Image processing method and device for double-layer metasurface, electronic equipment and system

Abstract

The invention relates to an image processing method, device, equipment and system for a double-layer metasurface. The method comprises the following steps: during decryption, using a bottom-layer metasurface unit in a double-layer metasurface and adopting electromagnetic waves of a first frequency to respectively restore a plurality of first password book images acquired from different terminals to obtain a plurality of second password book images; using the bottom layer metasurface unit and the covering layer metasurface unit in the double-layer metasurface and adopting electromagnetic waves of a second frequency to restore the obtained first key image to obtain a second key image; and determining a second original image according to the plurality of second password book images and the second key image. According to the technical scheme provided by the invention, the second password book image and the second key image are respectively determined by adopting two different frequencies. The cracking difficulty is increased, and the safety is improved.

Description

Technical Field

[0001] The present disclosure relates to the field of image processing technology, and in particular to a method, device, electronic device, and system for processing an image of a metasurface. Background Art

[0002] Metasurfaces are composed of subwavelength unit cells. Through microstructural design, they can flexibly control the phase, amplitude, and polarization characteristics of electromagnetic waves, enabling multi-dimensional parameter encryption. Existing metasurface encryption technologies use electromagnetic waves of a single frequency to encrypt images. This reliance on a single frequency makes them vulnerable to cracking and poses a low security risk. Summary of the Invention

[0003] In order to overcome the problems existing in the related art, the present disclosure provides an image processing method, device, electronic device and system for a double-layer metasurface to solve the above-mentioned problems in the related art.

[0004] According to a first aspect of an embodiment of the present disclosure, there is provided an image processing method for a double-layer metasurface, comprising:

[0005] During decryption, the bottom metasurface unit in the double-layer metasurface is used to restore multiple first codebook images obtained from different terminals using electromagnetic waves of a first frequency to obtain multiple second codebook images.

[0006] Using the bottom metasurface unit and the cover metasurface unit in the double-layer metasurface, and using electromagnetic waves of a second frequency, the obtained first key image is restored to obtain a second key image;

[0007] A second original image is determined based on the plurality of second codebook images and the second key image.

[0008] In a second aspect, the present application proposes an image processing method for a double-layer metasurface, comprising:

[0009] Before encryption, a first original image and a preset first auxiliary encrypted and decrypted image are obtained;

[0010] Determine a first key image according to the first original image and the preset first auxiliary encryption and decryption image;

[0011] During encryption, a plurality of first codebook images are determined according to the first key image and the preset first auxiliary encryption and decryption image;

[0012] The plurality of first codebook images are distributed and stored in a plurality of terminals, so that during decryption, the plurality of first codebook images obtained from different terminals are restored separately using a bottom metasurface unit in the double-layer metasurface and electromagnetic waves of a first frequency to obtain a plurality of second codebook images;

[0013] Using the bottom metasurface unit and the cover metasurface unit in the double-layer metasurface, and using electromagnetic waves of a second frequency, the obtained first key image is restored to obtain a second key image;

[0014] A second original image is determined based on the plurality of second codebook images and the second key image.

[0015] In a third aspect, an image processing device of a double-layer metasurface includes:

[0016] A first processing module is configured to, during decryption, utilize a bottom metasurface unit in the double-layer metasurface and electromagnetic waves of a first frequency to perform restoration processing on a plurality of first codebook images acquired from different terminals, thereby obtaining a plurality of second codebook images;

[0017] a second processing module, configured to utilize the bottom metasurface unit and the cover metasurface unit in the double-layer metasurface and electromagnetic waves of a second frequency to perform a restoration process on the acquired first key image to obtain a second key image;

[0018] The third processing module is configured to determine a second original image according to the plurality of second codebook images and the second key image.

[0019] In a fourth aspect, the present application also proposes an electronic device comprising a memory, a processor, and a computer program stored in the memory and runnable on the processor, wherein when the processor executes the computer program, the image processing method of the double-layer metasurface as described above is implemented.

[0020] In a fifth aspect, the present application also proposes a system comprising the above-mentioned electronic device, and further comprising a double-layer metasurface and an electromagnetic wave generating device respectively connected to the electronic device;

[0021] The electromagnetic wave generating device is used to generate electromagnetic waves under the control of the processor.

[0022] The technical solutions provided by the embodiments of the present disclosure may have the following beneficial effects:

[0023] The above-mentioned technical solution of this application utilizes a double-layer metasurface structure to realize dual-frequency control of electromagnetic waves, designs a dual verification algorithm based on XOR operation, combines the metasurface dual-frequency control with the XOR encryption algorithm, and completes the encrypted transmission of image information through holographic imaging, realizing a low-cost, high-security, and high-fault-tolerant encryption system.

[0024] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

[0026] Figure 1 is a flow chart showing an image decryption method of a double-layer metasurface according to an exemplary embodiment;

[0027] Figure 2 is a schematic diagram illustrating an image processing method of a double-layer metasurface according to an exemplary embodiment;

[0028] Figure 3 is a decryption flowchart according to an exemplary embodiment;

[0029] Figure 4 is a schematic diagram of a unit structure and S parameters of a double-layer metasurface according to an exemplary embodiment;

[0030] Figure 5 is a flow chart showing an image encryption method of a double-layer metasurface according to an exemplary embodiment;

[0031] Figure 6 is a flow chart showing another method for image encryption using a double-layer metasurface according to an exemplary embodiment;

[0032] Figure 7 is a comparison diagram of a simulation and an experiment of a decryption process according to an exemplary embodiment;

[0033] Figure 8 is a block diagram of an image processing device for a double-layer metasurface according to an exemplary embodiment;

[0034] Figure 9 is a block diagram of an electronic device according to an exemplary embodiment;

[0035] Figure 10 It is a block diagram of an image processing system of a double-layer metasurface according to an exemplary embodiment. DETAILED DESCRIPTION

[0036] Exemplary embodiments will be described in detail herein, with examples illustrated in the accompanying drawings. In the following description, when referring to the drawings, identical numerals in different figures represent identical or similar elements, unless otherwise indicated. The embodiments described in the following exemplary embodiments are not intended to represent all possible embodiments consistent with the present disclosure. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the present disclosure, as detailed in the appended claims.

[0037] It should be noted that all actions of acquiring signals, information or data in this application are carried out in compliance with the relevant data protection laws and policies of the country where they are located and with the authorization given by the owner of the corresponding device.

[0038] This application proposes a double-layer metasurface image processing method, see the attached Figure 1 , the method comprises the following steps:

[0039] In step S102, during decryption, the bottom metasurface unit in the double-layer metasurface is used to restore multiple first codebook images obtained from different terminals using electromagnetic waves of the first frequency to obtain multiple second codebook images.

[0040] In this embodiment, the electromagnetic wave generating device can be controlled to emit electromagnetic waves of the above-mentioned first frequency, and the electromagnetic wave generating device can also be controlled to emit electromagnetic waves of any frequency to the underlying metasurface. By controlling the underlying metasurface, the electromagnetic waves of the above-mentioned first frequency can be adjusted.

[0041] The bottom metasurface unit uses electromagnetic waves of the first frequency for processing, thereby converting the first codebook image into the second codebook image.

[0042] Obtaining multiple first codebook images from different terminals has the following effects:

[0043] Distributed storage reduces risk. Distributing the codebook image across different terminals prevents concentrated attacks that could occur on a single storage location. Even if a terminal is compromised, the attacker can only obtain a partial image and cannot directly restore the complete codebook, greatly reducing the risk of codebook leakage due to a single point of failure or attack.

[0044] Increased attack difficulty. Attackers need to attack multiple devices simultaneously to collect all images, which increases the complexity and cost of the attack. They need to possess attack techniques targeting different types of devices, coordinate multiple attacks, and collect and integrate information across multiple devices. In practice, this often faces many technical challenges and risks.

[0045] Strengthened authentication. If access to each first password book image requires specific authentication and authorization, then only authorized users who have successfully authenticated on multiple terminals can combine all images for restoration. This effectively establishes multiple authentication checkpoints, further strengthening control over password book access and preventing unauthorized access to the complete password information.

[0046] Improved data integrity. Images acquired by different terminals can verify and complement each other, helping to detect and correct potential data errors or corruption. If an image from one terminal fails, images from other terminals can serve as a reference, ensuring the final restored codebook has high data integrity and accuracy.

[0047] The first code book image is obtained by distributing it across different terminals. This significantly improves the security of the code book through distributed storage, increasing the difficulty of attacks, strengthening identity authentication, and improving data integrity, effectively protecting sensitive information from being easily obtained and cracked.

[0048] In step S104, the bottom metasurface unit and the cover metasurface unit in the double-layer metasurface are used to restore the acquired first key image using electromagnetic waves of a second frequency to obtain a second key image.

[0049] The first frequency and the second frequency are different.

[0050] In some embodiments, the first frequency is 8 GHz, and the second frequency is 5 GHz.

[0051] See attached Figure 2 , using the above-mentioned bottom layer metasurface unit and cover layer metasurface unit in the above-mentioned double-layer metasurface, and using 5GHz electromagnetic waves, the obtained first key image is restored to obtain the second key image.

[0052] The 8 GHz electromagnetic wave is used by the underlying metasurface unit to restore multiple first codebook images obtained from different terminals to obtain multiple second codebook images.

[0053] In step S106, a second original image is determined based on the plurality of second cipherbook images and the second key image.

[0054] In this embodiment, the second cipher book image and the second key image may be converted into digital matrices respectively, and the second original image may be obtained through conversion of the digital matrices.

[0055] The second original image is theoretically identical to the first original image before encryption by the encryption end.

[0056] See attached Figure 2-3 After performing an XOR operation on the digital matrix of the second codebook image and the digital matrix of the second key image, a second auxiliary reference image can be obtained, and then the final second original image can be obtained based on the second auxiliary reference image.

[0057] The technical solution of this application uses two different frequencies to determine the second codebook image and the second key image respectively. It has the following advantages:

[0058] Increased cracking difficulty. Information hiding is more complex. Using two frequencies means that the hacker must obtain and analyze two sets of image information at different frequencies. Not only must the hacker know that two frequencies of electromagnetic waves are used for imaging, but they must also analyze the image information corresponding to each frequency separately and the relationship between them. This is much more complex than cracking image information at a single frequency.

[0059] Frequency characteristics increase confusion. Electromagnetic waves of different frequencies produce different scattering and reflection characteristics when interacting with the metasurface. These characteristics are encoded in the image, giving the codebook and key images unique frequency-related features. Even if a cracker obtains the image, it is difficult to understand the meaning of these frequency-dependent characteristics, further increasing the difficulty of cracking.

[0060] Improved security. The two frequencies create a dual authentication mechanism. Only with both the correct codebook image (obtained by the first-frequency electromagnetic wave) and the key image (obtained by the second-frequency electromagnetic wave) can the original image be restored. This significantly improves security compared to single-image verification using a single frequency. Even if an attacker obtains the image from one frequency, they cannot restore the original image without the image from the other.

[0061] Reduces the risk of frequency cracking. In a single-frequency system, if a cracker learns and decrypts the frequency, the security of the entire system is completely compromised. Using two frequencies, even if information on one frequency is leaked, the other frequency still provides additional security, protecting the image information from easy restoration and adding a layer of defense to the system.

[0062] In step S106, see the attached Figure 2-3 , determining the original image according to the plurality of second cipherbook images and the second key image, specifically comprising the following steps:

[0063] A second codebook image matrix for each second codebook image and a second key image matrix for the second key image are determined.

[0064] An exclusive OR operation is performed on each of the second cipher book image matrices and the second key image matrix to obtain a second auxiliary encryption and decryption image matrix.

[0065] In this embodiment, see the attached Figure 2 In the figure, the second auxiliary encryption and decryption image shows the number 2.

[0066] Determine the second original image matrix according to the second key image matrix and the second auxiliary encryption / decryption image matrix.

[0067] In this embodiment, the second key image matrix and the second auxiliary encryption / decryption image matrix can be subjected to an exclusive OR operation to obtain the second original image matrix.

[0068] In a preferred embodiment, the content displayed in the second auxiliary encryption / decryption image is a number, and the number represents the number of rows or columns of the translation operation transformation of the second key image matrix.

[0069] According to the content displayed in the above-mentioned second auxiliary encryption / decryption image, perform a translation transformation operation on the second key image matrix to obtain the second key image matrix after the operation.

[0070] Perform an exclusive OR operation on the second key image matrix after the above operation, the second key image matrix, and the second auxiliary encryption / decryption image matrix to obtain the second original image matrix.

[0071] In the technical solution of the present invention, during decryption, two exclusive OR operations are used. The first exclusive OR operation obtains the second auxiliary encryption / decryption image matrix, and the second exclusive OR operation obtains the second original image matrix. The two exclusive OR operations increase the computational complexity and improve the security. Moreover, a translation transformation operation is performed on the second key image matrix to obtain the second key image matrix after the operation, and the above-mentioned second key image matrix after the operation is used to participate in the operation of the second original image matrix together, significantly improving the security.

[0072] Determine the second original image according to the second original image matrix.

[0073] In this embodiment, refer to Appendix Figure 2 , the second original image displays the Chinese character "中".

[0074] In some embodiments, refer to Appendix Figure 4 [[ID=二十八]]For the bottom-layer metasurface unit, there is at least a first frequency, and the phase difference between the reflection phase and the transmission phase corresponding to the first frequency is 180 degrees;

[0075] For the bottom-layer metasurface unit and the covering-layer metasurface unit, there is at least a second frequency, and the phase difference between the reflection phase and the transmission phase corresponding to the second frequency is 180 degrees.

[0076] Figure 4 The specific parts are described as follows:

[0077] (a) is a schematic diagram of the double-layer metasurface unit structure.

[0078] (b) is a schematic diagram of the covering-layer metasurface unit structure.

[0079] (c) Schematic diagram of the underlying metasurface unit structure.

[0080] (d) Equivalent circuit of the surface metal structure; the structural parameters of the present invention enable the unit amplitude response to reach 90% and the phase delay to reach 180°.

[0081] (e) Phase and amplitude response curves of the underlying metasurface unit; when the frequency is 8 GHz, the phase difference is 180 degrees.

[0082] (f) Phase and amplitude responses of the double-layer metasurface and the combination of the bottom metasurface unit structure parameters and the cover metasurface unit structure parameters. When the frequency is 5 GHz, the phase difference is 180 degrees.

[0083] The dual-frequency control of the physical superposition metasurface is explained as follows. According to the principle of circuit-type phase control, changing the admittance of the metasurface can change the reflection phase and transmission phase of the electromagnetic wave to achieve the desired phase response.

[0084] Preferably, the phase difference between the reflection phase and the transmission phase of the electromagnetic wave is 180 degrees.

[0085] Figure 4 In the figure, (a)-(c) show the structures of the bottom metasurface unit and the cover metasurface unit. From top to bottom, the bottom metasurface unit contains: a dipole patch metal sublayer, an intermediate dielectric sublayer, and a metal reflective sublayer;

[0086] The cover layer metasurface unit includes: a surface dipole patch sublayer and a dielectric sublayer.

[0087] The metal structures of the two unit dipole patches are similar. When the units are arranged into an array, it can be found that when the electromagnetic wave polarized in the x-direction is incident vertically on the junction surface along the -z direction, according to the equivalent circuit theory, an equivalent capacitance C is formed between the two units, and the x-direction metal structure generates an equivalent inductance L under the action of the electric field.

[0088] As shown in (d), the above structure can be regarded as an LC circuit consisting of an equivalent inductance L and an equivalent capacitance C in series, and its corresponding surface impedance can be expressed as .

[0089] Based on this analysis, the phase distribution of the bottom metasurface unit and the double-layer unit can be obtained respectively. As for the array distribution, it is necessary to arrange the bottom metasurface array first, and then arrange the cover metasurface phase code based on the code search.

[0090] In some embodiments, see Appendix Figure 4 , the dimensions of the above double-layer metasurface are as follows:

[0091] The underlying metasurface unit includes a dipole patch metal sub-layer, an intermediate dielectric sub-layer, and a metal reflector sub-layer;

[0092] The dipole patch metal sub-layer is in the shape of a "king", including a first part, a second part, a third part, and a fourth part;

[0093] Among them, the first part, the second part, and the third part are pairwise parallel;

[0094] The fourth part is perpendicular to the first part, the second part, and the third part respectively;

[0095] The size of the first part is equal to that of the second part;

[0096] The third part is located in the middle of the first part and the second part, and the first part and the second part are symmetric about the third part;

[0097] The width of the third part is equal to that of the fourth part;

[0098] The covering metasurface unit includes a dipole patch metal sub-layer and an intermediate dielectric sub-layer;

[0099] The size of the intermediate dielectric sub-layer of the covering metasurface unit is the same as that of the intermediate dielectric sub-layer of the underlying metasurface unit;

[0100] The dipole patch metal sub-layer of the covering metasurface unit is in the shape of a "king", including a first part, a second part, a third part, and a fourth part;

[0101] Among them, the size of the first part of the dipole patch metal sub-layer of the covering metasurface unit is the same as that of the first part of the dipole patch metal sub-layer in the underlying metasurface unit;

[0102] The size of the second part of the dipole patch metal sub-layer of the covering metasurface unit is the same as that of the second part of the dipole patch metal sub-layer in the underlying metasurface unit;

[0103] The length of the third part of the dipole patch metal sub-layer of the covering metasurface unit is the same as that of the third part of the dipole patch metal sub-layer in the underlying metasurface unit;

[0104] The width of the third part of the dipole patch metal sub-layer of the covering metasurface unit is different from that of the third part of the dipole patch metal sub-layer in the underlying metasurface unit; the width of the third part of the dipole patch metal sub-layer of the covering metasurface unit is smaller than that of the third part of the dipole patch metal sub-layer in the underlying metasurface unit;

[0105] The length of the fourth portion of the dipole patch metal sublayer of the cover metasurface unit is the same as the length of the fourth portion of the dipole patch metal sublayer in the bottom metasurface unit;

[0106] Among them, the width of the fourth part of the dipole patch metal sublayer of the covering layer supersurface unit is different from the width of the fourth part of the dipole patch metal sublayer in the underlying supersurface unit; the width of the fourth part of the dipole patch metal sublayer of the covering layer supersurface unit is smaller than the width of the fourth part of the dipole patch metal sublayer in the underlying supersurface unit.

[0107] In this embodiment, since the phase modulation mechanism of the bottom metasurface unit and the cover metasurface unit is the same, the bottom metasurface unit and the cover metasurface unit are designed as a composite whole. They have similar structures, so the same variables are used to name their parameters.

[0108] See attached Figure 4 ,After optimization and adjustment, the structural parameters of the bottom layer metasurface unit and the cover layer metasurface unit are shown in the following table:

[0109]

[0110] Where p is the side length of the bottom layer metasurface unit and the cover layer metasurface unit;

[0111] h is the thickness of the dielectric sublayer between the bottom metasurface unit and the cover metasurface unit;

[0112] t is the thickness of the metal reflective sublayer of the bottom metasurface unit and the cover metasurface unit, and also represents the thickness of the dipole patch metal sublayer. The thickness of the dipole patch metal sublayer is the same as the thickness of the metal reflective sublayer.

[0113] a is the length of the first part of the bottom layer super surface unit and the cover layer super surface unit;

[0114] b is the width of the first part of the bottom layer super surface unit and the cover layer super surface unit;

[0115] Figure 4 In the equation, lx is the length of the fourth part of the bottom layer super surface unit and the cover layer super surface unit;

[0116] ly is the length of the third part of the above-mentioned bottom layer super surface unit and cover layer super surface unit;

[0117] w is the width of the third part in the above-mentioned bottom layer super surface unit and covering layer super surface unit.

[0118] See attached Figure 5Comparison chart of simulation results and experimental results of the decryption process shown

[0119] Among them, (a)-(e) are the simulation processes from the second auxiliary encryption / decryption image "2" to the second original image "中";

[0120] (f)-(j) are the experimental processes from the second auxiliary encryption / decryption image "2" to the second original image "中".

[0121] Secondly, this application proposes an image processing method for a double-layer metasurface. Refer to the Figure 6 flowchart of an image encryption method for a double-layer metasurface shown, including the following steps:

[0122] In step S502, before encryption, obtain the first original image and a preset first auxiliary encryption / decryption image.

[0123] Among them, the above-mentioned first original image and the above-mentioned second original image are theoretically exactly the same.

[0124] The above-mentioned first auxiliary encryption / decryption image and the above-mentioned second auxiliary encryption / decryption image are theoretically exactly the same. [[ID=…]](此处省略完整翻译,因为未给出完整的标签对应翻译内容)

[0125] The first auxiliary encryption / decryption image is a preset random image.

[0126] Refer to the Figure 2 , the number "2" is shown in the first auxiliary encryption / decryption image. The first original image shows the Chinese character "中".

[0127] In step S504, determine the first key image according to the above-mentioned first original image and the above-mentioned preset first auxiliary encryption / decryption image.

[0128] In this embodiment, the first original image matrix of the above-mentioned first original image and the first auxiliary encryption / decryption image matrix of the above-mentioned preset first auxiliary encryption / decryption image can be subjected to arithmetic processing. After transformation, a recurrence matrix related to the first key matrix is obtained. Then, randomly set a sub-part of the first key matrix, and through the recurrence matrix of the correlation relationship, deduce the entire first key matrix, thereby obtaining the first key image.

[0129] In step S506, during encryption, determine multiple first cipherbook images according to the above-mentioned first key image and the above-mentioned preset first auxiliary encryption / decryption image.

[0130] In step S508, distribute the above-mentioned multiple first cipherbook images to be stored on multiple terminals, so that during decryption, use the bottom metasurface units in the double-layer metasurface, and use electromagnetic waves of the first frequency to respectively perform restoration processing on the multiple first cipherbook images obtained from different terminals to obtain multiple second cipherbook images.

[0131] In this embodiment, after the encryption end performs encryption to obtain multiple first cipher pad images, the first cipher pad images can be remotely transmitted to multiple different mobile terminals or a server for storage. During the transmission process, the first cipher pad images can also be encrypted using an encryption algorithm. When performing decryption, the decryption end needs to obtain the multiple first cipher pad images from different mobile terminals or servers.

[0132] The bottom metasurface unit and the cover metasurface unit in the double-layer metasurface are used, and electromagnetic waves of a second frequency are used to restore the acquired first key image to obtain a second key image.

[0133] A second original image is determined based on the plurality of second codebook images and the second key image.

[0134] The technical solution of the present application distributes the plurality of first codebook images to multiple terminals for storage during encryption, thereby improving security. Only when all the first codebooks are collected can the second original image be decrypted.

[0135] See attached Figure 2 In some embodiments, in step S504, during encryption, determining the first key image based on the first original image and the preset first auxiliary encryption and decryption image may further include the following steps:

[0136] In step S5042, before encryption, a basic sub-replication unit of the first key matrix of the first key image is randomly determined.

[0137] In this embodiment, the basic sub-replication unit may be k rows or k columns, where k is an integer greater than zero. The value of k is much smaller than N, where N is the total number of rows or columns of the first key matrix. The content of the basic sub-replication unit is randomly generated.

[0138] In step S5044, the first original image matrix of the first original image is determined respectively. and the first auxiliary encryption and decryption image matrix of the first auxiliary encryption and decryption image .

[0139] In this embodiment, the image can be converted into a digital matrix expression. Specifically, the brightness or darkness of each pixel can be represented by a binary number 1 or 0.

[0140] Theoretically, the first original image matrix above and the first auxiliary encryption and decryption image matrix of the first auxiliary encryption and decryption image It also satisfies the following calculation formula:

[0141] ;

[0142] ;

[0143] in, is the first auxiliary encryption and decryption image matrix;

[0144] is the first original image matrix;

[0145] is the first key matrix;

[0146] The first key translation matrix is ​​obtained by performing a cyclic translation transformation operation on the first key matrix.

[0147] Wherein, k is the number of cyclic translation transformations. Specifically, the first key matrix can be row-translated or column-translated. The number of translations is k.

[0148] For example, the first key matrix above Circularly shift left by k columns to get . k can be 2, which means circularly shifting left by two columns.

[0149] is the first codebook matrix;

[0150] is the second first codebook matrix;

[0151] is the nth first codebook matrix;

[0152] In step S5046, according to the first original image matrix and the first auxiliary encryption and decryption image matrix Determine the recurrence matrix.

[0153] In this embodiment, in the matrix XOR operation, two identical matrices are XORed to form an all-0 matrix, and any matrix XORed with an all-0 matrix is ​​the matrix itself. Therefore, according to the above formula, the first original image matrix and the first auxiliary encryption and decryption image matrix Perform XOR operation to obtain the recursive matrix.

[0154] ;

[0155] ;

[0156] because is the original key matrix It is obtained by performing the corresponding matrix operation (taking the left shift operation as an example), so The n columns and The n+k (if n+k>N, then n+kN) columns of the first key matrix are exactly the same. Therefore, the above formula is a recursive formula. Once the basic sub-replication unit of the first key matrix is ​​known, the entire first key matrix can be deduced based on the above formula.

[0157] For example, the basic sub-copy unit of the first key matrix may be the first column. The first column of pixel distribution. Automatically delivered All columns of pixel points are distributed. Stop when all columns are distributed to avoid infinite recursive loop.

[0158] It's worth noting that k satisfies the condition that N is divisible by k. If N is divisible by k, then k columns need to be randomly obtained. For example, when N is 6, k is 3, or k is 2.

[0159] Of course, the recursive algorithm does not converge completely in all cases. That is, when the last column of pixels is recursively transferred to the first column, the distribution of the pixels is different from the random pixels initially generated in the first column. However, when the value of N is much larger than the value of k, this non-convergence can be ignored, and the wrong pixels can be regarded as noise. Figure 3 Comparing the restored pattern and the original image, the image size N = 500 and the matrix operation number k = 3. Since N is much larger than k, the noise points in the three right columns of the restored image do not affect the quality of the entire image. Apart from these three noise points, the restored image is identical to the original image. However, when N and k are close, the quality of the restored image will be affected, potentially causing encryption errors. A new target matrix image must be selected to fully reproduce the target image. Therefore, it is best to avoid selecting a value of k that is too large.

[0160] In step S5048, the first key matrix is ​​determined according to the recursive matrix and the basic sub-copying unit of the first key matrix.

[0161] The following describes the operating principle of the above method:

[0162] Double verification algorithm: The XOR encryption algorithm uses this mechanism to replace the traditional modular addition operation with the XOR logic operation, and applies it to metasurface encryption, which is realized through metasurface holography.

[0163] In order to facilitate encryption, the first original image matrix (where M represents the matrix rows and N represents the matrix columns), the value of each element in the matrix is ​​0 or 1.

[0164] Mark the first original image matrix With these n codebook image matrices XOR can get the key matrix G0 M×N ;

[0165] After obtaining the above-mentioned first key matrix, a first key image may be determined, and a plurality of first codebook images may be determined by combining the first key image with the preset first auxiliary encryption and decryption image.

[0166] In some embodiments, in step S506, during encryption, determining a plurality of first codebook images according to the first key image and the preset first auxiliary encryption and decryption image may further include the following steps:

[0167] A plurality of first codebook images are determined based on the principle that an XOR operation on all first codebook image matrices equals a fixed value, and an XOR operation on non-all first codebook images does not equal the fixed value.

[0168] The fixed value is determined according to the first key image matrix and the preset first auxiliary encryption and decryption image matrix.

[0169] In this embodiment, according to the above formula ; Transformation yields the following equation:

[0170] = ;

[0171] It can be seen that the result of the XOR operation of all the first code book image matrices is equal to the fixed value .

[0172] It is worth noting that there is another condition that also needs to be met at the same time, that is, the results of the XOR operation on not all first codebook images are not equal to the fixed value.

[0173] For example, among the n first cipher book image matrices mentioned above, the result of an XOR operation on any number R of first cipher book image matrices cannot equal a fixed value. This ensures that only when all n first cipher book image matrices are collected can the fixed value be obtained. This improves security. Here, R is not equal to n.

[0174] For example, when n is 5, the results of performing an XOR operation on any two, three, or four first codebook image matrices are not equal to the fixed value.

[0175] The present invention proposes a physical layer superposition metasurface, in which the single-layer metasurface and the superimposed multi-layer metasurface respectively exhibit unique electromagnetic characteristics at different electromagnetic wave frequencies. This is similar to the common cascade metasurface, but not exactly the same. The cascade metasurface is to add another metasurface in front of a metasurface with complete functions, and the first-level metasurface creates the required conditions for the second-level metasurface. Such cascade metasurfaces have unique functions, and the functions do not affect each other, but cooperate with each other to produce specific phenomena. Cascade metasurfaces are often used in the field of vector vortex light, such as the first-level metasurface is used to generate specific vortex light, and the second-level metasurface produces unique phenomena under the irradiation of this vortex light. The realization of this cascade function requires very high precision for each metasurface, and it can only be made into a transmission-type metasurface, which is costly and not conducive to the realization of metasurface encryption.

[0176] The physical layer stacking metasurface proposed in this invention solves the aforementioned problems, realizing a reflective stacking metasurface. The bottom single-layer metasurface and the stacked multi-layer metasurface can independently load a holographic image, achieving physical-level encryption. For the logic algorithm encryption portion, an exclusive-OR operation is used to construct a holographic image in a preset space, and the encrypted information is loaded into the hologram via a coded metasurface. The exclusive-OR logic operation does not add additional pixels and overcomes the problem of traditional metasurface encryption, which stores information in a single degree of freedom of electromagnetic waves and is vulnerable to indiscriminate attacks by attackers.

[0177] The aforementioned dual-verification encryption scheme of this application, and the XOR dual-verification mechanism of this application, have extremely strong security and high robustness, and can resist various indiscriminate attacks. The first-layer decryption serves to confuse attackers and provides the key for the second-layer decryption, achieving the purpose of dual anti-counterfeiting. This encryption algorithm has a strong anti-counterfeiting function and ensures the security of the encryption system. Using the XOR dual-verification encryption algorithm, the original information is encrypted into two images, which are transmitted separately by the single-layer metasurface and the composite metasurface, and then decrypted using the reverse double-verification algorithm.

[0178] In the third aspect, the present application proposes an image processing device 2 of a double-layer metasurface, see the attached Figure 8 ,include:

[0179] The first processing module 21 is configured to, during decryption, utilize the bottom metasurface unit in the double-layer metasurface and electromagnetic waves of a first frequency to perform restoration processing on a plurality of first codebook images obtained from different terminals, thereby obtaining a plurality of second codebook images;

[0180] A second processing module 22 is configured to utilize the bottom metasurface unit and the cover metasurface unit in the double-layer metasurface and electromagnetic waves of a second frequency to perform a restoration process on the acquired first key image to obtain a second key image;

[0181] The third processing module 23 is configured to determine a second original image according to the plurality of second codebook images and the second key image.

[0182] In some embodiments, the third processing module 23 is further configured to determine a second codebook image matrix for each second codebook image and a second key image matrix for the second key image;

[0183] Performing an XOR operation on each of the second codebook image matrices and the second key image matrix to obtain a second auxiliary encryption and decryption image matrix;

[0184] Performing a column shift operation on the second key image matrix to obtain a second key image matrix after the operation;

[0185] determining a second original image matrix according to the operated second key image matrix and the second codebook image matrix;

[0186] A second original image is determined according to the second original image matrix.

[0187] Fourthly, see Appendix Figure 9 The present application proposes an electronic device 300, comprising a memory 32, a processor 30, and a computer program stored in the memory 32 and executable on the processor 30. When the processor 30 executes the computer program, the image data processing method of the double-layer metasurface as described in any one of the above items is implemented.

[0188] Exemplarily, the computer program 32 may be divided into one or more modules / units, which are stored in the memory 31 and executed by the processor 30 to implement the present application. The one or more modules / units may be a series of computer program instruction segments capable of performing specific functions, and the instruction segments are used to describe the execution process of the computer program 32 in the electronic device 300.

[0189] The electronic device 300 may be a computing device such as a desktop computer, a notebook, a PDA, or a cloud server. The electronic device may include, but is not limited to, a processor 30 and a memory 31. Those skilled in the art will appreciate that Figure 9 It is only an example of the electronic device 300 and does not constitute a limitation of the electronic device 300. It may include more or fewer components than shown in the figure, or a combination of certain components, or different components. For example, the above-mentioned electronic device may also include input and output devices, network access devices, buses, etc.

[0190] The processor 30 may be a central processing unit (CPU), other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA), other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor.

[0191] The memory 31 may be an internal storage unit of the electronic device 300, such as a hard drive or memory of the electronic device 300. Alternatively, the memory 31 may be an external storage device of the electronic device 300, such as a plug-in hard drive, a Smart Media Card (SMC), a Secure Digital (SD) card, a flash memory card, etc. Furthermore, the memory 31 may include both an internal storage unit of the electronic device 300 and an external storage device. The memory 31 is used to store the computer program and other programs and data required by the electronic device. The memory 31 may also be used to temporarily store data that has been output or is about to be output.

[0192] In a fourth aspect, the present application proposes an image processing system 900, see the attached Figure 10 , including the electronic device 300 as described above, and also including a double-layer metasurface 91 and an electromagnetic wave generating device 92 respectively connected to the electronic device 300.

[0193] The electromagnetic wave generating device 92 is used to generate electromagnetic waves under the control of the processor. The electromagnetic waves are provided to the double-layer metasurface.

[0194] The double-layer metasurface can be adjusted to a first frequency electromagnetic wave or a second frequency electromagnetic wave according to the above-mentioned electromagnetic wave.

[0195] The double-layer metasurface uses electromagnetic waves of a first frequency to restore multiple first codebook images obtained from different terminals to obtain multiple second codebook images.

[0196] The bottom metasurface unit and the cover metasurface unit in the double-layer metasurface are used, and electromagnetic waves of a second frequency are used to restore the acquired first key image to obtain a second key image.

[0197] An original image is determined based on the plurality of second codebook images and the second key image.

[0198] In some embodiments, the system further includes a communication device connected to the processor, the communication device being configured to receive a plurality of first codebook images from different terminals and receive a first key image.

[0199] Other embodiments of the present disclosure will readily occur to those skilled in the art after considering the specification and practicing the present disclosure. This application is intended to cover any variations, uses, or adaptations of the present disclosure that follow the general principles of the present disclosure and include common knowledge or customary techniques in the art not disclosed herein. The description and examples are to be considered as exemplary only, with the true scope and spirit of the present disclosure being indicated by the following claims.

[0200] It should be understood that the present disclosure is not limited to the exact structures that have been described above and shown in the drawings, and that various modifications and changes can be made without departing from the scope thereof. The scope of the present disclosure is limited only by the appended claims.

Claims

1. A method for processing an image of a double-layer metasurface, characterized in that: It includes: During decryption, using the underlying metasurface units in the double-layer metasurface, and adopting electromagnetic waves of the first frequency, respectively perform restoration processing on multiple first ciphertext images obtained from different terminals to obtain multiple second ciphertext images; Using the underlying metasurface units and the covering metasurface units in the double-layer metasurface, and adopting electromagnetic waves of the second frequency, perform restoration processing on the obtained first key image to obtain a second key image; wherein, the first frequency and the second frequency are different; Determine the second original image according to the multiple second ciphertext images and the second key image.

2. The image processing method of the double-layer metasurface according to claim 1, characterized in that The determining the second original image according to the multiple second ciphertext images and the second key image includes: Determine the second ciphertext image matrix of each second ciphertext image and the second key image matrix of the second key image; Perform an exclusive OR operation on each of the second ciphertext image matrices and the second key image matrix to obtain a second auxiliary encryption / decryption image matrix; Determine the second original image matrix according to the second key image matrix and the second auxiliary encryption / decryption image matrix; Determine the second original image according to the second original image matrix.

3. The image processing method of the double-layer metasurface according to claim 1, characterized in that The size design principle of the underlying metasurface units and the covering metasurface units is that for the underlying metasurface units, there is at least a first frequency, and the phase difference between the reflection phase and the transmission phase corresponding to the first frequency is 180 degrees; For the underlying metasurface units and the covering metasurface units, there is at least a second frequency, and the phase difference between the reflection phase and the transmission phase corresponding to the second frequency is 180 degrees.

4. The image processing method of the double-layer metasurface according to claim 3, characterized in that The first frequency is 8 GHz, and the second frequency is 5 GHz.

5. The image processing method of the double-layer metasurface according to claim 4, characterized in that: The sizes in the double-layer metasurface are as follows: The underlying metasurface unit includes: a dipole patch metal sublayer, an intermediate dielectric sublayer, and a metal reflection sublayer; The dipole patch metal sublayer is in the shape of a "king", including a first part, a second part, a third part, and a fourth part; Among them, the first part, the second part, and the third part are respectively parallel to each other in pairs; The fourth part is respectively perpendicular to the first part, the second part, and the third part; The size of the first part is equal to the size of the second part; The third part is located in the middle of the first part and the second part, and the first part and the second part are symmetric about the third part; The widths of the third part and the fourth part are equal; The covering metasurface unit includes a dipole patch metal sublayer and an intermediate dielectric sublayer; The size of the intermediate dielectric sublayer of the covering metasurface unit is the same as the size of the intermediate dielectric sublayer of the underlying metasurface unit; The dipole patch metal sublayer of the covering metasurface unit is in the shape of a "king", including a first part, a second part, a third part, and a fourth part; Among them, the size of the first part of the dipole patch metal sublayer of the covering metasurface unit is the same as the size of the first part of the dipole patch metal sublayer in the underlying metasurface unit; The second portion size of the dipole patch metal sublayer of the cover metasurface unit is the same as the second portion size of the dipole patch metal sublayer in the bottom metasurface unit; The length of the third portion of the dipole patch metal sublayer of the cover metasurface unit is the same as the length of the third portion of the dipole patch metal sublayer in the bottom metasurface unit; The width of the third portion of the dipole patch metal sublayer of the cover layer metasurface unit is smaller than the width of the third portion of the dipole patch metal sublayer in the bottom layer metasurface unit; The length of the fourth portion of the dipole patch metal sublayer of the cover metasurface unit is the same as the length of the fourth portion of the dipole patch metal sublayer in the bottom metasurface unit; The width of the fourth portion of the dipole patch metal sublayer of the cover layer metasurface unit is smaller than the width of the fourth portion of the dipole patch metal sublayer in the bottom layer metasurface unit.

6. A method for processing an image of a double-layer metasurface, characterized in that: include: Before encryption, a first original image and a preset first auxiliary encrypted and decrypted image are obtained; Determine a first key image according to the first original image and the preset first auxiliary encryption and decryption image; During encryption, a plurality of first codebook images are determined according to the first key image and the preset first auxiliary encryption and decryption image; The plurality of first codebook images are distributed and stored in a plurality of terminals, so that during decryption, the plurality of first codebook images obtained from different terminals are restored separately using a bottom metasurface unit in the double-layer metasurface and electromagnetic waves of a first frequency to obtain a plurality of second codebook images; Using the bottom metasurface unit and the cover metasurface unit in the double-layer metasurface, and using electromagnetic waves of a second frequency, the obtained first key image is restored to obtain a second key image; A second original image is determined based on the plurality of second codebook images and the second key image.

7. The image processing method of the double-layer metasurface according to claim 6, characterized in that: During encryption, determining a first key image according to the first original image and the preset first auxiliary encryption and decryption image includes: Before encryption, randomly determining a basic sub-replication unit of a first key matrix of the first key image; respectively determining an original image matrix of the first original image and a first auxiliary encryption and decryption image matrix of the first auxiliary encryption and decryption image; Determine a recursive matrix according to the first original image matrix and the first auxiliary encryption and decryption image matrix; The first key matrix is ​​determined according to the recursive matrix and the basic sub-copying unit of the first key matrix.

8. An image processing device for a double-layer metasurface, characterized in that: include: A first processing module is configured to, during decryption, utilize a bottom metasurface unit in the double-layer metasurface and electromagnetic waves of a first frequency to perform restoration processing on a plurality of first codebook images acquired from different terminals, thereby obtaining a plurality of second codebook images; a second processing module, configured to utilize the bottom metasurface unit and the cover metasurface unit in the double-layer metasurface and electromagnetic waves of a second frequency to perform a restoration process on the acquired first key image to obtain a second key image; The third processing module is configured to determine a second original image according to the plurality of second codebook images and the second key image.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the computer program, the image data processing method of the double-layer metasurface according to any one of claims 1 to 5, or 6 to 7 is implemented.

10. An image processing system, characterized in that: The electronic device according to claim 9, further comprising a double-layer metasurface and an electromagnetic wave generating device respectively connected to the electronic device; The electromagnetic wave generating device is used to generate electromagnetic waves under the control of the processor.

Images