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

Abstract

The present disclosure relates to a kind of double-layer metasurface image processing method, device, equipment and system.The method comprises: when decryption, using the bottom layer metasurface unit in double-layer metasurface, with the electromagnetic wave of first frequency, to the multiple first password book images obtained from different terminals, respectively, carry out restoration processing, obtain multiple second password book images;Using the bottom layer metasurface unit and cover layer metasurface unit in the double-layer metasurface, with the electromagnetic wave of second frequency, to the first key image obtained, carry out restoration processing, obtain second key image;According to the multiple second password book images and the second key image determine second original image.The above technical solution of the present application adopts two different frequencies to determine second password book image and second key image respectively.It is favorable to increase cracking difficulty and improve security.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of image processing, and particularly relates to a metasurface image processing method and device, electronic equipment and system. BACKGROUND

[0002] A metasurface is composed of subwavelength unit structures, and can flexibly control the phase, amplitude, polarization and other characteristics of electromagnetic waves through microstructure design to realize multi-dimensional parameter encryption. In existing metasurface encryption technology, a single frequency of electromagnetic waves is used to encrypt an image, and the security is not high because the encryption relies on a single frequency of electromagnetic waves. SUMMARY

[0003] To overcome the problems in the related art, the present disclosure provides a double-layer metasurface image processing method, device, electronic equipment and system to solve the above problems in the related art.

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

[0005] During decryption, the bottom layer metasurface unit in the double-layer metasurface is used to perform restoration processing on a plurality of first password book images obtained from different terminals by using electromagnetic waves of a first frequency, to obtain a plurality of second password book images;

[0006] The bottom layer metasurface unit and the cover layer metasurface unit in the double-layer metasurface are used to perform restoration processing on an obtained first key image by using electromagnetic waves of a second frequency, to obtain a second key image;

[0007] A second original image is determined according to the plurality of second password book images and the second key image.

[0008] In a second aspect, the present disclosure provides a double-layer metasurface image processing method, comprising:

[0009] Before encryption, a first original image and a pre-set first auxiliary encryption and decryption image are obtained;

[0010] A first key image is determined according to the first original image and the pre-set first auxiliary encryption and decryption image;

[0011] During encryption, a plurality of first password book images are determined according to the first key image and the pre-set first auxiliary encryption and decryption image;

[0012] The plurality of first password book images are distributed and saved in a plurality of terminals, so that during decryption, the bottom layer metasurface unit in the double-layer metasurface is used to perform restoration processing on a plurality of first password book images obtained from different terminals by using electromagnetic waves of a first frequency, to obtain a plurality of second password book images;

[0013] The first key image is obtained by using the bottom layer metasurface unit and the cover layer metasurface unit in the double-layer metasurface to perform restoration processing on the first key image obtained by using the electromagnetic wave of the second frequency.

[0014] A second original image is determined according to the plurality of second password images and the second key image.

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

[0016] The first processing module is configured to, when performing decryption, use the bottom layer metasurface unit in the double-layer metasurface to perform restoration processing on a plurality of first password images obtained from different terminals by using the electromagnetic wave of the first frequency, to obtain a plurality of second password images.

[0017] The second processing module is configured to use the bottom layer metasurface unit and the cover layer metasurface unit in the double-layer metasurface to perform restoration processing on a first key image obtained by using the electromagnetic wave of the second frequency, 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 password images and the second key image.

[0019] In a fourth aspect, the present application further provides an electronic device including a memory, a processor, and a computer program stored in the memory and executable on the processor, and the processor implements the image processing method of the double-layer metasurface as described above when executing the computer program.

[0020] In a fifth aspect, the present application further provides a system including the electronic device as described above, and further including a double-layer metasurface and an electromagnetic wave generating device connected to the electronic device respectively.

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

[0022] The technical solution provided by the embodiments of the present disclosure can include the following beneficial effects:

[0023] The above technical solution of the present application uses the double-layer metasurface structure to realize electromagnetic wave double-frequency regulation and control, designs a double verification algorithm based on XOR operation, combines the super surface double-frequency regulation and control and the XOR encryption algorithm, and completes image information encryption transmission through holographic imaging, to realize a low-cost, high-security, and high-fault-tolerant encryption system.

[0024] It should be understood that the foregoing general description and the following detailed description are only exemplary and explanatory, and cannot limit the present disclosure. BRIEF DESCRIPTION OF DRAWINGS

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

[0026] Figure 1 is a flowchart of an image decryption method of a double-layer metasurface according to an example embodiment;

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

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

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

[0030] Figure 5 is a flowchart of an image encryption method of a double-layer metasurface according to an example embodiment;

[0031] Figure 6 is a flowchart of another image encryption method of a double-layer metasurface according to an example embodiment;

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

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

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

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

[0036] The example embodiments will be described in detail herein with reference to the accompanying drawings. When the following description refers to arrangements in the drawings, identical numbers on different drawings represent the same or similar elements unless otherwise stated. The implementations described in the following example embodiments do not represent all implementations consistent with the present disclosure. Instead, they are merely examples of apparatuses and methods consistent with some aspects of the present disclosure as detailed in the appended claims.

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

[0038] The present application provides an image processing method of a double-layer metasurface, referring to the accompanying drawings Figure 1 , the method comprises the following steps:

[0039] In step S102, during decryption, the bottom-layer metasurface unit in the double-layer metasurface uses electromagnetic waves of the first frequency to respectively process a plurality of first codebook images obtained from different terminals to obtain a plurality of second codebook images.

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

[0041] After the bottom-layer metasurface unit processes the first codebook image using electromagnetic waves of the first frequency, the first codebook image is converted into the second codebook image.

[0042] Obtaining a plurality of first codebook images from different terminals has the following effects:

[0043] Decentralized storage reduces risk. By distributing codebook images across different terminals, the risk of concentrated attacks on a single storage location is avoided. Even if a terminal is compromised, attackers can only obtain partial images and cannot directly restore the complete codebook, greatly reducing the risk of codebook leakage due to single-point failure or attack.

[0044] Increased attack difficulty. Attackers need to attack multiple terminals simultaneously to collect all images, which increases the complexity and cost of attacks. They need to have attack techniques for different types of terminals and coordinate multiple attack operations to collect and integrate information across multiple terminals, which often faces many technical challenges and risks in actual operation.

[0045] Strengthen identity verification. If specific identity verification and authorization are required to obtain each first codebook image, only authorized users can collect all images for restoration after correct identity verification on multiple terminals. This is equivalent to setting multiple identity verification checkpoints, further enhancing control over codebook access and preventing unauthorized personnel from accessing complete code information.

[0046] Improve data integrity. The images obtained by different terminals can be verified and supplemented with each other, which helps to detect and correct possible data errors or damage. If the image of a certain terminal is problematic, the images of other terminals can be used as a reference to ensure that the final restored codebook has high data integrity and accuracy.

[0047] The dispersion of the first codebook image in different terminals improves the security of the codebook through the effects of dispersed storage, increased attack difficulty, strengthened identity verification, and improved data integrity, effectively protecting sensitive information from being easily obtained and cracked.

[0048] In step S104, the first key image obtained is restored using the bottom layer super surface unit and the cover layer super surface unit in the double-layer super surface 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] Referring to FIG. 1, Figure 2 The first key image obtained is restored using the bottom layer super surface unit and the cover layer super surface unit in the double-layer super surface to obtain a second key image.

[0052] The electromagnetic wave of 8 GHz is used by the bottom layer super surface unit to restore a plurality of first codebook images obtained from different terminals to obtain a plurality of second codebook images.

[0053] In step S106, a second original image is determined according to the plurality of second codebook images and the second key image.

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

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

[0056] Referring to FIG. 1, Figures 2-3 The digital matrix of the second codebook image and the digital matrix of the second key image are subjected to XOR operation to obtain a second auxiliary reference image, and the final second original image is obtained according to the second auxiliary reference image.

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

[0058] Increasing the difficulty of cracking. Information hiding is more complex. Using two frequencies means that there are two sets of image information under different frequencies that need to be obtained and analyzed by the cracker. The cracker not only needs to know that there are two frequencies of electromagnetic waves used for imaging, but also needs to analyze the image information corresponding to different frequencies and their relationship, which is much more complex than cracking image information under a single frequency.

[0059] Frequency characteristics increase confusion. Different frequencies of electromagnetic waves will produce different scattering, reflection and other characteristics when interacting with the metasurface. These characteristics are encoded in the image, making the password image and the key image have unique frequency-related features. Even if the cracker obtains the image, it is difficult to understand the meaning represented by these characteristics based on different frequencies, further increasing the difficulty of cracking.

[0060] Improving security. Two frequencies correspond to a double verification mechanism. Only with the correct password 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. Compared with single image verification under a single frequency, the security is greatly improved. Even if the cracker obtains the image under one of the frequencies, without the image under the other frequency, the original image cannot be restored.

[0061] Reducing the risk of frequency cracking. In a single frequency system, once the frequency is known and the decoding method is mastered by the cracker, the security of the entire system will be completely lost. By using two frequencies, even if the information related to one of the frequencies is leaked, the other frequency can still provide additional security protection to prevent the image information from being easily restored, adding an extra security line to the system.

[0062] In step S106, referring to FIG. 10, Figures 2-3 The original image is determined according to the plurality of second password images and the second key image, specifically including the following steps:

[0063] Determine the second password image matrix of each second password image and the second key image matrix of the second key image.

[0064] XOR operation is performed between the second password image matrix of each second password image and the second key image matrix to obtain a second auxiliary encryption and decryption image matrix.

[0065] In this embodiment, referring to FIG. 10, Figure 2 The second auxiliary encryption and decryption image displays 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 above-mentioned second key image matrix after the 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 adopted. 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, see Appendix Figure 2 , the second original image displays the Chinese character "中".

[0074] In some embodiments, see Appendix Figure 4 , 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 bottom layer metasurface unit structure.

[0080] (d) Surface metal structure equivalent circuit; the structure parameters of the application make the unit amplitude response reach 90%, and the phase delay is 180°.

[0081] (e) Bottom layer metasurface unit phase and amplitude response curve; when the frequency is 8Ghz, the phase difference value is 180 degrees.

[0082] (f) Double-layer metasurface phase and amplitude response and bottom layer metasurface unit structure parameter and cover layer metasurface unit structure parameter combination. When the frequency is 5Ghz, the phase difference value is 180 degrees.

[0083] The physical superposition of the metasurface double-frequency regulation is as follows: according to the circuit type phase regulation principle, changing the admittance of the metasurface can change the reflection phase and transmission phase of the electromagnetic wave, so as to achieve the required 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 middle, (a)-(c) show the structure of the bottom layer metasurface unit and the cover layer metasurface unit, from top to bottom, the bottom layer metasurface unit includes: a dipole patch metal sublayer, an intermediate dielectric sublayer and a metal reflection sublayer;

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

[0087] The two kinds of unit dipole patch metal structures are similar. Arranging the units into an array can find that when the electromagnetic wave polarized in the x direction is vertically incident on the 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 produces an equivalent inductance L under the action of the electric field.

[0088] Referring to (d) shown, the above structure can be regarded as an LC circuit with equivalent inductance L and equivalent capacitance C in series, and the corresponding surface impedance can be represented as .

[0089] According to this analysis, the phase distribution of the bottom layer metasurface unit and the double-layer unit can be obtained respectively, and for the array distribution, the bottom layer metasurface array is arranged first, and then the cover layer metasurface phase code is arranged according to the code.

[0090] In some embodiments, referring to the attached Figure 4 , the size of the above double-layer metasurface is as follows:

[0091] The bottom layer metasurface unit comprises a dipole patch metal sublayer, an intermediate medium sublayer and a metal reflection sublayer;

[0092] The dipole patch metal sublayer is a "Wang" shape, comprising a first part, a second part, a third part and a fourth part;

[0093] The first part, the second part and the third part are parallel to each other respectively;

[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 between the first part and the second part, and the first part and the second part are symmetrical about the third part;

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

[0098] The covering layer metasurface unit comprises a dipole patch metal sublayer and an intermediate medium sublayer;

[0099] The size of the intermediate medium sublayer of the covering layer metasurface unit is the same as that of the intermediate medium sublayer of the bottom layer metasurface unit;

[0100] The dipole patch metal sublayer of the covering layer metasurface unit is a "Wang" shape, comprising a first part, a second part, a third part and a fourth part;

[0101] The size of the first part of the dipole patch metal sublayer of the covering layer metasurface unit is the same as that of the first part of the dipole patch metal sublayer of the bottom layer metasurface unit;

[0102] The size of the second part of the dipole patch metal sublayer of the covering layer metasurface unit is the same as that of the second part of the dipole patch metal sublayer of the bottom layer metasurface unit;

[0103] The length of the third part of the dipole patch metal sublayer of the covering layer metasurface unit is the same as that of the third part of the dipole patch metal sublayer of the bottom layer metasurface unit;

[0104] The width of the third part of the dipole patch metal sublayer of the covering layer metasurface unit is different from that of the third part of the dipole patch metal sublayer of the bottom layer metasurface unit; the width of the third part of the dipole patch metal sublayer of the covering layer metasurface unit is less than that of the third part of the dipole patch metal sublayer of the bottom layer metasurface unit;

[0105] The length of the fourth part of the dipole patch metal sublayer of the covering layer metasurface unit is the same as the length of the fourth part of the dipole patch metal sublayer in the bottom layer metasurface unit.

[0106] The width of the fourth part of the dipole patch metal sublayer of the covering layer metasurface unit is different from the width of the fourth part of the dipole patch metal sublayer in the bottom layer metasurface unit; the width of the fourth part of the dipole patch metal sublayer of the covering layer metasurface unit is less than the width of the fourth part of the dipole patch metal sublayer in the bottom layer metasurface unit.

[0107] In the embodiment, since the phase modulation mechanisms of the bottom layer metasurface unit and the covering layer metasurface unit are the same, the bottom layer metasurface unit and the covering layer metasurface unit are designed as a composite whole, and they have similar structures, so the same variable is used for parameter naming.

[0108] Referring to FIG. 1, the bottom layer metasurface unit and the covering layer metasurface unit are designed as a composite whole, and they have similar structures, so the same variable is used for parameter naming. Figure 4 After optimization and adjustment, the structural parameters of the bottom layer metasurface unit and the covering layer metasurface unit are shown in the following table:

[0109]

[0110] Wherein, p is the side length of the bottom layer metasurface unit and the covering layer metasurface unit;

[0111] h is the thickness of the intermediate medium sublayer in the bottom layer metasurface unit and the covering layer metasurface unit;

[0112] t is the thickness of the metal reflection sublayer of the bottom layer metasurface unit and the covering layer metasurface unit, which also represents the thickness of the dipole patch metal sublayer. The thickness of the dipole patch metal sublayer is the same as that of the metal reflection sublayer.

[0113] a is the length dimension of the first part in the bottom layer metasurface unit and the covering layer metasurface unit;

[0114] b is the width dimension of the first part in the bottom layer metasurface unit and the covering layer metasurface unit;

[0115] Figure 4 lx is the length of the fourth part in the bottom layer metasurface unit and the covering layer metasurface unit;

[0116] ly is the length of the third part in the bottom layer metasurface unit and the covering layer metasurface unit;

[0117] w is the width of the third part in the bottom layer metasurface unit and the covering layer metasurface unit.

[0118] Referring to FIG. 1, the bottom layer metasurface unit and the covering layer metasurface unit are designed as a composite whole, and they have similar structures, so the same variable is used for parameter naming. Figure 5The simulation result of the decryption process is compared with the experimental result.

[0119] Wherein, (a)-(e) are the simulation process of the second auxiliary encryption and decryption image "2" to the second original image "China";

[0120] (f)-(j) are the experimental process of the second auxiliary encryption and decryption image "2" to the second original image "China".

[0121] In a second aspect, the application provides an image processing method of a double-layer metasurface, as shown in the accompanying Figure 6 The flowchart of the image encryption method of the double-layer metasurface is shown, which includes the following steps:

[0122] In step S502, before encryption, the first original image and the pre-set first auxiliary encryption and decryption image are obtained.

[0123] The first original image and the second original image are theoretically completely identical.

[0124] The first auxiliary encryption and decryption image and the second auxiliary encryption and decryption image are theoretically completely identical.

[0125] The first auxiliary encryption and decryption image is a pre-set random image.

[0126] Referring to the accompanying Figure 2 The first auxiliary encryption and decryption image shows the number "2". The first original image shows the Chinese character "China".

[0127] In step S504, the first key image is determined according to the first original image and the pre-set first auxiliary encryption and decryption image.

[0128] In this embodiment, the first original image matrix of the first original image and the first auxiliary encryption and decryption image matrix of the pre-set first auxiliary encryption and decryption image can be operated and processed, and after transformation, the recursive matrix of the associated relationship of the first key matrix is obtained. Then, the subpart of the first key matrix is randomly set, and the entire first key matrix is recursively obtained through the recursive matrix of the associated relationship, so that the first key image is obtained.

[0129] In step S506, during encryption, a plurality of first password book images are determined according to the first key image and the pre-set first auxiliary encryption and decryption image.

[0130] In step S508, the plurality of first password book images are distributed in a plurality of terminals for storage, so that during decryption, the bottom layer metasurface unit in the double-layer metasurface is used to restore the plurality of first password book images obtained from different terminals by using electromagnetic waves of the first frequency, and a plurality of second password book images are obtained.

[0131] In the embodiment, after the encryption terminal encrypts to obtain the plurality of first password image, the first password image can be transmitted to a plurality of different mobile terminals remotely or stored in a server. In the transmission process, the first password image can also be encrypted by using an encryption algorithm. When the decryption terminal decrypts, the plurality of first passwords mentioned above are obtained from different mobile terminals or servers.

[0132] The bottom layer super surface unit and the cover layer super surface unit in the double layer super surface are used to restore the obtained first key image by using electromagnetic waves of a second frequency to obtain a second key image.

[0133] A second original image is determined according to the plurality of second password images and the second key image.

[0134] The technical solution of the application improves the security by distributing the plurality of first password images in a plurality of terminals during encryption. Only when all the first passwords are collected, the second original image can be cracked.

[0135] Referring to the accompanying drawings Figure 2 In some embodiments, during encryption in step S504, the first key image is determined according to the first original image and the first auxiliary encryption and decryption image set in advance, which can further include the following steps:

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

[0137] In the embodiment, the basic sub-replication unit can be k rows or k columns. Wherein, k is an integer greater than zero. The value of k is much smaller than N, wherein 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 and the first auxiliary encryption and decryption image matrix of the first auxiliary encryption and decryption image are respectively determined.

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

[0140] In theory, the first original image matrix and the first auxiliary encryption and decryption image matrix of the first auxiliary encryption and decryption image also satisfy the following calculation formula:

[0141] ;

[0142] ;

[0143] wherein, is a first auxiliary encryption / decryption image matrix;

[0144] is a first original image matrix;

[0145] is a first key matrix;

[0146] is a first key translation matrix after a cyclic shift operation is performed on the first key matrix.

[0147] wherein k is a number of cyclic shift. Specifically, the first key matrix can be shifted in row or in column. The number of shift is k.

[0148] For example, the first key matrix is cyclically shifted left by k columns to obtain . k can be 2, indicating cyclically shifted left by two columns.

[0149] is a first first password matrix;

[0150] is a second first password matrix;

[0151] is an nth first password matrix;

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

[0153] In this embodiment, in the XOR operation of the matrix, two identical matrices XORed are a full 0 matrix, and any matrix XORed with a full 0 matrix is the matrix itself. Therefore, according to the above formula, the first original image matrix and the first auxiliary encryption / decryption image matrix are XORed to obtain the recurrence matrix.

[0154] ;

[0155] ;

[0156] Since is obtained by performing a cyclic shift operation on the original key matrix This is obtained by performing the corresponding matrix operations (taking a left shift operation as an example). n columns and The n+k (or n+kN if n+k>N) columns are completely identical. Therefore, the above formula is a recursive formula. Knowing the basic sub-replication units of the first key matrix, the entire first key matrix can be recursively derived according to the above formula.

[0157] For example, the basic sub-replication unit of the first key matrix can be the first column. (Randomly obtained) The first column shows the pixel distribution. (Automatic recursion is used.) Distribution of pixels in all columns. (After obtaining...) Stop when all columns are distributed to avoid infinite recursion.

[0158] It's important to note that k must satisfy the condition that N is divisible by k. If N is divisible by k, then k columns need to be randomly selected. For example, when N is 6, k could be 3 or k could be 2.

[0159] Of course, this recursive algorithm does not converge completely in all cases. Specifically, if the distribution of random pixels in the first column differs from the initially generated first column when the last column is iterated back to the first column, the algorithm will not converge. However, when N is much larger than k, this non-convergence can be ignored, and the erroneous pixels can be considered noise. Figure 3 The reconstruction compares the original image with the restored image. The image size is N=500, and the matrix operands are k=3. Since N is much larger than k, the noise points in the three columns on the right side of the restored image do not affect the overall image quality. Apart from these three columns of noise, the restored image is identical to the original image. However, when N is close to k, it affects the quality of the restored image and may cause encryption errors. In such cases, a suitable target matrix image needs to be selected to still achieve complete reproduction of the target image. Therefore, when selecting a value for k, it is important to avoid making it too large.

[0160] In step S5048, the first key matrix is ​​determined based on the recursive matrix and the basic sub-replication unit of the first key matrix.

[0161] The operational principle of the above method is explained below:

[0162] Dual verification algorithm: The XOR encryption algorithm uses this mechanism to replace the traditional modular addition operation with the XOR logic operation. It is applied to metasurface encryption and implemented through metasurface holography.

[0163] To facilitate encryption, the first original image matrix (where M represents the matrix row and N represents the matrix column), and the value of each element in the matrix is ​​0 or 1.

[0164] First original image matrix and the n cipher text image matrices XOR can obtain the key matrix G0 M×N ;

[0165] After obtaining the first key matrix, the first key image can be determined, and a plurality of first cipher text images are determined according to the first key image and the pre-set first auxiliary encryption and decryption image.

[0166] In some embodiments, in step S506, when encrypting, a plurality of first cipher text images are determined according to the first key image and the pre-set first auxiliary encryption and decryption image, which can further include the following steps:

[0167] A plurality of first cipher text images are determined according to the principle that XOR operation of all first cipher text image matrices is equal to a fixed value, and XOR operation of non-all first cipher text images is not equal to the fixed value.

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

[0169] In this embodiment, according to the above formula ; the following equation is obtained by transformation:

[0170] = ;

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

[0172] It is worth noting that another condition also needs to be met, that is, the result of XOR operation of non-all first cipher text images is not equal to the fixed value.

[0173] For example, in the above n first cipher text image matrices, the result of XOR operation of any number R of first cipher text image matrices cannot be equal to the fixed value, and only in this way can it be ensured that only when the n first cipher text image matrices are collected can the above fixed value be cracked. In this way, the security can be improved. Wherein, R is not equal to n.

[0174] For example, when n is 5, the result of XOR operation of any two, three or four first cipher text image matrices is not equal to the fixed value.

[0175] The application provides a physical layer superposed metasurface, a single-layer metasurface and a multi-layer metasurface after superposition, which respectively exhibit unique electromagnetic characteristics at different electromagnetic wave frequencies. This is similar to a common cascaded metasurface, but not exactly the same. The cascaded metasurface is to add a metasurface in front of a metasurface with complete functions, and the first-level metasurface creates conditions required by the second-level metasurface. Such a cascaded metasurface has unique functions, and the functions do not affect each other, but cooperate with each other to produce specific phenomena. The cascaded function implementation has high precision requirements for each metasurface, and can only be a transmission type metasurface, which has a large cost and is not conducive to the realization of metasurface encryption.

[0176] The physical layer superposed metasurface provided by the application solves the above problems and realizes a reflection type superposed metasurface. The bottom single-layer metasurface and the multi-layer metasurface after superposition can independently complete loading of a holographic image, and realize physical layer level encryption. For the logical algorithm encryption part, the holographic image of the preset space is constructed by using an exclusive or operation, and the encrypted information is loaded to the holographic image by using an encoding metasurface. The exclusive or logical operation does not increase additional pixel points, and can overcome the problem that the traditional metasurface encryption separately stores information on a single degree of freedom of electromagnetic waves, and the attacker cannot attack and crack without difference.

[0177] The double verification encryption scheme of the application has strong security and high robustness, and can resist various attacks without difference. The first layer decryption plays a role of confusing the attacker, and provides a key for the second layer decryption, so that the double anti-counterfeiting purpose is achieved. The encryption algorithm has strong anti-counterfeiting function, and ensures the security of the encryption system. The original information is encrypted into two images by using the exclusive or double verification encryption algorithm, and is respectively transmitted by the single-layer metasurface and the composite metasurface, and then is decrypted by using the reverse double verification algorithm.

[0178] In a third aspect, the application provides an image processing device 2 of a double-layer metasurface, as shown in the accompanying drawings, Figure 8 , comprising:

[0179] The first processing module 21 is configured to, when decrypting, use the bottom layer metasurface unit in the double-layer metasurface, adopt electromagnetic waves of a first frequency, and respectively perform restoration processing on a plurality of first password book images obtained from different terminals to obtain a plurality of second password book images.

[0180] The second processing module 22 is configured to use the bottom layer metasurface unit and the cover layer metasurface unit in the double-layer metasurface, adopt electromagnetic waves of a second frequency, and perform restoration processing on the obtained 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 password image and the second key image.

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

[0183] XOR operation is performed between the second password image matrix and the second key image matrix to obtain a second auxiliary encryption / decryption image matrix.

[0184] Column shifting operation is performed on the second key image matrix to obtain an operated second key image matrix.

[0185] The second original image matrix is determined according to the operated second key image matrix and the second password image matrix.

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

[0187] In a fourth aspect, referring to the accompanying drawings Figure 9 The present application provides an electronic device 300, which comprises a memory 32, a processor 30, and a computer program stored in the memory 32 and executable on the processor 30, and the processor 30 implements the image data processing method of the double-layer super surface according to any one of the above aspects when executing the computer program.

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

[0189] The electronic device 300 can be a desktop computer, a notebook computer, a palm computer, a cloud server, and other computing devices. The electronic device can include, but is not limited to, the processor 30 and the memory 31. Those skilled in the art can understand that Figure 9 The electronic device 300 is only an example and does not constitute a limitation on the electronic device 300, which can include more or fewer components than those shown, or combine certain components, or different components, for example, the electronic device can also include an input / output device, a network access device, a bus, etc.

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

[0191] The memory 31 can be an internal storage unit of the electronic device 300, such as a hard disk or a memory of the electronic device 300. The memory 31 can also be an external storage device of the electronic device 300, such as a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card, etc. provided on the electronic device 300. Further, the memory 31 can include both the internal storage unit and the external storage device of the electronic device 300. The memory 31 is used to store the computer program and other programs and data required by the electronic device. The memory 31 can also be used to temporarily store data that has been output or will be output.

[0192] In a fourth aspect, the present application provides an image processing system 900, as shown in FIG. 9, Figure 10 including the electronic device 300 as described above, and further including a double-layer metasurface 91 and an electromagnetic wave generating device 92 connected to the electronic device 300 respectively.

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

[0194] The double-layer metasurface can adjust the electromagnetic waves to be the first frequency electromagnetic waves or the second frequency electromagnetic waves according to the electromagnetic waves.

[0195] The double-layer metasurface uses the first frequency electromagnetic waves to restore a plurality of first password image obtained from different terminals to obtain a plurality of second password image.

[0196] The double-layer metasurface uses the second frequency electromagnetic waves to restore the first key image obtained to obtain the second key image by using the bottom metasurface unit and the cover metasurface unit in the double-layer metasurface.

[0197] determining the original image according to the plurality of second keystream images and the second key image.

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

[0199] Other embodiments of the present disclosure will be apparent to those skilled in the art from consideration of the specification and practice of the present disclosure. This application is intended to cover any variations, uses or adaptations of the present disclosure following the general principles thereof and including such departures from the present disclosure that come within known

[0200] It is to be understood that the present disclosure is not limited to the precise construction that has been described and shown in the accompanying drawings, and that various modifications and changes can be effected therein by those skilled in the art without departing from the scope of the present disclosure. The scope of the present disclosure is limited only by the claims that follow.

Claims

1. An image processing method of a double-layer metasurface, characterized in that, The method comprises the following steps: During decryption, using the bottom-layer metasurface unit in the double-layer metasurface, an electromagnetic wave with a first frequency is used to respectively restore a plurality of first password image obtained from different terminals to obtain a plurality of second password image; Using the bottom-layer metasurface unit and the cover-layer metasurface unit in the double-layer metasurface, an electromagnetic wave with a second frequency is used to restore the obtained first key image to obtain a second key image; wherein the first frequency and the second frequency are different; A second original image is determined according to the plurality of second password image and the second key image.

2. The image processing method of a double-layer metasurface according to claim 1, characterized in that, The method of determining the second original image according to the plurality of second password image and the second key image comprises: Determine the second password image matrix of each second password image and the second key image matrix of the second key image; XOR operation is performed between the second password image matrix of each second password image and the second key image matrix to obtain a second auxiliary encryption and decryption image matrix; A second original image matrix is determined according to the second key image matrix and the second auxiliary encryption and decryption image matrix; A second original image is determined according to the second original image matrix.

3. The method of claim 1, wherein, The size design principle of the bottom-layer metasurface unit and the cover-layer metasurface unit is that 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; For the bottom-layer metasurface unit and the cover-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.

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 method of claim 4, wherein, The size of the double-layer metasurface is as follows: The bottom-layer metasurface unit comprises a dipole patch metal sublayer, an intermediate dielectric sublayer, and a metal reflection sublayer; The dipole patch metal sublayer is "Wang" shaped, 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 parallel to each other in pairs; The fourth part is perpendicular to the first part, the second part, and the third part, respectively; The size of the first part and the second part is equal; The third part is located between the first part and the second part, and the first part and the second part are symmetrical about the third part; The width of the third part and the fourth part is equal; The cover-layer metasurface unit comprises a dipole patch metal sublayer and an intermediate dielectric sublayer; The size of the intermediate dielectric sublayer of the cover-layer metasurface unit is the same as that of the intermediate dielectric sublayer of the bottom-layer metasurface unit; The dipole patch metal sublayer of the cover-layer metasurface unit is "Wang" shaped, 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 cover-layer metasurface unit is the same as that of the first part of the dipole patch metal sublayer of the bottom-layer metasurface unit; The second part size of the dipole patch metal sublayer of the covering layer metasurface unit is the same as the second part size of the dipole patch metal sublayer in the bottom layer metasurface unit; The length of the third part of the dipole patch metal sublayer of the covering layer metasurface unit is the same as the length of the third part of the dipole patch metal sublayer in the bottom layer metasurface unit; The width of the third part of the dipole patch metal sublayer of the covering layer metasurface unit is less than the width of the third part of the dipole patch metal sublayer in the bottom layer metasurface unit; The length of the fourth part of the dipole patch metal sublayer of the covering layer metasurface unit is the same as the length of the fourth part of the dipole patch metal sublayer in the bottom layer metasurface unit; The width of the fourth part of the dipole patch metal sublayer of the covering layer metasurface unit is less than the width of the fourth part of the dipole patch metal sublayer in the bottom layer metasurface unit.

6. An image processing method of a double-layer metasurface, characterized in that, Comprise: Before encryption, obtain a first original image and a pre-set first auxiliary encryption and decryption image; Determine a first key image according to the first original image and the pre-set first auxiliary encryption and decryption image; When encrypting, determine a plurality of first password image according to the first key image and the pre-set first auxiliary encryption and decryption image; Distribute the plurality of first password image in a plurality of terminals for storage, so that when decrypting, using the bottom layer metasurface unit in the double layer metasurface, adopting electromagnetic wave of first frequency, a plurality of second password image is obtained by respectively restoring a plurality of first password image obtained from different terminals; Using the bottom layer metasurface unit and the covering layer metasurface unit in the double layer metasurface, adopting electromagnetic wave of second frequency, a second key image is obtained by restoring the obtained first key image; Determine a second original image according to the plurality of second password image and the second key image.

7. The method of image processing of a double-layer metasurface according to claim 6, wherein, When encrypting, determining a first key image according to the first original image and the pre-set first auxiliary encryption and decryption image, comprising: Before encryption, randomly determine the basic sub-replication unit of the first key matrix of the first key image; Determine the original image matrix of the first original image and the first auxiliary encryption and decryption image matrix of the first auxiliary encryption and decryption image respectively; Determine the recursive matrix according to the first original image matrix and the first auxiliary encryption and decryption image matrix; Determine the first key matrix according to the recursive matrix and the basic sub-replication unit of the first key matrix.

8. An image processing apparatus of a double-layer metasurface, characterized in that, Comprise: The first processing module is used for, when decrypting, using the bottom layer metasurface unit in the double layer metasurface, adopting electromagnetic wave of first frequency, a plurality of second password image is obtained by respectively restoring a plurality of first password image obtained from different terminals; The second processing module is used for, using the bottom layer metasurface unit and the covering layer metasurface unit in the double layer metasurface, adopting electromagnetic wave of second frequency, a second key image is obtained by restoring the obtained first key image; The third processing module is used for determining a second original image according to the plurality of second password image 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, characterized in that, The processor implements the image data processing method of the double-layer metasurface according to any one of claims 1-5 or 6-7 when executing the computer program.

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

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