Computational processing system for image quality enhancement for airborne dynamic imaging and method thereof

Abstract

The application discloses a kind of image quality enhancement computing processing systems and method for airborne dynamic imaging, it is related to the field of computational optics.System includes illumination module, collimating module, confocal module, beam splitting module, angle selection filter module, imaging module;Angle selection filter module changes the incident angle of light beam by physical movement or rotation, so that angle selection filter module excites Berreman mode in near-zero dielectric constant double-layer film, realizes the real-time switching of normal incidence low-pass denoising and oblique incidence high-pass sharpening.The application can realize the switching of two typical image processing functions by adjusting the incident angle without introducing electric control elements, so as to realize the functional integration of sharpening and denoising in a single optical structure, with millisecond-level angle switching, low power consumption, compact linear folding optical path, suitable for airborne high-speed imaging.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of computational optics, and particularly relates to a kind of image quality enhancement processing system and method for airborne dynamic imaging. BACKGROUND

[0002] Image processing technology as an important means of information acquisition and recognition, plays a vital role in airborne remote sensing, target tracking, situation awareness and autonomous flight and other aerospace applications. In the complex and changeable airborne dynamic imaging scene, high-speed motion platform and rapidly changing imaging target will cause image blur, noise enhancement and detail loss, thereby reducing the ability of target information acquisition and recognition accuracy. Image preprocessing link has important influence on image sharpness, target identifiability and the accuracy of subsequent decision, especially image sharpening (i.e. edge extraction) and denoising processing, has become a key step to improve dynamic image quality and information extraction efficiency. Traditional methods usually rely on electronic chips or digital algorithms, through convolution, Fourier transform, filtering and other ways to realize image processing function. However, traditional image processing methods mainly rely on electronic devices (such as computer), its calculation speed is limited, power consumption is high and there is processing delay, in high-speed motion, target burst change and other airborne tasks, it is difficult to meet the real-time and response speed of double requirements. In recent years, image processing methods based on optical analog computing have attracted widespread attention due to their huge speed advantage. The speed of optical computing is about six orders of magnitude faster than electronic computing, which can effectively solve the above problems. This method can directly process optical signals, realize fast parallel computing, and almost no energy consumption. Traditional optical analog image processing methods mostly use Fourier transform structure based on 4f system, which realizes image edge enhancement or frequency domain filtering processing through spatial filter. But this kind of system is large in size, it is difficult to be compatible with most instruments. With the development of nanophotonics technology, such as super surface, multilayer film, photonic crystal and other structures, can replace 4f system, realize the direct processing of image, so as to significantly shorten the overall length of the system.

[0003] While current technologies have made some progress in optical image processing, several significant shortcomings remain. First, current optical image processors based on nanophotonic structures, such as metasurfaces, multilayer films, and photonic crystals, typically have limited functionality, often only capable of performing specific operations like sharpening or edge enhancement. They lack multifunctional integration capabilities and struggle to meet complex and ever-changing image processing demands. Second, most of these devices are static structures, with their optical response and processing capabilities fixed during the design phase. They lack dynamic adjustment capabilities and cannot adaptively adjust to variations in image quality or noise levels in different application scenarios, severely limiting their practicality and flexibility. Furthermore, no purely optical system currently achieves efficient image denoising; most solutions still rely on subsequent electronic computation for image noise reduction. This not only increases system latency but also contradicts the initial goals of optical computing in terms of speed and energy consumption. Summary of the Invention

[0004] The purpose of this disclosure is to provide a computational processing system and method for image quality enhancement in airborne dynamic imaging, which can solve at least one of the aforementioned technical problems. The specific solution is as follows:

[0005] A computational processing system for image quality enhancement in airborne dynamic imaging includes:

[0006] Illumination module, collimation module, confocal module, beam splitter module, angle selection filter module, imaging module;

[0007] The lighting module is used to provide a light beam;

[0008] The collimation module is used to expand the beam into a collimated beam;

[0009] The confocal module is used to transmit the initial image of the object to the angle selection filter module;

[0010] The beam splitting module is used to split the light beam into a transmitted beam and a reflected beam;

[0011] The angle selection filtering module is used to control the angle of incidence of the beam and uses the Berreman mode for filtering, thereby realizing the functions of image denoising or sharpening.

[0012] The imaging module is used to receive the filtered image and convert the optical signal into an electrical signal;

[0013] The initial image is transmitted to the angle selection filtering module through the confocal module. The angle selection filtering module selects the filtering method according to the incident angle of the beam. After filtering, the imaging module receives the image with enhanced image quality.

[0014] Further, the angle of the control light beam incidence angle: the first angle interval and the second angle interval;

[0015] The angle is the first angle interval, the Berreman mode is excited to present a low-pass filter characteristic, and the image is denoised;

[0016] The angle is the second angle interval, the Berreman mode is excited to present a high-pass filter characteristic, and the image is sharpened;

[0017] The incidence angle corresponding to the first angle interval is smaller than the incidence angle corresponding to the second angle interval.

[0018] Further, the angle is a normal incidence state, and the first angle interval satisfies the condition: NA=0.

[0019] The angle is an oblique incidence state, and the second angle interval satisfies the condition: ; Wherein, NA represents the numerical aperture.

[0020] Further, the angle selection filter module is a double-layer film structure, including a near-zero dielectric constant film layer and a non-transparent metal substrate layer, and the near-zero dielectric constant film layer is arranged on the side of the metal substrate layer where the incident light beam is located.

[0021] Further, the metal substrate layer satisfies the condition: the metal material of the metal substrate layer has a real part of dielectric constant less than-20, and the thickness of the metal substrate layer is greater than 500nm.

[0022] Further, the near-zero dielectric constant film layer satisfies the condition: the thickness satisfies 0.002-0.05Ā; Wherein, Ā represents the average wavelength of the illumination module.

[0023] Further, the angle for controlling the light beam incidence angle includes: changing the incidence angle of the light beam by physically moving or rotating the angle selection filter module.

[0024] Further, the imaging module includes an imaging lens and a detector, and the detector is a high-speed CMOS camera or an InGaAs array.

[0025] The application also provides a computing processing method for image quality enhancement of airborne dynamic imaging, and the computing processing method comprises:

[0026] Obtaining an initial image from an imaging object;

[0027] By changing the angle of the light beam incidence angle, the Berreman mode is excited, and the filter characteristic of the optical transfer function based on the Berreman mode is controlled to filter;

[0028] output the filtered image.

[0029] Further, the angle of changing the light beam incidence angle comprises:

[0030] The angle is a first angle range in a normal incidence state, a low-pass filtering characteristic is generated by exciting a Berreman mode, and is used for image denoising processing.

[0031] The angle is a second angle range in an oblique incidence state, a high-pass filtering characteristic is generated by exciting a Berreman mode, and is used for image sharpening processing.

[0032] Compared with the prior art, the above scheme of the embodiment of the present application has at least the following beneficial effects:

[0033] 1. The image quality enhancement computing processing system and method for airborne dynamic imaging disclosed by the present application realize low-pass denoising and high-pass sharpening two opposite functions by using the Berreman mode angle selectivity of the near-zero dielectric constant thin film layer and only switching the incidence angle of two thin films.

[0034] 2. The image quality enhancement computing processing system and method for airborne dynamic imaging disclosed by the present application realize angle control through the angle selection filtering module, and realize high-speed, low-energy optical analog computing processing of image information without electronic calculation under the condition of no electrode, no lead and no static current.

[0035] 3. The image quality enhancement computing processing system and method for airborne dynamic imaging disclosed by the present application realize the function integration of sharpening and denoising in a single optical structure through the single-layer near-zero dielectric constant thin film layer and the straight-line folded light path, and the system is compact and does not need to occupy a large space. BRIEF DESCRIPTION OF DRAWINGS

[0036] The accompanying drawings, which are incorporated into and form part of the specification, illustrate embodiments consistent with the present disclosure and, together with the specification, serve to explain the principles of the present disclosure. It is apparent that the accompanying drawings in the following description are only some embodiments of the present disclosure, and other drawings can be obtained by those skilled in the art without creative labor on the basis of these drawings. In the drawings:

[0037] Figure 1 A schematic diagram of an image quality enhancement computing processing system for airborne dynamic imaging provided by the embodiment of the present application is shown in the accompanying drawings.

[0038] Figure 2A schematic diagram of optical simulation sharpening and denoising concept of near-zero dielectric constant thin film layer in a computing processing system for image quality enhancement of airborne dynamic imaging provided by the embodiment of the present application;

[0039] Figure 3 A schematic diagram of dispersion curve of near-zero dielectric constant thin film layer with different thickness in a computing processing system for image quality enhancement of airborne dynamic imaging provided by the embodiment of the present application;

[0040] Figure 4 A schematic diagram of angle-reflectance amplitude distribution curve in near-infrared band when the thickness of near-zero dielectric constant thin film layer is 0.1 μm in a computing processing system for image quality enhancement of airborne dynamic imaging provided by the embodiment of the present application.

[0041] The reference signs in the drawings include:

[0042] The laser light source 1, the beam expander 2, the imaging object 3, the first lens 4, the half mirror 5, the objective lens 6, the imaging lens 7, the angle selection filter module 8, and the high-speed CMOS camera 9. DETAILED DESCRIPTION

[0043] In order to make the objects, technical solutions and advantages of the present disclosure clearer, the following will further describe the present disclosure in detail with reference to the drawings. Obviously, the described embodiments are only a part of the embodiments of the present disclosure, but not all the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present disclosure.

[0044] It should also be noted that the terms "comprising", "containing" or any other variant thereof are intended to cover non-exclusive inclusion, so that the products or devices including a series of elements not only include those elements, but also include other elements not explicitly listed or inherent to such products or devices. Without more limitations, the element defined by the statement "comprising one" does not exclude the presence of another identical element in the product or device including the element.

[0045] The following will be described in detail with reference to the drawings. Figures 1-4 The optional embodiments of the present application will be described in detail.

[0046] The embodiment of the present application provides a computing processing system for image quality enhancement of airborne dynamic imaging, which comprises an illumination module, a collimation module, a confocal module, a beam splitting module, an angle selection filter module 8 and an imaging module.

[0047] The illumination module is used for providing an illumination beam; the collimation module is used for expanding the beam into a collimated beam; the confocal module is used for transmitting the initial image of the imaging object 3 to the angle selection filter module; the beam splitting module is used for splitting the beam into a transmitted beam and a reflected beam; the angle selection filter module 8 is used for controlling the angle of the beam incidence angle, filtering by using the Berreman mode, so as to realize the image denoising or sharpening function; and the imaging module is used for receiving the filtered image and converting the optical signal into an electrical signal. In the embodiment of the present application, the confocal module comprises a first lens 4 and an objective lens 6, which are equivalent to a telescope, and the image on the front focal plane of the first lens 4 is transmitted to the rear focal plane of the objective lens 6, and then to the angle selection filter module 8. The imaging module comprises an imaging lens 7 and a high-speed CMOS camera 9.

[0048] As shown in Figure 1 the embodiment of the present application, the illumination module is a laser light source 1. The collimation module is a beam expander 2. The embodiment of the present application further comprises an imaging object 3 for providing initial image information to be processed. The confocal module comprises a first lens 4 and an objective lens 6. The beam splitting module is a half mirror 5. The angle selection filter module 8 is a double-layer thin film structure, comprising a near-zero dielectric constant thin film layer and a metal substrate layer. The incident angle is adjusted by rotating the angle selection filter module 8 or changing the position of the angle selection filter module 8 through a high-precision motor, so as to change the angle of the beam focused on the near-zero dielectric constant thin film layer, that is, the NA value.

[0049] In the embodiment of the present application, the laser beam emitted by the laser light source 1 is expanded by the beam expander 2 to form a collimated beam and is incident to the imaging object 3, so as to generate an image light field carrying initial image information. The image light field is received by the first lens 4, and the beam transformed by the first lens 4 is split by the half mirror 5, and the light beam transmitted through the half mirror 5 is transmitted to the objective lens 6.

[0050] The split beam enters the objective lens 6, and after focusing by the objective lens 6, it is incident to the angle selection filter module 8. The angle selection filter module 8 is driven by a high-precision motor to perform precise displacement or rotation, so as to accurately adjust the angle of the focused beam incident to the angle selection filter module 8 for filtering. The reflected beam filtered and modulated by the angle selection filter module 8 returns along the original path, is received by the objective lens 6, is incident to the half mirror 5 again, is reflected by the half mirror 5, and enters the imaging lens 7. The imaging lens 7 transmits the received filtered beam to the high-speed CMOS camera 9 for detection, and the high-speed CMOS camera 9 converts the optical signal into an electrical signal and outputs.

[0051] According to the scalar diffraction theory of Fourier optics, when an object with a specific shape, that is, the imaging object 3 in the embodiment of the present application, is irradiated by a plane wave, its incident image light field can be expressed in the Fourier space as:

[0052] .

[0053] wherein, and respectively represent the spatial frequency of x-axis direction and y-axis direction, and also can respectively represent the direction of p-polarized light and s-polarized light; x, y respectively represent the direction of p-polarized light and s-polarized light; represents the Fourier form of optical wave electric field; i represents an imaginary number.

[0054] For the convenience of calculation, the spatial frequency can be represented by numerical aperture NA:

[0055] ;

[0056] wherein, k0 represents the wave vector of incident light; represents the wave vector of p-polarized light or s-polarized light. In the embodiment of the present application, only p-polarized light, i.e. the polarization light of x-axis direction, is used.

[0057] If a spatial modulator with incident angle dependence is arranged at the far field position of the imaging object 3, the different frequency components in the Fourier space can be filtered and modulated. The angle selection filter module 8 in the embodiment of the present application is the spatial modulator. The modulated Fourier space image light field is represented as:

[0058] .

[0059] wherein, represents the optical transfer function (OTF); represents the Fourier space optical wave electric field before modulation.

[0060] Therefore, in the embodiment of the present application, the physical process based on angle modulation can be regarded as a linear time-invariant system, and the OTF is the impulse response of the system. The imaging object 3 irradiated by the light beam usually contains rich information content from low frequency to high frequency in the frequency domain (Fourier space). In the image processing process, different OTFs with high-pass or low-pass characteristics need to be introduced for different processing targets, and such transfer functions usually show dependence on the incident angle. The technical scheme of the embodiment of the present application introduces the Green function method, which can realize fast and accurate optical simulation calculation without Fourier transform, and directly model and simulate the propagation behavior of the light beam on the planar optical structure.

[0061] The embodiment of the present application provides a preferred scheme, when the angle of the angle selection filter module 8 includes a first angle interval and a second angle interval;

[0062] When the angle is the first angle interval, the Berreman mode is excited to present low-pass filtering characteristics, and the denoising processing of the image is realized.

[0063] When the angle is in the second angle interval, the Berreman mode is excited to present a high-pass filtering characteristic, and the sharpening processing of the image is realized;

[0064] The incident angle corresponding to the first angle interval is smaller than the incident angle corresponding to the second angle interval.

[0065] The scheme of the embodiment of the present application excites the Berreman mode, and the angle of the angle-selective filtering module 8 is in the first angle interval, that is, the denoising is realized in the normal incidence. The angle of the angle-selective filtering module 8 is in the second angle interval, that is, the sharpening processing of the edge extraction is realized in the oblique incidence. In essence, because the Berreman mode has been realized, the normal incidence state and the oblique incidence state respectively have two different reflection optical transfer functions (OTF), so that the Berreman mode is excited, but different functions of denoising and sharpening are realized.

[0066] The embodiment of the present application provides a preferred scheme, and the incident angle of the angle-selective filtering module 8 is in the first angle interval: the normal incidence state, that is, NA = 0, = 0.

[0067] wherein, represents the incident angle of the angle-selective filtering module 8. The range satisfies the low-pass denoising.

[0068] The incident angle of the angle-selective filtering module 8 is in the second angle interval: the oblique incidence state, and the numerical aperture NA satisfies . That is arcsin , , and the range satisfies the oblique incidence high-pass sharpening.

[0069] This invention provides a preferred embodiment where the angle-selective filtering module 8 is a double-layer thin-film structure, a non-local film layer structure. According to Green's function theory, changing the angle of the angle-selective filtering module 8 manipulates the initial image information. The angle-selective filtering module 8 includes a near-zero dielectric constant thin film layer and a metal substrate layer. The near-zero dielectric constant thin film layer is disposed on the incident beam side of the metal substrate layer. The near-zero dielectric constant thin film layer is the core functional layer for achieving angle-selective filtering. Its optical characteristic is that its dielectric constant is close to zero at a specific wavelength, which is the physical basis for the Berreman mode effect. The near-zero dielectric constant thin film layer is located on the top layer of the double-layer structure and is the layer that the light beam first contacts and passes through. This invention provides a preferred embodiment where the material of the near-zero dielectric constant thin film layer is indium tin oxide (ITO), and the metal layer is gold (Au). The non-transparent metal substrate layer reflects almost all the light that penetrates the near-zero dielectric constant thin film layer back, forming a Fabry-Perot cavity interference effect. By confining the light beam to reflect back and forth within a near-zero dielectric constant thin film layer, the interaction intensity between the light and the near-zero dielectric constant thin film layer material is greatly enhanced, thereby stimulating the Berreman mode effect and making the angle-selective filtering module 8 strong enough for practical filtering.

[0070] This invention provides a preferred embodiment where the metal substrate layer meets the following condition: the thickness of the metal substrate layer is greater than 500 nm. The dielectric constant of the metal substrate layer includes a real part and an imaginary part. In this embodiment, the metal substrate layer is a metallic material with a real part of the dielectric constant less than -20. That is, the metal substrate layer is to be a near-perfect conductor. According to the Drude model, materials such as gold and silver have extremely high reflectivity in the wavelength range of 1.15–1.19 μm, and can therefore be used as the metal substrate layer in this embodiment. λ represents the wavelength of the light beam from the illumination module.

[0071] An embodiment of the present invention provides a preferred solution in which the thickness of the metal substrate layer is greater than 500 nm.

[0072] This invention provides a preferred embodiment where the near-zero dielectric constant thin film layer is made of indium tin oxide (ITO) and the metal layer is made of gold (Au). The thickness of the near-zero dielectric constant thin film layer satisfies: d = 0.002-0.05Ā. Here, Ā represents the average wavelength of the illumination module, i.e., the average wavelength of the laser light source 1; d represents the thickness of the near-zero dielectric constant thin film layer, and in this embodiment, Ā is 1.17 μm.

[0073] like Figure 2 As shown, Figure 2a is an optical simulation sharpening and denoising schematic diagram of an angle-based selection filtering module, the upper layer is a near-zero dielectric constant film layer, and the lower layer is a metal substrate layer, and the two functions of image edge extraction and denoising achieved through the near-zero dielectric constant film structure are displayed. The near-zero dielectric constant film layer (ENZ) material based on Berreman mode control has angle dependence. When the ENZ material with a subwavelength thickness is deposited on the surface of a metal substrate layer of an ideal electrical conductor (PEC), the ENZ material can exhibit obvious angle-dependent reflection characteristics in a wide spectral range, and the reflectivity is significantly reduced at a specific incident angle. In addition, the phenomenon is controlled by the thickness of the near-zero dielectric constant film layer, and different thicknesses correspond to different angle response characteristics. Figure 2 b is a dispersion curve under p-polarized light conditions in the Berreman model, the X-axis coordinate represents NA, the Y-axis coordinate represents the normalized wavelength, and the Z-axis coordinate represents the intensity. Figure 2 In b, the two operating points of NA=0 and NA=0.55 are highlighted. The optical responses under different NAs correspond to two different OTFs. When the NA is low, the Berreman mode is excited, the complex dielectric constant of the near-zero dielectric constant film layer is close to zero, the light field absorption is canceled out, the reflection is suddenly reduced, a low-pass filter is formed, and the image is smoothed and denoised. When the NA is high, the Berreman mode is excited, the metal substrate layer reflection is dominant, the high frequency is reserved, a high-pass filter is realized, and the image edge is sharpened. Thus, the computing processing system provided by the embodiment of the application can realize different image processing functions by controlling the film parameters of the near-zero dielectric constant film layer.

[0074] The technical scheme of the embodiment of the application controls the excitation of the Berreman mode by using the variable incident condition angle / NA with the fixed physical structure optical parameters, so as to dynamically switch the filtering performance OTF.

[0075] As shown in Figure 3 , the dispersion curve of the near-zero dielectric constant film layer based on the Berreman model is shown. Figure 3 As shown in a, with the increase of the thickness of the near-zero dielectric constant film layer, the low reflection region gradually shifts to a smaller numerical aperture NA direction, Figure 3 a is the dispersion relationship of the near-zero dielectric constant film layer under TM mode and p-polarized light conditions, and the expression is:

[0076] ;

[0077] Among them, , and respectively represent the dielectric constant of the air layer, the near-zero dielectric constant film layer, and the metal substrate layer; d represents the thickness of the near-zero dielectric constant film layer deposited on the metal substrate layer; represents the wave vector of the air layer; k0 represents the wave vector of the near-zero permittivity thin film layer; k1 represents the wave vector of the metal substrate layer; i represents an imaginary number; c represents the speed of light.

[0078] In the embodiments of the present application, =1, =0.1+0.1i, According to the Drude model, it is expressed as:

[0079] ;

[0080] wherein, ωp represents the plasma frequency, which is 1.366593×10 16 ; ν represents the collision frequency, which is 4.071504×10 13 .

[0081] Figure 3 b, 3c, and 3d respectively show the dispersion curves of the amplitude intensity of p-polarized light with NA, i.e. angle, for three thicknesses of the near-zero permittivity thin film layer, 0.05Ā, 0.008Ā, and 0.002Ā, respectively, showing the angle-dependent transfer function curves under the conditions of three different thicknesses of the near-zero permittivity thin film layer. The X-axis coordinate represents NA, the Y-axis coordinate represents the normalized wavelength, and the Z-axis coordinate represents the intensity. Ā represents the average wavelength of the laser light source 1. Figure 3 b, is the change of the amplitude intensity of p-polarized light with numerical aperture NA under the condition of a thicker near-zero permittivity thin film layer. Since the near-zero permittivity thin film layer is thicker, the excitation of the Berreman mode is not as obvious as that of the thin layer, resulting in little change in reflectivity within a wider NA range. Figure 3 c, is the change of the amplitude intensity of p-polarized light with numerical aperture NA under the condition of a medium-thickness near-zero permittivity thin film layer. Compared with 0.05Ā, the thin film of 0.008Ā can more effectively excite the Berreman mode, thereby showing more obvious changes in reflectivity at specific NA values. Figure 3 d, is the thinnest near-zero permittivity thin film layer, showing the strongest excitation effect of the Berreman mode. The response of the near-zero permittivity thin film layer to p-polarized light changes with the incident angle NA. The thickness of the near-zero permittivity thin film layer is one of the key parameters for regulating its optical properties, directly affecting the excitation of the Berreman mode and the shape of the optical transfer function. By adjusting the thickness of the near-zero permittivity thin film layer, the reflection, transmission, and absorption characteristics of light can be precisely controlled, and the technical scheme of real-time switching of normal-incidence low-pass noise reduction and oblique-incidence high-pass sharpening can be realized.

[0082] In the embodiment of the present application, indium tin oxide (ITO) material is selected as the near-zero dielectric constant film layer for simulation calculation. ITO belongs to transparent conductive oxide (TCO), and its optical properties are similar to those of metal, which can be characterized by the Drude model of doped semiconductors. In the embodiment of the present application, the dielectric constant expression of the near-zero dielectric constant film layer is:

[0083] ;

[0084] wherein, represents the high-frequency dielectric constant, which is 3.5; represents the free carrier damping coefficient, which is ; , represents the wave vector; c represents the speed of light.

[0085] As shown in Figure 4 a, the angle-reflection amplitude distribution curve of the ITO near-zero dielectric constant film layer with a thickness of 0.1 μm in the near-infrared wave band under the condition of an incident wavelength range of 1.15-1.19 μm, wherein the X-axis coordinate represents NA, the Y-axis coordinate represents the normalized wavelength, and the Z-axis coordinate represents the intensity. In the above wavelength range, the high-NA system shows a significant resonance phenomenon, i.e., the angle response characteristic. As shown in Figure 4 b, the image processing effects of sharpening and denoising under two different incident angle conditions. Under the condition of an incident wavelength of 1.17 µm, two numerical aperture NAs corresponding to the OTF are selected: normal incidence NA = 0 and oblique incidence NA = 0.91. The normal incidence condition is used for image denoising processing, and the corresponding simulation result is shown in Figure 4 b. As can be seen from the figure, the scatter noise in the processed image is effectively suppressed, and the image is smoother. The oblique incidence condition is used for image sharpening processing, and the corresponding simulation result is shown in Figure 4 b. As can be seen from the figure, the edges of the white strips in the processed image are clearer, and the details are enhanced. Therefore, Figure 4 it is verified that by adjusting the incident angle NA, the denoising (low-pass) and sharpening (high-pass) two image quality enhancement functions can be realized in the same optical structure, which embodies the multifunctionality and practicality of the angle-selective filtering module. The technical scheme provided in the embodiment of the present application shows significant effects in denoising and sharpening, the background noise is effectively suppressed, and the image edge details are enhanced.

[0086] The embodiment of the present application also provides a calculation processing method for image quality enhancement of airborne dynamic imaging, which comprises:

[0087] obtaining an initial image from an imaging object 3;

[0088] By changing the angle of the light beam incidence angle, the Berreman mode is excited, and the filtering characteristics of the Berreman mode-based optical transfer function are controlled to filter;

[0089] Output the filtered image.

[0090] By adjusting the light beam incidence angle, including:

[0091] The angle is a first angle range in a normal incidence state, and a low-pass filtering characteristic is generated by exciting the Berreman mode, which is used for image noise reduction processing.

[0092] The angle is a second angle range in an oblique incidence state, and a high-pass filtering characteristic is generated by exciting the Berreman mode, which is used for image sharpening processing.

[0093] Compared with the traditional method, the technical scheme provided by the embodiment of the present application has the following obvious advantages: by utilizing the angle selection characteristics of the ENZ material in the Berreman mode, only a single layer of near-zero dielectric constant film can realize two optical transfer functions of high pass and low pass in the same system, and the edge enhancement and noise removal functions are combined, which breaks through the limitation of the traditional nano-photonic structure that the function is single and multiple functions need multiple devices. The calculation processing method provided by the embodiment of the present application directly completes image processing in the optical domain, avoids the high delay and high energy consumption of traditional electronic calculation, and the optical simulation speed is significantly faster than electronic calculation, which can realize quasi-real-time processing in some application scenarios. Through modeling and simulation of actual ITO materials, the effectiveness and feasibility of the technical scheme of the embodiment of the present application in near-infrared imaging are verified, which has the advantages of simple structure, high integration, low energy consumption and strong adaptability, and provides a new scheme for high-speed optical processing in the fields of aerospace, autonomous driving and ocean engineering, and opens up a new direction for the development of optical simulation technology.

[0094] Finally, it should be noted that: the embodiments in the specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts of each embodiment can be referred to each other. For the system or device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the related parts can be referred to the method part.

[0095] The above embodiments are only used to illustrate the technical solutions of the present disclosure, but not limit them; although the present disclosure has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacements for some technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present disclosure.

Claims

1. A computational processing system for onboard dynamic imaging oriented image quality enhancement, characterized by, Including: A lighting module, a collimation module, a confocal module, a beam splitting module, an angle selection filtering module, and an imaging module; The lighting module is used to provide an illumination beam; The collimation module is used to expand the beam into a collimated beam; The confocal module is used to transmit the initial image of the imaging object to the angle selection filtering module; The beam splitting module is used to split the beam into a transmitted beam and a reflected beam; The angle selection filtering module is used to control the angle of the incident beam, and perform filtering using the Berreman mode, so as to achieve the function of image denoising or sharpening; The imaging module is used to receive the filtered image and convert the optical signal into an electrical signal; The initial image is transmitted to the angle selection filtering module through the confocal module, the angle selection filtering module selects the filtering method according to the angle of the incident beam, and after filtering, the imaging module receives the image with enhanced image quality; The angle of the incident beam includes: a first angle range and a second angle range; When the angle is within the first angle range, the Berreman mode is excited to exhibit low-pass filtering characteristics, so as to achieve denoising processing of the image; When the angle is within the second angle range, the Berreman mode is excited to exhibit high-pass filtering characteristics, so as to achieve sharpening processing of the image; The incident angle corresponding to the first angle range is smaller than the incident angle corresponding to the second angle range; The angle selection filtering module is a double-layer thin film structure, including a near-zero dielectric constant thin film layer and an opaque metal base layer, and the near-zero dielectric constant thin film layer is arranged on the incident beam side of the metal base layer.

2. The computing processing system of claim 1, wherein, When the angle is in the normal incidence state, the condition satisfied by the first angle range is: NA = 0; When the angle is in the oblique incidence state, the condition satisfied by the second angle range is: 0.22 < NA ≤ 0.91; where, NA represents the numerical aperture.

3. The computing processing system of claim 1, wherein, The condition satisfied by the metal base layer is: the metal base layer is a metal material with the real part of the dielectric constant less than -20, and the thickness of the metal base layer is greater than 500 nm.

4. The computing processing system of claim 1, wherein, The condition satisfied by the near-zero dielectric constant thin film layer is: the thickness satisfies 0.002 - 0.05ā; where, ā represents the average wavelength of the lighting module.

5. The computing processing system of claim 1, wherein, To control the angle of the incident beam, including: changing the incident angle of the beam by physically moving or rotating the angle selection filtering module.

6. The computing processing system of claim 1, wherein, The imaging module includes an imaging lens and a detector, and the detector is a high-speed CMOS camera or an InGaAs array.

7. A computing processing method for on-board dynamic imaging oriented image quality enhancement based on the computing processing system of any one of claims 1 to 6, characterized in that, The calculation and processing method includes: Obtaining the initial image from the imaging object; By changing the angle of the incident beam, exciting the Berreman mode, and controlling the filtering characteristics of the optical transfer function based on the Berreman mode for filtering; ​ 8. The computing processing method of claim 7, wherein, ​ ​ ​

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