CN120233376B - A distributed synthetic aperture imaging device and method based on information coherence theory - Google Patents

Abstract

The embodiment of the invention provides a distributed synthetic aperture imaging device and method based on an information coherence theory. The device comprises an optical information processing component, a beam splitter, a wavefront sensor, a phase modulator and an image sensor, wherein the optical information processing component is used for converting light into a plurality of sub-aperture light beams with different frequency bands, the beam splitter is used for splitting each sub-aperture light beam into a first light beam and a second light beam respectively, emitting the first light beam to the wavefront sensor and emitting the second light beam to the phase modulator, the wavefront sensor is used for detecting and obtaining common aberration of each first light beam, the phase modulator is used for compensating the phase of each incident second light beam according to the common aberration, emitting the compensated second light beams to the image sensor and performing coherent imaging, and the image sensor is used for recording images generated by coherent imaging. The limitations of the existing paradigm on synthetic aperture imaging techniques can be broken, making it suitable for use in a wider range of scenarios.

Description

Distributed synthetic aperture imaging device and method based on information coherence theory

Technical Field

The invention relates to the technical field of synthetic aperture imaging, in particular to a distributed synthetic aperture imaging device and method based on an information coherence theory.

Background

Synthetic aperture telescopes based on synthetic aperture imaging technology are core tools in the field of deep space exploration and space astronomical research, whose operation relies on optical coherence techniques. The reconstruction of the low-resolution images acquired by the plurality of sub-mirrors is realized in a coherent mode, so that the performance of the telescope with larger caliber is simulated.

In the related art, the implementation of the synthetic aperture technique often relies on a fizeau interferometer (image plane interference) and a michelson interferometer (pupil plane interference), both of which require the deployment of multiple sub-mirrors to expand the number of sub-apertures for effective observation. However, as the aperture of telescope systems continues to increase, the number of sub-mirrors that need to be deployed to achieve both of the foregoing increases.

With the increase of the number of sub-mirrors, the conventional manner of controlling the optical correlation between sub-mirrors by physical means and manufacturing processes faces serious challenges, and the existing manner of implementing optical coherence is difficult to meet the current requirements of the number of sub-mirrors, and bottleneck problems include complex manufacturing process, high cost, high system integration difficulty, insufficient imaging quality and the like, which restrict the further development and application potential of the synthetic aperture imaging technology.

Disclosure of Invention

The embodiment of the invention aims to provide a distributed synthetic aperture imaging device and method based on an information coherence theory, so that optical correlation is realized without depending on traditional physical means and manufacturing processes, and the constraint of the physical means and the manufacturing processes on a synthetic aperture imaging technology is broken, so that the synthetic aperture imaging technology can be effectively applied to a larger-scale (kilometer-scale) distributed optical system. The specific technical scheme is as follows:

In a first aspect of the application, there is provided a distributed synthetic aperture imaging device based on information coherence theory, comprising an optical information processing component, a beam splitter, a wavefront sensor, a phase modulator, an image sensor;

The optical information processing component is used for converting light rays entering the device into a plurality of sub-aperture light beams with different frequency bands and emitting the sub-aperture light beams to the beam splitter;

the beam splitter is used for splitting each incident sub-aperture beam into a first beam and a second beam, emitting the first beam to the wavefront sensor and emitting the second beam to the phase modulator;

The wavefront sensor is used for detecting and obtaining the common aberration of each first light beam and sending the common aberration to the phase modulator;

The phase modulator is used for compensating the phase of each incident second light beam according to the common aberration, and emitting each compensated second light beam to the image sensor for coherent imaging;

the image sensor is used for recording images generated by the coherent imaging.

In a possible embodiment, the phase modulator is a spatial light modulator for adjusting the loaded phase to be negative in response to a common aberration transmitted by the wavefront sensor.

In a possible embodiment, the apparatus further comprises a mirror disposed between the beam splitter and the spatial light modulator;

the outputting the second light beam to the phase modulator includes:

the second light beam is emitted to a reflector and is incident to the spatial light modulator under the reflection of the reflector;

and taking the direction from the beam splitter to the reflecting mirror as a first direction, and the direction from the reflecting mirror to the spatial light modulator as a second direction, wherein the included angle between the first direction and the second direction is larger than a first angle threshold.

In a possible embodiment, the apparatus further comprises a first fourier lens disposed between the beam splitter and the mirror, a second fourier lens disposed between the mirror and the spatial light modulator;

the first Fourier lens and the second Fourier lens form a 4F optical system;

The emitting the second light beam to a reflector and making the second light beam incident to the spatial light modulator under the reflection of the reflector comprises:

The second light beam is emitted to the reflecting mirror through the first Fourier lens, and is incident to the spatial light modulator through the second Fourier lens under the reflection of the reflecting mirror, wherein the first Fourier lens is used for carrying out Fourier transform on the incident light beam, and the second Fourier lens is used for carrying out inverse Fourier transform on the incident light beam.

In one possible embodiment, the optical information processing component is specifically configured to convert light incident on the device into a frequency domain, select a plurality of light beams with preset frequency bands from the frequency domain as sub-aperture light beams, and output each sub-aperture light beam to the beam splitter.

In one possible embodiment, the optical information processing component includes a third fourier lens and a fourth fourier lens;

the third Fourier lens and the fourth Fourier lens form a 4F optical system;

the third Fourier lens is used for projecting light rays incident on the device to a frequency spectrum surface;

And the fourth Fourier lens is used for selecting a plurality of components with preset frequency bands from the frequency spectrum surface as sub-apertures to obtain sub-aperture light beams and emitting the sub-aperture light beams to the beam splitter.

In a possible embodiment, the apparatus further comprises a focusing lens group disposed between the phase modulator and the image sensor;

the outputting the compensated second light beams to the image sensor includes:

And outputting the compensated second light beams to the image sensor through the focusing lens group, wherein the focusing lens group is used for focusing the passed light beams on the image sensor.

In one possible embodiment, the wavefront sensor is a shack-Hartmann wavefront sensor.

In a second aspect of the present application, there is provided a distributed synthetic aperture imaging method based on information coherence theory, the method comprising:

Transforming the light rays emitted or reflected by the imaging target into a plurality of sub-aperture light beams with different frequency bands;

the common aberration of each sub-aperture beam is obtained through detection of a wavefront sensor;

compensating the phase of each sub-aperture beam according to the common aberration through a phase modulator, and emitting each compensated sub-aperture beam to an image sensor for coherent imaging;

An image generated by the coherent imaging is recorded by the image sensor.

The embodiment of the invention has the beneficial effects that:

The distributed synthetic aperture imaging device and the method based on the information coherence theory provided by the embodiment of the application can obtain the common aberration of each sub-aperture beam by detecting the wave front of each sub-aperture beam, and then compensate the phase of each sub-aperture beam in an information domain according to the common aberration, so that the compensated beams are coherent in the information domain and can be coherently imaged at an image sensor. In other words, the distributed synthetic aperture imaging device and method based on the information coherence theory can reduce the requirements of the synthetic aperture imaging technology on processing and installation, thereby breaking the limit of the existing processing technology and installation technology on the synthetic aperture technology, improving the imaging quality of the synthetic aperture technology and reducing the implementation difficulty of the synthetic aperture technology.

Of course, it is not necessary for any one product or method of practicing the invention to achieve all of the advantages set forth above at the same time.

Drawings

In order to more clearly illustrate the embodiments of the invention or the technical solutions in the prior art, the drawings used in the embodiments or the description of the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the invention, and other embodiments may be obtained according to these drawings to those skilled in the art.

Fig. 1 is a schematic structural diagram of a distributed synthetic aperture imaging device based on information coherence theory according to the present application;

fig. 2 is a schematic diagram of a second structure of a distributed synthetic aperture imaging device based on the information coherence theory provided by the present application;

Fig. 3 is a schematic diagram of a third structure of a distributed synthetic aperture imaging device based on the information coherence theory provided by the present application;

fig. 4 is a schematic structural diagram of a distributed synthetic aperture imaging device based on the information coherence theory according to the present application;

fig. 5 is a schematic diagram of a fifth structure of a distributed synthetic aperture imaging device based on the information coherence theory according to the present application;

fig. 6 is a schematic diagram of a sixth structure of a distributed synthetic aperture imaging device based on the information coherence theory provided by the present application;

fig. 7 is a schematic diagram of a seventh structure of a distributed synthetic aperture imaging device based on the information coherence theory provided by the present application;

fig. 8 is a schematic diagram of an eighth structure of a distributed synthetic aperture imaging device based on the information coherence theory provided by the present application;

Fig. 9 is a schematic flow chart of a distributed synthetic aperture imaging method based on the information coherence theory.

Detailed Description

The following description of the embodiments of the present application will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present application, but not all embodiments. Based on the embodiments of the present application, all other embodiments obtained by the person skilled in the art based on the present application are included in the scope of protection of the present application.

In order to more clearly describe the distributed synthetic aperture imaging device and method based on the information coherence theory provided by the application, the application scenario of the distributed synthetic aperture imaging device and method based on the information coherence theory provided by the application will be described first by taking a synthetic aperture telescope as an example, it is to be understood that the synthetic aperture telescope is only one possible application scenario of the distributed synthetic aperture imaging device and method based on the information coherence theory provided by the application, and in other possible embodiments, the distributed synthetic aperture imaging device and method based on the information coherence theory provided by the application can also be applied to other scenarios where synthetic aperture imaging exists, and the following examples do not limit the application scenario.

Limited to the size of the single optical aperture, the information contained in the optical signal that can be acquired through the single optical aperture is often limited such that only limited information can be observed through the telescope of the single optical aperture. Therefore, in the related art, the detection can be performed through the plurality of optical apertures respectively, and the light beams of the optical apertures are subjected to coherent imaging at the image sensor by utilizing the coherent imaging principle, so that the image sensor can record interference fringes formed by coherent imaging, and as the interference fringes contain information of the light beams of the plurality of optical apertures, compared with a telescope with a single aperture, the telescope based on the synthetic aperture technology can observe more information, and as the number of the optical apertures increases, the information which can be observed is also more.

This approach requires optical coherence between the beams of each optical aperture, requires reasonable setup of the optical parameters and positions of each sub-mirror in the system for optical coherence between the beams of each optical aperture, and requires assurance that each sub-mirror is machined and installed exactly according to the designed optical parameters and positions. As the number of optical apertures increases, the higher the requirements for machining and mounting are, and the existing machining process and mounting technology are limited, and it is difficult to meet the requirements for machining and mounting in the case of a large number of optical apertures. This also results in a limited number of sub-apertures of the telescope based on synthetic aperture technology and thus limited information that can be observed.

Based on the information coherence theory, the application provides a distributed synthetic aperture imaging device and a method based on the information coherence theory, the common aberration of each sub-aperture beam is obtained by detecting the wave front of each sub-aperture beam, and then the phase of each sub-aperture beam is compensated in the information domain according to the common aberration, so that the compensated beams are coherent in the information domain and can be imaged coherently at an image sensor. In other words, the distributed synthetic aperture imaging device and method based on the information coherence theory can reduce the requirements of the synthetic aperture imaging technology on processing and installation, thereby breaking the limit of the existing processing technology and installation technology on the synthetic aperture technology, improving the imaging quality of the synthetic aperture technology and reducing the implementation difficulty of the synthetic aperture technology.

Referring to fig. 1, fig. 1 is a schematic diagram showing a first structure of a distributed synthetic aperture imaging device based on information coherence theory, which includes an optical information processing component 100, a beam splitter 200, a wavefront sensor 300, a phase modulator 400, and an image sensor 500.

The respective optical elements in fig. 1 will be described in order of light passing through the respective optical elements.

The optical information processing component 100 is configured to convert light of an incident device into a plurality of sub-aperture beams with different frequency bands and output the sub-aperture beams to the beam splitter 200. The optical information processing device 100 may be any optical element or combination of optical elements having sub-aperture beams for converting light into a plurality of different frequency bands. Illustratively, the optical information processing component 100 includes a 4F optical system that converts the incident light into the frequency domain by performing an optical fourier transform on the incident light, and then selects a plurality of components of a specific frequency band on the spectrum plane as sub-apertures to obtain sub-aperture beams. It should be understood that the 4F optical thread system is only one possible example of the optical information processing device 100, and in other possible embodiments, the optical information processing device 100 may also include other optical devices or optical device combinations with fourier transform and sub-aperture selection capabilities, which the present application is not limited to.

The beam splitter 200 is configured to split each sub-aperture beam of the cream-color into a first beam and a second beam, and output the first beam to the wavefront sensor 300 and the second beam to the phase modulator 400. The beam splitter 200 may be a beam splitter or an optical component having beam splitting capability, which is composed of a plurality of optical elements. For example, the beam splitter 200 may be a cube formed by bonding two triangular prisms, each sub-aperture beam is incident at an angle of 45 ° to the bonding surface of the two triangular prisms, and at the bonding surface, a part of the light is transmitted, another part is reflected, the transmitted light continues to exit the beam splitter 200 in the incident direction (hereinafter referred to as the original direction), and the reflected light exits the beam splitter 200 in the direction perpendicular to the incident direction (hereinafter referred to as the perpendicular direction). In this example, if the wavefront sensor 300 is disposed in the original direction of the beam splitter 200 and the phase modulator is disposed in the vertical direction of the beam splitter 200, the transmitted light is the second light beam, and the reflected light is the first light beam. Conversely, if the wavefront sensor 300 is disposed in the vertical direction of the beam splitter 200 and the phase modulator is disposed in the original direction of the beam splitter 200, the transmitted light beam is the first light beam, and the reflected light beam is the first light beam. For convenience of description, only the case where the transmitted light is the first light beam and the reflected light is the second light beam is taken as an example for illustration, and the principle of the case where the transmitted light is the second light beam and the reflected light is the first light beam is the same, and will not be described herein.

The wavefront sensor 300 is configured to detect a common aberration of each of the first light beams. The wavefront sensor 300 is any sensor capable of directly or indirectly detecting the common aberration of the incident optical fiber, where the direct detection refers to the signal sensed by the sensor being the common aberration, and the indirect detection refers to the signal sensed by the sensor not being the common aberration, but being capable of calculating the common aberration based on the signal sensed by the sensor. Illustratively, the wavefront sensor 300 of the present application may be a shack-Hartmann wavefront sensor.

It will be appreciated that the wavefront of the nth sub-aperture beam may be expressed in the form of equation (1):

...(1)

Wherein, the For the complex amplitude distribution of the nth sub-aperture imaging beam,For the amplitude of the nth sub-aperture imaging beam,The phase distribution of the beam is imaged for the nth sub-aperture. And the phase distribution of the nth sub-aperture imaging beam can be expressed as the form of formula (2):

...(2)

Wherein, the Namely the aforementioned common aberrationAberrations of the nth sub-aperture imaging beam relative to the other sub-aperture imaging beams. Therefore, the formula (1) can be rewritten as the formula (3):

...(3)

It can be seen that the wavefront of the sub-aperture beam depends on the common aberrations, so that the common aberrations can be detected by the wavefront sensor 300.

The phase modulator 400 is used for compensating the phase of each incident second light beam according to the common aberration, and emitting each compensated second light beam to the image sensor and performing coherent imaging. The phase modulator 400 is any optical element or combination of optical elements capable of modulating the phase of the incident light according to the actual requirements. The adjustment of the phase according to actual needs herein means that the phase can be adaptively modulated according to the difference of the common aberration detected by the wavefront sensor 300. Illustratively, taking a quarter wave plate as an example, it can only increase the phase of the incident light by one quarter period, and cannot adaptively modulate the phase according to the difference of the common aberration detected by the wavefront sensor 300, thus not meeting the requirements of the present application for the phase modulator 400. Taking the spatial light modulator as an example, the spatial light modulator can change the phase of the incident light with different amplitudes by loading different phases, so that the spatial light modulator can adaptively modulate the phase as long as the spatial light modulator is loaded with the phase corresponding to the common aberration detected by the wavefront sensor 300, and thus the spatial light modulator meets the requirements of the phase modulator 400 in the present application. That is, a spatial light modulator may be selected as the phase modulator 400, but this does not mean that the phase modulator 400 in the present application can be a spatial light modulator, and in other possible embodiments, the phase modulator 400 may be other optical elements or optical element combinations other than a spatial light modulator, which is not limited in any way by the present application.

Since the second beam and the first beam are two beams split by the beam splitter 200, the common aberration of the second beam and the common aberration of the first beam are the same, and the common aberration of the second beam is modulated according to the common aberration of the first beam, so that the common aberration of the second beam can be reduced or even completely eliminated, thereby improving the imaging quality.

Since the phase distributions of the first and second light beams are the same, it can be seen from the above formula (3) that if the common aberration is not eliminated, the intensity distribution in the imaged image can be expressed by the formula (4):

...(4)

wherein I is intensity distribution and N is number of sub-apertures.

Whereas for the case of completely eliminating the common aberration in the second beam, the intensity distribution can be expressed by equation (5):

...(5)

Moreover, it will be appreciated that the configuration shown in fig. 1 is merely a schematic diagram and does not represent that the optical elements are arranged in the orientation shown in fig. 1, and that the light beams do not propagate in the direction shown in fig. 1, and that the light beams shown in fig. 1 are merely for indicating the order in which the light beams pass through the optical elements, and do not indicate the actual direction of propagation.

For example, in fig. 1, the phase modulator 400 is located on the right side of the beam splitter 200 and is located on the left side of the image sensor 500, and the corresponding second light beam enters the wavefront sensor 300 from left to right and enters the image sensor 500 from left to right after compensating for the phase, which is merely for illustrating that the second light beam passes through the phase modulator 400 and the image sensor 500 sequentially after exiting the beam splitter 200, and does not indicate that the propagation direction of the second light beam after exiting the beam splitter 200 is always from left to right, or does not indicate that the propagation direction of the second light beam after exiting the beam splitter 200 is always unchanged.

The image sensor 500 is used to record an image generated by coherent imaging. The image sensor 500 is any sensor capable of sensing light emitted or reflected by an imaging target, and the wavelength band sensed by the image sensor 500 may be different according to actual requirements, including but not limited to a visible light band, a near infrared band, and the like.

While the optical elements shown in fig. 1 have been described above separately, it will be appreciated that other optical elements may be included in the apparatus in addition to the optical elements shown in fig. 1, and that, illustratively, in the case where the phase modulator 400 is a spatial light modulator 410, a mirror 600 may be included in the apparatus, the mirror 600 being located between the beam splitter 200 and the spatial light modulator 410, as shown in fig. 2.

The positioning of the mirror 600 between the beam splitter 200 and the spatial light modulator 410 herein means that the mirror 600 is positioned on the optical path of the light beam exiting the beam splitter 200 to the spatial light modulator 410, and it is not particularly specific that the mirror 600 is positioned on the line connecting the beam splitter 200 and the spatial light modulator 410, and the other is positioned between the two optical elements as described below.

In the example shown in fig. 2, the second light beam after exiting the beam splitter 200 is not directly incident on the spatial light modulator 410, but is first incident on the mirror 600, and is incident on the spatial light modulator 410 via reflection by the mirror 600. Also, if the direction from the beam splitter 200 to the mirror 600 is referred to as a first direction and the direction from the mirror 600 to the spatial light modulator 410 is referred to as a second direction in this example, the angle between the first direction and the second direction should be sufficiently large, which means that the angle between the first direction and the second direction is larger than the first angle threshold. For example, in the example shown in fig. 2, the angle between the first direction and the second direction is approximately 90 °.

It will be appreciated that to enable proper operation of spatial light modulator 410, it is desirable that the angle between the light incident on spatial light modulator 410 and the light exiting spatial light modulator 410 be sufficiently small, typically within 10 °. This also causes the light exiting the spatial light modulator 410 to be approximately opposite the light incident on the spatial light modulator 410.

If the light exiting the beam splitter 200 is directly incident on the spatial light modulator 410, the light exiting the spatial light modulator 410 propagates approximately from the spatial light modulator 410 in the direction of the beam splitter 200. At this time, in order to enable the image sensor 500 to record an image generated by coherent imaging, the image sensor 500 and the beam splitter 200 need to be disposed on the same side of the spatial light modulator 410 as shown in fig. 3, which easily causes collision between the image sensor 500 and the beam splitter 200, and increases the difficulty in designing the device.

Alternatively, the light emitted from the spatial light modulator 410 may be approximately regarded as propagating in the opposite direction of the second direction, and the image generated by coherent imaging may be recorded by disposing the image sensor 500 in the opposite direction of the second direction of the spatial light modulator 410. Because the included angle between the second direction and the first direction is large enough, a larger included angle still exists between the opposite direction of the second direction and the first direction, that is, the image sensor 500 and the beam splitter 200 are arranged on different sides of the spatial light modulator 410, so that the mutual collision between the image sensor 500 and the beam splitter 200 is effectively avoided, and the design difficulty of the device is reduced.

Also, based on the example shown in fig. 2, as shown in fig. 4, the apparatus may further include a first fourier lens 710 and a second fourier lens 720.

The first fourier lens 710 is disposed between the beam splitter 200 and the mirror 600, the second fourier lens 720 is disposed between the mirror 600 and the spatial light modulator 410, and the first fourier lens 710 and the second fourier lens 720 constitute a 4F optical system.

In the example shown in fig. 4, the light rays exiting the beam splitter 200 enter the spatial light modulator 410 via the first fourier lens 710, the mirror 600, and the second fourier lens 720 in this order. In this example, the optical field of the second beam is better modulated by adding a first fourier lens 710 and a second fourier lens 720 between the beam splitter 200 and the spatial light modulator 410 to make up a 4F optical system, providing the imaging quality of coherent imaging of the second beam.

Also, as shown in fig. 5, in order to make the compensated second light beam perform better coherent imaging on the image sensor 500, a focusing lens group 800 may be further provided in the apparatus, and the focusing lens group 800 is disposed between the phase modulator 400 and the image sensor 500, for focusing the compensated second light beam on the image sensor 500. In the example shown in fig. 5, after the compensated second light beam exits the phase modulator 400, it enters the image sensor 500 via focusing of the focusing lens group 800.

The focusing lens group 800 may be composed of a plurality of lenses or may be composed of only one lens, so long as focusing of the compensated second light beam can be effectively achieved, which is not limited in any way by the present application. Also, similarly to the foregoing fig. 1, fig. 5 does not represent that the optical elements are arranged in the orientation shown in fig. 5, and that the light beams do not propagate in the direction shown in fig. 5, and that the light beams shown in fig. 5 are merely for showing the order in which the light beams pass through the optical elements, and do not show the true propagation direction. For example, in the case where the focus lens group 800 is provided on the basis of the example shown in fig. 4, the focus lens group 800 is located at the position shown in fig. 6.

While the optical elements not shown in fig. 1 and which may be included in the apparatus have been described above as an example, it is to be understood that the above-mentioned mirror 600, first fourier lens 710, second fourier lens 720, and focusing lens group 800 are merely four possible examples, and the apparatus provided by the present application is not limited to the optical elements shown in fig. 1 and the mirror 600, first fourier lens 710, second fourier lens 720, and focusing lens group 800, and in other possible embodiments, the mirror 600, first fourier lens 710, second fourier lens 720, and other optical elements other than the focusing lens group 800 may be included in the apparatus, which is not limited in any way by the present application.

The optical information processing module 100 shown in fig. 1 described above will be described in detail. As described above with reference to fig. 1, the optical information processing device 100 is configured to convert incident light into sub-aperture beams with a plurality of different frequency bands and output the sub-aperture beams to the beam splitter 200.

In one possible embodiment, the optical information processing device 100 may convert the light of the incident device into a frequency domain, so as to select a plurality of light beams with preset frequency bands from the frequency domain as sub-aperture light beams. It is understood that the optical information processing device 100 is used as an optical element, and converting light into a frequency domain refers to converting light into a frequency domain by means of optical fourier transform.

Illustratively, as shown in FIG. 7, the optical information processing assembly 100 includes a third Fourier lens 110 and a fourth Fourier lens 120. The third fourier lens 110 and the fourth fourier lens 120 constitute a 4F optical system. In this example, the third fourier lens 110 is used to optically fourier transform the incident light, thereby transforming the incident light into the frequency domain. In this way, by selecting a plurality of components of the preset frequency band as sub-apertures in the spectrum plane, each sub-aperture beam can be obtained, and these sub-aperture beams are emitted through the fourth fourier lens 120, and the fourth fourier lens 120 is used for performing inverse fourier transform on the beam transformed to the frequency domain, so as to transform these beams again from the frequency domain to the time domain.

Also, to enable light rays exiting the optical information processing assembly 100 to be precisely incident on the beam splitter 200, the fourth fourier lens 120 may also be used to collimate the light beam to avoid that a portion of the light beam cannot be incident on the beam splitter 200.

Having described the structure of the optical information processing assembly 100, the optical elements shown in fig. 1, and the optical elements not shown in fig. 1 but possibly included in the apparatus, respectively, an exemplary description of the distributed synthetic aperture imaging apparatus based on the theory of information coherence provided by the present application will be made with reference to the optical elements mentioned in the foregoing examples, and reference may be made to fig. 8, in which the apparatus includes the optical information processing assembly 100, the beam splitter 200, the shack-hartmann wavefront sensor 310, the first fourier lens 710, the mirror 600, the second fourier lens 720, the spatial light modulator 410, the focusing lens group 800, and the image sensor 500. Wherein the optical information processing component 100 comprises a third fourier lens 110 and a fourth fourier lens 120.

The optical elements in fig. 8 have been described above separately, so reference to the above description is omitted here. In the example shown in fig. 8, light rays emitted or reflected by the imaging target enter the beam splitter 200 via the third fourier lens 110, the fourth fourier lens 120 in order, and have been converted into a plurality of sub-aperture light beams when entering the beam splitter 200. These sub-aperture beams are split into two at the beam splitter 200, wherein one part (i.e., the first beam above) is incident on the shack-hartmann wavefront sensor 310 after exiting the beam splitter 200, and the other part (i.e., the second beam above) is sequentially passed through the first fourier lens 710, the mirror 600, the second fourier lens 720, the spatial light modulator 410, the focusing lens group 800, and finally is incident on the image sensor 500, and coherently imaged on the image sensor 500.

Corresponding to the foregoing distributed synthetic aperture imaging device based on the information coherence theory, the present application further provides a distributed synthetic aperture imaging method based on the information coherence theory, as shown in fig. 9, including:

In step S901, light emitted or reflected by the imaging target is converted into sub-aperture beams with a plurality of different frequency bands.

I.e. corresponds to the functions of the aforementioned optical information processing component 100. Reference may be made to the above description of the optical information processing assembly 100, which is not repeated here.

In step S902, the common aberration of each sub-aperture beam is detected by the wavefront sensor.

I.e. corresponds to the functionality of the wavefront sensor 300 described previously. Reference may be made to the above description of the wavefront sensor 300, which is not repeated here.

In step S903, the phase modulator compensates the phase of each sub-aperture beam according to the common aberration, and outputs each compensated sub-aperture beam to the image sensor for coherent imaging.

I.e. corresponds to the function of the aforementioned phase modulator 400. Reference may be made to the above description of the phase modulator 400, which is not repeated here.

In step S904, an image generated by coherent imaging is recorded by an image sensor.

I.e., corresponds to the functions of the aforementioned image sensor 500. Reference may be made to the description of the image sensor 500 above, and the description thereof will not be repeated here.

The distributed synthetic aperture imaging device and the method based on the information coherence theory provided by the application can obtain the common aberration of each sub-aperture beam by detecting the wave fronts of each sub-aperture beam, and then compensate the phase of each sub-aperture beam in an information domain according to the common aberration, so that the compensated beams are coherent in the information domain and can be coherently imaged at an image sensor. In other words, the distributed synthetic aperture imaging device and method based on the information coherence theory can reduce the requirements of the synthetic aperture imaging technology on processing and installation, thereby breaking the limit of the existing processing technology and installation technology on the synthetic aperture technology, improving the imaging quality of the synthetic aperture technology and reducing the implementation difficulty of the synthetic aperture technology.

It is noted that relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises an element.

In this specification, each embodiment is described in a related manner, and identical and similar parts of each embodiment are all referred to each other, and each embodiment mainly describes differences from other embodiments. In particular, for the method embodiments, since they are substantially similar to the apparatus embodiments, the description is relatively simple, and reference is made to the description of the method embodiments in part.

The foregoing description is only of the preferred embodiments of the present invention and is not intended to limit the scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention are included in the protection scope of the present invention.

Claims (10)

1. A distributed synthetic aperture imaging device based on an information coherence theory, which is characterized by comprising an optical information processing component, a beam splitter, a wavefront sensor, a phase modulator and an image sensor;

The optical information processing component is used for converting light rays entering the device into a plurality of sub-aperture light beams with different frequency bands and emitting the sub-aperture light beams to the beam splitter;

the beam splitter is used for splitting each incident sub-aperture beam into a first beam and a second beam, emitting the first beam to the wavefront sensor and emitting the second beam to the phase modulator;

The wavefront sensor is used for detecting and obtaining the common aberration of each first light beam and sending the common aberration to the phase modulator;

The phase modulator is used for compensating the phase of each incident second light beam according to the common aberration, and emitting each compensated second light beam to the image sensor for coherent imaging;

the image sensor is used for recording images generated by the coherent imaging.

2. The apparatus of claim 1, wherein the phase modulator is a spatial light modulator for adjusting the phase of the loading to be negative in response to a common aberration transmitted by the wavefront sensor.

3. The apparatus of claim 2, further comprising a mirror disposed between the beam splitter and the spatial light modulator;

the outputting the second light beam to the phase modulator includes:

the second light beam is emitted to a reflector and is incident to the spatial light modulator under the reflection of the reflector;

and taking the direction from the beam splitter to the reflecting mirror as a first direction, and the direction from the reflecting mirror to the spatial light modulator as a second direction, wherein the included angle between the first direction and the second direction is larger than a first angle threshold.

4. The apparatus of claim 3, further comprising a first fourier lens disposed between the beam splitter and the mirror, a second fourier lens disposed between the mirror and the spatial light modulator;

the first Fourier lens and the second Fourier lens form a 4F optical system;

The emitting the second light beam to a reflector and making the second light beam incident to the spatial light modulator under the reflection of the reflector comprises:

The second light beam is emitted to the reflecting mirror through the first Fourier lens, and is incident to the spatial light modulator through the second Fourier lens under the reflection of the reflecting mirror, wherein the first Fourier lens is used for carrying out Fourier transform on the incident light beam, and the second Fourier lens is used for carrying out inverse Fourier transform on the incident light beam.

5. The apparatus of claim 1, wherein the optical information processing component is specifically configured to convert light incident on the apparatus into a frequency domain, and select a plurality of light beams with preset frequency bands from the frequency domain as sub-aperture light beams, and output each sub-aperture light beam to the beam splitter.

6. The apparatus of claim 5, wherein the optical information processing component comprises a third fourier lens and a fourth fourier lens;

the third Fourier lens and the fourth Fourier lens form a 4F optical system;

the third Fourier lens is used for projecting light rays incident on the device to a frequency spectrum surface;

And the fourth Fourier lens is used for selecting a plurality of components with preset frequency bands from the frequency spectrum surface as sub-apertures to obtain sub-aperture light beams and emitting the sub-aperture light beams to the beam splitter.

7. The apparatus of claim 6 wherein said fourth fourier lens is further configured to collimate each of said sub-aperture beams.

8. The apparatus of any one of claims 1-7, further comprising a focusing lens group disposed between the phase modulator and the image sensor;

the outputting the compensated second light beams to the image sensor includes:

And outputting the compensated second light beams to the image sensor through the focusing lens group, wherein the focusing lens group is used for focusing the passed light beams on the image sensor.

9. The apparatus of any of claims 1-7, wherein the wavefront sensor is a shack-hartmann wavefront sensor.

10. A distributed synthetic aperture imaging method based on information coherence theory, the method comprising:

Transforming the light rays emitted or reflected by the imaging target into a plurality of sub-aperture light beams with different frequency bands;

the common aberration of each sub-aperture beam is obtained through detection of a wavefront sensor;

compensating the phase of each sub-aperture beam according to the common aberration through a phase modulator, and emitting each compensated sub-aperture beam to an image sensor for coherent imaging;

An image generated by the coherent imaging is recorded by the image sensor.