A distributed synthetic aperture imaging device and method based on information coherence theory

Abstract

Embodiments of the present invention provide a distributed synthetic aperture imaging device and method based on information coherence theory. The device comprises 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 convert light into multiple sub-aperture beams of different frequency bands. The beam splitter is configured to split each sub-aperture beam into a first beam and a second beam, and emit the first beam to the wavefront sensor and the second beam to the phase modulator. The wavefront sensor is configured to detect the common aberration of each first beam. The phase modulator is configured to compensate the phase of each incident second beam according to the common aberration, and emit the compensated second beams to the image sensor for coherent imaging. The image sensor is configured to record the image generated by the coherent imaging. This method can break the limitations of existing paradigms on synthetic aperture imaging technology, making it applicable to a wider range of scenarios.

Description

Technical Field

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

[0002] Synthetic aperture telescopes (STARs), based on synthetic aperture imaging technology, are core tools for deep space exploration and space astronomy research. Their operation relies on optical coherence technology, which reconstructs low-resolution images collected by multiple sub-mirrors in a coherent manner, thereby simulating the performance of a larger telescope.

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

[0004] However, as the number of sub-mirrors increases, the traditional method of controlling the optical correlation between sub-mirrors through physical means and manufacturing processes faces severe challenges. The existing methods of achieving optical coherence are difficult to meet the current demand for the number of sub-mirrors. Bottlenecks include complex manufacturing processes, high costs, difficulty in system integration, 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 information coherence theory, which can achieve optical correlation without relying on traditional physical means and manufacturing processes. This breaks the constraints of physical means and manufacturing processes on synthetic aperture imaging technology and enables synthetic aperture imaging technology to be effectively applied to larger-scale (kilometer-level) distributed optical systems. The specific technical solution is as follows:

[0006] In a first aspect of the present application, a distributed synthetic aperture imaging device based on information coherence theory is provided, wherein 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 used to convert the light incident on the device into a plurality of sub-aperture beams of different frequency bands and emit them to the beam splitter;

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

[0009] The wavefront sensor is used 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 incident second light beam according to the common aberration, and emit each compensated second light beam to the image sensor for coherent imaging;

[0011] The image sensor is used 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 adjust the loaded phase to a negative common aberration in response to the common aberration sent by the wavefront sensor.

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

[0014] The step of emitting the second light beam to the phase modulator includes:

[0015] emit the second light beam to the reflector, and then reflect the second light beam from the reflector and enter the spatial light modulator;

[0016] A direction from the beam splitter to the reflector is a first direction, a direction from the reflector to the spatial light modulator is a second direction, and an 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 step of emitting the second light beam to a reflector and causing the second light beam to enter the spatial light modulator under reflection from the reflector comprises:

[0020] The second light beam is emitted to the reflector through the first Fourier lens, and is reflected by the reflector and incident on the spatial light modulator through the second Fourier lens. The first Fourier lens is used to perform Fourier transform on the incident light beam, and the second Fourier lens is used to perform inverse Fourier transform on the incident light beam.

[0021] In a possible embodiment, the optical information processing component is specifically used to convert the light incident on the device into the frequency domain, and select multiple light beams of preset frequency bands from the frequency domain as sub-aperture beams, and emit each of the sub-aperture 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 used to project the light incident on the device onto a spectrum plane;

[0025] The fourth Fourier lens is used to select components of multiple preset frequency bands from the frequency spectrum plane as sub-apertures to obtain sub-aperture beams and emit the sub-aperture beams 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] The step of emitting the compensated second light beams to the image sensor includes:

[0028] Each of the compensated second light beams is emitted to the image sensor through the focusing lens group, and the focusing lens group is used to focus the passing light beams 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 information coherence theory is provided, the method comprising:

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

[0032] Obtaining the common aberration of each sub-aperture light beam by detecting with a wavefront sensor;

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

[0034] The image generated by the coherent imaging is recorded by the image sensor.

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

[0036] Embodiments of the present invention provide a distributed synthetic aperture imaging device and method based on information coherence theory. By detecting the wavefronts of each sub-aperture beam, the shared aberration of each sub-aperture beam is obtained. The phase of each sub-aperture beam is then compensated in the information domain based on the shared aberration, thereby making the compensated beam coherent in the information domain and capable of coherent imaging at the image sensor. Because the sub-aperture beams are made coherent by compensating the phase in the information domain, the distributed synthetic aperture imaging device and method based on information coherence theory provided by the present application do not require the sub-aperture beams to be optically coherent before compensation. Therefore, even if errors occur in the manufacturing or installation of the sub-mirrors in the device, synthetic aperture imaging can still be effectively achieved. In other words, the distributed synthetic aperture imaging device and method based on information coherence theory provided by the present application can reduce the processing and installation requirements of synthetic aperture imaging technology, thereby breaking the limitations of existing processing and installation technologies on synthetic aperture technology. This not only improves the imaging quality of synthetic aperture technology, but also reduces the difficulty of implementing synthetic aperture technology.

[0037] Of course, it is not necessary to achieve all of the advantages described above simultaneously in order to implement any product or method of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other embodiments can also be obtained based on these drawings.

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

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

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

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

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

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

[0045] Figure 7 This is a seventh structural diagram of the distributed synthetic aperture imaging device based on information coherence theory provided in this application;

[0046] Figure 8 This is a schematic diagram of the eighth structure of the distributed synthetic aperture imaging device based on information coherence theory provided in this application;

[0047] Figure 9 A schematic flow chart of the distributed synthetic aperture imaging method based on information coherence theory provided in this application. DETAILED DESCRIPTION

[0048] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field based on this application are within the scope of protection of the present invention.

[0049] In order to more clearly illustrate the distributed synthetic aperture imaging device and method based on information coherence theory provided by the present application, the application scenarios of the distributed synthetic aperture imaging device and method based on information coherence theory provided by the present application will be explained below using 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 information coherence theory provided by the present application. In other possible embodiments, the distributed synthetic aperture imaging device and method based on information coherence theory provided by the present application can also be applied to other scenarios where synthetic aperture imaging exists. The following examples do not impose any limitations on this.

[0050] Limited by the size of a single optical aperture, the information contained in the light signal that can be acquired through a single optical aperture is often limited, resulting in a single-aperture telescope being able to observe only limited information. Therefore, related technologies utilize multiple optical apertures for separate detection, and utilize the principle of coherent imaging to coherently image the light beams from each optical aperture at the image sensor, allowing the image sensor to record the interference fringes formed by the coherent imaging. Because the interference fringes contain information from the light beams of multiple optical apertures, telescopes based on synthetic aperture technology can observe more information than single-aperture telescopes, and as the number of optical apertures increases, the amount of information that can be observed also increases.

[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, the optical parameters and positions of each sub-mirror in the system need to be reasonably set, and it is necessary to ensure that each sub-mirror is processed and installed strictly in accordance with the designed optical parameters and positions. As the number of optical apertures increases, the requirements for processing and installation become higher. However, due to the limitations of existing processing and installation technologies, it is difficult to meet the processing and installation requirements for a large number of optical apertures. This also leads to a limit on the number of sub-apertures of telescopes based on synthetic aperture technology, and thus the information it can observe will also be limited.

[0052] Based on this, the present application provides a distributed synthetic aperture imaging device and method based on information coherence theory. By detecting the wavefront of each sub-aperture beam, the common aberration of each sub-aperture beam is obtained. Then, based on the common aberration, the phase of each sub-aperture beam is compensated in the information domain, so that the compensated beam is coherent in the information domain and can be coherently imaged at the image sensor. Because 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 information coherence theory provided by the present application does not require each sub-aperture beam 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 achieved. In other words, the distributed synthetic aperture imaging device and method based on information coherence theory provided by the present application can reduce the processing and installation requirements of synthetic aperture imaging technology, thereby breaking the limitations of existing processing and installation technologies on synthetic aperture technology, not only improving the imaging quality of synthetic aperture technology, but also reducing the difficulty of implementing synthetic aperture technology.

[0053] The following is an explanation of the distributed synthetic aperture imaging device (hereinafter referred to as the device) based on the information coherence theory provided by this application. Figure 1 , Figure 1 The figure shows a first structural schematic diagram of the distributed synthetic aperture imaging device provided by the present application, 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.

[0054] The following will be discussed in the order in which the light passes through each optical element. Figure 1 Each optical element in is described.

[0055] The optical information processing component 100 is used to transform the light of the incident device into a plurality of sub-aperture beams of different frequency bands and emit them to the beam splitter 200. The optical information processing component 100 can be any optical element or combination of optical elements capable of transforming light into a plurality of sub-aperture beams of different frequency bands. Exemplarily, the optical information processing component 100 includes a 4F optical system, which performs an optical Fourier transform on the incident light to convert the light into the frequency domain, and then selects components of a plurality of specific frequency bands on the spectrum plane as each sub-aperture to obtain each sub-aperture 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 may also include other optical components or combinations of optical components with Fourier transform and sub-aperture selection capabilities, and the present application does not impose any restrictions on this.

[0056] Beam splitter 200 is used to split each milky yellow sub-aperture beam into a first beam and a second beam, respectively. The first beam is emitted to wavefront sensor 300, and the second beam is emitted to phase modulator 400. Beam splitter 200 can be composed of a single beam splitter or an optical assembly with beam splitting capabilities composed of multiple optical elements. For example, beam splitter 200 can be formed by gluing two triangular prisms together to form a cube. Each sub-aperture beam is incident at a 45° angle to the gluing plane of the two triangular prisms. At the gluing plane, a portion of the light is transmitted, while another portion is reflected. The transmitted light continues to exit beam splitter 200 in the direction of incidence (hereinafter referred to as the original direction), while the reflected light exits beam splitter 200 in a direction perpendicular to the incident direction (hereinafter referred to as the perpendicular direction). In this example, if wavefront sensor 300 is positioned in the original direction of beam splitter 200 and the phase modulator is positioned in the perpendicular direction of beam splitter 200, the transmitted light is the second beam, and the reflected light is the first beam. Conversely, if the wavefront sensor 300 is positioned perpendicular to the beam splitter 200 and the phase modulator is positioned in the original direction of the beam splitter 200, the transmitted light is the aforementioned first beam, and the reflected light is also the aforementioned first beam. For ease of description, the following example uses the case where the transmitted light is the first beam and the reflected light is the second beam. The principles for the case where the transmitted light is the second beam and the reflected light is the first beam are the same and are not further elaborated here.

[0057] Wavefront sensor 300 is used to detect the shared aberrations of each first light beam. Wavefront sensor 300 is any sensor capable of directly or indirectly detecting the shared aberrations of the incident optical fiber. Direct detection herein means that the sensor's sensed signal is the shared aberration, while indirect detection means that the sensor's sensed signal is not the shared aberration, but the shared aberration can be calculated based on the sensed signal. Exemplarily, wavefront sensor 300 in this application may be a Shack-Hartmann wavefront sensor.

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

[0059] …(1)

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

[0061] …(2)

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

[0063] …(3)

[0064] It can be seen that the wavefront of the sub-aperture 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 phase of each incident second light beam according to the common aberration, 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 needs. Adjusting the phase according to actual needs herein means: being able to adaptively modulate the phase according to the different common aberrations detected by the wavefront sensor 300. For example, 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, and therefore does not meet the requirements for the phase modulator 400 in this application. Taking a spatial light modulator as an example, a spatial light modulator can change the phase of incident light at different amplitudes by loading different phases. Therefore, as long as the spatial light modulator loads the phase corresponding to the common aberration detected by the wavefront sensor 300, adaptive phase modulation can be achieved. Therefore, the spatial light modulator meets the requirements of the phase modulator 400 in this application. In other words, 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 a spatial light modulator, and this application does not impose any restrictions on this.

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

[0067] Since the phase distribution of the first and second beams is the same, it can be seen from the above formula (3) that if the common aberration is not eliminated, the intensity distribution in the image obtained by imaging can be expressed by formula (4):

[0068] …(4)

[0069] Where I is the intensity distribution and N is the number of subapertures.

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

[0071] …(5)

[0072] And, understandably, Figure 1 The structure shown is only a schematic diagram and does not represent the optical components according to Figure 1 The azimuths shown in the figure are arranged in the same way, and the beams are not arranged in the same way Figure 1 Propagation in the direction shown, Figure 1 The light beams shown in FIG. 1 are only used to indicate the order in which the light beams pass through the optical elements, and do not indicate the actual propagation direction.

[0073] For example, Figure 1 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 enters the wavefront sensor 300 from left to right, and enters the image sensor 500 from left to right after phase compensation. This only means that the second light beam passes through the phase modulator 400 and the image sensor 500 in sequence after being emitted from the beam splitter 200, and does not mean that it propagates from left to right after being emitted from the beam splitter 200, nor does it mean that its propagation direction has not changed after being emitted from the beam splitter 200.

[0074] Image sensor 500 is used to record the image generated by coherent imaging. Image sensor 500 is any sensor capable of sensing light emitted or reflected by the imaging target. Depending on actual needs, image sensor 500 can sense different wavelengths, including but not limited to visible light and near-infrared wavelengths.

[0075] The above has been Figure 1 The various optical elements shown in the figure are described, and it is understood that, except for Figure 1 The optical elements shown in FIG. 3 may further include other optical elements, for example, Figure 2 As shown, in the case where the phase modulator 400 is a spatial light modulator 410 , the device may further include a reflector 600 , which is located between the beam splitter 200 and the spatial light modulator 410 .

[0076] In this article, the reflector 600 is located between the beam splitter 200 and the spatial light modulator 410, which means that the reflector 600 is located on the optical path of the light emitted from the beam splitter 200 to the spatial light modulator 410, and does not specifically mean that the reflector 600 is located on the line connecting the beam splitter 200 and the spatial light modulator 410. The same applies to other mirrors located between two optical elements below.

[0077] exist Figure 2In the example shown, the second light beam does not directly enter the spatial light modulator 410 after exiting the beam splitter 200, but first enters the reflector 600, and then enters the spatial light modulator 410 through reflection from the reflector 600. Moreover, if the direction from the beam splitter 200 to the reflector 600 in this example is recorded as the first direction, and the direction from the reflector 600 to the spatial light modulator 410 is recorded as the second direction, then the angle between the first direction and the second direction should be sufficiently large. In this article, the angle between the first direction and the second direction should be sufficiently large 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 is understood that in order for the spatial light modulator 410 to function properly, the angle between the light incident on the spatial light modulator 410 and the light emitted from the spatial light modulator 410 must be sufficiently small, typically within 10°. This ensures that the light emitted from the spatial light modulator 410 is approximately in the opposite direction of the light incident on the spatial light modulator 410.

[0079] If the light emitted from the beam splitter 200 directly enters the spatial light modulator 410, the light emitted from the spatial light modulator 410 propagates approximately from the spatial light modulator 410 to the beam splitter 200. At this time, in order to enable the image sensor 500 to record the image generated by coherent imaging, Figure 3 As shown, the image sensor 500 and the beam splitter 200 need to be arranged on the same side of the spatial light modulator 410, which easily leads to conflict between the image sensor 500 and the beam splitter 200, increasing the design difficulty of the device.

[0080] And choose Figure 2 In the example shown, the light emitted from the spatial light modulator 410 can be roughly considered to propagate in the direction opposite to the second direction. In this case, the image generated by coherent imaging can be recorded by simply placing the image sensor 500 in the direction opposite to the second direction of the spatial light modulator 410. Because the angle between the second direction and the first direction is sufficiently large, the direction opposite to the second direction also forms a large angle with the first direction. In other words, the image sensor 500 and the beam splitter 200 are placed on different sides of the spatial light modulator 410, effectively avoiding interference between the image sensor 500 and the beam splitter 200, and reducing the design difficulty of the device.

[0081] and, Figure 2 Based on the example shown, Figure 4 As 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 reflector 600 , and the second Fourier lens 720 is disposed between the reflector 600 and the spatial light modulator 410 . The first Fourier lens 710 and the second Fourier lens 720 form a 4F optical system.

[0083] exist Figure 4 In the example shown, light emitted from the beam splitter 200 passes through the first Fourier lens 710, the reflector 600, and the second Fourier lens 720 in sequence and enters 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 is better modulated, thereby improving the imaging quality of the coherent imaging of the second light beam.

[0084] And, as Figure 5 As shown, in order to make the compensated second light beam form a better coherent image on the image sensor 500, the device can also include a focusing lens group 800, which is arranged 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. Figure 5 In the example shown, after being emitted from the phase modulator 400 , the compensated second light beam is focused by the focusing lens group 800 and enters the image sensor 500 .

[0085] The focusing lens group 800 can be composed of multiple lenses or only one lens, as long as it can effectively focus the compensated second light beam. This application does not impose any restrictions on this. Figure 1 , Figure 5 It does not mean that each optical component is Figure 5 The azimuths shown in the figure are arranged in the same way, and the beams are not arranged in the same way Figure 5 Propagation in the direction shown, Figure 5 The light beams shown in FIG are only used to indicate the order in which the light beams pass through the optical elements, and do not indicate the actual propagation direction. Figure 4 The example shown is based on the case where a focusing lens group 800 is provided. The focusing lens group 800 is located at Figure 6 At the location shown.

[0086] The above has been Figure 1 The optical elements that are not shown but may be included in the device are exemplarily described. It is understood that the above-mentioned reflector 600, the first Fourier lens 710, the second Fourier lens 720, and the focusing lens group 800 are only four possible examples, and the device provided in this application is not limited to only include Figure 1The optical elements shown include the reflector 600, the first Fourier lens 710, the second Fourier lens 720, and the focusing lens group 800. In other possible embodiments, the device may also include other optical elements besides the reflector 600, the first Fourier lens 710, the second Fourier lens 720, and the focusing lens group 800, and this application does not impose any limitations on this.

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

[0088] In one possible embodiment, the optical information processing component 100 may convert light from an incident device into the frequency domain, thereby selecting light beams in multiple preset frequency bands from the frequency domain as sub-aperture beams. It is understood that as an optical element, the optical information processing component 100 converts light into the frequency domain by performing an optical Fourier transform.

[0089] For example, Figure 7 As 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, thereby transforming the incident light into the frequency domain. In this way, by selecting components of multiple preset frequency bands as sub-apertures on the spectrum plane, each sub-aperture light beam can be obtained. These sub-aperture light beams are emitted through the fourth Fourier lens 120. The fourth Fourier lens 120 is used to perform an inverse Fourier transform on the light beam transformed into the frequency domain, thereby transforming these light rays back from the frequency domain to the time domain.

[0090] Furthermore, in order to ensure that the light emitted from the optical information processing component 100 can accurately enter the beam splitter 200 , the fourth Fourier lens 120 can also be used to collimate the light beam to prevent part of the light beam from failing to enter the beam splitter 200 .

[0091] The structure of the optical information processing component 100, Figure 1 The optical elements shown in Figure 1 The optical elements that are not shown in the figure but may be included in the device are described. The following is an exemplary description of the distributed synthetic aperture imaging device based on information coherence theory provided by the present application in combination with the optical elements mentioned in the above examples. Figure 8In this example, the apparatus includes: an optical information processing component 100, a beam splitter 200, a Shack-Hartmann wavefront sensor 310, a first Fourier lens 710, a reflector 600, a second Fourier lens 720, a spatial light modulator 410, a focusing lens group 800, and an image sensor 500. The optical information processing component 100 includes a third Fourier lens 110 and a fourth Fourier lens 120.

[0092] Figure 8 The various optical elements have been described above, so please refer to the relevant description above and do not repeat them here. Figure 8 In the illustrated example, light emitted or reflected by the imaging target sequentially passes through the third Fourier lens 110 and the fourth Fourier lens 120 before entering the beam splitter 200. Upon entering the beam splitter 200, the light has been transformed into multiple sub-aperture beams. These sub-aperture beams are split into two at the beam splitter 200. One portion (the first beam, referred to above) exits the beam splitter 200 and enters the Shack-Hartmann wavefront sensor 310. The other portion (the second beam, referred to above) exits the beam splitter 200 and sequentially passes through the first Fourier lens 710, the reflector 600, the second Fourier lens 720, the spatial light modulator 410, and the focusing lens group 800 before finally entering the image sensor 500, where a coherent image is formed.

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

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

[0095] That is, it corresponds to the function of the aforementioned optical information processing component 100. Please refer to the above description of the optical information processing component 100, which will not be repeated here.

[0096] Step S902: Detecting and obtaining the common aberration of each sub-aperture light beam through a wavefront sensor.

[0097] That is, it corresponds to the function of the aforementioned wavefront sensor 300. Please refer to the above description of the wavefront sensor 300, which will not be repeated here.

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

[0099] That is, it corresponds to the function of the aforementioned phase modulator 400. Please refer to the above description of the phase modulator 400, which will not be repeated here.

[0100] Step S904: Record the image generated by coherent imaging through the image sensor.

[0101] That is, it corresponds to the function of the aforementioned image sensor 500. Please refer to the above description of the image sensor 500, which will not be repeated here.

[0102] By selecting the distributed synthetic aperture imaging method based on 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 is compensated in the information domain based on the common aberration, so that the compensated beam is 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 information coherence theory provided in this application does not require the sub-aperture beams 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 achieved. In other words, the distributed synthetic aperture imaging device and method based on information coherence theory provided in this application can reduce the processing and installation requirements of synthetic aperture imaging technology, thereby breaking the limitations of existing processing and installation technologies on synthetic aperture technology, not only improving the imaging quality of synthetic aperture technology, but also reducing the difficulty of implementing synthetic aperture technology.

[0103] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply the existence of any such actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or device comprising the element.

[0104] Each embodiment in this specification is described in a related manner. Similar portions between the embodiments can be referenced to each other. Each embodiment focuses on the differences from other embodiments. In particular, the method embodiments are generally similar to the apparatus embodiments, so their description is relatively simple. For related portions, reference can be made to the description of the method embodiments.

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

Claims

1. A distributed synthetic aperture imaging device based on 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 used to convert the light incident on the device into a plurality of sub-aperture beams of different frequency bands and emit them to the beam splitter; The beam splitter is used to split the incident sub-aperture light beams into a first light beam and a second light beam, and emit the first light beam to the wavefront sensor and emit the second light beam to the phase modulator; The wavefront sensor is used to detect the common aberration of each of the first light beams and send it to the phase modulator; The phase modulator is configured to compensate the phase of each incident second light beam according to the common aberration, and emit each compensated second light beam to the image sensor for coherent imaging; The image sensor is used 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 adjust the loaded phase to a negative of the common aberration in response to the common aberration sent by the wavefront sensor.

3. The device according to claim 2, characterized in that The apparatus further includes a reflector disposed between the beam splitter and the spatial light modulator; The step of emitting the second light beam to the phase modulator includes: emit the second light beam to the reflector, and then reflect the second light beam from the reflector and enter the spatial light modulator; A direction from the beam splitter to the reflector is a first direction, a direction from the reflector to the spatial light modulator is a second direction, and an 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 step of emitting the second light beam to a reflector and causing the second light beam to enter the spatial light modulator under reflection from the reflector comprises: The second light beam is emitted to the reflector through the first Fourier lens, and is reflected by the reflector and incident on the spatial light modulator through the second Fourier lens. The first Fourier lens is used to perform Fourier transform on the incident light beam, and the second Fourier lens is used to perform inverse Fourier transform on the incident light beam.

5. The device according to claim 1, characterized in that The optical information processing component is specifically used to convert the light incident on the device into the frequency domain, and select multiple light beams of preset frequency bands from the frequency domain as sub-aperture beams, and emit each of the sub-aperture beams 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 a spectrum plane; The fourth Fourier lens is used to select components of multiple preset frequency bands from the frequency spectrum plane as sub-apertures to obtain sub-aperture beams and emit the sub-aperture beams to the beam splitter.

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

8. The device according to any one of claims 1 to 7, characterized in that: The device further includes a focusing lens group disposed between the phase modulator and the image sensor; The step of emitting the compensated second light beams to the image sensor includes: Each of the compensated second light beams is emitted to the image sensor through the focusing lens group, and the focusing lens group is used to focus the passing light beams on the image sensor.

9. The device according to any one of claims 1 to 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 comprises: Convert the light emitted or reflected by the imaging target into multiple sub-aperture beams of different frequency bands; Obtaining the common aberration of each sub-aperture light beam by detecting with a wavefront sensor; Compensating the phase of each of the sub-aperture beams according to the common aberration by a phase modulator, and emitting the compensated sub-aperture beams to an image sensor for coherent imaging; The image generated by the coherent imaging is recorded by the image sensor.

Images