DMD-based wavelength multiplexing dual-channel dynamic information encryption device and encryption method

Abstract

The invention discloses a DMD-based wavelength multiplexing dual-channel dynamic information encryption device and encryption method. The device comprises a light beam preprocessing module, a pseudo-color image generation module, a beam splitter and a ciphertext image generation module. The method comprises the following steps: respectively carrying out light beam preprocessing on a red laser signal and a blue laser signal, and outputting parallel emergent laser signals with two wavelengths; modulation and Fourier transform processing are carried out according to the parallel emergent laser signals with the two wavelengths, and a dual-channel pseudo-color ciphertext image is generated; performing beam splitting processing on the dual-channel pseudo-color ciphertext image to obtain a dual-channel pseudo-color ciphertext image; a dual-channel pseudo-color ciphertext image is collected, and a dual-channel optical ciphertext image and a Fourier leaf surface are generated. According to the invention, parallel encryption of a plurality of optical channels can be realized, and the encryption efficiency and security of information are remarkably improved. The DMD-based wavelength multiplexing dual-channel dynamic information encryption device and the DMD-based wavelength multiplexing dual-channel dynamic information encryption method can be widely applied to the technical field of information encryption security.

Description

Technical Field

[0001] The present invention relates to the technical field of information encryption security, and in particular to a wavelength-division multiplexing dual-channel dynamic information encryption device and encryption method based on DMD. Background Art

[0002] In the information age, the amount of data has increased explosively. How to process a large amount of data at high speed under low power consumption has become a difficult problem that people urgently need to solve. Especially during the transmission of secret information, security risks always threaten the confidentiality and integrity of information. Therefore, developing a secure and efficient information encryption technology has become the key to solving these problems. With its remarkable characteristics such as parallel processing, fast operation speed, and low power consumption, optical information processing technology has stood out in the big data era. Using optical information processing means to process a large amount of private data can give full play to its technical advantages of high speed and low power consumption, effectively improve the data processing efficiency, and reduce energy consumption.

[0003] In the past few decades, various optical encryption methods have been proposed and demonstrated. For example, the double random phase encoding scheme introduces two independent random phase masks in the input plane and the Fourier spectrum plane to encrypt information, thus opening up a new field of optical image encryption. At the same time, chaos-based image encryption has received increasing attention. Due to its complexity, ergodicity, and sensitivity, it is suitable for cryptography. Since chaos was first introduced into cryptography, many chaotic systems have gradually been applied to image encryption. In addition, as an artificially designed micro-nano structure, metasurface can effectively adjust various degrees of freedom of light with its ultra-thin thickness, showing great potential in the next-generation optical encryption and anti-counterfeiting fields. These works have made optical information encryption technology more reliable and secure.

[0004] Although the past optical encryption technologies have made certain progress, it cannot be ignored that these technologies have significant limitations. Most of the current mainstream optical encryption methods highly rely on complex algorithms to reconstruct the target information or flexibly control the degrees of freedom of the light field through metasurfaces for encryption. However, in practical applications, the computational complexity of the algorithms is extremely high. It not only requires a large amount of computing resources, but also consumes a lot of time and energy costs during the operation process. The processing difficulty of metasurfaces is high, the structural requirements are precise, and the encrypted information cannot be dynamically changed, making it difficult to meet the requirement of parallel encryption of multiple pieces of information. Summary of the Invention

[0005] In order to solve the above technical problems, the purpose of the present invention is to provide a wavelength-division multiplexing dual-channel dynamic information encryption device and encryption method based on DMD, which can realize parallel encryption of multiple optical channels, significantly improving the encryption efficiency and security of information.

[0006] The first technical solution adopted by the present invention is: a wavelength-division multiplexing dual-channel dynamic information encryption device based on DMD, including a beam preprocessing module, a pseudo-color image generation module, a beam splitter and a ciphertext image generation module. The output end of the beam preprocessing module is connected to the input end of the pseudo-color image generation module. The output end of the pseudo-color image generation module is connected to the input end of the beam splitter. The output end of the beam splitter is connected to the input end of the ciphertext image generation module, where:

[0007] The beam preprocessing module is used to preprocess the red laser signal and the blue laser signal respectively, and output parallel outgoing laser signals with two wavelengths;

[0008] The pseudo-color image generation module is used to perform modulation and Fourier transform processing according to the parallel outgoing laser signals with two wavelengths, and generate a dual-channel pseudo-color ciphertext image;

[0009] The beam splitter is used to split the dual-channel pseudo-color ciphertext image to obtain a first pseudo-color ciphertext image and a second pseudo-color ciphertext image;

[0010] The ciphertext image generation module collects the first pseudo-color ciphertext image and the second pseudo-color ciphertext image, and generates the Fourier planes of the first optical ciphertext image and the second optical ciphertext image.

[0011] Further, the beam preprocessing module specifically includes a red laser, a blue laser, a first laser beam expander, a second laser beam expander, a first aperture, a second aperture, a reflector and a dichroic mirror. The first laser beam expander and the first aperture are sequentially placed along the beam output direction of the red laser. The dichroic mirror is placed at the beam output end of the first aperture. The second laser beam expander and the second aperture are sequentially placed along the beam output direction of the blue laser. The reflector is placed at the beam output end of the second aperture, where:

[0012] The red laser is used to emit a red laser signal;

[0013] The blue laser is used to emit a blue laser signal;

[0014] The first laser beam expander and the second laser beam expander are respectively used to expand the red laser signal and the blue laser signal, and output the expanded red laser signal and the expanded blue laser signal;

[0015] The first aperture and the second aperture are used to crop the expanded red laser signal and the expanded blue laser signal, and output the cropped red laser signal and the cropped blue laser signal;

[0016] The reflecting mirror and the dichroic mirror are used to combine the cropped red laser signal and the cropped blue laser signal in a beam to obtain a parallel output laser signal with two wavelengths.

[0017] Further, the pseudo-color image generation module specifically includes a first DMD, a first Fourier lens, a second DMD, and a second Fourier lens. The first DMD, the first Fourier lens, the second DMD, and the second Fourier lens are arranged in sequence along the output direction of the optical path, where:

[0018] The first DMD is used to perform wavefront modulation on the parallel output laser signal with two wavelengths, and combine with the written image to output a dual-channel pseudo-color image;

[0019] The first Fourier lens is used to perform Fourier transform processing on the dual-channel pseudo-color image to output a preliminary dual-channel Fourier plane image corresponding to different wavelengths;

[0020] The second DMD is used to perform amplitude modulation on the preliminary dual-channel Fourier plane image to obtain a modulated dual-channel Fourier plane image;

[0021] The second Fourier lens is used to perform inverse Fourier transform processing on the modulated dual-channel Fourier plane image to generate a dual-channel pseudo-color ciphertext image.

[0022] Further, the ciphertext image generation module specifically includes a first CCD camera, a third Fourier lens, and a second CCD camera. The first CCD camera is connected to the first output end of the beam splitter, and the second CCD camera is connected to the second output end of the beam splitter through the third Fourier lens, where:

[0023] The first CCD camera is used to collect the first pseudo-color ciphertext image and generate a first optical ciphertext image;

[0024] The third Fourier lens is used to perform Fourier transform processing on the second pseudo-color ciphertext image to obtain a transformed second pseudo-color ciphertext image;

[0025] The second CCD camera is used to collect the transformed second pseudo-color ciphertext image and generate a Fourier plane of the second optical ciphertext image.

[0026] The second technical solution adopted by the present invention is: a wavelength multiplexing dual-channel dynamic information encryption method based on DMD, including the following steps:

[0027] Perform beam preprocessing on the red laser signal and the blue laser signal respectively, and output a parallel output laser signal with two wavelengths;

[0028] Modulate and perform Fourier transform processing on the parallel output laser signal with two wavelengths to generate a dual-channel pseudo-color ciphertext image;

[0029] Perform beam splitting on the dual-channel pseudo-color ciphertext image to obtain a first pseudo-color ciphertext image and a second pseudo-color ciphertext image;

[0030] Collect the first pseudo-color ciphertext image and the second pseudo-color ciphertext image to generate the Fourier planes of the first optical ciphertext image and the second optical ciphertext image.

[0031] Furthermore, the step of respectively performing beam preprocessing on the red laser signal and the blue laser signal and outputting a parallel output laser signal with two wavelengths specifically includes:

[0032] Obtain the red laser signal and the blue laser signal;

[0033] Perform beam expansion on the red laser signal and the blue laser signal to output an expanded red laser signal and an expanded blue laser signal;

[0034] Perform clipping processing on the expanded red laser signal and the expanded blue laser signal to output a clipped red laser signal and a clipped blue laser signal;

[0035] Merge the clipped red laser signal and the clipped blue laser signal to obtain a parallel output laser signal with two wavelengths.

[0036] Furthermore, the step of modulating and performing Fourier transform processing on the parallel output laser signal with two wavelengths to generate a dual-channel pseudo-color ciphertext image specifically includes:

[0037] Perform wavefront modulation on the parallel output laser signal with two wavelengths and combine it with the writing image to output a dual-channel pseudo-color image;

[0038] Perform Fourier transform processing on the dual-channel pseudo-color image to output a preliminary dual-channel Fourier plane image corresponding to different wavelengths;

[0039] Perform amplitude modulation on the preliminary dual-channel Fourier plane image to obtain a modulated dual-channel Fourier plane image;

[0040] Perform inverse Fourier transform processing on the modulated dual-channel Fourier plane image to generate a dual-channel pseudo-color ciphertext image.

[0041] Furthermore, the step of collecting the first pseudo-color ciphertext image and the second pseudo-color ciphertext image to generate the Fourier planes of the first optical ciphertext image and the second optical ciphertext image specifically includes:

[0042] Collect the first pseudo-color ciphertext image to generate a first optical ciphertext image;

[0043] Perform Fourier transform processing on the second pseudo-color ciphertext image to obtain the transformed second pseudo-color ciphertext image;

[0044] Collect the transformed second pseudo-color ciphertext image to generate the Fourier plane of the second optical ciphertext image.

[0045] The beneficial effects of the method and device of the present invention are as follows: By respectively performing beam preprocessing on the red laser signal and the blue laser signal, the present invention outputs parallel outgoing laser signals with two wavelengths; further, based on the parallel outgoing laser signals with two wavelengths, modulation and Fourier transform processing are performed to generate a dual-channel pseudo-color ciphertext image. Based on the mechanism of wavelength multiplexing, the Fourier domain of the optical images corresponding to different wavelengths is used as the information encryption channel, and multi-channel parallel dynamic information encryption is realized through the amplitude regulation of the DMD. Then, the dual-channel pseudo-color ciphertext image is split to obtain the first pseudo-color ciphertext image and the second pseudo-color ciphertext image. Finally, the first pseudo-color ciphertext image and the second pseudo-color ciphertext image are collected to generate the Fourier plane of the first optical ciphertext image and the second optical ciphertext image, which can perform the same optical information processing operations on each channel, thereby realizing the parallel encryption of multiple optical channels, significantly improving the information encryption efficiency, and greatly enhancing the security and reliability of information encryption. Brief Description of the Drawings

[0046] Figure 1 is a schematic structural diagram of the wavelength multiplexing dual-channel dynamic information encryption device based on DMD of the present invention;

[0047] Figure 2 is a schematic step flow diagram of the wavelength multiplexing dual-channel dynamic information encryption method based on DMD of the present invention;

[0048] Figure 3 is a schematic diagram of parallel dynamic information encryption provided by a specific embodiment of the present invention;

[0049] Figure 4 is a schematic diagram of the experimental encryption and decryption effects provided by a specific embodiment of the present invention.

[0050] Reference Numerals: 1, red laser; 2, blue laser; 31, first laser beam expander; 32, second laser beam expander; 41, first aperture; 42, second aperture; 5, reflector; 6, dichroic mirror; 7, first DMD; 8, first Fourier lens; 9, second DMD; 10, beam splitter; 11, second Fourier lens; 12, first CCD camera; 13, third Fourier lens; 14, second CCD camera. Detailed Description of the Embodiment

[0051] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. For the step numbers in the following embodiments, they are only set for the convenience of elaboration and explanation, and no limitation is imposed on the order between steps. The execution order of each step in the embodiments can be adaptively adjusted according to the understanding of those skilled in the art.

[0052] First of all, it should be noted that most of the current mainstream optical encryption methods highly rely on complex algorithms to reconstruct the target information or flexibly control the degrees of freedom of the light field through metasurfaces for encryption. However, in practical applications, the computational complexity of the algorithms is extremely high, which not only requires a large amount of computing resource investment but also consumes a relatively large amount of time and energy costs during the operation process. The processing difficulty of metasurfaces is high, the structural requirements are precise, and the encrypted information cannot be dynamically changed, making it difficult to meet the requirements of parallel encryption of multiple pieces of information simultaneously. The organic combination of the wavelength multiplexing principle and optical information processing technology brings a new opportunity to solve this dilemma. Each wavelength of light wave can be regarded as an independent optical information encryption channel. Utilizing this characteristic, we can perform the same optical information processing operations on each channel, thereby realizing parallel encryption of multiple optical channels. This method has the remarkable advantages of high-speed processing and low power consumption.

[0053] Refer to Figure 1 , the present invention provides a wavelength multiplexing dual-channel dynamic information encryption device based on DMD. The device includes a beam preprocessing module, a pseudo-color image generation module, a beam splitter, and a ciphertext image generation module. The output end of the beam preprocessing module is connected to the input end of the pseudo-color image generation module, the output end of the pseudo-color image generation module is connected to the input end of the beam splitter, and the output end of the beam splitter is connected to the input end of the ciphertext image generation module.

[0054] First of all, it should be noted that the second DMD is placed at the focal plane position of the first Fourier lens, the beam splitter is placed between the second Fourier lens and the first CCD camera, the first CCD camera is placed at the focal plane of the second Fourier lens, and the second CCD camera is placed at the focal plane of the third Fourier lens.

[0055] The beam preprocessing module is used to perform beam preprocessing on the red laser signal and the blue laser signal respectively, and output parallel outgoing laser signals with two wavelengths;

[0056] Specifically, the beam preprocessing module specifically includes a red laser 1, a blue laser 2, a first laser beam expander 31, a second laser beam expander 32, a first aperture 41, a second aperture 42, a reflector 5 and a dichroic mirror 6. The first laser beam expander and the first aperture are sequentially arranged along the beam output direction of the red laser, and the dichroic mirror is placed at the beam output end of the first aperture. The second laser beam expander and the second aperture are sequentially arranged along the beam output direction of the blue laser, and the reflector is placed at the beam output end of the second aperture. Among them, the red laser is used to emit a red laser signal; the blue laser is used to emit a blue laser signal; the first laser beam expander and the second laser beam expander are respectively used to expand the red laser signal and the blue laser signal, and output the expanded red laser signal and the expanded blue laser signal; the first aperture and the second aperture are used to crop the expanded red laser signal and the expanded blue laser signal, and output the cropped red laser signal and the cropped blue laser signal; the reflector and the dichroic mirror are used to combine the cropped red laser signal and the cropped blue laser signal to obtain a parallel output laser signal with two wavelengths.

[0057] In this embodiment, the laser beam expander is used to expand and collimate the laser beams emitted by lasers with different wavelengths; the aperture is used to limit the size of the laser beam; and separate the ciphertext images with different wavelengths.

[0058] The pseudo-color image generation module is used to perform modulation and Fourier transform processing according to the parallel output laser signal with two wavelengths to generate a dual-channel pseudo-color ciphertext image;

[0059] Specifically, the pseudo-color image generation module specifically includes a first DMD 7, a first Fourier lens 8, a second DMD 9 and a second Fourier lens 11. The first DMD, the first Fourier lens, the second DMD and the second Fourier lens are sequentially arranged along the output direction of the optical path. Among them, the first DMD is used to perform wavefront modulation on the parallel output laser signal with two wavelengths, and combine with the written image to output a dual-channel pseudo-color image; the first Fourier lens is used to perform Fourier transform processing on the dual-channel pseudo-color image to output a preliminary dual-channel Fourier plane image corresponding to different wavelengths; the second DMD is used to perform amplitude modulation on the preliminary dual-channel Fourier plane image to obtain a modulated dual-channel Fourier plane image; the second Fourier lens is used to perform inverse Fourier transform processing on the modulated dual-channel Fourier plane image to generate a dual-channel pseudo-color ciphertext image.

[0060] In this embodiment, the first DMD can change the state of each micromirror according to the written image, and is used for wavefront modulation of two-wavelength laser beams, reflecting a pseudocolor image with different colors in different regions. The optical images corresponding to different wavelengths are respectively used as carriers for information encryption. The first Fourier lens is used to perform Fourier transform processing on the pseudocolor image, and the Fourier planes of the two different wavelengths are respectively used as channels for encrypted information; the second DMD performs amplitude modulation on the Fourier plane images of the two encrypted channels according to the two input encrypted information, so that the two plaintext information on the second DMD are simultaneously loaded onto the Fourier plane images of the two encrypted channels; the second Fourier lens is used to perform inverse Fourier transform processing on the amplitude-modulated Fourier image to generate a pseudocolor ciphertext image.

[0061] The beam splitter 10 is used to split the dual-channel pseudocolor ciphertext image to obtain a first pseudocolor ciphertext image and a second pseudocolor ciphertext image;

[0062] In this embodiment, the beam splitter is used to duplicate the pseudocolor ciphertext image, so that the two ciphertext plane images are split into two paths by the beam splitter and are respectively recorded by the CCD cameras.

[0063] The ciphertext image generation module collects the first pseudocolor ciphertext image and the second pseudocolor ciphertext image, and generates the Fourier planes of the first optical ciphertext image and the second optical ciphertext image.

[0064] Specifically, the ciphertext image generation module specifically includes a first CCD camera 12, a third Fourier lens 13 and a second CCD camera 14. The first CCD camera is connected to the first output end of the beam splitter, and the second CCD camera is connected to the second output end of the beam splitter through the third Fourier lens. Among them, the first CCD camera is used to collect the first pseudocolor ciphertext image and generate the first optical ciphertext image; the third Fourier lens is used to perform Fourier transform processing on the second pseudocolor ciphertext image to obtain the transformed second pseudocolor ciphertext image; the second CCD camera is used to collect the transformed second pseudocolor ciphertext image and generate the Fourier plane of the second optical ciphertext image.

[0065] In this embodiment, the first CCD camera is used to collect the pseudocolor ciphertext image; the third Fourier lens is used to perform Fourier transform processing on the duplicated pseudocolor ciphertext image; the second CCD camera is used to collect the Fourier planes of different wavelengths of the pseudocolor ciphertext image passing through the third Fourier lens.

[0066] Therefore, in this embodiment, a helium-neon laser (DH-HN300, Daheng Optics) with a wavelength of 630 nm and a laser diode module (CPS450, Thorlabs) with a wavelength of 450 nm are adopted. The operating wavelengths of these two laser beams are exactly within the modulation band range of the DMD, and the laser beams they output become the light sources of the optical path after collimation. A laser beam expander is further set. The laser beam expander selected for the experimental device is 20 times magnified, and its applicable wavelength range is 400 - 650 nm. Its main function is to uniformly expand the diameter of the input beam. Then, a diaphragm is set. The area of the laser beam after being expanded by the beam expander is larger than the effective range of the entire DMD, which will cause unnecessary diffraction in optical imaging and thus damage the imaging quality of the entire system. Therefore, a diaphragm is set at the output of the beam expander to cut the beam to match the size of the image displayed on the first DMD. When separating the encrypted images with different wavelengths reflected by the second DMD, this diaphragm is also used to complete the separation. For the reflecting mirror and dichroic mirror, in order to make the red light and blue light merge and then be incident parallel to the effective area of the first DMD, a combination of a reflecting mirror and a dichroic mirror is adopted. The dichroic mirror has a transmittance greater than 90% for wavelengths of 565 nm - 800 nm and a reflectance greater than 98% for wavelengths of 380 nm - 535 nm. The reflecting mirror is placed at 45° on the blue light path to make the blue light beam perpendicular to the original beam. At the intersection of the blue light beam and the red light beam, the dichroic mirror is placed at 45°, so that the red light and blue light beams merge and exit parallel. Further, the first DMD (DMD#1) is set: DMD#1 (DLP6500, resolution: 1920×1080, 8 bit) is located on the imaging plane of the optical 4f system and is directly serially connected to the computer. The DMD can adjust the deflection state of each micromirror unit irradiated by the laser according to different images input by the computer. After amplitude modulation by the DMD, the laser light source can generate corresponding images. For the first Fourier lens (L1), the input optical images with different wavelengths generated by DMD#1 are Fourier-transformed to transform the images from the real domain to the spatial frequency domain. Then, the second DMD (DMD#2) is set. According to the two input encrypted messages, amplitude modulation is performed on the Fourier plane images of the two encrypted channels, so that the two plaintext messages on DMD#2 are simultaneously loaded onto the Fourier plane images of the two encrypted channels; further, a beam splitter is set. In order to be able to observe the encrypted images generated in real time on the optical encryption platform and the spatial frequency domain state after being modulated by DMD#2 at the same time, we split the spatial spectrum signal after being modulated by DMD#2 through a 50:50 beam splitter, and the split optical signals enter different image collection devices for imaging respectively. For the second Fourier lens (L2), the spatial frequency domain light field after being modulated by DMD#2 is inverse Fourier-transformed to convert the spatial frequency of different wavelengths to the image domain, thereby generating a pseudo-color encrypted image.Finally, set up CAM1 to collect optical ciphertext images of different wavelengths with encrypted information and monitor the final imaging quality in real time. The third Fourier lens (L3) further performs Fourier transform on the optical ciphertext image signals generated by the beam splitter to generate Fourier domain images of different wavelengths in subsequent image devices. And CAM2 is responsible for observing in real time the Fourier domain images of different wavelengths after being modulated by DMD#2.

[0067] Refer to Figure 2 , the wavelength multiplexing dual-channel dynamic information encryption method based on DMD includes the following steps:

[0068] S100. Perform beam preprocessing on the red laser signal and the blue laser signal respectively, and output parallel outgoing laser signals with two wavelengths;

[0069] Specifically, obtain the red laser signal and the blue laser signal; perform beam expansion processing on the red laser signal and the blue laser signal to output the expanded red laser signal and the expanded blue laser signal; perform clipping processing on the expanded red laser signal and the expanded blue laser signal to output the clipped red laser signal and the clipped blue laser signal; combine the clipped red laser signal and the clipped blue laser signal to obtain parallel outgoing laser signals with two wavelengths.

[0070] S200. Perform modulation and Fourier transform processing according to the parallel outgoing laser signals with two wavelengths to generate dual-channel pseudo-color ciphertext images;

[0071] Specifically, perform wavefront modulation on the parallel outgoing laser signals with two wavelengths, and combine with the written image to output a dual-channel pseudo-color map; perform Fourier transform processing on the dual-channel pseudo-color map to output a preliminary dual-channel Fourier plane image corresponding to different wavelengths; perform amplitude modulation on the preliminary dual-channel Fourier plane image to obtain a modulated dual-channel Fourier plane image; perform inverse Fourier transform processing on the modulated dual-channel Fourier plane image to generate dual-channel pseudo-color ciphertext images.

[0072] In this embodiment, two incident light fields of different wavelengths are incident on the first DMD on which the original image is uploaded, so as to generate a pseudo-color image with different colors in different regions. The second DMD performs corresponding amplitude modulation on the Fourier planes of the two different wavelength images of the pseudo-color map according to the input encrypted information, so that different plaintext information on the second DMD is simultaneously loaded onto the Fourier plane of the pseudo-color map.

[0073] S300. Perform beam splitting on the dual-channel pseudo-color ciphertext images to obtain a first pseudo-color ciphertext image and a second pseudo-color ciphertext image;

[0074] S400. Collect the first pseudo-color ciphertext image and the second pseudo-color ciphertext image, and generate the Fourier planes of the first optical ciphertext image and the second optical ciphertext image.

[0075] Specifically, collect the first pseudo-color ciphertext image to generate the first optical ciphertext image; perform Fourier transform processing on the second pseudo-color ciphertext image to obtain the transformed second pseudo-color ciphertext image; collect the transformed second pseudo-color ciphertext image to generate the Fourier plane of the second optical ciphertext image.

[0076] In this embodiment, after the two modulated Fourier planes undergo inverse Fourier transform, a pseudo-color ciphertext image is generated and recorded by the CCD camera. Additionally, it should be noted that when the second DMD is used for amplitude modulation, the plaintext information is hidden in the Fourier information plane of the pseudo-color ciphertext image, and the plaintext information cannot be obtained only from the surface of the pseudo-color ciphertext image. It is necessary to first separate the pseudo-color ciphertext image into two ciphertext images of different wavelengths according to different wavelengths, and then perform Fourier transform on the two ciphertext images of different wavelengths using numerical calculation software to obtain the encrypted information in each encryption channel.

[0077] Therefore, in the embodiment of the present invention, first, the laser beams emitted by two lasers with different wavelengths are collimated and expanded, and after being reflected by the first DMD, a pseudo-color image with different colors corresponding to different regions is generated. After passing through the Fourier lens, the optical image of each wavelength is transformed into spatial frequency and incident on the second DMD. By computer controlling the second DMD, two plaintext information are simultaneously encrypted onto the spatial frequencies of two wavelengths to generate two modulated Fourier plane images. The two modulated Fourier plane images then pass through the Fourier lens to generate a pseudo-color ciphertext image, and the ciphertext images of each wavelength are separated by an aperture and recorded by the CCD camera.

[0078] Finally, combined with the attached Figure 3 and the attached Figure 4 As shown, the wavelength-division multiplexing optical dual-channel parallel information encryption method based on DMD in this embodiment is described as follows:

[0079] 1) Generation of dual-channel pseudo-color images. Load the original image onto the first DMD. The first DMD changes the state of each micromirror according to the image written by the computer, so that the DMD modulates the amplitude of the incident light of two wavelengths to generate a pseudo-color image as the carrier for information encryption.

[0080] 2) Implementation of dual-channel parallel encryption: The pseudo-color image is processed by Fourier transform. The images corresponding to different wavelengths are all transformed into corresponding Fourier plane images, which are irradiated on different modulation regions of the second DMD. Two different regions of the second DMD respectively perform amplitude modulation on the Fourier plane images of the images with different wavelengths according to the two input plaintext messages. Some spectral components with encrypted information in the modulated Fourier plane images will be reflected out of the subsequent optical path, so that the two plaintext messages on the second DMD are respectively loaded onto the Fourier planes of the images corresponding to different wavelengths;

[0081] 3) Generation of dual-channel pseudo-color ciphertext images: After the Fourier plane images carrying different encrypted information are processed by inverse Fourier transform, pseudo-color ciphertext images are generated. The pseudo-color ciphertext images are divided into Channel 1 and Channel 2 according to different wavelengths. Among them, for each channel, a CCD camera is used to record;

[0082] 4) Obtaining decryption information: After performing Fourier transform processing on the ciphertext images of Channel 1 and Channel 2 using numerical calculation software, the information hidden in each encryption channel can be obtained.

[0083] Figure 4 This is the effect diagram of realizing dual-channel information encryption and decryption in the Fourier domain of optical images by the embodiment of the present invention. By simultaneously injecting red and blue laser beams onto DMD#1, the micromirrors of DMD#1 will partially reflect the corresponding colors and convert them into pseudo-color optical images. Through Fourier transform, the spatial frequency pattern of the pseudo-color image can be obtained. By controlling DMD#2, ciphertext information (for example, the number "1" and the letter "A") is loaded onto the spatial frequency pattern of the pseudo-color image. Finally, the modulated spatial frequency is converted into a pseudo-color ciphertext image through inverse Fourier transform. Compared with the pseudo-color image before encryption, almost no encryption features can be observed in the pseudo-color ciphertext image. Therefore, the security of information can be ensured by encrypting information in the Fourier domain of the image. If the encrypted message is to be restored, the pseudo-color ciphertext image should be divided into images of two different regions, Channel 1 and Channel 2, according to different wavelengths. Perform Fourier transform on the separated ciphertext images of different wavelengths to obtain the encrypted information. In Figure 3 In the experimental results shown, in the decrypted Fourier pattern, the encrypted number "1" and letter "A" are clearly presented, verifying the decryption performance of the proposed optical encryption scheme. Therefore, we have proven that different information can be encrypted in different channels simultaneously by using the wavelength multiplexing mechanism.

[0084] In summary, the embodiments of the present invention provide a wavelength-division multiplexing parallel dynamic information encryption system and method based on DMD (Digital Micromirror Device). Based on the mechanism of wavelength-division multiplexing, the Fourier domain of optical images corresponding to different wavelengths is used as the information encryption channel, and multi-channel parallel dynamic information encryption is achieved through the amplitude modulation of DMD. This method not only significantly improves the encryption efficiency of information, but also greatly enhances the security and reliability of information encryption, providing a more powerful guarantee means for information security protection.

[0085] Therefore, the embodiments of the present invention have the following improvements compared with the prior art:

[0086] 1) A wavelength-division multiplexing dual-channel parallel dynamic information encryption method based on DMD is proposed. The diversity of wavelengths can provide multiple channels for information encryption. Among them, two wavelengths of red light and blue light are selected as two independent information encryption channels, effectively improving the optical information encryption efficiency.

[0087] 2) The proposed wavelength-division multiplexing dual-channel parallel dynamic information encryption method based on DMD has no restrictions on the carrier of the encrypted information and the type of the encrypted information, greatly expanding the applicable scope of this method in theory.

[0088] 3) For the proposed wavelength-division multiplexing dual-channel parallel dynamic information encryption system based on DMD, if you want to decrypt these encrypted images, you need to separate the ciphertext images according to different colors or wavelengths, and then perform Fourier transform processing. If someone does not know this step, they cannot correctly obtain the encrypted information. This requirement for demultiplexing ensures the security of information to a certain extent.

[0089] The content in the above method embodiments is applicable to the system embodiments of the present invention. The functions specifically implemented by the system embodiments of the present invention are the same as those of the above method embodiments, and the beneficial effects achieved are also the same as those of the above method embodiments.

[0090] The above is a specific description of the preferred embodiments of the present invention. However, the present invention is not limited to the described embodiments. Those skilled in the art can make various equivalent deformations or substitutions without departing from the spirit of the present invention, and these equivalent deformations or substitutions are all included within the scope defined by the claims of this application.

Claims

1. A wavelength-division multiplexing dual-channel dynamic information encryption device based on DMD, characterized in that It includes a beam preprocessing module, a pseudo-color image generation module, a beam splitter, and a ciphertext image generation module. The output end of the beam preprocessing module is connected to the input end of the pseudo-color image generation module. The output end of the pseudo-color image generation module is connected to the input end of the beam splitter. The output end of the beam splitter is connected to the input end of the ciphertext image generation module, where: The beam preprocessing module is used to preprocess the red laser signal and the blue laser signal respectively, and output parallel outgoing laser signals with two wavelengths; The pseudo-color image generation module is used to perform modulation and Fourier transform processing according to the parallel outgoing laser signals with two wavelengths, and generate a two-channel pseudo-color ciphertext image; The beam splitter is used to split the two-channel pseudo-color ciphertext image to obtain a first pseudo-color ciphertext image and a second pseudo-color ciphertext image; The ciphertext image generation module collects the first pseudo-color ciphertext image and the second pseudo-color ciphertext image, and generates the Fourier planes of the first optical ciphertext image and the second optical ciphertext image.

2. The wavelength multiplexing dual-channel dynamic information encryption device based on DMD according to claim 1, wherein The beam preprocessing module specifically includes a red laser, a blue laser, a first laser beam expander, a second laser beam expander, a first aperture, a second aperture, a reflector, and a dichroic mirror. The first laser beam expander and the first aperture are sequentially placed along the beam output direction of the red laser. The dichroic mirror is placed at the beam output end of the first aperture. The second laser beam expander and the second aperture are sequentially placed along the beam output direction of the blue laser. The reflector is placed at the beam output end of the second aperture, where: The red laser is used to emit a red laser signal; The blue laser is used to emit a blue laser signal; The first laser beam expander and the second laser beam expander are respectively used to expand the red laser signal and the blue laser signal, and output the expanded red laser signal and the expanded blue laser signal; The first aperture and the second aperture are used to crop the expanded red laser signal and the expanded blue laser signal, and output the cropped red laser signal and the cropped blue laser signal; The reflector and the dichroic mirror are used to combine the cropped red laser signal and the cropped blue laser signal to obtain parallel outgoing laser signals with two wavelengths.

3. The wavelength multiplexing dual-channel dynamic information encryption device based on DMD according to claim 2, wherein The pseudo-color image generation module specifically includes a first DMD, a first Fourier lens, a second DMD, and a second Fourier lens. The first DMD, the first Fourier lens, the second DMD, and the second Fourier lens are sequentially arranged along the output direction of the optical path, where: The first DMD is used to perform wavefront modulation on the parallel outgoing laser signals with two wavelengths, and combine with the written image to output a two-channel pseudo-color image; The first Fourier lens is used to perform Fourier transform processing on the two-channel pseudo-color image, and output a preliminary two-channel Fourier plane image corresponding to different wavelengths; The second DMD is used to perform amplitude modulation on the preliminary two-channel Fourier plane image to obtain a modulated two-channel Fourier plane image; The second Fourier lens is used to perform an inverse Fourier transform on the modulated dual-channel Fourier plane image to generate a dual-channel pseudo-color ciphertext image.

4. The wavelength multiplexing dual-channel dynamic information encryption device based on DMD according to claim 3, characterized in that, The ciphertext image generation module specifically includes a first CCD camera, a third Fourier lens, and a second CCD camera. The first CCD camera is connected to the first output end of the beam splitter, and the second CCD camera is connected to the second output end of the beam splitter through the third Fourier lens, where: The first CCD camera is used to collect the first pseudo-color ciphertext image and generate a first optical ciphertext image; The third Fourier lens is used to perform a Fourier transform on the second pseudo-color ciphertext image to obtain the transformed second pseudo-color ciphertext image; The second CCD camera is used to collect the transformed second pseudo-color ciphertext image and generate the Fourier plane of the second optical ciphertext image.

5. The wavelength multiplexing dual-channel dynamic information encryption method based on DMD is characterized in that, It includes the following steps: Perform beam preprocessing on the red laser signal and the blue laser signal respectively, and output parallel outgoing laser signals with two wavelengths; Perform modulation and Fourier transform processing according to the parallel outgoing laser signals with two wavelengths to generate a dual-channel pseudo-color ciphertext image; Perform beam splitting on the dual-channel pseudo-color ciphertext image to obtain a first pseudo-color ciphertext image and a second pseudo-color ciphertext image; Collect the first pseudo-color ciphertext image and the second pseudo-color ciphertext image to generate the Fourier plane of the first optical ciphertext image and the second optical ciphertext image.

6. The wavelength multiplexing dual-channel dynamic information encryption method based on DMD according to claim 5, characterized in that, The step of performing beam preprocessing on the red laser signal and the blue laser signal respectively and outputting parallel outgoing laser signals with two wavelengths specifically includes: Obtain the red laser signal and the blue laser signal; Perform beam expansion on the red laser signal and the blue laser signal, and output the expanded red laser signal and the expanded blue laser signal; Perform clipping processing on the expanded red laser signal and the expanded blue laser signal, and output the clipped red laser signal and the clipped blue laser signal; Combine the clipped red laser signal and the clipped blue laser signal to obtain parallel outgoing laser signals with two wavelengths.

7. The wavelength multiplexing dual-channel dynamic information encryption method based on DMD according to claim 6, characterized in that The step of performing modulation and Fourier transform processing according to the parallel outgoing laser signals with two wavelengths to generate a dual-channel pseudo-color ciphertext image specifically includes: Perform wavefront modulation on the parallel outgoing laser signals with two wavelengths, and combine with the written image to output a dual-channel pseudo-color image; Perform Fourier transform processing on the dual-channel pseudo-color image to output a preliminary dual-channel Fourier plane image corresponding to different wavelengths; Perform amplitude modulation on the preliminary dual-channel Fourier plane image to obtain a modulated dual-channel Fourier plane image; Perform an inverse Fourier transform on the modulated dual-channel Fourier plane image to generate a dual-channel pseudo-color ciphertext image.

8. The wavelength multiplexing dual-channel dynamic information encryption method based on DMD according to claim 7, wherein, The step of collecting the first pseudo-color ciphertext image and the second pseudo-color ciphertext image to generate the Fourier plane of the first optical ciphertext image and the second optical ciphertext image specifically includes: Collect the first pseudo-color ciphertext image to generate a first optical ciphertext image; Perform Fourier transform processing on the second pseudo-color ciphertext image to obtain the transformed second pseudo-color ciphertext image; Collect the transformed second pseudo-color ciphertext image to generate the Fourier plane of the second optical ciphertext image.

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