Infrared complex image formation of moving targets and sub-mirror array synthetic aperture imaging method and system

Abstract

The present disclosure provides a method and system for forming an infrared complex image of a moving target and performing synthetic aperture imaging using a sub-mirror array. The method comprises: using a spatial light modulator to phase-modulate an initial linearly polarized laser local oscillator to obtain an orthogonal phase-modulated laser local oscillator; using a depolarizing beam splitter in each sub-mirror module to combine the orthogonal phase-modulated laser local oscillator and a target infrared signal processed by Fourier transform to obtain a combined beam signal; using a direct array detector to receive the combined beam signal, generate a holographic image corresponding to the sub-mirror module, and combine the laser local oscillator image to construct an infrared complex image corresponding to the sub-mirror module; and performing synthetic aperture imaging on the infrared complex images corresponding to the multiple sub-mirror modules based on sub-mirror array parameters and target distance parameters to obtain a synthetic aperture imaging result, wherein the infrared complex images corresponding to each of the multiple sub-mirror modules are obtained at the same moment during the motion of the moving target.

Description

Technical Field

[0001] The present disclosure relates to the fields of optical synthetic aperture telescopes, computational imaging, signal processing and infrared imaging detection technology, and in particular to a method and system for infrared complex image formation of a moving target and synthetic aperture imaging of a sub-mirror array. Background Art

[0002] The resolution of an optical system is limited by the diffraction limit, so increasing the optical system aperture is an effective way to improve resolution. Therefore, using a large-aperture single-aperture telescope can achieve high-resolution infrared imaging. Therefore, to achieve long-range high-resolution imaging detection, a large-aperture telescope is required. However, large-aperture single-aperture telescopes currently face challenges in manufacturing and platform support.

[0003] Optical synthetic aperture telescope systems based on stitching imaging or interferometric imaging are effective alternatives to large-aperture single-aperture telescope systems. However, this method first requires the realization of optical synthetic aperture through hardware equipment such as mechanical structures, and then the collection and reception of optical synthetic aperture imaging results. This places high demands on the accuracy of hardware such as the system's optical path fine-tuning mechanism. Summary of the Invention

[0004] In view of the above problems, the present disclosure provides a method and system for infrared complex image formation of a moving target and synthetic aperture imaging of a sub-mirror array.

[0005] According to a first aspect of the present disclosure, a method for forming an infrared complex image of a moving target and performing synthetic aperture imaging using a sub-mirror array is provided, comprising:

[0006] Using a spatial light modulator, the initial linearly polarized laser local oscillator is phase modulated to obtain an orthogonal phase modulated laser local oscillator;

[0007] In each sub-mirror module,

[0008] The orthogonal phase modulated laser local oscillator and the target infrared signal after Fourier transform processing are beam-combined using a depolarizing beam splitter prism for beam combining to obtain a combined beam signal, wherein the sub-mirrors in the sub-mirror module are used to perform Fourier transform processing on the received target infrared signal corresponding to the moving target, and the sub-mirror array includes a plurality of the above-mentioned sub-mirror modules;

[0009] Using a direct array detector to receive the combined beam signal, and generate a holographic image corresponding to the sub-mirror module;

[0010] constructing an infrared complex image corresponding to the sub-mirror module based on the holographic image and the laser local oscillator image corresponding to the sub-mirror module, wherein the laser local oscillator image is a laser local oscillator image corresponding to the orthogonal phase modulated laser local oscillator acquired by the direct array detector when the sub-mirror in the sub-mirror module is blocked;

[0011] According to the sub-mirror array parameters and the target distance parameters, synthetic aperture imaging processing is performed on the infrared complex images corresponding to the multiple sub-mirror modules to obtain synthetic aperture imaging results corresponding to the above-mentioned moving targets, wherein the infrared complex images corresponding to the multiple sub-mirror modules are obtained at the same moment of the movement process of the above-mentioned moving targets.

[0012] A second aspect of the present disclosure provides a moving target infrared complex image formation and sub-mirror array synthetic aperture imaging system, comprising:

[0013] A spatial light modulator is used to phase modulate an initial linearly polarized laser local oscillator to obtain an orthogonal phase modulated laser local oscillator;

[0014] In each sub-mirror module,

[0015] a depolarizing beam splitter prism for beam combining, used to combine the orthogonal phase modulated laser local oscillator and the target infrared signal after Fourier transform processing to obtain a combined beam signal, wherein the sub-mirrors in the sub-mirror module are used to perform Fourier transform processing on the received target infrared signal corresponding to the moving target, and the sub-mirror array includes a plurality of the above-mentioned sub-mirror modules;

[0016] A direct array detector, configured to receive the combined beam signal and generate a holographic image corresponding to the sub-mirror module;

[0017] a calculation module, configured to construct an infrared complex image corresponding to the sub-mirror module based on the holographic image and the laser local oscillator image corresponding to the sub-mirror module, wherein the laser local oscillator image is a laser local oscillator image corresponding to the quadrature phase modulated laser local oscillator acquired by the direct array detector when the sub-mirror in the sub-mirror module is blocked;

[0018] The above-mentioned calculation module is also used to perform synthetic aperture imaging processing on the infrared complex images corresponding to the multiple sub-mirror modules according to the sub-mirror array parameters and the target distance parameters, so as to obtain synthetic aperture imaging results corresponding to the above-mentioned moving targets, wherein the infrared complex images corresponding to the multiple sub-mirror modules are obtained at the same moment of the movement process of the above-mentioned moving targets.

[0019] According to the method and system for forming an infrared complex image of a moving target and using a sub-mirror array for synthetic aperture imaging, the present invention provides a method and system for combining a laser local oscillator with a spatial light modulator and using a direct array detector to realize a coherent array function for a moving target. This allows forming an infrared complex image based on the holographic image and the laser local oscillator image corresponding to the sub-mirror module, and based on the sub-mirror array parameters and the target distance parameters, real-time synthetic aperture imaging of a moving target at a low speed can be realized on a computing module. Compared with traditional large-aperture single-aperture telescopes, the method of the present invention greatly reduces the difficulty of equipment manufacturing. Compared with traditional optical synthetic aperture imaging systems, the method of the present invention has the characteristics of low hardware precision requirements such as fine-tuning mechanisms, and provides a foundation for the development of future large-aperture imaging systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The above contents and other objects, features and advantages of the present disclosure will become more apparent through the following description of the embodiments of the present disclosure with reference to the accompanying drawings, in which:

[0021] Figure 1 A diagram schematically illustrates an application scenario of a moving target infrared complex image formation and a sub-mirror array synthetic aperture imaging method according to an embodiment of the present disclosure;

[0022] Figure 2 A flow chart schematically illustrates a method for forming an infrared complex image of a moving target and a sub-mirror array synthetic aperture imaging method according to an embodiment of the present disclosure;

[0023] Figure 3 The schematic diagram of the structure of the sub-mirror array according to the embodiment of the present disclosure is shown;

[0024] Figure 4 Schematically shows a flow chart for constructing an infrared complex image according to an embodiment of the present disclosure;

[0025] FIG5( a ) schematically shows an amplitude diagram of an infrared complex image corresponding to a single sub-mirror according to an embodiment of the present disclosure;

[0026] FIG5( b ) schematically shows a phase diagram of an infrared complex image corresponding to a single sub-mirror according to an embodiment of the present disclosure;

[0027] FIG5( c ) schematically shows a spatial sampling signal of an infrared complex image corresponding to a single sub-mirror according to an embodiment of the present disclosure;

[0028] Figure 6 A flowchart for obtaining a synthetic aperture imaging result according to an embodiment of the present disclosure is schematically shown;

[0029] FIG7( a ) schematically shows an amplitude diagram of a synthetic aperture imaging result according to an embodiment of the present disclosure;

[0030] FIG7( b ) schematically shows a phase diagram of a synthetic aperture imaging result according to an embodiment of the present disclosure;

[0031] FIG7( c ) schematically illustrates a spatial sampling signal of a synthetic aperture imaging result according to an embodiment of the present disclosure;

[0032] FIG7( d ) schematically shows an X-direction slice comparison diagram of a single-mirror infrared complex image and a synthetic aperture imaging result according to an embodiment of the present disclosure;

[0033] FIG7( e ) schematically shows a Y-direction slice comparison diagram of a single-mirror infrared complex image and a synthetic aperture imaging result according to an embodiment of the present disclosure; and

[0034] Figure 8 The schematic diagram of the moving target infrared complex image formation and sub-mirror array synthetic aperture imaging system according to an embodiment of the present disclosure is schematically shown. DETAILED DESCRIPTION

[0035] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are merely exemplary and are not intended to limit the scope of the present disclosure. In the detailed description below, for ease of explanation, many specific details are set forth to provide a comprehensive understanding of the embodiments of the present disclosure. However, it is apparent that one or more embodiments may also be implemented without these specific details. In addition, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessary confusion of the concepts of the present disclosure.

[0036] The terms used herein are only for describing specific embodiments and are not intended to limit the present disclosure. The terms "comprise," "include," etc. used herein indicate the presence of the features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0037] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification and should not be interpreted in an idealized or overly rigid manner.

[0038] When expressions such as "at least one of A, B, and C, etc." are used, they should generally be interpreted in accordance with the meaning commonly understood by those skilled in the art (for example, "a system having at least one of A, B, and C" should include but is not limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc.).

[0039] In the technical solutions disclosed herein, the user information (including but not limited to user personal information, user image information, user device information, such as location information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved are all information and data authorized by the user or fully authorized by all parties, and the collection, storage, use, processing, transmission, provision, disclosure and application of the relevant data comply with relevant laws, regulations and standards, take necessary confidentiality measures, do not violate public order and good morals, and provide corresponding operation entrances for users to choose to authorize or refuse.

[0040] In scenarios where personal information is used for automated decision-making, the methods, devices, and systems provided by the embodiments of the present disclosure all provide users with corresponding operation portals for them to choose to agree or reject the automated decision-making results; if the user chooses to reject, the expert decision-making process will be entered. The expression "automated decision-making" here refers to the activity of automatically analyzing and evaluating an individual's behavioral habits, interests and hobbies, or economic, health, credit status, etc. through computer programs and making decisions. The expression "expert decision-making" here refers to the activity of making decisions by people who specialize in a certain field, have specialized experience, knowledge, and skills, and have reached a certain level of professionalism.

[0041] Figure 1 The application scenario diagram of the moving target infrared complex image formation and sub-mirror array synthetic aperture imaging method according to an embodiment of the present disclosure is schematically shown.

[0042] like Figure 1 As shown, the application scenario 100 according to this embodiment may include a spatial light modulator 110, a moving target 120, a sub-mirror array 130, and a computing module 140. The sub-mirror array 130 includes a plurality of sub-mirror modules, namely, sub-mirror module 130_1 to sub-mirror module 130_N, where N is the number of sub-mirror modules and N is an integer greater than or equal to 1. Each sub-mirror module may include a sub-mirror 131, a depolarizing beam splitter prism 132 for beam combining, and a direct array detector 133.

[0043] The moving target infrared complex image formation and sub-mirror array synthetic aperture imaging methods provided in the embodiments of the present disclosure can generally be performed by a spatial light modulator 110, a sub-mirror array 130, and a computing module 140. The spatial light modulator 110 can be used to phase modulate an initial linearly polarized laser local oscillator to obtain an orthogonal phase modulated laser local oscillator.

[0044] According to an embodiment of the present disclosure, for each sub-mirror module, the sub-mirror 131 can be used to perform Fourier transform processing on the target infrared signal to obtain the target infrared signal after Fourier transform processing; the depolarizing beam splitter prism 132 used for beam combining can perform beam combining processing on the orthogonal phase modulated laser local oscillator and the target infrared signal after Fourier transform processing to obtain a combined beam signal; the direct array detector 133 can be used to receive the combined beam signal to generate a holographic image corresponding to the sub-mirror module.

[0045] According to an embodiment of the present disclosure, the calculation module 140 can be used to construct an infrared complex image corresponding to the sub-mirror module based on the holographic image and laser local oscillator image corresponding to the sub-mirror module; the calculation module 140 can also be used to perform synthetic aperture imaging processing on the infrared complex images corresponding to multiple sub-mirror modules according to the sub-mirror array parameters and the target distance parameters, so as to obtain a synthetic aperture imaging result corresponding to the moving target.

[0046] It should be understood that Figure 1 The number of sub-mirror modules, spatial light modulators, and computing modules in the embodiment is merely illustrative. Any number of sub-mirror modules, spatial light modulators, and computing modules may be used depending on the implementation requirements.

[0047] The following will be based on Figure 1 The scene described by Figures 2 to 8 The moving target infrared complex image formation and sub-mirror array synthetic aperture imaging method and system of the disclosed embodiment are described in detail.

[0048] Figure 2 The flowchart of the method for forming an infrared complex image of a moving target and synthetic aperture imaging of a sub-mirror array according to an embodiment of the present disclosure is schematically shown.

[0049] like Figure 2 As shown, the method 200 includes operations S210 to S250.

[0050] In operation S210 , a spatial light modulator is used to phase-modulate an initial linearly polarized laser local oscillator to obtain an orthogonal phase modulated laser local oscillator.

[0051] According to the embodiments of the present disclosure, since a two-step phase-shift digital hologram is subsequently used to construct an infrared complex image, the phase modulation is required to be 0° and 90°. Therefore, the phase modulation processing of the spatial light modulator 110 can make the initial linearly polarized laser local oscillator form a 0° and 90° phase modulation of a small number of equally spaced pixels in the row or column direction of the direct array detector, thereby realizing orthogonal phase modulation of the laser local oscillator to obtain an orthogonal phase modulated laser local oscillator.

[0052] For example, the initial linearly polarized laser local oscillator is phase-modulated at 0° and 90° with every other pixel in the row or column direction of the direct array detector. The laser local oscillator on the pixels in the odd-numbered rows is phase-modulated at 0°, while the laser local oscillator on the pixels in the even-numbered rows is phase-modulated at 90°.

[0053] The orthogonal phase modulated laser local oscillator is a linearly polarized laser local oscillator.

[0054] In operation S220, in each sub-mirror module, a depolarization beam splitter prism for beam combining is used to combine the orthogonal phase modulated laser local oscillator and the target infrared signal after Fourier transform processing to obtain a combined beam signal.

[0055] Among them, the sub-mirrors in the sub-mirror module are used to perform Fourier transform processing on the received target infrared signals corresponding to the moving targets, and the sub-mirror array may include multiple sub-mirror modules.

[0056] According to an embodiment of the present disclosure, a target infrared signal corresponding to a moving target can illuminate a sub-mirror in a plurality of sub-mirror modules, and the sub-mirror can receive the target infrared signal and perform Fourier transform processing on the target infrared signal to obtain a target infrared signal after Fourier transform processing.

[0057] According to an embodiment of the present disclosure, the orthogonal phase modulated laser local oscillator can be given to the depolarizing beam splitter prism in multiple sub-mirror modules. The depolarizing beam splitter prism can be used to combine the orthogonal phase modulated laser local oscillator and the target infrared signal after Fourier transform processing to obtain a combined beam signal, thereby realizing spatial optical path mixing of the laser local oscillator and the target optical signal.

[0058] In operation S230, a direct array detector is used to receive the combined beam signal and generate a holographic image corresponding to the sub-mirror module.

[0059] According to an embodiment of the present disclosure, after obtaining a combined beam signal using a depolarizing beam splitter prism for combining beams, a direct array detector can receive the combined beam signal to generate a holographic image corresponding to the sub-mirror module, that is, the direct array detectors in the sub-mirror modules 130_1~130_N can generate a holographic image of the corresponding sub-mirror module.

[0060] In operation S240, an infrared complex image corresponding to the sub-mirror module is constructed based on the holographic image and the laser local oscillation image corresponding to the sub-mirror module.

[0061] Among them, the laser local oscillator image is a laser local oscillator image corresponding to the orthogonal phase modulated laser local oscillator obtained by directly collecting the array detector when the sub-mirror in the sub-mirror module is blocked.

[0062] According to an embodiment of the present disclosure, for a certain sub-mirror module, the sub-mirrors in the sub-mirror module can be blocked in advance, and the depolarizing beam splitter prism used for beam combining in the sub-mirror module can only receive the orthogonal phase modulated laser local oscillator. Then, the direct array detector in the sub-mirror module can collect and obtain the laser local oscillator image corresponding to the orthogonal phase modulated laser local oscillator.

[0063] According to an embodiment of the present disclosure, based on the principle of two-step phase-shift digital holography, the laser local oscillator image and the holographic image corresponding to the sub-mirror module are used to construct an infrared complex image corresponding to the sub-mirror module, that is, finally, an infrared complex image corresponding to each of the N sub-mirror modules can be obtained.

[0064] In operation S250, synthetic aperture imaging processing is performed on the infrared complex images corresponding to each of the plurality of sub-mirror modules according to the sub-mirror array parameters and the target distance parameters to obtain a synthetic aperture imaging result corresponding to the moving target.

[0065] The infrared complex images corresponding to the multiple sub-mirror modules are obtained at the same moment of the moving target's motion process.

[0066] According to an embodiment of the present disclosure, for a certain moment in the movement of a moving target, through multiple sub-mirror modules 130_1~130_N and a computing module, infrared complex images corresponding to each of the multiple sub-mirror modules can be obtained, that is, N infrared complex images are finally obtained.

[0067] According to an embodiment of the present disclosure, based on the sub-mirror array parameters and the target distance parameters, synthetic aperture imaging processing is performed on the N infrared complex images at that moment to obtain a synthetic aperture imaging result corresponding to the moving target at that moment.

[0068] According to the embodiments of the present disclosure, a laser local oscillator and a spatial light modulator are combined and a direct array detector is used to realize a coherent array function for a moving target, so that an infrared complex image can be formed according to the holographic image and the laser local oscillator image corresponding to the sub-mirror module, and based on the sub-mirror array parameters and the target distance parameters, real-time synthetic aperture imaging of a moving target at a low speed can be realized on the computing module; compared with traditional large-aperture single-aperture telescopes, the method of the present disclosure greatly reduces the difficulty of equipment manufacturing; compared with traditional optical synthetic aperture imaging systems, the method of the present disclosure has the characteristics of low hardware precision requirements such as fine-tuning mechanisms, and provides a foundation for the development of future large-aperture imaging systems.

[0069] Figure 3 The structural diagram of the sub-mirror array according to an embodiment of the present disclosure is schematically shown.

[0070] like Figure 3As shown, the sub-mirror array may include a plurality of sub-mirror modules, namely sub-mirror module 1 to sub-mirror module N, that is, sub-mirror module 130_1 to sub-mirror module 130_N.

[0071] According to an embodiment of the present disclosure, each sub-mirror module may include a sub-mirror, a quarter-wave plate, a depolarizing beam splitter prism for beam combining, a polarizer, and a direct array detector.

[0072] According to an embodiment of the present disclosure, after the initial linearly polarized laser local oscillator is phase-modulated by a spatial light modulator to obtain an orthogonal phase-modulated laser local oscillator, the orthogonal phase-modulated laser local oscillator needs to be given to each sub-mirror module for beam combining with the target infrared signal after Fourier transform processing. The orthogonal phase-modulated laser local oscillator can then be split by a depolarizing beam splitter prism to obtain the same number of laser local oscillators as the sub-mirror modules.

[0073] According to the embodiment of the present disclosure, Figure 3 As shown in the figure, before the orthogonal phase modulated laser local oscillator enters the sub-mirror module 130_1, it first passes through a depolarizing beam splitter prism to split the orthogonal phase modulated laser local oscillator to obtain two laser local oscillators, one of which enters the sub-mirror module 130_1, and the other laser local oscillator passes through a depolarizing beam splitter prism to split the laser local oscillator to obtain two laser local oscillators, one of which passes through a reflector to enter the sub-mirror module 130_2, and the other laser local oscillator passes through a depolarizing beam splitter prism until it passes through two reflectors and enters the last sub-mirror module 130_N.

[0074] Among them, before entering the multiple sub-mirror modules, the orthogonal phase modulated laser local oscillator can be passed through a depolarizing beam splitter prism for splitting to obtain two laser local oscillators, and then the two laser local oscillators are each passed through a depolarizing beam splitter prism for splitting to obtain four laser local oscillators, and then the four laser local oscillators are each passed through a depolarizing beam splitter prism for splitting until the number of laser local oscillators obtained is consistent with the number of sub-mirror modules, and then the multiple laser local oscillators obtained are sequentially entered into a corresponding sub-mirror module.

[0075] Among them, the depolarizing beam splitter prisms in the sub-mirror module are all used for beam combining, and the remaining depolarizing beam splitter prisms are all used for light splitting.

[0076] According to an embodiment of the present disclosure, a sub-mirror can be used to receive a target infrared signal and perform Fourier transform processing on the target infrared signal. A quarter-wave plate and a polarizer can be used to adjust the orthogonal phase modulated laser local oscillator to a linearly polarized signal consistent with the polarization direction of the target infrared signal. That is, the quarter-wave plate can be used to adjust the polarization direction of the orthogonal phase modulated laser local oscillator and, in combination with the polarizer, adjust the polarization direction of the orthogonal phase modulated laser local oscillator to be consistent with the polarization direction of the target infrared signal.

[0077] According to an embodiment of the present disclosure, in each sub-mirror module, the target infrared signal passes through the sub-mirror and the depolarizing beam splitter prism for beam combining in sequence, and the orthogonal phase modulated laser local oscillator passes through the 1 / 4 wave plate and the depolarizing beam splitter prism for beam combining in sequence, so that the target infrared signal after Fourier transform processing and the orthogonal phase modulated laser local oscillator are beam combined in the depolarizing beam splitter prism for beam combining to obtain a combined signal, and then passes through a polarizer to polarize the combined signal, so that the direct array detector can receive the polarized combined signal to generate a holographic image.

[0078] Among them, the orthogonal phase modulated laser local oscillator is processed by the 1 / 4 wave plate in the sub-mirror module to form a circularly polarized laser local oscillator.

[0079] According to an embodiment of the present disclosure, in the sub-mirror module, since the orthogonal phase modulated laser local oscillator needs to be combined with the target infrared signal after Fourier transform processing, the polarization direction of the orthogonal phase modulated laser local oscillator can be adjusted to be consistent with the polarization direction of the target infrared signal through a 1 / 4 wave plate and a polarizer before combining the beams, so that the polarization direction of the combined beam signal received by the direct array detector is consistent, so as to facilitate subsequent synthetic aperture imaging.

[0080] Figure 4 The flowchart of constructing an infrared complex image according to an embodiment of the present disclosure is schematically shown.

[0081] like Figure 4 As shown, the method 400 includes operations S410 to S450.

[0082] In operation S410, the laser local oscillator image and the holographic image are respectively split and processed according to the phase modulation conditions determined by the orthogonal phase modulation of the laser local oscillator, thereby obtaining a first laser local oscillator image and a second laser local oscillator image corresponding to the laser local oscillator image, and a first holographic image and a second holographic image corresponding to the holographic image.

[0083] According to embodiments of the present disclosure, the phase modulation determined by quadrature phase modulated laser local oscillators can characterize the phase modulation of each pixel in the laser local oscillator image and the holographic image. The quadrature phase modulated laser local oscillator can be phase modulated at 0° and 90° at intervals of one pixel in the row or column direction of a direct array detector. The laser local oscillator image and the holographic image can then be separated to obtain images at 0° and 90° modulation of the laser local oscillator, respectively.

[0084] The splitting process can be characterized as extracting pixels modulated at 0° and 90° according to the modulation interval and splicing them in sequence.

[0085] According to an embodiment of the present disclosure, a laser local oscillator image can be split into a first laser local oscillator image under 0° phase modulation of the laser local oscillator and a second laser local oscillator image under 90° phase modulation; a holographic image can be split into a first holographic image under 0° phase modulation of the laser local oscillator and a second holographic image under 90° phase modulation.

[0086] For example, in the orthogonal phase modulation of the laser local oscillator, the laser local oscillator on the pixels in the odd rows is phase modulated at 0°, and the laser local oscillator on the pixels in the even rows is phase modulated at 90°. In this way, the laser local oscillator image and the holographic image can be split into two images according to the parity of the row where the pixels are located.

[0087] In operation S420, an infrared image of a target is constructed based on the first laser local oscillator image, the second laser local oscillator image, the first holographic image, and the second holographic image using an independent component analysis algorithm.

[0088] According to the embodiments of the present disclosure, when a moving target is in continuous motion, a direct array detector cannot simultaneously capture an image corresponding to the target's infrared signal while continuously acquiring a holographic image. Therefore, because the holographic image is acquired by combining the target infrared signal with a quadrature phase modulated laser local oscillator (QPM) laser local oscillator (LO) beam using a direct array detector, an independent component analysis algorithm can be used to construct a target infrared image corresponding to the target infrared signal based on the first and second LLO images, the first and second holographic images, and subsequently construct an infrared complex image.

[0089] In operation S430, a real part image of the infrared complex image is constructed based on the first laser local oscillator image, the first holographic image, and the target infrared image.

[0090] According to an embodiment of the present disclosure, based on the principle of two-step phase-shift digital holography, the real image of the infrared complex image can be constructed according to the first laser local oscillator image, the first holographic image and the target infrared image, that is, based on the first laser local oscillator image and the first holographic image under 0° phase modulation and the target infrared image, the real image of the infrared complex image can be constructed.

[0091] In operation S440, an imaginary image of the infrared complex image is constructed based on the second laser local oscillator image, the second holographic image, and the target infrared image.

[0092] According to the embodiments of the present disclosure, based on the principle of two-step phase-shift digital holography, the imaginary image of the infrared complex image can be constructed according to the second laser local oscillator image, the second holographic image and the target infrared image, that is, based on the second laser local oscillator image and the second holographic image under 90° phase modulation and the target infrared image, the imaginary image of the infrared complex image can be constructed.

[0093] In operation S450, an infrared complex image corresponding to the sub-mirror module is constructed based on the real image and the imaginary image.

[0094] According to an embodiment of the present disclosure, based on the real image and imaginary image corresponding to the infrared complex image obtained above, an infrared complex image corresponding to the sub-mirror module can be constructed.

[0095] According to the embodiments of the present disclosure, since the orthogonal phase modulated laser local oscillator is obtained by phase modulation at 0° and 90° with a small number of pixels spaced apart in the row or column direction of the direct array detector, it is necessary to separate the pixels with 0° and 90° phase modulation in the laser local oscillator image and the holographic image according to the modulation interval to obtain images under 0° phase modulation and 90° phase modulation, so as to provide conditions for the implementation of the synchronous phase-shifting digital holography algorithm while reducing the image resolution, and construct the target infrared image based on the first laser local oscillator image, the second laser local oscillator image, the first holographic image and the second holographic image, so that the real part information and the imaginary part information can be constructed respectively according to the images under 0° phase modulation and 90° phase modulation and the target infrared image, thereby successfully constructing the infrared complex image.

[0096] FIG5( a ) schematically shows an amplitude diagram of an infrared complex image corresponding to a single sub-mirror according to an embodiment of the present disclosure.

[0097] FIG5( b ) schematically shows a phase diagram of an infrared complex image corresponding to a single sub-mirror according to an embodiment of the present disclosure.

[0098] FIG5( c ) schematically shows a spatial sampling signal of an infrared complex image corresponding to a single sub-mirror according to an embodiment of the present disclosure.

[0099] According to an embodiment of the present disclosure, as shown in FIG5(a) and FIG5(b), the image entropy of the infrared complex image corresponding to the single mirror is approximately 11.3973, the contrast is approximately 0.3780, and the signal-to-noise ratio is approximately 8.1661 dB; as shown in FIG5(c), the spatial sampling signal corresponding to the infrared complex image of the single mirror covers a range of approximately 60 mm (X direction) × 15 mm (Y direction) in the spatial domain.

[0100] Figure 6 A flowchart for obtaining synthetic aperture imaging results according to an embodiment of the present disclosure is schematically shown.

[0101] like Figure 6 As shown, the method 600 includes operations S610 to S670.

[0102] In operation S610, an inverse Fourier transform process is performed on the infrared complex image corresponding to each sub-mirror module to obtain a spatial sampling signal in a spatial sampling domain.

[0103] According to the embodiments of the present disclosure, the infrared complex images corresponding to each sub-mirror module are all located in the image domain. The infrared complex images can be subjected to inverse Fourier transform to obtain spatial sampling signals of the infrared complex images in the spatial sampling domain, so that the infrared complex images can be subsequently registered and compensated based on the spatial sampling signals.

[0104] In operation S620, a spatial sampling domain linear phase, a spatial sampling domain constant phase, and an image domain linear phase corresponding to the infrared complex image are constructed according to the sub-mirror array parameters and the target distance parameters.

[0105] According to the embodiments of the present disclosure, the sub-mirror array parameters are related to the sub-mirrors, direct array detectors, etc., and the spatial sampling domain linear phase, spatial sampling domain constant phase and image domain linear phase corresponding to the infrared complex image can be constructed based on the sub-mirror array parameters and the target distance parameters.

[0106] In operation S630, registration processing is performed on the infrared complex image according to the spatial sampling signal and the spatial sampling domain linear phase to obtain a registered spatial sampling signal.

[0107] According to an embodiment of the present disclosure, a spatial sampling signal corresponding to an infrared complex image is multiplied by a corresponding spatial sampling domain linear phase to implement registration processing of the infrared complex image and obtain a spatial sampling signal after registration processing.

[0108] In operation S640 , phase compensation is performed on the infrared complex image according to the registered spatial sampling signal and the spatial sampling domain constant phase to obtain a phase-compensated spatial sampling signal.

[0109] According to an embodiment of the present disclosure, the spatial sampling signal after the registration processing is multiplied by the spatial sampling domain constant phase to perform phase compensation processing on the infrared complex image, so that the phases of the spatial sampling signals are the same, thereby obtaining the spatial sampling signal after phase compensation.

[0110] In operation S650, Fourier transform processing is performed on the phase-compensated spatial sampling signal to obtain a new infrared complex image.

[0111] According to an embodiment of the present disclosure, since the spatial sampling signal after phase compensation needs to be shifted, the spatial sampling signal after phase compensation can be first subjected to Fourier transform processing to obtain a new infrared complex image in the image domain.

[0112] In operation S660, the spatial sampling signal after phase compensation is shifted according to the new infrared complex image and the image domain linear phase to obtain an infrared complex image after the spatial sampling signal is shifted.

[0113] According to an embodiment of the present disclosure, the new infrared complex image is multiplied by an image domain linear phase to perform translation processing on the phase-compensated spatial sampling signal, thereby obtaining an infrared complex image after the spatial sampling information is translated.

[0114] In operation S670, the infrared complex images after the spatial sampling signals corresponding to the sub-mirrors in the multiple sub-mirror modules are translated are coherently accumulated to obtain a synthetic aperture imaging result.

[0115] According to embodiments of the present disclosure, the infrared complex image after the spatial sampling signal is shifted is obtained by performing registration processing, phase compensation processing, and translation processing on the infrared complex image. At a given moment, the infrared complex images after the spatial sampling signal corresponding to each of the multiple sub-mirror modules can be coherently accumulated to obtain a synthetic aperture imaging result corresponding to the moving target at that moment.

[0116] According to the embodiments of the present disclosure, based on the sub-mirror array parameters and the target distance parameters, the spatial sampling domain linear phase, the spatial sampling domain constant phase and the image domain linear phase corresponding to the infrared complex image can be constructed to perform registration processing, phase compensation processing and translation processing on the infrared complex image, so as to improve the resolution of the synthetic aperture imaging result.

[0117] FIG7( a ) schematically shows an amplitude diagram of a synthetic aperture imaging result according to an embodiment of the present disclosure.

[0118] FIG7( b ) schematically shows a phase diagram of a synthetic aperture imaging result according to an embodiment of the present disclosure.

[0119] FIG7( c ) schematically illustrates a spatial sampling signal of a synthetic aperture imaging result according to an embodiment of the present disclosure.

[0120] FIG7( d ) schematically shows an X-direction slice comparison diagram of a single-mirror infrared complex image and a synthetic aperture imaging result according to an embodiment of the present disclosure.

[0121] FIG7( e ) schematically shows a Y-direction slice comparison diagram of a single-mirror infrared complex image and a synthetic aperture imaging result according to an embodiment of the present disclosure.

[0122] According to an embodiment of the present disclosure, the synthetic aperture imaging in Figures 7(a) to 7(e) uses 3-aperture imaging as an example, that is, N is 3. As shown in Figures 7(a) to 7(c), the image entropy of the synthetic aperture imaging results is 11.0211 and the contrast is 0.6324. As shown in Figures 7(d) and 7(e), under the conditions that the X- and Y-direction resolutions of the single-mirror infrared complex image are 6mm and 24mm, respectively, the synthetic aperture imaging results improve the image resolutions in the X and Y directions to 3.815mm and 8.98mm, respectively. Among them, before the synthetic aperture refers to the single-mirror infrared complex image; after the synthetic aperture refers to the synthetic aperture imaging result. The vertical axis in Figures 7(d) and 7(e) is Amplitude, with the unit being dB.

[0123] According to an embodiment of the present disclosure, the above-mentioned method for forming an infrared complex image of a moving target and synthetic aperture imaging of a sub-mirror array also includes: aligning and coherently accumulating multiple frames of synthetic aperture imaging results to obtain a high signal-to-noise ratio synthetic aperture imaging result, wherein the multiple frames of synthetic aperture imaging results are obtained at different moments in the motion process of the moving target.

[0124] According to the embodiments of the present disclosure, since the moving target is constantly moving, multiple frames of synthetic aperture imaging results obtained at different moments can be registered and coherently accumulated to obtain a synthetic aperture imaging result with a high signal-to-noise ratio.

[0125] Based on Figures 7(a) to 7(e), after the 7-frame synthetic aperture imaging results were registered and coherently added, the image entropy of the resulting image was reduced to 10.8059, the contrast was increased to 0.7634, and the signal-to-noise ratio was increased from 12.4218 dB to 14.6633 dB.

[0126] According to the embodiments of the present disclosure, multi-frame synthetic aperture imaging results formed during the motion of a moving target can achieve high signal-to-noise ratio imaging of the moving target through registration and coherent accumulation processing.

[0127] According to the embodiments of the present disclosure, the sub-mirror array parameters include the diameter, focal length and arrangement of the sub-mirrors in multiple sub-mirror modules, the pixel size, number of pixels and integration time of the direct array detector, and the wavelength of the initial linearly polarized laser local oscillator; the target distance parameter is the distance between the moving target and the plane where the sub-mirrors in the sub-mirror array are located at the initial moment of the moving target's movement.

[0128] According to an embodiment of the present disclosure, the target distance parameter can be measured by a distance measuring device.

[0129] According to the embodiments of the present disclosure, since sub-mirrors, direct array detectors, initial linearly polarized laser local oscillators, etc. are required in the process of synthetic aperture imaging, synthetic aperture imaging processing can be performed on the infrared complex image based on parameters related to the sub-mirrors, direct array detectors, etc., that is, the sub-mirror array parameters and the target distance parameters, so as to perform registration, phase compensation and other processing on the infrared complex image, thereby improving the contrast and signal-to-noise ratio of the synthetic aperture imaging results.

[0130] According to an embodiment of the present disclosure, the above-mentioned method for infrared complex image formation of a moving target and synthetic aperture imaging of a sub-mirror array also includes: determining the field of view range corresponding to a single pixel in the direct array detector based on the pixel size of the direct array detector, the focal length of the sub-mirror and the target distance parameters, so as to limit the moving distance of the moving target to not exceed the field of view range corresponding to the single pixel in the direct array detector within the integration time of the direct array detector; determining the field of view range and overlapping field of view range of each sub-mirror in the sub-mirror array based on the arrangement of the sub-mirrors in multiple sub-mirror modules, the pixel size and number of pixels of the direct array detector, the focal length of the sub-mirror and the target distance parameters, so as to limit the moving distance of the moving target to not exceed the overlapping field of view range during the process of the direct array detector collecting holographic images.

[0131] Among them, the sub-mirrors in multiple sub-mirror modules are arranged on the same plane to form a one-dimensional or two-dimensional array, and have overlapping fields of view, and the moving target is located in the overlapping fields of view; the plane where the moving target's movement direction is located is parallel to the plane where the sub-mirrors in the sub-mirror array are arranged.

[0132] According to embodiments of the present disclosure, during synthetic aperture imaging of a moving target, the target's direction and speed need to be constrained. The target's speed is limited by the direct array detector's integration time, pixel size and number of pixels, the holographic image acquisition frame rate, the sub-mirror array's sub-mirror focal lengths and arrangement, and the target distance.

[0133] According to the embodiments of the present disclosure, the field of view range corresponding to a single pixel in the direct array detector can be obtained based on the pixel size of the direct array detector, the focal length of the sub-mirror and the target distance parameters, and it is required that within the integration time of the direct array detector, the movement distance of the moving target does not exceed the field of view range corresponding to a single pixel in the direct array detector; according to the arrangement of the sub-mirrors, the pixel size and number of pixels of the direct array detector, the focal length of the sub-mirror and the target distance parameters, the field of view range of each sub-mirror in the sub-mirror array and its overlapping field of view range can be obtained. In the process of the direct array detector collecting multiple frames of holographic images, it is required that the movement distance of the moving target does not exceed the overlapping field of view range of the sub-mirror array.

[0134] According to the embodiments of the present disclosure, since the movement distance and movement speed of the moving target are limited by the sub-mirror array parameters and the target distance parameters, by using a direct array detector with a short integration time and small-sized pixels and a sub-mirror with a long focal length, and designing the arrangement of the sub-mirrors in the sub-mirror array to increase the overlapping field of view, the sub-mirror array can perform synthetic aperture imaging on high-speed moving targets.

[0135] According to an embodiment of the present disclosure, the initial linearly polarized laser local oscillator adopts a continuous wave signal or a pulse signal, and the pulse width of the pulse signal is greater than or equal to the integration time of the direct array detector; when the initial linearly polarized laser local oscillator adopts a pulse signal, the initial linearly polarized laser local oscillator achieves synchronization with the direct array detector through a synchronization signal generated by a signal generator.

[0136] According to the embodiments of the present disclosure, the initial linearly polarized laser local oscillator can adopt a continuous wave signal or a pulse signal, and the pulse width of the pulse signal needs to be no less than the integration time of the direct array detector; under the condition that the initial linearly polarized laser local oscillator adopts a pulse signal, the initial linearly polarized laser local oscillator can be synchronized with the direct array detector through the synchronization signal of the signal generator, so that the direct array detector can collect the holographic image in time.

[0137] According to an embodiment of the present disclosure, during the movement of a moving target, a periodic pulse signal can be used as a synchronization signal to enable multiple direct array detectors to synchronously capture multiple frames of holographic images, and to construct infrared complex images, synthetic aperture imaging results and real-time high-resolution imaging results of the moving target.

[0138] According to the embodiments of the present disclosure, based on the synchronization signal, the synchronization operation of the initial linearly polarized laser local oscillator and the direct array detector is achieved, so that the direct array detector can collect the holographic image in a timely manner. The synchronization signal can also be used to control multiple direct array detectors to synchronously collect holographic images, so as to accurately and timely generate the corresponding infrared complex image and synthetic aperture imaging results.

[0139] Figure 8 The schematic diagram of the moving target infrared complex image formation and sub-mirror array synthetic aperture imaging system according to an embodiment of the present disclosure is schematically shown.

[0140] like Figure 8 As shown, the moving target infrared complex image formation and sub-mirror array synthetic aperture imaging system includes a laser local oscillator module 810, a calculation module 820 and multiple sub-mirror modules 130_1~130_N.

[0141] According to an embodiment of the present disclosure, the spatial light modulator in the laser local oscillator module 810 is used to perform phase modulation on an initial linearly polarized laser local oscillator to obtain an orthogonal phase modulated laser local oscillator.

[0142] According to the embodiments of the present disclosure, each sub-mirror module includes a sub-mirror, a quarter-wave plate, a polarizer, and a direct array detector. In each sub-mirror module, a depolarizing beam splitter for beam combining can be used to combine the orthogonal phase modulated laser local oscillator and the target infrared signal after Fourier transform processing to obtain a combined beam signal; the direct array detector can be used to receive the combined beam signal and generate a holographic image corresponding to the sub-mirror module.

[0143] Among them, the sub-mirror in the sub-mirror module is used to perform Fourier transform processing on the received target infrared signal corresponding to the moving target; the 1 / 4 wave plate and the polarizer are used to adjust the polarization direction of the orthogonal phase modulated laser local oscillator to be consistent with the polarization direction of the target infrared signal; when the direct array detector receives the combined beam signal, the combined beam signal first passes through the polarizer.

[0144] According to an embodiment of the present disclosure, the computing module 820 can be used to construct an infrared complex image corresponding to the sub-mirror module based on the holographic image and the laser local oscillator image corresponding to the sub-mirror module, wherein the laser local oscillator image is a laser local oscillator image corresponding to the orthogonal phase modulated laser local oscillator obtained by directly collecting the array detector when the sub-mirror in the sub-mirror module is blocked.

[0145] According to an embodiment of the present disclosure, the calculation module 820 can also be used to perform synthetic aperture imaging processing on the infrared complex images corresponding to each of the multiple sub-mirror modules based on the sub-mirror array parameters and the target distance parameters, so as to obtain a synthetic aperture imaging result corresponding to the moving target, wherein the infrared complex images corresponding to each of the multiple sub-mirror modules are obtained at the same moment of the moving target's movement process.

[0146] The computing module 820 may be composed of a computer, and is mainly used to construct infrared complex images, perform synthetic aperture imaging processing, and construct real-time high-resolution imaging results of moving targets.

[0147] According to the embodiments of the present disclosure, a laser local oscillator and a spatial light modulator are combined and a direct array detector is used to realize a coherent array function for a moving target, so that an infrared complex image can be formed according to the holographic image and the laser local oscillator image corresponding to the sub-mirror module, and based on the sub-mirror array parameters and the target distance parameters, real-time synthetic aperture imaging of a moving target at a low speed can be realized on the computing module; compared with traditional large-aperture single-aperture telescopes, the method of the present disclosure greatly reduces the difficulty of equipment manufacturing; compared with traditional optical synthetic aperture imaging systems, the method of the present disclosure has the characteristics of low hardware precision requirements such as fine-tuning mechanisms, and provides a foundation for the development of future large-aperture imaging systems.

[0148] According to an embodiment of the present disclosure, the moving target infrared complex image formation and sub-mirror array synthetic aperture imaging system also includes a laser local oscillator module 810 and a signal generator 830; the laser local oscillator module 810 may include a laser, a collimator, a depolarizing spectroscopic prism for splitting light, and a spatial light modulator.

[0149] According to an embodiment of the present disclosure, the signal generator 830 can be used to generate a synchronization signal so that the direct array detector can achieve synchronous acquisition through the synchronization signal, that is, the direct array detectors in multiple sub-mirror modules synchronously acquire holographic images.

[0150] According to an embodiment of the present disclosure, a laser is used to generate an initial linearly polarized laser local oscillator. This initial linearly polarized laser local oscillator passes through a collimator, a depolarizing beam splitter, and a spatial light modulator to obtain an orthogonal phase modulated laser local oscillator. This orthogonal phase modulated laser local oscillator is then split by a depolarizing beam splitter for light splitting. The collimator can be used to adjust the direction and shape of the initial linearly polarized laser local oscillator to improve the stability of the initial linearly polarized laser local oscillator.

[0151] According to an embodiment of the present disclosure, the laser local oscillator module can be used to phase modulate the initial linearly polarized laser local oscillator to obtain an orthogonal phase modulated laser local oscillator for use in subsequent synthetic aperture imaging; the signal generator is used to generate a synchronization signal to enable the direct array detector to synchronously capture images, and can also enable the initial linearly polarized laser local oscillator and the direct array detector to work synchronously, so that the direct array detector can timely capture and obtain holographic images.

[0152] It should be understood that Figure 8 The number of sub-mirror modules, depolarizing beam splitters and reflectors in the embodiment is merely illustrative. Any number of sub-mirror modules, depolarizing beam splitters and reflectors may be provided as required.

[0153] Those skilled in the art will appreciate that the features described in the various embodiments of the present disclosure may be combined and / or coupled in various ways, even if such combinations or couplings are not explicitly described in the present disclosure. In particular, the features described in the various embodiments of the present disclosure may be combined and / or coupled in various ways without departing from the spirit and teachings of the present disclosure. All such combinations and / or couplings fall within the scope of the present disclosure.

[0154] The above describes the embodiments of the present disclosure. However, these embodiments are for illustrative purposes only and are not intended to limit the scope of the present disclosure. Although each embodiment has been described separately above, this does not mean that the measures in each embodiment cannot be advantageously used in combination. Without departing from the scope of the present disclosure, those skilled in the art may make various substitutions and modifications, which should all fall within the scope of the present disclosure.

Claims

1. A method for forming a moving target infrared complex image and using a sub-mirror array for synthetic aperture imaging, comprising: Using a spatial light modulator, the initial linearly polarized laser local oscillator is phase modulated to obtain an orthogonal phase modulated laser local oscillator; In each sub-mirror module, The orthogonal phase modulated laser local oscillator and the target infrared signal after Fourier transform processing are beam combined using a depolarizing beam splitter prism for beam combining to obtain a combined beam signal, wherein the sub-mirrors in the sub-mirror module are used to perform Fourier transform processing on the received target infrared signal corresponding to the moving target, and the sub-mirror array includes a plurality of the sub-mirror modules; Using a direct array detector to receive the combined beam signal and generate a holographic image corresponding to the sub-mirror module; constructing an infrared complex image corresponding to the sub-mirror module according to the holographic image and the laser local oscillator image corresponding to the sub-mirror module, wherein the laser local oscillator image is a laser local oscillator image corresponding to the orthogonal phase modulated laser local oscillator acquired by the direct array detector when the sub-mirror in the sub-mirror module is blocked; According to the sub-mirror array parameters and the target distance parameters, synthetic aperture imaging processing is performed on the infrared complex images corresponding to the multiple sub-mirror modules to obtain a synthetic aperture imaging result corresponding to the moving target, wherein the infrared complex images corresponding to the multiple sub-mirror modules are obtained at the same moment of the moving target.

2. The method according to claim 1, wherein The sub-mirror module includes a sub-mirror, a quarter-wave plate, a depolarizing beam splitter prism for beam combining, a polarizer, and a direct array detector; the method further includes: The quarter wave plate and the polarizer are used to adjust the orthogonal phase modulated laser local oscillator and the target infrared signal to linear polarization signals with consistent polarization directions.

3. The method according to claim 1, wherein The step of constructing an infrared complex image corresponding to the sub-mirror module according to the holographic image and the laser local oscillator image corresponding to the sub-mirror module comprises: Separating the laser local oscillator image and the holographic image according to a phase modulation condition determined by the quadrature phase modulated laser local oscillator to obtain a first laser local oscillator image and a second laser local oscillator image corresponding to the laser local oscillator image, and a first holographic image and a second holographic image corresponding to the holographic image; constructing a target infrared image based on the first laser local oscillator image, the second laser local oscillator image, the first holographic image, and the second holographic image using an independent component analysis algorithm; constructing a real image of the infrared complex image according to the first laser local oscillator image, the first holographic image and the target infrared image; constructing an imaginary image of the infrared complex image according to the second laser local oscillator image, the second holographic image and the target infrared image; Based on the real image and the imaginary image, an infrared complex image corresponding to the sub-mirror module is constructed.

4. The method according to claim 1, wherein The method of performing synthetic aperture imaging processing on the infrared complex images corresponding to each of the plurality of sub-mirror modules according to the sub-mirror array parameters and the target distance parameters to obtain a synthetic aperture imaging result corresponding to the moving target includes: For the infrared complex image corresponding to each of the sub-mirror modules, perform inverse Fourier transform processing on the infrared complex image to obtain a spatial sampling signal in a spatial sampling domain; Constructing a spatial sampling domain linear phase, a spatial sampling domain constant phase, and an image domain linear phase corresponding to the infrared complex image according to the sub-mirror array parameters and the target distance parameters; performing registration processing on the infrared complex image according to the spatial sampling signal and the spatial sampling domain linear phase to obtain a registered spatial sampling signal; performing phase compensation processing on the infrared complex image according to the spatial sampling signal after the registration processing and the spatial sampling domain constant phase to obtain a phase-compensated spatial sampling signal; Performing Fourier transform processing on the phase-compensated spatial sampling signal to obtain a new infrared complex image; performing translation processing on the spatial sampling signal after the phase compensation according to the new infrared complex image and the image domain linear phase to obtain an infrared complex image after the spatial sampling signal is translated; The infrared complex images after the spatial sampling signals corresponding to the sub-mirrors in the multiple sub-mirror modules are translated are coherently accumulated to obtain the synthetic aperture imaging result.

5. The method according to claim 4, further comprising: The multiple frames of synthetic aperture imaging results are registered and coherently accumulated to obtain a synthetic aperture imaging result with a high signal-to-noise ratio, wherein the multiple frames of synthetic aperture imaging results are obtained at different moments in the motion process of the moving target.

6. The method according to claim 2, wherein: The sub-mirror array parameters include the diameter, focal length and arrangement of the sub-mirrors in the multiple sub-mirrors in the sub-mirror module, the pixel size, number of pixels and integration time of the direct array detector, and the wavelength of the initial linearly polarized laser local oscillator; the target distance parameter is the distance between the moving target and the plane where the sub-mirrors in the sub-mirror array are located at the initial moment of the movement of the moving target.

7. The method according to claim 6, wherein: The sub-mirrors in the plurality of sub-mirror modules are arranged on the same plane to form a one-dimensional or two-dimensional array and have overlapping fields of view, and the moving target is located in the overlapping fields of view; the plane where the moving target moves is parallel to the plane where the sub-mirrors in the sub-mirror array are arranged; the method further comprises: Determining a field of view corresponding to a single pixel in the direct array detector based on a pixel size of the direct array detector, a focal length of the sub-mirror, and the target distance parameter, so as to limit the moving distance of the moving target to not exceed the field of view corresponding to the single pixel in the direct array detector within an integration time of the direct array detector; According to the arrangement of the sub-mirrors in the multiple sub-mirror modules, the pixel size and the number of pixels of the direct array detector, the focal length of the sub-mirror and the target distance parameters, the field of view range and the overlapping field of view range of each sub-mirror in the sub-mirror array are determined, so as to limit the movement distance of the moving target to not exceed the overlapping field of view range during the process of the direct array detector collecting the holographic image.

8. The method according to claim 1, wherein The initial linearly polarized laser local oscillator uses a continuous wave signal or a pulse signal, and the pulse width of the pulse signal is greater than or equal to the integration time of the direct array detector; when the initial linearly polarized laser local oscillator uses the pulse signal, the initial linearly polarized laser local oscillator achieves synchronous operation with the direct array detector through the synchronization signal generated by the signal generator.

9. A moving target infrared complex image formation and sub-mirror array synthetic aperture imaging system, comprising: A spatial light modulator is used to phase modulate an initial linearly polarized laser local oscillator to obtain an orthogonal phase modulated laser local oscillator; In each sub-mirror module, a depolarizing beam splitter prism for beam combining, configured to combine the quadrature phase modulated laser local oscillator and the target infrared signal after Fourier transform processing to obtain a combined beam signal, wherein the sub-mirrors in the sub-mirror module are configured to perform Fourier transform processing on the received target infrared signal corresponding to the moving target, and the sub-mirror array includes a plurality of the sub-mirror modules; a direct array detector, configured to receive the combined beam signal and generate a holographic image corresponding to the sub-mirror module; a calculation module, configured to construct an infrared complex image corresponding to the sub-mirror module based on a holographic image and a laser local oscillator image corresponding to the sub-mirror module, wherein the laser local oscillator image is a laser local oscillator image corresponding to the quadrature phase modulated laser local oscillator acquired by the direct array detector when the sub-mirror in the sub-mirror module is blocked; The calculation module is further used to perform synthetic aperture imaging processing on the infrared complex images corresponding to each of the multiple sub-mirror modules according to the sub-mirror array parameters and the target distance parameters, so as to obtain a synthetic aperture imaging result corresponding to the moving target, wherein the infrared complex images corresponding to each of the multiple sub-mirror modules are obtained at the same moment of the moving target's movement process.

10. The system according to claim 9, further comprising: Laser local oscillator module and signal generator; the laser local oscillator module includes a laser, a collimator, a depolarizing beam splitter prism for light splitting, and a spatial light modulator; The signal generator is used to generate a synchronization signal so that the direct array detector can achieve synchronous acquisition through the synchronization signal; The laser is used to generate the initial linearly polarized laser local oscillator; The depolarization beam splitter prism for light splitting is used to split the orthogonal phase modulated laser local oscillator.

Images