Light modulation unit, image processing apparatus, and vehicle

Abstract

The invention discloses a light modulation unit, an image processing device and a vehicle, and belongs to the technical field of image processing. The light modulation unit comprises a first convex lens, a second convex lens and a metasurface element, the first convex lens is used for converting a space signal of the incident polarized light carrying the image information into a frequency signal; the metasurface element is located on a focal plane between the first convex lens and the second convex lens and is used for performing phase modulation on the incident polarized light based on the polarization direction of the incident polarized light and preset phase distribution in the metasurface element; and the second convex lens is used for converting the frequency signal of the incident polarized light after phase modulation into a space signal. According to the light modulation unit provided by the invention, sub-wavelength level regulation and control of incident polarized light can be realized, high resolution in an image processing process can be ensured, the integrity of image detail information is ensured, and the reliability of image processing is improved.

Description

Technical Field

[0001] This application relates to the field of image processing technology, and in particular to an optical modulation unit, an image processing device, and a vehicle. Background Technology

[0002] Image processing technology is one of the core supporting technologies for the transformation of modern transportation from manual to intelligent and efficient operation, providing an indispensable technical foundation for autonomous driving, intelligent traffic management, and travel safety. For example, image edge enhancement technology can accurately enhance the contour boundaries of key targets such as vehicles, lane lines, traffic signs, and pedestrians, providing clear feature basis for subsequent accurate recognition and decision-making.

[0003] In related technologies, common image processing techniques are usually divided into two categories: algorithms and optics. Algorithm-based image processing techniques usually rely on the use of integrated circuits for digital domain calculations, while optical image processing techniques rely on various types of optical modulation units, such as spiral phase plates and liquid crystal spatial light modulators, to perform parallel modulation of the light field carrying image information.

[0004] However, among the methods mentioned above, algorithmic image processing techniques have high computation time and energy consumption, which significantly increases the hardware cost of vehicles, while optical image processing techniques have the problem of large hardware structure space occupation, affecting integrated applications. Summary of the Invention

[0005] This application provides an optical modulation unit, an image processing apparatus, and a vehicle to solve the technical problems existing in the related art. Specifically, it includes the following technical solutions.

[0006] In a first aspect, this application provides an optical modulation unit, the optical modulation unit comprising a first convex lens and a second convex lens with equal focal lengths, and a polarization-tunable metasurface element; the first convex lens is used to convert the spatial signal of incident polarized light carrying image information into a frequency signal; the metasurface element is located on the focal plane between the first convex lens and the second convex lens, and is used to perform phase modulation on the incident polarized light based on the polarization direction of the incident polarized light and a preset phase distribution in the metasurface element; the second convex lens is used to convert the frequency signal of the phase-modulated incident polarized light into a spatial signal.

[0007] In some possible implementations, the metasurface element includes a substrate and a plurality of nanoscale optical modulation units; the substrate is parallel to the focal plane; the plurality of nanoscale optical modulation units are located on a first surface of the substrate facing the first convex lens, and each of the plurality of nanoscale optical modulation units includes a first axis parallel to a first direction on the plane of the substrate and a second axis parallel to a second direction on the plane of the substrate, the first axis and the second axis being perpendicular to each other and having different lengths.

[0008] In some possible implementations, the phase distribution includes a first phase distribution corresponding to the first axis; the metasurface is also used to phase modulate the incident polarized light according to the first phase distribution when the polarization direction of the incident polarized light is parallel to the first axis.

[0009] In some possible implementations, the image information includes first edge information perpendicular to the first axis, the incident polarized light includes a first edge light signal carrying the first edge information, and the first phase distribution includes a first edge enhancement phase for enhancing the first edge light signal.

[0010] In some possible implementations, the phase distribution includes a second phase distribution corresponding to the second axis; the metasurface is also used to phase modulate the incident polarized light according to the second phase distribution when the polarization direction of the incident polarized light is parallel to the second axis.

[0011] In some possible implementations, the image information includes second edge information perpendicular to the second axis, the incident polarized light includes a second edge light signal carrying the second edge information, and the second phase distribution includes a second edge enhancement phase for enhancing the second edge light signal.

[0012] In some possible implementations, the substrate includes a first surface facing the first convex lens; the plurality of nanoscale optical modulation units are periodically spaced on the first surface.

[0013] In some possible implementations, the plurality of nanoscale optical modulation units have the same height.

[0014] Secondly, this application provides an image processing apparatus, which includes the optical modulation unit described in the first aspect of this application or any possible embodiment of the first aspect.

[0015] Thirdly, this application provides a vehicle that includes the image processing apparatus as described in the second aspect of claim.

[0016] The beneficial effects of the technical solution provided in this application include at least the following:

[0017] The technical solution provided in this application, on the one hand, employs a combination of Fourier optical architecture and metasurface elements, enabling parallel processing of incident polarized light carrying image information. This helps reduce time and energy consumption costs during image processing, improving efficiency. On the other hand, by modulating the phase of incident polarized light based on polarization direction and a preset phase distribution, the metasurface can differentially modulate the incident polarized light under different polarization directions through different phase distributions integrated within it. This achieves functional integration while avoiding hardware redundancy, making it suitable for miniaturization and integration scenarios. Furthermore, since the metasurface can achieve subwavelength-level control of incident polarized light, it helps ensure high resolution during image processing, maintains the integrity of image detail information, and improves the reliability of image processing. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the structure of the optical modulation unit provided in the embodiments of this application;

[0020] Figure 2 This is a schematic diagram of the structure of the metasurface element provided in the embodiments of this application;

[0021] Figure 3 This is a schematic diagram of the normalized intensity of emitted polarized light and its image after imaging, provided in an embodiment of this application.

[0022] Figure 4 This is a schematic diagram of the normalized intensity of the emitted polarized light and the image after imaging, provided in another embodiment of this application;

[0023] Figure 5 This is a schematic diagram of the normalized intensity of emitted polarized light and the image after imaging, provided in another embodiment of this application.

[0024] The reference numerals in the attached figures are as follows:

[0025] 10. First convex lens; 20. Second convex lens; 30. Metasurface element;

[0026] 31. Substrate; 32. Multiple nanoscale optical modulation units;

[0027] 32a, First axis; 32b, Second axis; X, First direction; Y, Second direction. Detailed Implementation

[0028] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0029] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0030] Figure 1 This is a schematic diagram of the structure of the optical modulation unit provided in an embodiment of this application. (Reference) Figure 1 The optical modulation unit provided in this application embodiment includes a first convex lens 10 and a second convex lens 20 with equal focal lengths, and a polarization-tunable metasurface element 30. The focal length indicates the distance from the optical center of the first convex lens 10 to a bright spot formed by the convergence of all parallel light rays after refraction by the convex lens, or the convergence of their backward extensions.

[0031] The first convex lens 10 can be used to convert the spatial signal of incident polarized light carrying image information into a frequency signal.

[0032] For example, the first convex lens 10 is any type of convex lens that converges incident polarized light, such as a biconvex lens, plano-convex lens, concave-convex lens, or aspherical convex lens. Image information includes, but is not limited to, information such as color, brightness, texture, and shape. Incident polarized light is used to indicate light incident on the light modulation unit with a specific vibration direction, such as linearly polarized light whose vibration direction is always along a straight line. Incident polarized light carrying image information is, for example, light reflected from an object after being illuminated by a source of incident polarized light and then passing through the first convex lens 10. In some embodiments, the source of the incident polarized light is, for example, parallel light.

[0033] The spatial signal of incident polarized light indicates the spatial distribution of image information, such as color, brightness, texture, and shape—that is, where is bright, where is dark, and what color is in certain areas. The frequency signal of incident polarized light indicates the rate of change of the spatial signal, also known as the spatial frequency. The faster the spatial signal changes, the higher the corresponding spatial frequency; conversely, the slower the spatial signal changes, the lower the corresponding spatial frequency. There is a correspondence between the frequency signal of incident polarized light and the spatial signal / image information. For example, if the image information includes stripe information, the spatial signal of the incident polarized light will show changes in brightness, color, and texture at the locations corresponding to the stripes, resulting in a higher spatial frequency at those locations.

[0034] When the object plane containing the image information coincides with the focal plane of the first convex lens 10, the incident polarized light originating from the object plane carries a spatial signal corresponding to the image information. After passing through the first convex lens 10, the lens 10 rearranges the incident polarized light rays through refraction, guiding rays with different spatial frequencies from the spatial signal carried by the incident polarized light rays to different positions on the other focal plane of the first convex lens 10, forming a distribution of different spatial frequencies on the focal plane, i.e., the frequency signal of the incident polarized light. The object plane indicates the plane containing the image information, and the focal plane indicates parallel light rays parallel to the principal optical axis of the first convex lens 10. After refraction by the convex lens, all rays eventually converge, or their backward extensions converge to form a plane that is parallel to the plane containing the first convex lens 10 and at a distance equal to the focal length of the first convex lens 10.

[0035] The metasurface element 30 is located on the focal plane between the first convex lens 10 and the second convex lens 20, and is used to perform phase modulation on the incident polarized light based on the polarization direction of the incident polarized light and the preset phase distribution in the metasurface element 30.

[0036] For example, the metasurface element 30 is used to indicate an ultrathin optical device composed of nanoscale optical modulation units, such as nanopillars and nanopores, arranged in a specific pattern. The thickness is typically only a few hundred nanometers to a few micrometers, and it can be used, but is not limited to, modulating the phase of incident polarized light. The preset phase distribution in the metasurface indicates the arrangement of the nanoscale optical modulation units on the metasurface after designing the phase change of the incident polarized light according to the expected image processing effects, such as edge enhancement, focusing, and filtering. The polarization direction is an inherent property of incident polarized light and is used to describe the vibration direction of the incident polarized light.

[0037] As described above, the incident polarized light is, for example, linearly polarized light whose vibration direction is always along a straight line. In this case, phase modulation of the incident polarized light is performed based on the polarization direction of the incident polarized light and the preset phase distribution in the metasurface element 30 for indication. After the incident polarized light reaches the metasurface element 30, the metasurface element 30 can perform different phase modulations on the incident polarized light based on its own preset phase distribution, depending on the different vibration directions of the incident polarized light. In other words, the metasurface element 30 has polarization sensitivity, that is, the metasurface element 30 can identify the vibration direction of the incident polarized light and perform differentiated phase modulation on the incident polarized light according to the different vibration directions of the incident polarized light.

[0038] Therefore, the nanoscale optical modulation unit in the metasurface element 30 is anisotropic, that is, the physical and optical properties of the nanoscale optical modulation unit are different in different directions.

[0039] Figure 2 This is a schematic diagram of the structure of the metasurface element provided in an embodiment of this application. See also... Figure 2 The metasurface element provided in this application embodiment includes a substrate 31 and a plurality of nanoscale optical modulation units 32.

[0040] The substrate 31 is parallel to the focal plane, specifically the focal plane between the first convex lens 10 and the second convex lens 20. Multiple nanoscale optical modulation units 32 are located on the first surface of the substrate 31 facing the first convex lens 10. Each nanoscale optical modulation unit 32 includes a first axis 32a parallel to a first direction X on the plane of the substrate 31 and a second axis parallel to a second direction Y on the plane of the substrate 31. The first axis 32a and the second axis 32b are perpendicular to each other and have different lengths.

[0041] Considering that in practical applications, given a fixed material for the nanoscale optical modulation unit, the phase change of the incident polarized light by different nanoscale optical modulation units is typically influenced by factors such as the height of the nanoscale optical modulation unit, the length of the first axis 32a, and the length of the second axis 32b. Therefore, the phase distribution of the metasurface can be obtained by differentiating the height, length of the first axis 32a, and length of the second axis 32b of the multiple nanoscale optical modulation units 32 in the metasurface element 30.

[0042] Furthermore, considering the significant technological challenges in adjusting the height of nanoscale optical modulation units in practical applications, and the substantial impact of this height adjustment on the stability of the mechanical and optical properties of the metasurface element 30, in some embodiments, multiple nanoscale optical modulation units 32 are designed with identical heights to ensure the consistency and reliability of the phase modulation of incident polarized light by the metasurface element 30. In this case, the phase distribution of the metasurface element 30 can be designed by adjusting the lengths of the first axis 32a and the second axis 32b of the multiple nanoscale optical modulation units 32.

[0043] For example, when the incident polarized light is near-infrared light with a wavelength fluctuating around 800 nm, the height of the plurality of nanoscale optical modulation units 32 is 350 nm-450 nm, such as 350, 360, 370, 380, 390, 400, 410, 420, 430, 440, 450 nm, etc.; the length of the first axis 32a of any nanoscale optical modulation unit among the plurality of nanoscale optical modulation units 32 is 40 nm-140 nm, such as 40 nm, 50 nm, 60 nm. The length of the second axis 32b of any nanoscale optical modulation unit among the multiple nanoscale optical modulation units 32 is 40nm-140nm, for example, 40nm, 50nm, 60nm, 70nm, 80nm, 90nm, 100nm, 110nm, 120, 130, 140nm, or other values ​​within the above range;

[0044] To ensure the controllability of the phase modulation function of the metasurface element 30 for incident polarized light, in some embodiments, when the substrate 31 includes a first surface facing the first convex lens 10, a plurality of nanoscale optical modulation units 32 are periodically spaced on the first surface. For example, when the incident polarized light is near-infrared light with a wavelength fluctuating around 800 nm, the distance between the center points of any two adjacent nanoscale optical modulation units 32 in the first direction X and the second direction Y is 350 nm-370 nm, such as 350, 355, 360, 365, 370 nm, or other values ​​within the above range. This application does not impose any limitations in this regard.

[0045] It should be noted that, Figure 2 The shape of the nanoscale optical modulation unit shown is only illustrative and not limiting. For example, the nanoscale optical modulation unit can also be any shape with a first axis 32a and a second axis 32b that are perpendicular to each other and have different lengths, such as a rectangle, parallelogram, or rhombus, parallel to the substrate 31. This application does not impose any limitations in this regard.

[0046] As mentioned above, when the nanoscale optical modulation unit in the metasurface element 30 is anisotropic, the metasurface element 30 can exhibit polarization sensitivity and perform differentiated phase modulation on the incident polarized light according to the different vibration directions of the incident polarized light.

[0047] For example, if the phase distribution of the metasurface element 30 includes a first phase distribution corresponding to the first axis 32a, the metasurface can be used to phase modulate the incident polarized light according to the first phase distribution when the polarization direction of the incident polarized light is parallel to the first axis 32a. The correspondence between the first axis 32a and the first phase distribution is used to indicate the phase distribution designed for the desired image processing effect of incident polarized light whose vibration direction is parallel to the first axis 32a.

[0048] In some embodiments, the image information includes first edge information perpendicular to the first axis 32a, the incident polarized light includes a first edge light signal carrying the first edge information, and the first phase distribution includes a first edge enhancement phase for enhancing the first edge light signal.

[0049] When the image information includes first edge information perpendicular to the first axis 32a, the frequency signal obtained by the incident polarized light carrying the image information after passing through the first convex lens 10 includes a high-frequency signal corresponding to the first edge information, i.e., a frequency signal with a higher spatial frequency. In this case, the first edge enhancement phase is, for example, a phase distribution obtained by superimposing a Hilbert phase and a spiral phase matched with the first edge information. Hilbert can be used, but is not limited to, to apply a fixed phase delay, such as a phase delay of π / 2, to the high-frequency signal corresponding to the first edge information. The spiral phase matched with the first edge information can be used, but is not limited to, to gain the high-frequency signal through electromagnetic resonance using a nanoscale optical modulation unit. The form of the first edge enhancement phase can be, for example, referred to the following formula (1):

[0050]

[0051] in, For the first edge enhancement phase, angle() means extracting the angular component of the expression in parentheses, where i is the imaginary unit. x represents the coordinates of the nanoscale optical modulation unit on the first surface of the metasurface element 30 along the first direction, and y represents the coordinates of the nanoscale optical modulation unit on the first surface of the metasurface element 30 along the second direction.

[0052] For example, if the phase distribution of the metasurface element 30 includes a second phase distribution corresponding to the second axis 32b, the metasurface can be used to phase modulate the incident polarized light according to the second phase distribution when the polarization direction of the incident polarized light is parallel to the second axis 32b. The correspondence between the second axis 32b and the second phase distribution is used to indicate the phase distribution designed for the desired image processing effect of incident polarized light whose vibration direction is parallel to the second axis 32b.

[0053] In some embodiments, the image information includes second edge information perpendicular to the second axis 32b, the incident polarized light includes a second edge light signal carrying the second edge information, and the second phase distribution includes a second edge enhancement phase for enhancing the second edge light signal.

[0054] When the image information includes second edge information perpendicular to the second axis, the frequency signal obtained after the incident polarized light carrying the image information passes through the first convex lens 10 includes a high-frequency signal corresponding to the second edge information. In this case, the second edge enhancement phase is, for example, a phase distribution obtained by superimposing a Hilbert phase and a spiral phase matched with the second edge information. The Hilbert phase can be used, but is not limited to, to apply a fixed phase delay, such as a phase delay of π / 2, to the high-frequency signal corresponding to the second edge information. The spiral phase matched with the second edge information can be used, but is not limited to, to gain the high-frequency signal through electromagnetic resonance via a nanoscale optical modulation unit. The form of the second edge enhancement phase can be, for example, referred to the following formula (2):

[0055]

[0056] in, To enhance the phase at the second edge, angle() indicates the extraction of the angular component of the expression in parentheses, where i is the imaginary unit. x represents the coordinates of the nanoscale optical modulation unit on the first surface of the metasurface element 30 along the first direction, and y represents the coordinates of the nanoscale optical modulation unit on the first surface of the metasurface element 30 along the second direction.

[0057] In some embodiments, the method for fabricating the metasurface element 30 provided in this application includes, for example: determining a desired image processing effect; determining the phase distribution of the metasurface element 30 based on the desired image processing effect; querying a structural parameter database of nanoscale optical modulation elements based on the phase distribution; determining the structural parameter distribution of multiple nanoscale optical modulation elements based on the structural parameter database of nanoscale optical modulation elements; and fabricating the metasurface element 30 based on the structural parameter distribution of the nanoscale optical modulation elements. The structural parameter database of nanoscale optical modulation elements is used to indicate the mapping relationship between the phase distribution of the metasurface and the structural parameter distribution of multiple nanoscale optical modulation elements. For example, when the heights of multiple nanoscale optical modulation elements are consistent, the lengths of the first axis 32a and the second axis 32b of the nanoscale optical modulation units at different positions in the multiple nanoscale optical modulation elements correspond to a specific phase distribution in the phase distribution of the metasurface element 30.

[0058] The second convex lens 20 is used to convert the frequency signal of the phase-modulated incident polarized light into a spatial signal.

[0059] For example, the frequency signal of the phase-modulated incident polarized light is converted into a spatial signal to indicate the spatial signal exhibited by the phase-modulated incident polarized light after passing through the second convex lens 20 and the outgoing polarized light formed on the focal plane of the second convex lens 20, such as the color, brightness, texture, etc. of the image at different positions.

[0060] The algebraic relationship between the outgoing polarized light and the incident polarized light after passing through the second convex lens 20 can be found in the following formula (3):

[0061] E out =IFT{φ 1 / 2 ·FT[E in ]} (3)

[0062] Among them, E out For the emitted polarized light, φ 1 / 2 For the first edge-enhanced phase or the second edge-enhanced phase, or other phase distributions integrated in the metasurface element 30, E in For incident polarized light, FT stands for Fourier transform, and IFT stands for inverse Fourier transform.

[0063] Figure 3 This is a schematic diagram of the normalized intensity of emitted polarized light and its image after imaging, provided in an embodiment of this application.

[0064] Figure 4 This is a schematic diagram of the normalized intensity of the emitted polarized light and the image after imaging, provided in another embodiment of this application.

[0065] Figure 5This is a schematic diagram of the normalized intensity of emitted polarized light and the image after imaging, provided in another embodiment of this application.

[0066] like Figure 3 As shown, Figure 3 The three rows of images shown, from top to bottom, in the first row, from left to right, are: the image formed by incident polarized light carrying lane line information when the image information is the barrier arm in the first state; the curve of the intensity of the incident polarized light carrying lane line information after normalization processing as a function of position, with the horizontal axis x representing position (cm) and the vertical axis y representing light intensity; the image formed by outgoing polarized light carrying lane line information; and the curve of the intensity of outgoing polarized light carrying lane line information after normalization processing as a function of position, with the horizontal axis x representing position (cm) and the vertical axis y representing light intensity.

[0067] Figure 3 The three rows of images shown, from left to right in the second row from the top, are: the image formed by the incident polarized light carrying the barrier gate information when the image information is the barrier gate information in the first state; the curve of the intensity of the incident polarized light carrying the barrier gate information after normalization processing as a function of position, with the horizontal axis x representing position (cm) and the vertical axis y representing light intensity; the image formed by the outgoing polarized light carrying the barrier gate information; and the curve of the intensity of the outgoing polarized light carrying the barrier gate information after normalization processing as a function of position, with the horizontal axis x representing position (cm) and the vertical axis y representing light intensity.

[0068] Figure 3 The three rows of images shown, from left to right in the third row from top to bottom, are: the image formed by the incident polarized light carrying the barrier gate information when the image information is the barrier gate information in the second state; the curve of the intensity of the incident polarized light carrying the barrier gate information after normalization processing as a function of position, with the horizontal axis x representing position (cm) and the vertical axis y representing light intensity; the image formed by the outgoing polarized light carrying the barrier gate information; and the curve of the intensity of the outgoing polarized light carrying the barrier gate information after normalization processing as a function of position, with the horizontal axis x representing position (cm) and the vertical axis y representing light intensity.

[0069] from Figure 3 It can be seen that the optical modulation unit provided in this application embodiment has a good recognition effect for at least two edge information when the image information includes edge information in at least two different directions. In other words, the optical modulation unit provided in this application embodiment can achieve a tunable one-dimensional edge detection effect according to the polarization direction of the incident polarized light.

[0070] like Figure 4 As shown, Figure 4The three rows of images shown, from top to bottom, in the first row, from left to right, are: the image formed by the incident polarized light carrying the image information (the image of the letter E) with a wavelength of 790nm; the normalized curve of the intensity of the incident polarized light carrying the image information as a function of position (x-axis represents position in cm, y-axis represents intensity); the image formed by the outgoing polarized light carrying the image information; and the normalized curve of the intensity of the outgoing polarized light carrying the image information as a function of position (x-axis represents position in cm, y-axis represents intensity).

[0071] Figure 4 The three rows of images shown, from left to right in the second row from the top, are: the image formed by the incident polarized light carrying the image information when the image information is the letter E and the wavelength of the incident polarized light is 800nm; the normalized curve of the intensity of the incident polarized light carrying the image information as a function of position, with the horizontal axis x representing position (cm) and the vertical axis y representing light intensity; the image formed by the outgoing polarized light carrying the image information; and the normalized curve of the intensity of the outgoing polarized light carrying the image information as a function of position, with the horizontal axis x representing position (cm) and the vertical axis y representing light intensity.

[0072] Figure 4 The three rows of images shown, from left to right in the third row from top to bottom, are: the image formed by the incident polarized light carrying the image information when the image information is the letter E and the wavelength of the incident polarized light is 790nm; the normalized curve of the intensity of the incident polarized light carrying the image information as a function of position, with the horizontal axis x representing position (cm) and the vertical axis y representing light intensity; the image formed by the outgoing polarized light carrying the image information; and the normalized curve of the intensity of the outgoing polarized light carrying the image information as a function of position, with the horizontal axis x representing position (cm) and the vertical axis y representing light intensity.

[0073] from Figure 4 It can be seen that the optical modulation unit provided in this application embodiment has a good filtering effect when the wavelength fluctuation range of the incident polarized light is 790nm to 810nm. In other words, the working band of the optical modulation unit provided in this application embodiment is at least 20nm.

[0074] like Figure 5 As shown, Figure 5The three rows of images shown, from top to bottom, in the first row, from left to right, are: the image formed by the incident polarized light carrying the image information when the image information is the letter E and the incident angle of the polarized light is 0°; the curve of the normalized light intensity of the incident polarized light carrying the image information as a function of position, with the horizontal axis x representing position (cm) and the vertical axis y representing light intensity; the image formed by the outgoing polarized light carrying the image information; and the curve of the normalized light intensity of the outgoing polarized light carrying the image information as a function of position, with the horizontal axis x representing position (cm) and the vertical axis y representing light intensity.

[0075] Figure 5 In the three rows of images shown, the second row from the top, from left to right, represents: when the image information is the letter E and the incident angle of the polarized light is 1°; the normalized curve of the intensity of the incident polarized light carrying the image information as a function of position, with the horizontal axis x representing position (cm) and the vertical axis y representing light intensity; the image formed by the outgoing polarized light carrying the image information; and the normalized curve of the intensity of the outgoing polarized light carrying the image information as a function of position, with the horizontal axis x representing position (cm) and the vertical axis y representing light intensity.

[0076] Figure 5 The three rows of images shown, from left to right in the third row from top to bottom, are as follows: when the image information is the letter E and the incident angle of the polarized light is 2°; the curve of the intensity of the incident polarized light carrying the image information after normalization processing as a function of position, with the horizontal axis x representing position (cm) and the vertical axis y representing light intensity; the image formed by the outgoing polarized light carrying the image information; and the curve of the intensity of the outgoing polarized light carrying the image information after normalization processing as a function of position, with the horizontal axis x representing position (cm) and the vertical axis y representing light intensity.

[0077] from Figure 5 It can be seen that the optical modulation unit provided in this application embodiment has good adaptability to the angular deviation of the incident polarized light.

[0078] The technical solution provided in this application, on the one hand, employs a combination of Fourier optical architecture and metasurface elements, enabling parallel processing of incident polarized light carrying image information. This helps reduce time and energy consumption costs during image processing, improving efficiency. On the other hand, by modulating the phase of incident polarized light based on polarization direction and a preset phase distribution, the metasurface can differentially modulate the incident polarized light under different polarization directions through different phase distributions integrated within it. This achieves functional integration while avoiding hardware redundancy, making it suitable for miniaturization and integration scenarios. Furthermore, since the metasurface can achieve subwavelength-level control of incident polarized light, it helps ensure high resolution during image processing, maintains the integrity of image detail information, and improves the reliability of image processing.

[0079] In other possible embodiments, this application also provides an image processing apparatus, which includes the above-described components. Figure 1 The optical modulation unit described in several embodiments thereof.

[0080] In some other possible implementations, this application also provides a vehicle that includes the image processing apparatus described above.

[0081] It should also be noted that the terms "first," "second," etc. (if applicable) in the specification and claims of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0082] The term "and / or" in the embodiments of this application is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone.

[0083] The above description is only for the purpose of enabling those skilled in the art to understand the technical solution of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the principles of this application shall be included within the scope of protection of this application.

Claims

1. An optical modulation unit, characterized in that, The optical modulation unit includes a first convex lens (10) and a second convex lens (20) with equal focal lengths, and a polarization-tunable metasurface element (30). The first convex lens (10) is used to convert the spatial signal of the incident polarized light carrying image information into a frequency signal; The metasurface element (30) is located on the focal plane between the first convex lens (10) and the second convex lens (20), and is used to perform phase modulation on the incident polarized light based on the polarization direction of the incident polarized light and the preset phase distribution in the metasurface element (30); The second convex lens (20) is used to convert the frequency signal of the phase-modulated incident polarized light into a spatial signal.

2. The optical modulation unit according to claim 1, characterized in that, The metasurface element (30) includes a substrate (31) and multiple nanoscale optical modulation units (32); The substrate (31) is parallel to the focal plane; The plurality of nanoscale optical modulation units (32) are located on the first surface of the substrate (31) facing the first convex lens (10). Each of the plurality of nanoscale optical modulation units (32) includes a first axis (32a) parallel to a first direction (X) on the plane where the substrate (31) is located and a second axis (32b) parallel to a second direction (Y) on the plane where the substrate (31) is located. The first axis (32a) and the second axis (32b) are perpendicular to each other and the first axis (32a) and the second axis (32b) have different lengths.

3. The optical modulation unit according to claim 2, characterized in that, The phase distribution includes a first phase distribution corresponding to the first axis (32a); The metasurface is also used to perform phase modulation on the incident polarized light according to the first phase distribution when the polarization direction of the incident polarized light is parallel to the first axis (32a).

4. The optical modulation unit according to claim 3, characterized in that, The image information includes first edge information perpendicular to the first axis (32a), and the incident polarized light includes a first edge light signal carrying the first edge information; The first phase distribution includes a first edge enhancement phase for enhancing the first edge optical signal.

5. The optical modulation unit according to claim 2, characterized in that, The phase distribution includes a second phase distribution corresponding to the second axis (32b); The metasurface is also used to perform phase modulation on the incident polarized light according to the second phase distribution when the polarization direction of the incident polarized light is parallel to the second axis (32b).

6. The optical modulation unit according to claim 5, characterized in that, The image information includes second edge information perpendicular to the second axis (32b), and the incident polarized light includes a second edge light signal carrying the second edge information; The second phase distribution includes a second edge enhancement phase for enhancing the second edge optical signal.

7. The optical modulation unit according to any one of claims 2-6, characterized in that, The substrate (31) includes a first surface facing the first convex lens (10); The plurality of nanoscale optical modulation units (32) are periodically spaced on the first surface.

8. The optical modulation unit according to any one of claims 2-6, characterized in that, The multiple nanoscale optical modulation units (32) have the same height.

9. An image processing apparatus, characterized in that, The image processing apparatus includes the optical modulation unit according to any one of claims 1-8.

10. A vehicle, characterized in that, The vehicle includes the image processing apparatus of claim 9.

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