Moving target infrared complex image forming and sub-mirror array synthetic aperture imaging method and system

Abstract

The invention provides a moving target infrared complex image forming and sub-mirror array synthetic aperture imaging method and system. The method comprises the following steps: performing phase modulation on an initial linear polarization laser local oscillator by using a spatial light modulator to obtain a quadrature phase modulation laser local oscillator; in each sub-mirror module, a depolarization beam splitting prism is used for carrying out beam combination processing on the quadrature phase modulation laser local oscillator and the target infrared signal subjected to Fourier transform processing, and a beam combination signal is obtained; receiving the beam combination signal by using a direct array detector, generating a holographic image corresponding to the sub-mirror module, and constructing an infrared complex image corresponding to the sub-mirror module by combining a laser local oscillator image; according to the sub-mirror array parameters and the target distance parameters, synthetic aperture imaging processing is carried out on the infrared complex images corresponding to the sub-mirror modules, a synthetic aperture imaging result is obtained, and the infrared complex images corresponding to the sub-mirror modules are obtained at the same moment in the moving process of the moving target.

Description

Technical Field

[0001] The present invention relates to the fields of optical synthetic aperture telescope, 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 the optical system is limited by the diffraction limit, so increasing the aperture of the optical system is an effective way to increase the resolution. Therefore, using a large-aperture single-aperture telescope can achieve infrared high-resolution imaging. Therefore, in order to achieve long-distance high-resolution imaging detection, a large-aperture telescope is required, but currently large-aperture single-aperture telescopes have problems such as difficulty in processing and manufacturing and difficulty in platform loading.

[0003] The optical synthetic aperture telescope system based on stitching imaging or interferometric imaging is an effective alternative to the large-aperture single-aperture telescope system. However, this method first needs to realize the optical synthetic aperture through hardware equipment such as mechanical structure, and then collect and receive the optical synthetic aperture imaging results. This places high requirements 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 a moving target infrared complex image and a sub-mirror array synthetic aperture imaging is provided, comprising:

[0006] Using a spatial light modulator, phase modulating the initial linearly polarized laser local oscillator 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 combined by using a depolarizing beam splitter prism for beam combining to obtain a combined beam signal, wherein 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, and the sub-mirror array includes a plurality of the 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] According to the holographic image and the laser local oscillator image corresponding to the sub-mirror module, an infrared complex image corresponding to the sub-mirror module is constructed, 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 moving 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 for beam combining 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-mirror in the sub-mirror module is used for Fourier transform processing of 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, used to receive the combined beam signal and generate a holographic image corresponding to the sub-mirror module;

[0017] A calculation module, used for 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;

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

[0019] According to the method and system for infrared complex image formation of moving targets and sub-mirror array synthetic aperture imaging provided by the present invention, 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 a traditional large-aperture single-aperture telescope, the method of the present invention greatly reduces the difficulty of equipment manufacturing; compared with a traditional optical synthetic aperture imaging system, the method of the present invention has the characteristics of low hardware precision requirements such as a fine-tuning mechanism, etc., and provides a foundation for the development of future large-aperture imaging systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The above contents and other purposes, 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 schematic diagram showing 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 of a method for forming a moving target infrared complex image and a sub-mirror array synthetic aperture imaging according to an embodiment of the present disclosure is schematically shown;

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

[0024] Figure 4 Schematically shows a flow chart of 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 of 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 shows 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 A schematic diagram of a moving target infrared complex image formation and a 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 exemplary only and are not intended to limit the scope of the present disclosure. In the following detailed description, 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 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 existence of the features, steps, operations and / or components, but do not exclude the existence or addition of one or more other features, steps, operations or components.

[0037] All terms (including technical and scientific terms) used herein 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 using expressions such as "at least one of A, B, and C, etc.", they should generally be interpreted according to the meaning of the expression 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 solution of the present disclosure, 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 the scenario of using personal information for automated decision-making, the methods, devices, and systems provided by the embodiments of the present disclosure provide users with corresponding operation portals for users 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 a person'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, wherein the sub-mirror array 130 includes a plurality of sub-mirror modules, namely, sub-mirror module 130_1 to sub-mirror module 130_N, 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 method provided by the embodiments of the present disclosure can generally be performed by the spatial light modulator 110, the sub-mirror array 130 and the computing module 140. The spatial light modulator 110 can be used to phase modulate the 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 computing module 140 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; the computing module 140 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.

[0046] It should be understood that Figure 1 The number of sub-mirror modules, spatial light modulators and computing modules in the embodiment is only for illustration. Any number of sub-mirror modules, spatial light modulators and computing modules may be provided according to the implementation requirements.

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

[0048] Figure 2 The flowchart of the infrared complex image formation of a moving target and the sub-mirror array synthetic aperture imaging method 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 made to form 0° and 90° phase modulations every 1 pixel in the row or column direction of the direct array detector. The laser local oscillator on the pixels of the odd-numbered interval rows is 0° phase modulated, and the laser local oscillator on the pixels of the even-numbered interval rows is 90° phase modulated.

[0053] Wherein, 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 the embodiments 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, and 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, the combined beam signal is received by using a direct array detector to 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 detector 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 oscillator 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-mirror 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 the embodiments of the present disclosure, based on the two-step phase-shift digital holography principle, 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, ultimately 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 the embodiments of the present disclosure, for a moving target at a certain moment in the moving process, 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 a traditional large-aperture single-aperture telescope, the method of the present disclosure greatly reduces the difficulty of equipment manufacturing; compared with a traditional optical synthetic aperture imaging system, the method of the present disclosure has the characteristics of low hardware precision requirements such as a fine-tuning mechanism, etc., which provides a basis 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 to be combined 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 embodiments 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 light splitting to obtain two laser local oscillators, and then the two laser local oscillators are each passed through a depolarizing beam splitter prism for light splitting to obtain four laser local oscillators, and then the four laser local oscillators are each passed through a depolarizing beam splitter prism for light 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 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 the embodiments of the present disclosure, the sub-mirror can be used to receive the target infrared signal to perform Fourier transform processing on the target infrared signal. The 1 / 4 wave plate and the polarizer can be used to adjust the orthogonal phase modulated laser local oscillator to a linear polarized signal consistent with the polarization direction of the target infrared signal, that is, the 1 / 4 wave plate can be used to adjust the polarization direction of the orthogonal phase modulated laser local oscillator, and combined with the polarizer, the polarization direction of the orthogonal phase modulated laser local oscillator is adjusted to be consistent with the polarization direction of the target infrared signal.

[0077] According to the embodiments 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 beam signal, and then passes through a polarizer to polarize the combined beam signal, so that the direct array detector can receive the polarized combined beam 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 the embodiments 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 the beam is combined, 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 split and processed respectively according to the phase modulation conditions determined by the orthogonal phase modulation laser local oscillator to obtain the first laser local oscillator image and the second laser local oscillator image corresponding to the laser local oscillator image and the first holographic image and the second holographic image corresponding to the holographic image.

[0083] According to the embodiments of the present disclosure, the phase modulation determined by the orthogonal phase modulated laser local oscillator can characterize the phase modulation of each pixel in the laser local oscillator image and the holographic image. The orthogonal phase modulated laser local oscillator can be phase modulated at 0° and 90° at 1 pixel interval in the row or column direction of the direct array detector, and the laser local oscillator image and the holographic image can be split into images under the laser local oscillator 0° and 90° modulation 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 modulated laser local oscillator, the laser local oscillator on the pixels in odd rows is phase modulated at 0°, and the laser local oscillator on the pixels in even rows is phase modulated at 90°. Thus, 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 according to the first laser local oscillator image, the second laser local oscillator image, the first holographic image, and the second holographic image by using an independent component analysis algorithm.

[0088] According to the embodiments of the present disclosure, when the moving target is in continuous motion, the direct array detector cannot simultaneously acquire an image corresponding to the target infrared signal while continuously acquiring the holographic image. Therefore, since the holographic image is acquired by the direct array detector after the target infrared signal and the orthogonal phase modulated laser local oscillator are combined, the independent component analysis algorithm can be used to construct the target infrared image corresponding to the target infrared signal according to the first laser local oscillator image, the second laser local oscillator image, the first holographic image and the second holographic image, so as to be used for the subsequent construction of the infrared complex image.

[0089] In operation S430, a real 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 the embodiments 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 and the target infrared image under 90° phase modulation, 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 of 0° and 90° phase modulation in the laser local oscillator image and the holographic image according to the modulation interval, so as 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 holographic algorithm while reducing the image resolution, and construct 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, 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 an 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 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 has a coverage range of approximately 60 mm (X direction) × 15 mm (Y direction) in the spatial domain.

[0100] Figure 6 A flowchart for obtaining a synthetic aperture imaging result 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, for the infrared complex image corresponding to each sub-mirror module, an inverse Fourier transform process is performed on the infrared complex image 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 located in the image domain, and the infrared complex images can be inversely Fourier transformed to obtain spatial sampling signals of the infrared complex images in the spatial sampling domain, so as to subsequently perform registration and compensation processing on the infrared complex images 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, the infrared complex image is registered 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 spatial sampling signal after the registration processing and the spatial sampling domain constant phase to obtain a spatial sampling signal after phase compensation.

[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, and the spatial sampling signals after phase compensation are obtained.

[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 the embodiments 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 firstly 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 spatial sampling signal after phase compensation, 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 plurality of sub-mirror modules are translated are coherently accumulated to obtain a synthetic aperture imaging result.

[0115] According to the embodiments of the present disclosure, the infrared complex image after the spatial sampling signal is translated is obtained after the infrared complex image is subjected to registration processing, phase compensation processing and translation processing. At a certain moment, the infrared complex images after the spatial sampling signal corresponding to each of the multiple sub-mirror modules are coherently accumulated to obtain the 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, a spatial sampling domain linear phase, a spatial sampling domain constant phase and an 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] FIG. 7( a ) schematically shows an amplitude diagram of a synthetic aperture imaging result according to an embodiment of the present disclosure.

[0118] FIG. 7( b ) schematically shows a phase diagram of a synthetic aperture imaging result according to an embodiment of the present disclosure.

[0119] FIG7( c ) schematically shows 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 the embodiment of the present disclosure, the synthetic aperture imaging in FIG. 7 (a) to FIG. 7 (e) uses 3-aperture imaging as an example, that is, N is 3. As shown in FIG. 7 (a) to FIG. 7 (c), the image entropy of the synthetic aperture imaging result is 11.0211, and the contrast is 0.6324; as shown in FIG. 7 (d) and FIG. 7 (e), under the condition that the resolution of the single-mirror infrared complex image in the X direction and the Y direction are 6 mm and 24 mm respectively, the synthetic aperture imaging result increases the image resolution in the X direction and the Y direction to 3.815 mm and 8.98 mm respectively, wherein before the synthetic aperture refers to the single-mirror infrared complex image; after the synthetic aperture refers to the synthetic aperture imaging result, and the ordinate of FIG. 7 (d) and FIG. 7 (e) is Amplitude, and the unit is dB.

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

[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 times may be registered and coherently accumulated to obtain a synthetic aperture imaging result with a high signal-to-noise ratio.

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

[0126] According to the embodiments of the present disclosure, multiple frames of 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 and focal length of the sub-mirrors and the arrangement of the sub-mirrors in a plurality of 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, sub-mirror array parameters and 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 according to 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 movement 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 according to 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 movement 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 direction of the moving target is located is parallel to the plane where the sub-mirrors in the sub-mirror array are arranged.

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

[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 the single pixel in the direct array detector; the field of view range of each sub-mirror in the sub-mirror array and its overlapping field of view range can be obtained based on the arrangement of the sub-mirrors, 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, and 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 moving distance and 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-size 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 capture 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 use them 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 acquire the holographic image in a timely manner. The synchronization signal can also be used to control multiple direct array detectors to synchronously acquire the holographic image, 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 a plurality of 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 prism 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 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 motion 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 a traditional large-aperture single-aperture telescope, the method of the present disclosure greatly reduces the difficulty of equipment manufacturing; compared with a traditional optical synthetic aperture imaging system, the method of the present disclosure has the characteristics of low hardware precision requirements such as a fine-tuning mechanism, etc., which provides a basis 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 beam splitter prism for light splitting, 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; the initial linearly polarized laser local oscillator passes through a collimator, a depolarizing beam splitter, and a spatial light modulator in sequence to obtain an orthogonal phase modulated laser local oscillator. The orthogonal phase modulated laser local oscillator is then split by a depolarizing beam splitter for 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 the embodiments 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 so that the direct array detector can synchronously capture images, and can also make the initial linearly polarized laser local oscillator and the direct array detector work synchronously so that the direct array detector can capture the holographic image in a timely manner.

[0152] It should be understood that Figure 8 The number of sub-mirror modules, depolarizing beam splitters and reflectors in the embodiment is only for illustration. Any number of sub-mirror modules, depolarizing beam splitters and reflectors may be provided according to the implementation requirements.

[0153] It will be appreciated by those skilled in the art that the features described in the various embodiments of the present disclosure may be combined and / or combined in a variety of ways, even if such combinations or combinations are not explicitly described in the present disclosure. In particular, without departing from the spirit and teachings of the present disclosure, the features described in the various embodiments of the present disclosure may be combined and / or combined in a variety of ways. All of these combinations and / or combinations fall within the scope of the present disclosure.

[0154] The embodiments of the present disclosure are described above. However, these embodiments are only for illustrative purposes and are not intended to limit the scope of the present disclosure. Although the embodiments are described above, this does not mean that the measures in the various embodiments cannot be used in combination to advantage. Without departing from the scope of the present disclosure, those skilled in the art may make a variety of 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 a sub-mirror array synthetic aperture imaging method, comprising: The spatial light modulator is used to phase modulate the initial linearly polarized laser local oscillator 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 combined by using a depolarizing beam splitter prism for beam combining to obtain a combined beam signal, wherein 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, 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 each of the multiple sub-mirror modules 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 process 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 polarizing plate 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: According to the phase modulation condition determined by the orthogonal phase modulated laser local oscillator, the laser local oscillator image and the holographic image are respectively split and processed 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 according to the first laser local oscillator image, the second laser local oscillator image, the first holographic image and the second holographic image by 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; According to the sub-mirror array parameters and the target distance parameters, 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; Performing registration processing on the infrared complex image according to the spatial sampling signal and the spatial sampling domain linear phase to obtain a spatial sampling signal after registration processing; According to the spatial sampling signal after the registration processing and the spatial sampling domain constant phase, the infrared complex image is subjected to phase compensation processing to obtain the spatial sampling signal after the phase compensation; Performing Fourier transform processing on the phase-compensated spatial sampling signal to obtain a new infrared complex image; According to the new infrared complex image and the image domain linear phase, the spatial sampling signal after the phase compensation is subjected to translation processing 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 and focal length of the sub-mirror and the arrangement of the sub-mirrors in the 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 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 direction of the moving target is located is parallel to the plane where the sub-mirrors in the sub-mirror array are arranged; the method further comprises: Determine the field of view range corresponding to a single pixel in the direct array detector according to the pixel size of the direct array detector, the 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 range corresponding to the single pixel in the direct array detector within the integration time of the direct array detector; The field of view range and overlapping field of view range of each sub-mirror in the sub-mirror array are determined according to the arrangement of the sub-mirrors in the plurality of 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, 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 capturing the holographic image.

8. The method according to claim 1, wherein: 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 the 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.

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, used for beam combining 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 for Fourier transform processing of 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, used 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 according to 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 orthogonal 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 also 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 time during the movement process of the moving target.

10. The system according to claim 9, further comprising: A laser local oscillator module and a 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 depolarizing beam splitter prism for beam splitting is used to split the orthogonal phase modulated laser local oscillator.

Images