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

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 assembly, a beam splitter, a wavefront sensor, a phase modulator and an image sensor, the optical information processing assembly is used for converting the 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, 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 the common aberration of the first light beams; 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; and the image sensor is used for recording an image generated by coherent imaging. And the limitation of the existing normal form on the synthetic aperture imaging technology can be broken, so that the method is applicable to wider scenes.

Description

Technical Field

[0001] The present invention relates to the field of synthetic aperture imaging technology, and particularly to a distributed synthetic aperture imaging device and method based on the information coherence theory. Background Art

[0002] The synthetic aperture telescope based on synthetic aperture imaging technology is a core tool in the fields of deep space exploration and space astronomy research, and its operation depends on optical coherence technology. By means of coherence, the low-resolution images collected by multiple sub-mirrors are reconstructed to simulate the performance of a telescope with a larger aperture.

[0003] In related technologies, the implementation of synthetic aperture technology often relies on the Fizeau interferometer (image plane interference) and the Michelson interferometer (pupil plane interference). Both of these implementation methods require the deployment of multiple sub-mirrors to expand the number of sub-apertures for effective observation. However, as the aperture of the telescope system continues to increase, the number of sub-mirrors required for the implementation of the above two methods also increases accordingly.

[0004] With the increase in the number of sub-mirrors, the traditional method of controlling the optical correlation between sub-mirrors through physical means and manufacturing processes faces severe challenges. The existing methods for achieving optical coherence are difficult to meet the current requirements for the number of sub-mirrors. The bottleneck problems include complex manufacturing processes, high costs, large system integration difficulties, and insufficient imaging quality. These factors restrict the further development and application potential of synthetic aperture imaging technology. Summary of the Invention

[0005] The purpose of the embodiments of the present invention is to provide a distributed synthetic aperture imaging device and method based on the information coherence theory, so as to achieve no longer relying on traditional physical means and manufacturing processes to achieve optical correlation, thereby breaking the constraints of physical means and manufacturing processes on synthetic aperture imaging technology, and enabling synthetic aperture imaging technology to be effectively applied to larger-scale (kilometer-level) distributed optical systems. The specific technical solutions are as follows:

[0006] In the first aspect of the present application, a distributed synthetic aperture imaging device based on the information coherence theory is provided. The device includes an optical information processing component, a beam splitter, a wavefront sensor, a phase modulator, and an image sensor;

[0007] The optical information processing component is configured to transform the light incident on the device into sub-aperture light beams of multiple different frequency bands and output them to the beam splitter;

[0008] The beam splitter is configured to split each incident sub-aperture light beam into a first light beam and a second light beam, output the first light beam to the wavefront sensor, and output the second light beam to the phase modulator;

[0009] The wavefront sensor is configured to detect the common aberration of each of the first light beams and send it to the phase modulator;

[0010] The phase modulator is configured to compensate the phase of each of the incident second light beams according to the common aberration, and output the compensated second light beams to the image sensor for coherent imaging;

[0011] The image sensor is configured to record the image generated by the coherent imaging.

[0012] In a possible embodiment, the phase modulator is a spatial light modulator, and the spatial light modulator is configured to respond to the common aberration sent by the wavefront sensor and adjust the loaded phase to the negative of the common aberration.

[0013] In a possible embodiment, the device further includes a reflector disposed between the beam splitter and the spatial light modulator;

[0014] The outputting the second light beam to the phase modulator includes:

[0015] Outputting the second light beam to the reflector, and under the reflection of the reflector, the second light beam is incident on the spatial light modulator;

[0016] Taking the direction from the beam splitter to the reflector as the first direction and the direction from the reflector to the spatial light modulator as the second direction, the included angle between the first direction and the second direction is greater than a first angle threshold.

[0017] In a possible embodiment, the device further includes a first Fourier lens disposed between the beam splitter and the reflector, and a second Fourier lens disposed between the reflector and the spatial light modulator;

[0018] The first Fourier lens and the second Fourier lens form a 4F optical system;

[0019] The outputting the second light beam to the reflector and under the reflection of the reflector, the second light beam is incident on the spatial light modulator includes:

[0020] Outputting the second light beam to the reflector via the first Fourier lens, and under the reflection of the reflector, the second light beam is incident on the spatial light modulator via the second Fourier lens. The first Fourier lens is configured to perform Fourier transform on the incident light beam, and the second Fourier lens is configured to perform inverse Fourier transform on the incident light beam.

[0021] In a possible embodiment, the optical information processing component is specifically configured to convert the light incident on the device into the frequency domain, select light beams of multiple preset frequency bands from the frequency domain as sub-aperture light beams, and output each of the sub-aperture light beams to the beam splitter.

[0022] In a possible embodiment, the optical information processing component includes a third Fourier lens and a fourth Fourier lens;

[0023] The third Fourier lens and the fourth Fourier lens form a 4F optical system;

[0024] The third Fourier lens is configured to project the light incident on the device onto the spectrum plane;

[0025] The fourth Fourier lens is configured to select components of multiple preset frequency bands from the spectrum plane as sub-apertures to obtain each sub-aperture light beam and output the sub-aperture light beam to the beam splitter.

[0026] In a possible embodiment, the device further includes a focusing lens group disposed between the phase modulator and the image sensor;

[0027] Outputting each of the compensated second light beams to the image sensor includes:

[0028] Outputting each of the compensated second light beams to the image sensor via the focusing lens group, where the focusing lens group is configured to focus the passed light beam on the image sensor.

[0029] In a possible embodiment, the wavefront sensor is a Shack-Hartmann wavefront sensor.

[0030] In a second aspect of the present application, a distributed synthetic aperture imaging method based on the information coherence theory is provided. The method includes:

[0031] Converting the light emitted or reflected by the imaging target into sub-aperture light beams of multiple different frequency bands;

[0032] Detecting the common aberration of each of the sub-aperture light beams through a wavefront sensor;

[0033] Compensating the phase of each of the sub-aperture light beams according to the common aberration through a phase modulator, and outputting each of the compensated sub-aperture light beams to an image sensor for coherent imaging;

[0034] Recording the image generated by the coherent imaging through the image sensor.

[0035] Advantageous effects of the embodiments of the present invention:

[0036] A distributed synthetic aperture imaging device and method based on the information coherence theory provided by the embodiments of the present invention can obtain the common aberration of each sub-aperture beam by detecting the wavefront of each sub-aperture beam, and then compensate the phase of each sub-aperture beam in the information domain according to the common aberration, so that the compensated beams are coherent in the information domain and can be coherently imaged at the image sensor. Since the coherence of each sub-aperture beam is achieved by compensating the phase in the information domain, the distributed synthetic aperture imaging device and method based on the information coherence theory provided by this application do not require the optical coherence of each sub-aperture beam before compensation. Therefore, even if there are errors in the processing or installation of each sub-mirror in the device, synthetic aperture imaging can be effectively achieved. In other words, the distributed synthetic aperture imaging device and method based on the information coherence theory provided by this application can reduce the requirements for processing and installation of synthetic aperture imaging technology, thereby breaking the limitations of existing processing technology and installation technology on synthetic aperture technology. It can not only improve the imaging quality of synthetic aperture technology, but also reduce the implementation difficulty of synthetic aperture technology.

[0037] Of course, it is not necessary for any product or method implementing the present invention to achieve all the above-mentioned advantages simultaneously. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention, and those of ordinary skill in the art can also obtain other embodiments based on these drawings.

[0039] Figure 1 It is the first structural schematic diagram of the distributed synthetic aperture imaging device based on the information coherence theory provided by this application;

[0040] Figure 2 It is the second structural schematic diagram of the distributed synthetic aperture imaging device based on the information coherence theory provided by this application;

[0041] Figure 3 It is the third structural schematic diagram of the distributed synthetic aperture imaging device based on the information coherence theory provided by this application;

[0042] Figure 4 It is the fourth structural schematic diagram of the distributed synthetic aperture imaging device based on the information coherence theory provided by this application;

[0043] Figure 5 It is the fifth structural schematic diagram of the distributed synthetic aperture imaging device based on the information coherence theory provided by this application;

[0044] Figure 6The sixth schematic structural diagram of the distributed synthetic aperture imaging device based on the information coherence theory provided by this application;

[0045] Figure 7 The seventh schematic structural diagram of the distributed synthetic aperture imaging device based on the information coherence theory provided by this application;

[0046] Figure 8 The eighth schematic structural diagram of the distributed synthetic aperture imaging device based on the information coherence theory provided by this application;

[0047] Figure 9 The schematic flow diagram of the distributed synthetic aperture imaging method based on the information coherence theory provided by this application. Specific embodiments

[0048] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art based on this application belong to the scope of protection of the present invention.

[0049] To more clearly illustrate the distributed synthetic aperture imaging device and method based on the information coherence theory provided by this application, the application scenarios of the distributed synthetic aperture imaging device and method based on the information coherence theory provided by this application will be described below taking a synthetic aperture telescope as an example. It can 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 this application. In other possible embodiments, the distributed synthetic aperture imaging device and method based on the information coherence theory provided by this application can also be applied to other scenarios where synthetic aperture imaging exists. The following examples do not impose any restrictions on this.

[0050] Limited by the size of a single optical aperture, the information contained in the optical signals that can be obtained through a single optical aperture is often limited, so that a telescope with a single optical aperture can only observe limited information. Therefore, in the related art, multiple optical apertures can be used for detection respectively, and the coherent imaging principle is used to make the light beams of each optical aperture coherently image at the image sensor, so that the image sensor can record the interference fringes formed by the coherent imaging. Since the interference fringes contain the information of the light beams of multiple optical apertures, compared with a telescope with a single aperture, a telescope based on the synthetic aperture technology can observe more information, and as the number of optical apertures increases, more information can be observed.

[0051] This method requires optical coherence between the light beams of each optical aperture. To achieve optical coherence between the light beams of each optical aperture, it is necessary to reasonably set the optical parameters and positions of each sub - mirror in the system, and it is also necessary to ensure that each sub - mirror is processed and installed strictly according to the designed optical parameters and positions. As the number of optical apertures increases, the requirements for processing and installation become higher. However, limited by the existing processing technology and installation technology, it is difficult to meet the requirements for processing and installation in the case of a large number of optical apertures. This also limits the number of sub - apertures of the telescope based on synthetic aperture technology, and thus the information that can be observed will also be restricted accordingly.

[0052] Based on this, the present application provides a distributed synthetic aperture imaging device and method based on information coherence theory. By detecting the wavefronts of the light beams of each sub - aperture, the common aberration of the light beams of each sub - aperture can be obtained, and then the phases of the light beams of each sub - aperture are compensated in the information domain according to the common aberration, so that the compensated light beams are coherent in the information domain and can be coherently imaged at the image sensor. Since the coherence of the light beams of each sub - aperture is achieved by compensating the phase in the information domain, the distributed synthetic aperture imaging device and method provided by the present application do not require the light beams of each sub - aperture to be optically coherent before compensation. Therefore, even if there are errors in the processing or installation of each sub - mirror in the device, synthetic aperture imaging can be effectively realized. In other words, the distributed synthetic aperture imaging device and method provided by the present application can reduce the requirements for processing and installation of synthetic aperture imaging technology, thereby breaking the limitations of the existing processing technology and installation technology on synthetic aperture technology. It can not only improve the imaging quality of synthetic aperture technology but also reduce the implementation difficulty of synthetic aperture technology.

[0053] The following will describe the distributed synthetic aperture imaging device based on information coherence theory provided by the present application (hereinafter referred to as the device). Refer to Figure 1 , Figure 1 FIG. 10 shows a first structural schematic diagram of the distributed synthetic aperture imaging device provided by the present application, including: an optical information processing component 100, a beam splitter 200, a wavefront sensor 300, a phase modulator 400, and an image sensor 500.

[0054] The following will sequentially describe each optical element in Figure 1 according to the order of the light passing through each optical element.

[0055] The optical information processing component 100 is configured to transform the light rays of the incident device into sub-aperture light beams of multiple different frequency bands and output them to the beam splitter 200. The optical information processing component 100 can be any optical element or combination of optical elements that has the ability to transform light rays into sub-aperture light beams of multiple different frequency bands. Exemplarily, the optical information processing component 100 includes a 4F optical system. By performing an optical Fourier transform on the incident light rays, the light rays are converted into the frequency domain, and then components of multiple specific frequency bands are selected on the spectral plane as each sub-aperture to obtain each sub-aperture light beam. It can be understood that the 4F optical system is only one possible example of the optical information processing component 100. In other possible embodiments, the optical information processing component 100 can also include other optical components or combinations of optical components that have the ability of Fourier transform and sub-aperture selection. The present application does not impose any restrictions on this.

[0056] The beam splitter 200 is configured to split each milky-yellow sub-aperture light beam into a first light beam and a second light beam respectively, output the first light beam to the wavefront sensor 300, and output the second light beam to the phase modulator 400. The beam splitter 200 can be composed of a beam splitter mirror, or can be an optical component with beam splitting ability composed of multiple optical elements. Exemplarily, the beam splitter 200 can be a cube formed by gluing two triangular prisms. Each sub-aperture light beam is incident at an angle of 45° with the gluing surface of the two triangular prisms. At the gluing surface, part of the light is transmitted and the other part is reflected. The transmitted light continues to be output from the beam splitter 200 along the incident direction (hereinafter referred to as the original direction), and the reflected light will be output from the beam splitter 200 along the direction perpendicular to the incident direction (hereinafter referred to as the perpendicular direction). In this example, if the wavefront sensor 300 is arranged in the original direction of the beam splitter 200 and the phase modulator is arranged in the perpendicular direction of the beam splitter 200, then the transmitted light is the aforementioned second light beam, and the reflected light is the aforementioned first light beam. Conversely, if the wavefront sensor 300 is arranged in the perpendicular direction of the beam splitter 200 and the phase modulator is arranged in the original direction of the beam splitter 200, then the transmitted light is the aforementioned first light beam, and the reflected light is the aforementioned first light beam. For the convenience of description hereinafter, 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. The principle for 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 elaborated here.

[0057] The wavefront sensor 300 is used to detect the common aberration of each first light beam. The wavefront sensor 300 is any sensor that can directly or indirectly detect the common aberration of the incident optical fiber. In this article, directly detecting means that the signal sensed by the sensor is the common aberration, and indirectly detecting means that the signal sensed by the sensor is not the common aberration, but the common aberration can be calculated based on the signal it senses. Exemplarily, the wavefront sensor 300 in this application can be a Shack-Hartmann wavefront sensor.

[0058] It can be understood that the wavefront of the nth sub-aperture light beam can be expressed in the form of formula (1):

[0059] …(1)

[0060] Where, is the complex amplitude distribution of the nth sub-aperture imaging light beam, is the amplitude of the nth sub-aperture imaging light beam, is the phase distribution of the nth sub-aperture imaging light beam. And the phase distribution of the nth sub-aperture imaging light beam can be expressed in the form of formula (2):

[0061] …(2)

[0062] Where, is the aforementioned common aberration, and is the aberration of the nth sub-aperture imaging light beam relative to other sub-aperture imaging light beams. Therefore, formula (1) can be rewritten as formula (3):

[0063] …(3)

[0064] It can be seen that the wavefront of the sub-aperture light beam depends on the common aberration, so the common aberration can be detected by the wavefront sensor 300.

[0065] The phase modulator 400 is used to compensate the phases of the incident second light beams according to the common aberrations, and emit the compensated second light beams to the image sensor for coherent imaging. The phase modulator 400 is any optical element or combination of optical elements that can modulate the phase of the incident light according to actual requirements. Adjusting the phase according to actual requirements in this article means: being able to adaptively modulate the phase according to the different common aberrations detected by the wavefront sensor 300. Exemplarily, taking a quarter-wave plate as an example, it can only increase the phase of the incident light by a quarter of a cycle and cannot adaptively modulate the phase according to the different common aberrations detected by the wavefront sensor 300, so it does not meet the requirements for the phase modulator 400 in this application. Taking a spatial light modulator as an example, by loading different phases, the spatial light modulator can change the phase of the incident light with different amplitudes. Therefore, as long as the spatial light modulator is loaded with the phase corresponding to the common aberration detected by the wavefront sensor 300, adaptive modulation of the phase can be achieved. Therefore, the spatial light modulator meets the requirements for the phase modulator 400 in this application. That is, a spatial light modulator can be selected as the phase modulator 400, but this does not mean that the phase modulator 400 in this application can only be a spatial light modulator. In other possible embodiments, the phase modulator 400 can also be other optical elements or combinations of optical elements other than the spatial light modulator, and this application does not make any restrictions on this.

[0066] Since the second light beam and the first light beam are two light beams formed by splitting the light beam through the beam splitter 200, the common aberrations of the second light beam and the first light beam are the same. Modulating the common aberration of the second light beam according to the common aberration of the first light beam can reduce or even completely eliminate the common aberration in the second light beam, thereby improving the imaging quality.

[0067] Since the phase distributions of the first light beam and the second light beam are the same, it can be seen from the foregoing formula (3) that if the common aberration is not eliminated, the intensity distribution in the imaged image can be expressed by formula (4):

[0068] …(4)

[0069] Where, I is the intensity distribution, and N is the number of sub-apertures.

[0070] For the case where the common aberration in the second light beam is completely eliminated, the intensity distribution can be expressed by formula (5):

[0071] …(5)

[0072] And, it can be understood that Figure 1 The structure shown is only a schematic diagram and does not represent that each optical element is arranged according toFigure 1 the azimuthal arrangement shown in Figure 1 and the light beams do not propagate in the directions shown in Figure 1 The light beams shown in

[0073] are only used to represent the order of the light beams passing through the respective optical elements, and do not represent the actual propagation directions. Figure 1 For example,

[0074] in

[0075] the phase modulator 400 is located on the right side of the beam splitter 200 and on the left side of the image sensor 500. Correspondingly, the second light beam is incident on the wavefront sensor 300 from left to right and, after compensating for the phase, is incident on the image sensor 500 from left to right. This only illustrates that the second light beam passes through the phase modulator 400 and the image sensor 500 in sequence after exiting the beam splitter 200, and does not mean that it propagates from left to right all the time after exiting the beam splitter 200, nor does it mean that its propagation direction remains unchanged all the time after exiting the beam splitter 200. Figure 1 Figure 1 Figure 2

[0076]

[0077] Figure 2 ​​​​​In the example shown, after the second light beam exits the beam splitter 200, it does not directly enter the spatial light modulator 410. Instead, it first enters the mirror 600 and then enters the spatial light modulator 410 after being reflected by the mirror 600. Moreover, if the direction from the beam splitter 200 to the mirror 600 in this example is denoted as the first direction, and the direction from the mirror 600 to the spatial light modulator 410 is denoted as the second direction, then the angle between the first direction and the second direction should be large enough. In this article, that the angle between the first direction and the second direction is large enough means that: the angle between the first direction and the second direction is greater than the first angle threshold. For example, in Figure 2 In the example shown, the angle between the first direction and the second direction is approximately 90°.

[0078] It can be understood that, to enable the spatial light modulator 410 to work properly, it is required that the angle between the light ray incident on the spatial light modulator 410 and the light ray exiting the spatial light modulator 410 is small enough, usually required to be within 10°. This also makes the light ray exiting the spatial light modulator 410 approximately reverse to the light ray incident on the spatial light modulator 410.

[0079] If the light ray exiting the beam splitter 200 directly enters the spatial light modulator 410, then the light ray exiting the spatial light modulator 410 approximately propagates in the direction from the spatial light modulator 410 to the beam splitter 200. At this time, to enable the image sensor 500 to record the image generated by coherent imaging, then as Figure 3 shown, it is necessary to set the image sensor 500 and the beam splitter 200 on the same side of the spatial light modulator 410, which easily leads to conflicts between the image sensor 500 and the beam splitter 200 and increases the design difficulty of the device.

[0080] However, by selecting the Figure 2 example shown, the light ray exiting the spatial light modulator 410 can be approximately regarded as propagating in the opposite direction of the second direction. At this time, only by setting the image sensor 500 in the opposite direction of the second direction of the spatial light modulator 410 can the image generated by coherent imaging be recorded. Also, since the angle between the second direction and the first direction is large enough, the opposite direction of the second direction and the first direction still have a large angle, that is, the image sensor 500 and the beam splitter 200 are set on different sides of the spatial light modulator 410, effectively avoiding conflicts between the image sensor 500 and the beam splitter 200 and reducing the design difficulty of the device.

[0081] Moreover, Figure 2 on the basis of the example shown, as Figure 4 shown, the device may further include a first Fourier lens 710 and a second Fourier lens 720.

[0082] The first Fourier lens 710 is disposed between the beam splitter 200 and the mirror 600, and the second Fourier lens 720 is disposed between the mirror 600 and the spatial light modulator 410. The first Fourier lens 710 and the second Fourier lens 720 form a 4F optical system.

[0083] In Figure 4 the illustrated example, the light rays emitted from the beam splitter 200 sequentially pass through the first Fourier lens 710, the mirror 600, and the second Fourier lens 720 and then enter the spatial light modulator 410. In this example, by adding the first Fourier lens 710 and the second Fourier lens 720 between the beam splitter 200 and the spatial light modulator 410 to form a 4F optical system, the light field of the second light beam can be better modulated, and the imaging quality of the coherent imaging of the second light beam can be provided.

[0084] And, as Figure 5 shown, in order to enable the compensated second light beam to better perform coherent imaging on the image sensor 500, a focusing lens group 800 can also be provided in the device. The focusing lens group 800 is disposed between the phase modulator 400 and the image sensor 500 and is used to focus the compensated second light beam on the image sensor 500. In Figure 5 the illustrated example, after the compensated second light beam exits from the phase modulator 400, it enters the image sensor 500 through the focusing of the focusing lens group 800.

[0085] The focusing lens group 800 can be composed of multiple lenses or can be composed of only one lens, as long as it can effectively focus the compensated second light beam. The present application does not make any limitation in this regard. And, similarly to the foregoing Figure 1 , Figure 5 it does not mean that the optical elements are arranged in the orientation shown in Figure 5 , and the light beams do not propagate in the directions shown in Figure 5 . The light beams shown in Figure 5 are only used to represent the order of the light beams passing through the optical elements and do not represent the real propagation directions. Exemplarily, for the case where the focusing lens group 800 is provided on the basis of the example shown in Figure 4 , the focusing lens group 800 is located at the position shown in Figure 6 .

[0086] The optical elements that have not been shown but can be included in the device have been described exemplarily above. It can be understood that the mirror 600, the first Fourier lens 710, the second Fourier lens 720, and the focusing lens group 800 mentioned above are only four possible examples, and do not limit that the device provided by the present application can only include Figure 1 Figure 1 ​The optical elements shown, as well as the mirror 600, the first Fourier lens 710, the second Fourier lens 720, and the focusing lens group 800. In other possible embodiments, the device may further include other optical elements other than the mirror 600, the first Fourier lens 710, the second Fourier lens 720, and the focusing lens group 800. The present application does not make any limitations in this regard.

[0087] The following will be a detailed description of Figure 1 the optical information processing component 100 shown in the foregoing Figure 1 As described above, the optical information processing component 100 is used to transform the incident light into sub-aperture beams of multiple different frequency bands and output them to the beam splitter 200.

[0088] In a possible embodiment, the optical information processing component 100 may be to convert the incident light of the device into the frequency domain, so as to select the beams of multiple preset frequency bands from the frequency domain as sub-aperture beams. It can be understood that, as an optical element, the optical information processing component 100 converting the light into the frequency domain means converting the light into the frequency domain by means of optical Fourier transform.

[0089] Exemplarily, as Figure 7 shown, the optical information processing component 100 includes a third Fourier lens 110 and a fourth Fourier lens 120. The third Fourier lens 110 and the fourth Fourier lens 120 form a 4F optical system. In this example, the third Fourier lens 110 is used to perform an optical Fourier transform on the incident light, so as to transform the incident light into the frequency domain. Thus, by selecting the components of multiple preset frequency bands as sub-apertures on the spectral plane, the sub-aperture beams can be obtained. These sub-aperture beams are output via the fourth Fourier lens 120, and the fourth Fourier lens 120 is used to perform an inverse Fourier transform on the beam transformed into the frequency domain, so as to transform these lights back from the frequency domain to the time domain.

[0090] Moreover, in order to enable the light output from the optical information processing component 100 to accurately enter the beam splitter 200, the fourth Fourier lens 120 can also be used to collimate the beam to prevent some beams from not being able to enter the beam splitter 200.

[0091] The structure of the optical information processing component 100 has been described above respectively, Figure 1 each optical element shown in Figure 1 and the optical elements not shown but possibly included in the device have been described. The following will be an exemplary description of the distributed synthetic aperture imaging device provided by the present application in combination with the optical elements mentioned in the foregoing examples. Please refer to Figure 8, in this example, the device includes: an optical information processing component 100, a beam splitter 200, a Shack-Hartmann wavefront sensor 310, a first Fourier lens 710, a mirror 600, a second Fourier lens 720, a spatial light modulator 410, a focusing lens group 800, and an image sensor 500. Among them, the optical information processing component 100 includes a third Fourier lens 110 and a fourth Fourier lens 120.

[0092] Figure 8 Each optical element in has been described separately above, so the relevant description above can be referred to and will not be repeated here. Figure 8 In the example shown, the light emitted or reflected by the imaging target sequentially passes through the third Fourier lens 110 and the fourth Fourier lens 120 and is incident on the beam splitter 200, and has been transformed into multiple sub-aperture beams when incident on the beam splitter 200. These sub-aperture beams are each split into two at the beam splitter 200. 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) sequentially passes through the first Fourier lens 710, the mirror 600, the second Fourier lens 720, the spatial light modulator 410, and the focusing lens group 800 after exiting the beam splitter 200, and finally is incident on the image sensor 500 and coherently forms an image on the image sensor 500.

[0093] Corresponding to the aforementioned distributed synthetic aperture imaging device based on the information coherence theory, the present application also provides a distributed synthetic aperture imaging method based on the information coherence theory, as Figure 9 shown, including:

[0094] Step S901, transforming the light emitted or reflected by the imaging target into multiple sub-aperture beams of different frequency bands.

[0095] That is, corresponding to the function of the aforementioned optical information processing component 100. The relevant description of the optical information processing component 100 above can be referred to and will not be repeated here.

[0096] Step S902, detecting the common aberration of each of the sub-aperture beams through a wavefront sensor.

[0097] That is, corresponding to the function of the aforementioned wavefront sensor 300. The relevant description of the wavefront sensor 300 above can be referred to and will not be repeated here.

[0098] Step S903, compensating the phase of each of the sub-aperture beams according to the common aberration through a phase modulator, and emitting the compensated sub-aperture beams to an image sensor for coherent imaging.

[0099] That is, it corresponds to the function of the aforementioned phase modulator 400. For relevant descriptions of the phase modulator 400, reference can be made to the above, and details will not be repeated here.

[0100] Step S904, record the image generated by coherent imaging through an image sensor.

[0101] That is, it corresponds to the function of the aforementioned image sensor 500. For relevant descriptions of the image sensor 500, reference can be made to the above, and details will not be repeated here.

[0102] By using the distributed synthetic aperture imaging method based on the coherence theory provided in this application, the common aberration of each sub-aperture beam can be obtained by detecting the wavefront of each sub-aperture beam, and then the phase of each sub-aperture beam can be compensated in the information domain according to the common aberration, so that the compensated beams are coherent in the information domain and can be coherently imaged at the image sensor. Since the coherence of each sub-aperture beam is achieved by compensating the phase in the information domain, the distributed synthetic aperture imaging device and method based on the information coherence theory provided in this application do not require the optical coherence of each sub-aperture beam before compensation. Therefore, even if there are errors in the processing or installation of each sub-mirror in the device, synthetic aperture imaging can be effectively realized. In other words, the distributed synthetic aperture imaging device and method based on the information coherence theory provided in this application can reduce the requirements for processing and installation of synthetic aperture imaging technology, thus breaking the limitations of existing processing technology and installation technology on synthetic aperture technology, not only improving the imaging quality of synthetic aperture technology, but also reducing the implementation difficulty of synthetic aperture technology.

[0103] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "including one..." does not exclude the existence of another identical element in the process, method, article or device including the said element.

[0104] Each embodiment in this specification is described in a related manner. For the same or similar parts among the embodiments, reference can be made to each other. Each embodiment focuses on the differences from other embodiments. In particular, for the method embodiments, since they are basically similar to the device embodiments, the description is relatively simple, and reference can be made to the relevant parts of the method embodiments for the relevant content.

[0105] The above are only the preferred embodiments of the present invention and are not intended to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention are all included in the protection scope of the present invention.

Claims

1. A distributed synthetic aperture imaging device based on the information coherence theory, characterized in that The device includes an optical information processing component, a beam splitter, a wavefront sensor, a phase modulator, and an image sensor; The optical information processing component is configured to transform the light incident on the device into sub-aperture beams of multiple different frequency bands and output them to the beam splitter; The beam splitter is configured to split each incident sub-aperture beam into a first beam and a second beam respectively, output the first beam to the wavefront sensor, and output the second beam to the phase modulator; The wavefront sensor is configured to detect the common aberration of each of the first beams and send it to the phase modulator; The phase modulator is configured to compensate the phase of each incident second beam according to the common aberration, and output each compensated second beam to the image sensor for coherent imaging; The image sensor is configured to record the image generated by the coherent imaging.

2. The device according to claim 1, characterized in that, The phase modulator is a spatial light modulator, and the spatial light modulator is configured to respond to the common aberration sent by the wavefront sensor and adjust the loaded phase to the negative of the common aberration.

3. The device according to claim 2, characterized in that, The device further includes a reflector disposed between the beam splitter and the spatial light modulator; The outputting the second beam to the phase modulator includes: Outputting the second beam to the reflector, and making it incident on the spatial light modulator under the reflection of the reflector; Taking the direction from the beam splitter to the reflector as the first direction, and the direction from the reflector to the spatial light modulator as the second direction, the included angle between the first direction and the second direction is greater than a first angle threshold.

4. The device according to claim 3, characterized in that, The device further includes a first Fourier lens disposed between the beam splitter and the reflector, and a second Fourier lens disposed between the reflector and the spatial light modulator; The first Fourier lens and the second Fourier lens form a 4F optical system; The outputting the second beam to the reflector and making it incident on the spatial light modulator under the reflection of the reflector includes: Outputting the second beam to the reflector via the first Fourier lens, and making it incident on the spatial light modulator via the second Fourier lens under the reflection of the reflector. The first Fourier lens is used to perform Fourier transform on the incident beam, and the second Fourier lens is used to perform inverse Fourier transform on the incident beam.

5. The device according to claim 1, characterized in that, The optical information processing component is specifically configured to convert the light incident on the device to the frequency domain, select beams of multiple preset frequency bands from the frequency domain as sub-aperture beams, and output each sub-aperture beam to the beam splitter.

6. The device according to claim 5, characterized in that 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 to project the light incident on the device onto the spectrum plane; The fourth Fourier lens is used to select components of multiple preset frequency bands from the spectrum plane as sub-apertures to obtain each sub-aperture beam and output the sub-aperture beam to the beam splitter.

7. The device according to claim 6, characterized in that, The fourth Fourier lens is further configured to collimate each of the sub-aperture beams.

8. The device according to any one of claims 1 to 7, characterized in that, The apparatus further includes a focusing lens group disposed between the phase modulator and the image sensor; The emitting the compensated second beams to the image sensor includes: Emitting the compensated second beams to the image sensor via the focusing lens group, where the focusing lens group is configured to focus the passed beams on the image sensor.

9. The device according to any one of claims 1-7, characterized in that The wavefront sensor is a Shack-Hartmann wavefront sensor.

10. A distributed synthetic aperture imaging method based on information coherence theory, characterized in that, The method includes: Converting the light emitted or reflected by an imaging target into a plurality of sub-aperture beams of different frequency bands; Detecting the common aberration of each of the sub-aperture beams through a wavefront sensor; Compensating the phase of each of the sub-aperture beams according to the common aberration through a phase modulator, and emitting the compensated sub-aperture beams to an image sensor for coherent imaging; Recording, by the image sensor, an image generated by the coherent imaging.

Images