sensing module (13) adopts any one in following algorithm to realize compressed sensing: coupling track algorithm MP, orthogonal coupling track algorithm OMP, base track algorithm BP, greedy reconstruction algorithm, LASSO, LARS, GPSR, Bayesian Estimation algorithm, magic, IST, TV, StOMP, CoSaMP, LBI, SP, l1_ls, smp algorithm, SpaRSA algorithm, TwIST algorithm, l ₀reconstruction algorithm, l ₁reconstruction algorithm, l ₂reconstruction algorithm; Sparse base adopts any one in dct basis, wavelet basis, Fourier transform base, gradient base, gabor transform-based; In the time that institute's observation texts and pictures picture itself has good sparse property,, by the variation of sparse base, directly original signal is not rebuild.

The 14. astronomical spectrum picture acquisition methods of realizing according to the hypersensitive light spectrum image-forming astronomical telescope based on second order compressed sensing described in claim 1-13, comprising:

Step 1) step obtained of light signal:

Described the first randomizer (10_1) generation random number is used for controlling described the first spatial light modulator (2), described the second randomizer (10_2) produces random number and is used for controlling described second space photomodulator (6); Described the first spatial light modulator (2) realizes the Stochastic Modulation to light signal in image dimension according to random number, described second space photomodulator (6) is realized the Stochastic Modulation to light signal in spectrum dimension according to random number; Described single photon point probe (8) is surveyed the single photon in the utmost point low light level to be measured, exports after the single photon signal collecting being converted to the electric signal of impulse form; Described counter (9) records the electric pulse number of the representative single photon number that described single photon point probe (8) sends; Described control module (11) is controlled coordination to whole hypersensitive light spectrum image-forming astronomical telescope, comprise job control and the transmitting of synchronizing pulse trigger pip to each parts, guarantee described counter (9), described the first spatial light modulator (2) and described second space photomodulator (6) synchronous working;

Step 3) single photon number and the pretreated step of stochastic matrix;

Step 4) compressed sensing spectrum picture recover step;

The stochastic matrix that the single photon number that described counter (9) records and described the first randomizer (10_1), described the second randomizer (10_2) generate all deposits in described packet memory (12); The stochastic matrix that described compressed sensing module (13) first utilizes single photon number in described packet memory (12) and corresponding described the second randomizer (10_2) to generate carries out the reconstruction of compressed sensing algorithm, obtains the curve of spectrum under each Stochastic Modulation of described the first spatial light modulator (2); Then utilize and in each the curve of spectrum, represent that the photon numerical value of a certain wavelength carries out the reconstruction of compressed sensing algorithm with the stochastic matrix that corresponding described the first randomizer (10_1) generates, and obtains the astronomic graph picture of a certain wavelength; Respectively the astronomic graph of different wave length is looked like to rebuild, obtain the astronomical spectrum picture of utmost point low light level level.

15. astronomical spectrum picture acquisition methods according to claim 14, is characterized in that, in step 1) also comprise before described second space photomodulator (6) step that above each pixel corresponding wavelength is demarcated; This step comprises:

Choose several specific wavelengths laser instrument transmitting specific wavelength light or leach the light of some specific wavelength from wide spectrum light source with optical filter, then the light of these special wavelength is irradiated into optical system from astronomical telescope camera lens, by the modulation condition of described second space photomodulator (6) is controlled, utilize described single photon point probe (8) to measure the photon number of upper each pixel of described second space photomodulator (6), photon number corresponding these specific wavelengths of peaked location of pixels that distribute; The wavelength that other location of pixels are corresponding can calculate according to linear distribution.

16. according to the astronomical spectrum picture acquisition methods described in claims 14 or 15, it is characterized in that, in step 1) also comprise before the step that reduces noise of instrument; This step comprises: instrument is carried out to enclosed package, or the transmitance of raising optics, or the cleanliness of raising instrument internal, or the efficiency of raising spectrum beam splitting system (4), or the parameter including detection efficiency, dark counting of raising single photon point probe (8), or improve stability of instrument.

17. according to the astronomical spectrum picture acquisition methods described in claims 14 or 15 or 16, it is characterized in that, in step 1) also comprise that before employing active optics or adaptive optics improve the step of signal noise ratio (snr) of image; Wherein, described active optics initiatively changes the shape of primary mirror minute surface by actuator, revises the impact that the deformation of the minute surface causing due to gravity, temperature and wind-force itself brings imaging, reduces consequent optical distortion; First described adaptive optics need to detect wavefront distortion situation, then by the small-sized variable shape minute surface that carries actuator that is arranged on telescope focal plane rear, wavefront is corrected in real time, thereby is repaired the distortions of factor to light wave wavefront such as atmospheric turbulence.