Dual-aperture-based long-wave infrared dynamic spatial modulation device and method

Abstract

The application discloses a long-wave infrared dynamic space modulation device and method based on double coding apertures, and belongs to the technical field of optics. The application avoids the diffraction effect in the long-wave infrared space modulation process by selecting a large-size coding pixel coding aperture, adopts a double coding aperture space light modulation structure, separately performs space modulation on target light beams, and realizes coding effect superposition through beam combination, so that the space modulation resolution of the large-size coding pixel coding aperture is improved. On the premise of guaranteeing the space modulation resolution requirement and without increasing the coding aperture area, the diffraction effect in the long-wave infrared space modulation process is avoided by selecting the large-size coding pixel coding aperture. The application introduces the use of a displacement table, and the position of the moving coding template is transformed for multiple times within the single information acquisition time of the system, so that the effective coding area in the optical path is transformed, more coding superposition effects are generated, and the coding resolution and the coding gray scale are further improved.

Description

Technical Field

[0001] This invention belongs to the field of optical technology, specifically relating to a dynamic spatial modulation device and modulation method based on dual-coded aperture for long-wave infrared spatial modulation. Background Technology

[0002] Spatial light modulators (SLMs) can load information onto a one-dimensional or two-dimensional optical data field by spatially altering the phase, polarization, intensity, wavelength distribution, and conversion between coherent and incoherent light. This allows for the effective utilization of light's inherent speed, parallelism, and interconnectivity. They are key components in systems such as real-time optical information processing, optical computing, and optical neural networks. A SLM contains many independent units arranged in a one-dimensional or two-dimensional array. Each unit is independently controlled by optical information and electrical signals, utilizing various physical effects (such as the Pockels effect, Kerr effect, acousto-optic effect, magneto-optic effect, semiconductor self-electro-optic, and light refraction effect) to modify its own optical properties, thereby modulating the light waves illuminating it. Based on the readout method, SLMs can be classified as reflective or transmissive; and based on the input control signal, they can be classified as optically addressed (OA-SLM) or electrically addressed (EA-SLM).

[0003] As the most intuitive parameter of the optical field, light field intensity has been widely studied and applied in optical projection, beam shaping, image processing and analysis, and optical data processing and storage through spatial modulation of light amplitude. Currently, commonly used spatial light modulators include liquid crystal spatial light modulators, such as Liquid Crystal on Silicon (LCoS), Digital Micromirror Devices (DMDs), and Coded Aperture (CA). Liquid crystal spatial light modulators utilize the photoelectric effect of liquid crystals to control the light field, leveraging the optical rotation of long-pitch liquid crystal molecules and two polarizers with aligned polarization directions. Modulation is achieved by controlling the voltage to induce changes in the liquid crystal, which in turn alters the transmittance at spatial locations. Liquid crystal on silicon abandons the transmissive structure, using CMOS integrated circuit chips coated with liquid crystal silicon as reflective LCD substrates, improving light efficiency, achieving spatial resolutions up to 4K, and refresh rates up to several hundred hertz. A spatial light modulator (DMD) is an array of multiple micromirrors. Using electrostatic interaction, the rotation of the micromirrors controls the opening and closing of the optical switches, thus loading a template. Light selectively enters the optical path at the open switch and deviates from it at the closed switch. It boasts advantages such as high frequency (up to tens of kHz) and high spatial resolution (1K-2K). The encoding aperture, on the other hand, is a template formed by coating or etching transparent and opaque pixel units on a substrate material. When a beam passes through the template, spatial modulation is achieved. Spatial light modulators encode optical signals by controlling the state of the encoded pixels, thus selecting whether or not the light signal passes through space. These devices, as spatial light modulators, have been developed into various mature products with wide applications in scientific research and commercial fields. However, in the infrared band, such as long-wave infrared and above, the minimum coded pixel size of the spatial light modulator is at most a few tens of micrometers, and often even smaller, in order to ensure spatial modulation resolution. When applied in the long-wave infrared band, diffraction occurs because the device's coded pixel size is smaller than or close to the modulation target wavelength, which affects light utilization and the system's imaging performance. Summary of the Invention

[0004] The purpose of this invention is to provide a dynamic spatial light modulation device and method based on dual-encoding apertures. By selecting a large-size encoding pixel encoding aperture, the diffraction effect in the long-wave infrared spatial modulation process is reduced, thereby reducing the impact of the diffraction effect on the imaging system performance during light modulation. A dual-encoding aperture spatial light modulation structure is employed to spatially modulate the target light beam separately, and the encoding effect is superimposed through beam combining, improving the spatial modulation resolution of the large-size encoding pixel encoding aperture. While ensuring the spatial modulation resolution requirements and without increasing the encoding aperture area, a large-size encoding pixel encoding aperture that reduces diffraction effects during modulation is selected. By introducing a displacement stage, the position of the moving encoding template is changed multiple times within a single information acquisition time of the system, thereby achieving effective encoding region transformation, producing more encoding superposition effects, and further improving the encoding resolution and the number of encoding gray levels.

[0005] The objective of this invention is achieved through the following technical solution:

[0006] The present invention discloses a long-wave infrared dynamic spatial modulation device based on dual-encoding aperture, comprising a collimating lens, a first dichroic mirror, a fixed encoding aperture, a first reflecting mirror, a movable encoding aperture, a displacement stage, a second reflecting mirror, a second dichroic mirror, and an imaging lens.

[0007] The target light is collimated by a collimating lens to become parallel light. The parallel light then enters a first dichroic mirror for beam splitting. The first beam is transmitted through the first dichroic mirror and travels forward along the principal optical axis, passing sequentially through a fixed coding aperture and a second dichroic mirror. Spatial light modulation is performed using the fixed coding aperture with large-size coding pixels and loaded coding template information, forming a first spatial modulation optical path. The second beam is reflected through the first dichroic mirror and travels forward parallel to the principal optical axis after passing through a first reflecting mirror in a direction perpendicular to the principal optical axis. It then passes through a moving coding aperture and undergoes spatial light modulation using the moving coding aperture with loaded coding template information, forming a second spatial modulation optical path. After changing direction via the second reflecting mirror, it is transmitted through the second dichroic mirror and merges with the first spatial modulation optical path, forming an image on the image plane of the imaging lens. This achieves the superposition of the optical path modulation effects of the first and second spatial modulation optical paths. A dual-encoding-aperture spatial light modulation structure, based on a fixed encoding aperture and a moving encoding aperture, enables the superposition of sub-optical path encoding effects of the target light on the image plane of the imaging lens group. By selecting a large-size encoding pixel aperture to reduce diffraction effects during long-wave infrared spatial modulation, and through encoding superposition using the dual-encoding-aperture spatial light modulation structure, the spatial modulation resolution of the large-size encoding pixel aperture is improved. This allows for the selection of a large-size encoding pixel aperture with reduced diffraction effects while maintaining spatial modulation resolution requirements without increasing the encoding aperture area, and also improves the number of encoding gray levels through encoding superposition. Parallel light is generated by a collimating lens, and the positions of the fixed and moving encoding apertures in the two sub-optical paths are designed to maintain consistency, ensuring that the subsequent first and second spatial light modulation optical paths have the same magnification on the image plane of the imaging lens, thereby ensuring the accuracy of the encoding template superposition process and the control precision of the moving encoding aperture. The position of the moving encoding aperture is controlled by a displacement stage to achieve encoding template transformation within the effective encoding area of ​​the moving encoding aperture, thus realizing long-wave infrared spatial modulation of the dynamic encoding aperture.

[0008] To improve the manufacturability of the encoding aperture, preferably, the large-sized encoding pixel size encoding template is a random binary matrix.

[0009] This invention also discloses a long-wave infrared dynamic spatial modulation method based on dual-coded aperture, implemented using the aforementioned dynamic spatial light modulation device based on dual-coded aperture. When the template information loaded by the large-size coded pixel coded aperture is selected as a random binary matrix, the dynamic long-wave infrared spatial modulation method based on dual-coded aperture includes the following steps:

[0010] Step 1: The target light enters the first dichroic mirror through the collimating lens, forming two sub-light paths. One of the beams passes through the dichroic mirror and travels forward along the principal optical axis, denoted as sub-light path 1. The other beam is reflected by the first dichroic mirror, travels forward perpendicular to the principal optical path, and then changes direction after being reflected by the first reflecting mirror, propagating forward parallel to the principal optical axis, denoted as sub-light path 2.

[0011] Step 2: The two optical paths propagate forward, and template information is loaded at the fixed encoding aperture and the moving encoding aperture respectively, resulting in the first spatial modulation optical path and the second spatial modulation optical path.

[0012] In the designed coding template, the size of a single coded pixel is s1*s1, where s1 is larger than the size of the coded pixel that diffracts with the target band, and its distribution is a random binary matrix C∈R. M×N Where R represents the set of real numbers, M×N represents the data dimension, and is also the resolution of the encoding template. In the binary template, 1 represents a transparent pixel, and 0 represents an opaque pixel. The fixed encoding aperture and the moving encoding aperture maintain optical symmetry in the positions of the two sub-beams, so that they have the same optical imaging magnification at the image plane of the imaging lens.

[0013] Step 3: After the encoding modulation is completed through the encoding aperture, the first spatial modulation optical path is reflected by the second dichroic mirror, and the optical path is deflected by 90°. The second spatial modulation optical path is reflected by the second mirror, and the optical path is deflected by 90°. After being transmitted through the second dichroic mirror, the first spatial modulation optical path and the second spatial modulation optical path are combined.

[0014] Step 4: The merged light paths are imaged by the imaging lens, and the superposition and encoding effect of the two spatial light modulation light paths is obtained on the image plane of the imaging lens.

[0015] Denote the fixed coding aperture and the moving coding aperture in the two paths as M1 and M2 respectively, and calibrate the effective template ranges M1' and M2' of M1 and M2 in the optical path. That is, the resolution of the effective coding area actually used is m×n (m<M, n<N). The calibration process is as follows: Place the light source at the target position, block the sub-optical path 1 and the sub-optical path 2 in two directions after the light passes through the first dichroic mirror, place the detector at the image plane position of the imaging lens, then the template information loaded by the fixed coding aperture and the moving coding aperture is separately imaged on the detector, and the position of the moving coding aperture is adjusted by observing the output image of the detector so that the two templates are pixel-aligned on the image plane. Select a partial area of the aligned template as the effective coding area, that is, the coding area corresponding to the coding image field applied in subsequent image processing and other processes. The spatial modulation optical paths carrying the template information of the two coding apertures respectively achieve the superposition of the coding modulation effects of the two independent templates on the image plane of the imaging lens. It is known that the minimum coding unit size of a single coding aperture is designed as s1*s1, the coding template resolution is M×N, and the coding templates M1' and M2' are superimposed at the image plane of the imaging lens. Denote the final superimposed template on the image plane of the imaging lens as M, which is expressed as follows:

[0016] M = M1' + M2'

[0017] Since both templates are random binary matrices, through superposition, the cutting of coding units between the two coding templates can be realized, and a superimposed coding template M with a coding pixel size smaller than s1×s1 can be obtained. At the same time, the spatial coding resolution is greater than m×n, thus realizing non-diffractive higher-resolution gray coding.

[0018] Step 5: Control the displacement of the moving coding template within a single image acquisition time to achieve the superposition of multiple coding templates, further improving the coding spatial resolution and the number of coding gray levels.

[0019] By controlling the exposure time of the acquisition system and the position of the moving coding aperture, within the single exposure time of the acquisition system, the displacement stage drives M2 to move k times in the direction perpendicular to the optical path, and the effective coding area of M2 generates a changing coding M2' k , k = 1, 2…, then at the final image plane position, the superposition modulation effect of M1 and k + 1 different M2 templates is obtained, and the mathematical expression is as follows:

[0020]

[0021] Through the superposition of the coding effects within a single exposure time, a variety of equivalent coding effects are generated more flexibly. As the number of template superpositions increases, the coding spatial resolution and the number of coding gray levels are improved.

[0022] Beneficial effects:

[0023] 1. The present invention discloses a long-wave infrared dynamic spatial modulation device and method based on dual-encoding aperture. By selecting a large-size encoding pixel encoding template, the influence of diffraction effect on the imaging system performance during long-wave infrared spatial modulation is reduced. Since the encoding is superimposed through a dual-encoding aperture spatial light modulation structure, the spatial modulation resolution of the large-size encoding pixel encoding template is improved. Thus, it is possible to select a large-size encoding pixel encoding template that reduces the occurrence of diffraction effect while ensuring the spatial modulation resolution requirements and without increasing the encoding aperture area.

[0024] 2. Due to limitations in processing methods and technologies, most encoding apertures can only achieve the encoding effect of binary templates. This invention discloses a long-wave infrared dynamic spatial modulation device and method based on dual encoding apertures. It forms a dual-encoding aperture spatial light modulation structure based on a fixed encoding aperture and a moving encoding aperture. The target light is used to superimpose the encoding effects of the sub-optical paths on the image plane of the imaging lens, achieving a grayscale encoding effect.

[0025] 3. The long-wave infrared dynamic spatial modulation method based on dual-coding aperture disclosed in this invention, through the use of a displacement stage, enables multiple effective area transformations of the moving coding template within a single acquisition time, producing multiple coding superposition effects. This invention, in conjunction with the detector's exposure acquisition time control, can continuously move the coding template within the exposure time to generate higher resolution spatial grayscale coding modulation effects. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the structure of the long-wave infrared dynamic spatial modulation device based on dual-coded aperture proposed in this invention.

[0027] Figure 2 Figure 1 is a schematic diagram of template overlay and segmentation. (a) and (b) are 2×2 large pixel size templates, which are the templates loaded by the coding aperture in the optical path. The red box area represents a pixel. Figure 2 is a schematic diagram of two templates being overlaid. The yellow box is the overlaid coding pixel. It shows that the original large-size coding pixel can be cut by coding overlay to achieve a smaller-size coding pixel, while generating grayscale coding.

[0028] Figure 3 Figure 1 shows a schematic diagram of the superimposed template obtained by moving the moving template in one dimension (perpendicular to the optical path direction). Figures (a) and (b) show the template loaded by the coding aperture in the optical path, where (a) is the fixed template and (b) is the moving template. The part selected by the green box is the actual effective coding area used in the optical path. Figure (c) shows the effect of the moving coding aperture shifting twice (i.e., a total of 4 coding templates superimposed, including the initial template and the templates generated by the two shifts). Figure (d) is a magnified view of the part selected by the red box in Figure (c).

[0029] Figure 4 For Figure 3 The diagram shows the superimposed templates obtained by moving the template a certain number of times in one dimension. Figures (a) and (b) show the templates loaded by the coding aperture in the optical path. The part selected by the green box is the actual effective coding area used in the optical path. Figure (c) shows the effect of superimposing a total of 8 coding templates by moving the coding aperture 6 times (including the initial template and the templates generated by the two movements). Figure (d) is a magnified view of the part selected by the red box in Figure (c).

[0030] Figure 5 This is a schematic diagram of a superimposed template obtained by moving a movable template in a two-dimensional direction (perpendicular to the optical axis). This involves adding a displacement stage to allow the movable template to move in two perpendicular directions to the optical axis. Figures (a) and (b) show the template loaded with the encoding aperture in the optical path. The area selected by the green box is the actual effective encoding region used in the optical path. Figure (c) shows the effect of moving the encoding aperture twice (i.e., the superposition of four encoding templates, including the initial template and the templates generated by the two movements). Figure (d) is a magnified view of the area selected by the red box in Figure (c).

[0031] Figure 6 The grayscale histograms of the overlaid equivalent templates are shown in Figure (a). Figure 3 The grayscale histogram of template 3.(c) is shown in Figure (b). Figure 4 The grayscale histogram of template 4.(c) shows that, compared with the random binary modulation template loaded with the coded aperture, the equivalent modulation template obtained by the method proposed in this invention can improve the grayscale level of the modulation template. Moreover, as the number of moves increases, the number of superimposed templates increases, and the improvement effect becomes more obvious.

[0032] Figure 7 To simulate the results of overlay templates and modulation using a single-path coded aperture. Figure (a) shows the original image, and Figure (b) shows the result using... Figure 3 The result of modulation using the fixed template 3.(b) is shown in Figure (c). Figure 3 The result of modulation using the superimposed template 3.(c) in the image.

[0033] Wherein: 1—collimating lens, 2—first dichroic mirror, 3—first reflecting mirror, 4—fixed coding template, 5—moving coding template, 6—second dichroic mirror, 7—second reflecting mirror, 8—imaging lens, 9—image plane of imaging lens. Detailed Implementation

[0034] like Figure 1As shown, the long-wave infrared dynamic spatial modulation device based on dual-encoding aperture disclosed in this embodiment includes a collimating lens 1, a first dichroic mirror 2, a fixed encoding aperture, a first reflecting mirror 3, a moving encoding aperture, a displacement stage, a second reflecting mirror 7, a second dichroic mirror 6, and an imaging lens group 8.

[0035] The target light is collimated by the collimating lens 1 to become parallel light. This parallel light then enters the first dichroic mirror 2 for beam splitting. Specifically: the first beam is the transmitted light from the first dichroic mirror 2, which travels forward along the principal optical axis, passing sequentially through a fixed encoding aperture and a second dichroic mirror 6. Spatial light modulation is achieved using the fixed encoding aperture with a large-size encoding pixel and loaded encoding template information, forming a first spatial modulation optical path. The second beam is the reflected light from the first dichroic mirror 2, which travels along the direction perpendicular to the principal optical axis through the first reflecting mirror 3 and then propagates parallel to the principal optical axis. It passes through a moving encoding aperture, where spatial light modulation is achieved using the moving encoding aperture with loaded encoding template information, forming a second spatial modulation optical path. This path then changes direction via the second reflecting mirror 7, is transmitted through the second dichroic mirror 6, and merges with the first spatial modulation optical path, forming an image on the image plane 9 of the imaging lens. This achieves the superposition of the optical path modulation effects of the first and second spatial modulation optical paths. Figure 2 As shown, a dual-encoding-aperture spatial light modulation structure is formed based on a fixed encoding aperture and a moving encoding aperture. The target light is imaged on the image plane of the imaging lens group, achieving superposition of the encoding effects of the two sub-optical paths. By selecting a large-size encoding pixel encoding aperture to reduce the diffraction effect in the long-wave infrared spatial modulation process, the dual-encoding-aperture spatial light modulation structure is used to complete the encoding superposition. During the superposition process, the two encoding aperture encoding pixels are segmented, thereby improving the spatial modulation resolution of the large-size encoding pixel encoding aperture. This allows for the selection of a large-size encoding pixel encoding aperture with reduced diffraction effect while ensuring the spatial modulation resolution requirements and without increasing the encoding aperture area. Furthermore, the superposition process increases the grayscale level of the encoding. Parallel light is generated by the collimating lens 1, and the positions of the fixed encoding aperture and the moving encoding aperture in the two sub-optical paths are designed to remain relatively consistent to ensure that the subsequent first and second spatial light modulation optical paths have the same magnification on the image plane 9 of the imaging lens, thus ensuring the accuracy of the encoding template superposition process. By adjusting the position of the moving encoder aperture using a displacement stage, the encoder template within the effective encoding area of ​​the moving encoder aperture is transformed, thereby achieving long-wave infrared spatial modulation of the dynamic encoder aperture.

[0036] To improve the manufacturability of the encoding aperture, the large-sized encoding pixel size encoding template is a random binary matrix.

[0037] This embodiment also discloses a long-wave infrared dynamic spatial modulation method based on dual-coded aperture, implemented using the aforementioned long-wave infrared dynamic spatial light modulation device based on dual-coded aperture. When the template information loaded by the large-size coded pixel coded aperture is selected as a random binary matrix, and the target light wavelength is 8-12μm, the long-wave infrared dynamic spatial modulation method based on dual-coded aperture includes the following steps:

[0038] Step 1: The target light enters the first dichroic mirror 2 through the collimating lens 1, forming two sub-light paths. One of the beams passes through the dichroic mirror and travels forward along the principal optical axis, denoted as sub-light path 1. The other beam is reflected by the first dichroic mirror 2, travels forward perpendicular to the principal optical path, and then changes direction after being reflected by the first reflecting mirror 3, propagating forward parallel to the principal optical axis, denoted as sub-light path 2.

[0039] Step 2: The two optical paths propagate forward, and template information is loaded at the fixed encoding aperture and the moving encoding aperture respectively, resulting in the first spatial modulation optical path and the second spatial modulation optical path.

[0040] Both the fixed and movable encoding apertures are squares with sides of 17 mm. The size of a single encoded pixel in the encoding template is s1×s1, where s1=32μm. Experiments have verified that this pixel size of the encoding aperture effectively suppresses the diffraction effect on image quality during modulation. The encoding template is distributed as a random binary matrix C∈R. M×N Where R represents the set of real numbers, and M×N represents the data dimension, which is also the resolution of the encoding template. In this example, M=N=512. In the binary template, 1 represents a transparent pixel, and 0 represents an opaque pixel. The positions of the moving encoding aperture and the movable encoding aperture in the two sub-beam paths are kept optically symmetrical, so that they have the same optical imaging magnification at the image plane 9 of the imaging lens.

[0041] Step 3: After the encoding and modulation are completed through the encoding aperture, the first spatial modulation light path is reflected by the second dichroic mirror 6, and the light path is deflected by 90°. The second spatial modulation light path is reflected by the second mirror 7, and the light path is deflected by 90°. Then it is transmitted through the second dichroic mirror 6, and the first spatial modulation light path and the second spatial modulation light path are combined.

[0042] Step 4: The merged light paths are imaged by imaging lens 8, and the superimposed encoding effect of the encoding templates loaded by the encoding apertures of the two spatial light modulation light paths is obtained on the image plane of imaging lens 8.

[0043] Denote the fixed coding aperture and the moving coding aperture in the two paths as M1 and M2 respectively, and calibrate the effective template ranges M1' and M2' of M1 and M2 in the optical path. That is, the resolution of the effective coding area actually used is m×n (m < M, n < N). The calibration process is as follows: Place the light source at the target position, block the sub-optical path 1 and the sub-optical path 2 respectively in two directions after the light passes through the first dichroic mirror 2, and place the detector at the image plane 9 of the imaging lens. Then the template information loaded by the fixed coding aperture and the moving coding aperture is separately imaged on the detector. By observing the output image of the detector, adjust the position of the moving coding aperture so that the two templates are pixel-aligned on the image plane. Select a partial area of the aligned template as the effective coding area, that is, the coding area corresponding to the coding image field applied in subsequent image processing and other processes. The spatial modulation optical paths carrying the template information of the two coding apertures respectively achieve the superposition of the coding modulation effects of the two independent templates at the image plane 8 of the imaging lens. Given that the minimum coding unit size of a single coding aperture is designed as s1×s1, the resolution of the coding template is M×N, and the coding templates M1' and M2' are superimposed at the image plane 9 of the imaging lens. Denote the superimposed template at the final imaging lens image plane 9 as M, which is expressed as follows:

[0044] M = M1' + M2'

[0045] Since both templates are random binary matrices, through superposition, the coding units between the two coding templates can be cut, obtaining a superimposed coding template M with a coding pixel size smaller than s1×s1, and at the same time the spatial coding resolution is greater than m×n, thus achieving non-diffractive higher-resolution gray coding.

[0046] Step 5: Control the displacement of the moving coding template 5 within the single image acquisition time to achieve multiple coding template superpositions, further improving the coding spatial resolution and the coding gray level.

[0047] By controlling the exposure time of the acquisition system and the position of the moving coding aperture, as Figure 3 shown, within the single exposure time of the acquisition system, the displacement stage drives M2 to move k times in the direction perpendicular to the optical path, and the effective coding area of M2 generates a changing coding M2' k , k = 1, 2…, then at the final image plane position, the superposition modulation effect of M1 and k + 1 different M2 templates is obtained, and the mathematical expression is as follows: <000012><0>

[0049] Through the superposition of the coding effects within the single exposure time, a variety of equivalent coding effects are generated more flexibly. As the number of template superpositions increases (as Figure 5 shown) and the displacement dimension of the moving template increases (as Figure 6As shown in the figure, the coding space resolution and the number of coding gray levels will be further improved.

[0050] The above detailed description further illustrates the purpose, technical solution, and beneficial effects of the invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A long-wave infrared dynamic spatial modulation device based on dual-coded aperture, characterized in that: It includes a collimating lens, a first dichroic mirror, a fixed coded aperture, a first reflecting mirror, a movable coded aperture, a displacement stage, a second reflecting mirror, a second dichroic mirror, and an imaging lens; The target light is collimated by a collimating lens to become parallel light. This parallel light then enters a first dichroic mirror for beam splitting. Specifically: the first beam is transmitted through the first dichroic mirror, passing sequentially along the principal optical axis through a fixed encoding aperture and a second dichroic mirror. Spatial light modulation is performed using the fixed encoding aperture with its large-size encoding pixel and loaded encoding template information, forming a first spatial modulation optical path. The second beam is reflected through the first dichroic mirror, propagating parallel to the principal optical axis after passing through the first reflecting mirror in a direction perpendicular to the principal optical axis. It then passes through a moving encoding aperture, where spatial light modulation is performed again using the moving encoding aperture with its large-size encoding pixel and loaded encoding template information, forming a second spatial modulation optical path. After changing direction via the second reflecting mirror, it is transmitted through the second dichroic mirror and merges with the first spatial modulation optical path, forming an image on the image plane of the imaging lens. This achieves the superposition of the optical path modulation effects of the first and second spatial modulation optical paths, resulting in a dual-encoding system based on the fixed and moving encoding apertures. The aperture spatial light modulation structure superimposes the sub-optical path encoding effects of the target light on the image plane of the imaging lens. By selecting a large-size encoding pixel aperture, the diffraction effect in the long-wave infrared spatial modulation process is reduced, thereby reducing the impact of the diffraction effect on the imaging system performance. The encoding superposition is completed through a dual-encoding aperture spatial light modulation structure, improving the spatial modulation resolution of the large-size encoding pixel aperture. Thus, it is possible to select a large-size encoding pixel aperture that reduces the occurrence of diffraction effects while ensuring the spatial modulation resolution requirements and without increasing the encoding aperture area. Furthermore, the grayscale encoding level is improved through encoding superposition. Parallel light is generated by a collimating lens to ensure that the subsequent first and second spatial light modulation optical paths have the same magnification, thereby ensuring the accuracy of the encoding template superposition process. The position of the moving encoding aperture is controlled by a displacement stage to realize the transformation of the encoding template within the effective encoding area, thereby achieving long-wave infrared spatial modulation of the dynamic encoding aperture.

2. The long-wave infrared dynamic spatial modulation device based on dual-coded aperture as described in claim 1, characterized in that: The large-size encoded pixel encoding template is a random binary matrix.

3. A long-wave infrared dynamic spatial modulation method based on dual-coded aperture, implemented based on the long-wave infrared dynamic spatial modulation device based on dual-coded aperture as described in claim 1 or 2, characterized in that: Includes the following steps, Step 1: The target light passes through the collimating lens to become parallel light, which enters the first dichroic mirror, forming two sub-light paths. One of the beams passes through the dichroic mirror and propagates forward along the principal optical axis, which is called the first sub-light path. The other beam is reflected by the dichroic mirror, perpendicular to the principal optical path, and then changes direction after being reflected by the first reflecting mirror, and propagates forward parallel to the principal optical axis, which is called the second sub-light path. Step 2: The two optical paths propagate forward, and template information is loaded at the fixed encoding aperture and the moving encoding aperture respectively, resulting in the first spatial modulation optical path and the second spatial modulation optical path; Step 3: After the encoding modulation is completed through the encoding aperture, the first spatial modulation optical path is reflected by the second dichroic mirror, and the optical path is deflected by 90°. The second spatial modulation optical path is reflected by the second mirror, and the optical path is deflected by 90°. After being transmitted through the second dichroic mirror, the first spatial modulation optical path and the second spatial modulation optical path are combined. Step 4: The converged optical path is imaged by an imaging lens, and the superimposed encoding effect of the encoding templates loaded by the two spatial light modulation optical path encoding apertures is obtained on the image plane of the imaging lens; Step 5: By controlling the displacement of the moving encoding template within a single image acquisition time, multiple encoding template superpositions are achieved, improving the encoding spatial resolution and the encoding gray level.

4. The long-wave infrared dynamic spatial modulation method based on dual-coded aperture as described in claim 3, characterized in that: In Step 2, In the designed coding template, the size of a single coded pixel is s1×s1, where s1 is larger than the size of the coded pixel that diffracts with the target band, and its distribution is a random binary matrix C∈R. M×N Where R represents the set of real numbers, M×N represents the data dimension, and is also the resolution of the encoding template. In the binary template, 1 represents a transparent pixel and 0 represents an opaque pixel. The positions of the moving encoding aperture and the movable encoding aperture in the two sub-light paths are kept optically symmetrical, so that they have the same optical imaging magnification at the position of the image plane of the imaging lens.

5. The long-wave infrared dynamic spatial modulation method based on dual-coded aperture as described in claim 4, characterized in that: In Step 4, The fixed encoding aperture and the moving encoding aperture in the two paths are respectively denoted as M1 and M2, and the effective template ranges M1' and M2' of M1 and M2 are calibrated in the optical path, that is, the resolution of the actual used effective encoding area is m×n (m < M, n < N); the calibration process is as follows: place the light source at the target position, block the first sub-optical path and the second sub-optical path respectively in the two directions after the light passes through the first dichroic mirror, place the detector at the image plane position of the imaging lens, then the template information loaded by the fixed encoding aperture and the moving encoding aperture are respectively imaged on the detector alone, and the position of the moving encoding aperture is adjusted by observing the output image of the detector, so that the two templates are pixel-aligned on the image plane; select a partial area of the aligned templates as the effective encoding area, that is, the encoding area corresponding to the encoding image field applied in the subsequent image processing process; The spatial modulation optical paths carrying the template information of the two encoding apertures respectively achieve the superposition of the encoding modulation effects of the two independent templates on the image plane of the imaging lens.

6. The long-wave infrared dynamic spatial modulation method based on dual-coded aperture as described in claim 5, characterized in that: In Step 5, By controlling the exposure time of the acquisition system and the position of the moving encoding aperture, within a single exposure time of the acquisition system, the displacement stage moves M2 k times in the vertical optical path direction, resulting in a changing encoding M2' in the effective encoding area of ​​M2. k If k = 1, 2, ..., then at the final image plane position, the superposition modulation effect of M1 and k+1 different M2 templates is obtained; by superimposing the encoding effect of a single exposure time, a variety of equivalent encoding effects can be generated more flexibly. As the number of template superpositions increases, the encoding space resolution and the number of encoding gray levels are improved.

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