Compressed ultrafast imaging device, method and storage medium based on time stretching

Abstract

The application discloses a time-stretch-based compressed ultrafast imaging device and method and a storage medium. The time-stretch-based compressed ultrafast imaging device comprises a laser generation module, a collimation module, a laser conversion module, an encoding module, an image acquisition module and a control processing module. The laser generation module is used for emitting laser. The collimation module is connected with the laser generation module in an optical path and is used for collimating the laser. The laser conversion module is connected with the collimation module in an optical path and is used for converting the collimated laser into spatial light. The encoding module is connected with the laser conversion module in an optical path and is used for encoding according to the spatial light. The image acquisition module is connected with the encoding module. The control processing module is in communication connection with the laser generation module and the image acquisition module respectively, is used for obtaining a target image sequence frame according to an observation image sent by the image acquisition module, and can effectively improve the time resolution of ultrafast imaging.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high-speed imaging, and particularly relates to a compressed ultrafast imaging device and method based on time stretching and a storage medium. BACKGROUND

[0002] Ultrafast imaging technology is a key core technology for exploring unknown transient processes. Ultrafast imaging technology can record transient events that cannot be repeated or are difficult to produce. In related technologies, compressed ultrafast photography (CUP) is one of the most common imaging systems in ultrafast imaging, and is widely used in visualizing two-dimensional spatial information ultrafast imaging. However, the time resolution of CUP imaging is limited by the response time resolution of the stripe tube in the stripe camera, and the time resolution that can be achieved is only picoseconds, so the time resolution of ultrafast imaging is low. SUMMARY

[0003] Embodiments of the present application provide a compressed ultrafast imaging device and method based on time stretching and a storage medium, which can effectively improve the time resolution of ultrafast imaging.

[0004] In a first aspect, the embodiments of the present application provide a compressed ultrafast imaging device based on time stretching, comprising:

[0005] A laser generation module, configured to emit laser light;

[0006] A collimation module, optically connected with the laser generation module, configured to collimate the laser light;

[0007] A laser conversion module, optically connected with the collimation module, configured to convert the collimated laser light into spatial light;

[0008] An encoding module, optically connected with the laser conversion module, configured to encode the spatial light;

[0009] An image acquisition module, connected with the encoding module;

[0010] A control processing module, in communication connection with the laser generation module and the image acquisition module respectively, configured to obtain a target image sequence frame according to an observation image sent by the image acquisition module.

[0011] According to the first aspect of the present application, a time-stretched compressed ultrafast imaging device has at least the following beneficial effects: the time-stretched compressed ultrafast imaging device includes: a laser generation module, a collimation module, a laser conversion module, an encoding module, an image acquisition module, and a control processing module, wherein the collimation module is optically connected to the laser generation module, the laser conversion module is optically connected to the collimation module, the encoding module is optically connected to the laser conversion module, the image acquisition module is connected to the encoding module, and the control processing module is communicatively connected to the laser generation module and the image acquisition module, respectively. The control processing module controls the laser generation module to emit laser light, then uses the collimation module to collimate the laser light to improve the directional stability of the laser light, then converts the collimated laser light into spatial light via the laser conversion module so that the encoding module can encode the spatial light. After the spatial light is encoded, it is optically transmitted to the image acquisition module, which is used to acquire an observation image. The control processing module then obtains a target image sequence frame based on the observation image sent by the image acquisition module, thereby effectively improving the temporal resolution of ultrafast imaging. Based on the time-stretching compressed ultrafast imaging device provided by the present application, a laser conversion module is used to time-stretch the laser to obtain spatial light, and then the encoding module is used to spatially separate and encode the spatial light. After the spatial light is encoded, it is transmitted to the image acquisition module via an optical path, which can realize the shooting of ultrafast dynamic scenes. Then, the control processing module obtains the target image sequence frame according to the observation image sent by the image acquisition module to reconstruct the target image sequence frame of the ultrafast dynamic scene. Compared with the CUP imaging used in the related art which is limited by the response time resolution of the streak tube in the streak camera, the time resolution of ultrafast imaging can be effectively improved.

[0012] According to some embodiments of the first aspect of the present application, the laser generation module includes a laser and an attenuator, and the laser is optically connected to the attenuator.

[0013] According to some embodiments of the first aspect of the present application, the collimation module includes a first reflector, a second reflector, and a third reflector, and the first reflector, the second reflector, and the third reflector are optically connected in sequence.

[0014] According to some embodiments of the first aspect of the present application, the laser conversion module includes a first collimator, a second collimator and a time disperser, and the time disperser is optically connected to the first collimator and the second collimator respectively.

[0015] According to some embodiments of the first aspect of the present application, the encoding module includes a spatial disperser, a fourth reflector, a fifth reflector, a sixth reflector, a first lens, a second lens, a third lens, a fourth lens and a mask plate, and the spatial disperser, the fourth reflector, the fifth reflector, the first lens, the second lens, the mask plate, the third lens, the fourth lens and the sixth reflector are optically connected in sequence.

[0016] In a second aspect, an embodiment of the present application provides a method for compressive ultrafast imaging based on time stretching, which is applied to a control processing module of the compressive ultrafast imaging device based on time stretching described in the first aspect, comprising:

[0017] Acquiring the observation image sent by the image acquisition module;

[0018] Processing the observed image using an underdetermined set of equations to obtain an original signal corresponding to the observed image;

[0019] The original signal is reconstructed according to a two-step iterative shrinkage / thresholding algorithm to obtain the target image sequence frames.

[0020] The time-stretching-based compressed ultrafast imaging method according to the second aspect of the present application has at least the following beneficial effects: acquiring the observation image sent by the image acquisition module, then processing the observation image using an underdetermined set of equations to obtain the original signal corresponding to the observation image, which can effectively improve the computational efficiency, and then reconstructing the original signal according to a two-step iterative shrinkage / thresholding algorithm to ensure accurate reconstruction of the original signal and obtain a target image sequence frame, which can effectively improve the temporal resolution of ultrafast imaging.

[0021] According to some embodiments of the second aspect of the present application, the underdetermined system of equations is y=Φx=Φψs=As,

[0022] Where y represents the known measurement value, y∈R m , Φ represents the measurement matrix, the size of Φ is M×N, x represents the original signal, x∈R n , ψ represents the sparse basis matrix, s represents the sparse coefficient, the number of non-zero elements in s is c, and c <m<n,A表示感知矩阵,A=Φψ,A的大小为M×N。

[0023] According to some embodiments of the second aspect of the present application, the processing the observed image using the underdetermined equations to obtain the original signal corresponding to the observed image includes:

[0024] When the sensing matrix satisfies the restricted equidistance characteristic criterion, a target sparse coefficient is obtained by using a preset signal reconstruction algorithm;

[0025] The original signal is determined according to the target sparse coefficient and the underdetermined equation group.

[0026] According to some embodiments of the second aspect of the present application, the two-step iterative shrinkage / thresholding algorithm is

[0027]

[0028] Among them, ‖·‖2 is the l2 norm, ‖·‖ TV is the TV function, r represents the weight ratio of the adjustment regularization parameter to the measurement fidelity, I represents the dynamic scene data, T represents the time-space integration operator, S represents the time shear operator in the vertical direction, C represents the encoding operator, and E represents the image data of the observed image.

[0029] In a third aspect, an embodiment of the present application further provides a computer-readable storage medium, wherein the computer-readable storage medium stores computer-executable instructions, and the computer-executable instructions are used to enable a computer to execute the time-stretching-based compressive ultrafast imaging method as described in the second aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The accompanying drawings are used to provide a further understanding of the technical solution of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the technical solution of the present invention and do not constitute a limitation to the technical solution of the present invention.

[0031] Figure 1 This is a module schematic diagram of a time-stretching-based compressive ultrafast imaging device provided by one embodiment of the present application;

[0032] Figure 2 This is a schematic diagram of the optical path of a time-stretching-based compressive ultrafast imaging device provided by another embodiment of the present application;

[0033] Figure 3 is a flowchart of the steps of a time-stretching-based compressive ultrafast imaging method provided by another embodiment of the present application;

[0034] Figure 4 This is a flowchart of the steps of obtaining the original signal corresponding to the observed image provided by another embodiment of the present application;

[0035] Figure 5 This is a flowchart of the steps of a time-stretching-based compressive ultrafast imaging method provided in another embodiment of the present application. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0037] It can be understood that, although the functional modules are divided in the device schematic diagram, and the logical order is shown in the flowchart, in some cases, the steps shown or described can be performed in a manner different from the module division in the device or the order in the flowchart. The terms "first", "second", and the like in the specification, claims, or above-mentioned drawings are used to distinguish similar objects, and do not necessarily describe a specific order or sequence.

[0038] The application provides a time-stretching-based compressed ultrafast imaging device, method and storage medium, wherein the time-stretching-based compressed ultrafast imaging device comprises a laser generation module, a collimation module, a laser conversion module, an encoding module, an image acquisition module and a control processing module, wherein the collimation module is optically connected with the laser generation module, the laser conversion module is optically connected with the collimation module, the encoding module is optically connected with the laser conversion module, the image acquisition module is connected with the encoding module, and the control processing module is communicatively connected with the laser generation module and the image acquisition module. The control processing module controls the laser generation module to emit laser, and then collimates the laser by using the collimation module to improve the directional stability of the laser, and then converts the collimated laser into spatial light by using the laser conversion module, so as to encode the spatial light by using the encoding module, and then transmit the spatial light to the image acquisition module by using the optical path, and the image acquisition module is used to acquire observation images, and then the control processing module obtains a target image sequence frame according to the observation images sent by the image acquisition module, which can effectively improve the time resolution of ultrafast imaging. According to the time-stretching-based compressed ultrafast imaging device provided in the application, the laser is time-stretched to obtain spatial light by using the laser conversion module, and then the spatial light is spatially separated and encoded by using the encoding module, and then the spatial light is transmitted to the image acquisition module by using the optical path after being encoded, which can realize the shooting of an ultrafast dynamic scene, and then the control processing module obtains a target image sequence frame according to the observation images sent by the image acquisition module, so as to reconstruct the target image sequence frame of the ultrafast dynamic scene, which can effectively improve the time resolution of ultrafast imaging compared with the CUP imaging in the related art which is limited by the response time resolution of the stripe tube in the stripe camera.

[0039] The embodiments of the application are further described below with reference to the drawings.

[0040] Reference Figure 1 , Figure 1 is a module schematic diagram of a time-stretching-based compressed ultrafast imaging device provided by an embodiment of the application, and the time-stretching-based compressed ultrafast imaging device 100 comprises:

[0041] The laser generation module 110 is used to emit laser.

[0042] The collimation module 120 is optically connected to the laser generating module 110 and is used to collimate the laser;

[0043] The laser conversion module 130 is optically connected to the collimation module 120 and is used to convert the collimated laser into spatial light;

[0044] The encoding module 140 is optically connected to the laser conversion module 130 and is used to encode according to the spatial light;

[0045] An image acquisition module 150 , which is connected to the encoding module 140 ;

[0046] The control processing module 160 is in communication with the laser generating module 110 and the image acquisition module 150 respectively. The control processing module 160 is used to obtain a target image sequence frame according to the observation image sent by the image acquisition module 150 .

[0047] It should be noted that the embodiments of the present application do not limit the specific type of image acquisition module 150; it may be a synchronous streak camera, a femtosecond streak camera, or a high dynamic range streak camera. It is understood that a synchronous streak camera can synchronously capture spatial data or spectral data and has the characteristics of fast response speed, high temporal resolution, and high reliability. Using a synchronous streak camera can effectively improve the accuracy of image acquisition.

[0048] It can be understood that the control processing module 160 controls the laser generation module 110 to emit laser, and then collimates the laser by using the collimation module 120 to improve the directional stability of the laser, and then converts the collimated laser into spatial light by using the laser conversion module 130, so as to code according to the spatial light by using the coding module 140. Since the spatial light has different pulse frequency components, different spatial coordinates are corresponded according to different pulse frequency components, so as to realize coding. After the spatial light completes coding, the spatial light is transmitted to the image acquisition module 150 through an optical path. The image acquisition module 150 is used to acquire an observation image, and then the target image sequence frame is obtained according to the observation image sent by the image acquisition module 150 by using the control processing module 160, so as to effectively improve the time resolution of the ultrafast imaging. Based on the time-stretch-based compressed ultrafast imaging device 100 provided in the application, the laser conversion module 130 is used to time-stretch the laser to obtain spatial light, and then the spatial light is spatially separated and coded by using the coding module 140. After the spatial light completes coding, the spatial light is transmitted to the image acquisition module 150 through an optical path. The shooting of the ultrafast dynamic scene can be realized, and then the target image sequence frame of the ultrafast dynamic scene is reconstructed by using the control processing module 160 according to the observation image sent by the image acquisition module 150. Compared with the CUP imaging in the related art, which is limited by the response time resolution of the stripe tube in the stripe camera, the specific light source constraint condition is not required, the optical path is simple, the light loss can be effectively reduced, and the time resolution of the ultrafast imaging can be effectively improved.

[0049] With reference to Figure 2 In some embodiments of the application, the laser generation module 110 includes a laser 111 and an attenuator 112, and the laser 111 is optically connected with the attenuator 112.

[0050] It should be noted that the specific type of the laser 111 is not limited in the embodiments of the application, and the laser 111 can be a femtosecond laser, an optical fiber laser, or an ultrashort pulse laser. It can be understood that the femtosecond laser has the characteristics of large energy, short pulse, high speed, and high resolution. The femtosecond laser is used as the laser, so as to ensure the light quality and spectral stability of the laser emitted by the laser.

[0051] It can be understood that the output power of the laser 111 can be 1300nw, and the wavelength can be 800nm. The light outlet of the attenuator 112 can be 0.05%, which can effectively reduce the light intensity of the laser.

[0052] It can be understood that the laser 111 emits laser, and since the laser 111 is optically connected with the attenuator 112, the laser passes through the attenuator 112 along the optical path to reduce the light intensity of the laser, so as to avoid the problem that the image acquisition module 150 is damaged due to overexposure, and also to ensure the accuracy of the ultrafast imaging.

[0053] In some embodiments of the present application, the collimation module 120 includes a first mirror 121, a second mirror 122, and a third mirror 123, which are sequentially connected in the optical path.

[0054] It should be noted that the embodiments of the present application do not limit the specific structure of the collimation module 120, which can include the first mirror 121, the second mirror 122, and the third mirror 123, or more than three mirrors, etc., as long as it can achieve the collimation of the laser.

[0055] It can be understood that the laser passes through the attenuator 112 and then sequentially passes through the first mirror 121, the second mirror 122, and the third mirror 123, so that the laser becomes collimated laser, thereby improving the directional stability of the laser. Moreover, the laser is adjusted in angle by the first mirror 121, the second mirror 122, and the third mirror 123, so that the height of the laser is the same as the slit height of the image acquisition module 150, thereby reducing the height difference and improving the accuracy of the observation image collected by the image acquisition module 150.

[0056] In some embodiments of the present application, the laser conversion module 130 includes a first collimator 131, a second collimator 132, and a temporal disperser 133, which are respectively connected in the optical path.

[0057] It should be noted that the embodiments of the present application do not limit the specific structure of the laser conversion module 130, which can include the first collimator 131, the second collimator 132, and the temporal disperser 133, or more than three collimators and temporal dispersers 133, etc., as long as it can achieve the conversion of the collimated laser into spatial light.

[0058] It can be understood that the laser passes through the collimation module 120 and then enters the laser conversion module 130 along the optical path, wherein the laser conversion module includes the first collimator 131, the second collimator 132, and the temporal disperser 133, which are respectively connected in the optical path. The collimated laser sequentially passes through the first collimator 131, the temporal disperser 133, and the second collimator 132. The collimated laser first passes through the first collimator 131 for collimation to ensure the directional stability of the laser, then enters the temporal disperser 133, so that the pulse spectrum mapping or time stretching of the laser is 1D time data flow, which can reduce light loss, and then passes through the second collimator 132 to be converted into spatial light.

[0059] In some embodiments of the present application, the encoding module 140 includes a spatial disperser 141, a fourth reflector 142, a fifth reflector 143, a sixth reflector 144, a first lens 145, a second lens 146, a third lens 147, a fourth lens 148 and a mask plate 149, and the spatial disperser 141, the fourth reflector 142, the fifth reflector 143, the first lens 145, the second lens 146, the mask plate 149, the third lens 147, the fourth lens 148 and the sixth reflector 144 are optically connected in sequence.

[0060] It should be noted that the embodiments of the present application do not limit the specific structure of the encoding module 140, which may include a spatial disperser 141, a fourth reflector 142, a fifth reflector 143, a sixth reflector 144, a first lens 145, a second lens 146, a third lens 147, a fourth lens 148 and a mask plate 149, or it may include a spatial disperser 141, more than three reflectors, more than four lenses and a mask plate 149, etc.

[0061] It can be understood that the focal length of the first lens 145 can be 75 mm, the focal length of the second lens 146 can be 100 mm, and the first optical 4f system composed of the first lens 145 and the second lens 146 makes the rainbow light beam focus on the mask plate 149. The focal length of the third lens 147 can be 100 mm, and the focal length of the fourth lens 148 can be 150 mm. The second optical 4f system composed of the third lens 147 and the fourth lens 148 can realize optical filtering.

[0062] It is understood that the spatial light enters the encoding module 140 along an optical path. The encoding module 140 includes a spatial disperser 141, a fourth reflector 142, a fifth reflector 143, a sixth reflector 144, a first lens 145, a second lens 146, a third lens 147, a fourth lens 148, and a mask 149. The spatial disperser 141, the fourth reflector 142, the fifth reflector 143, the first lens 145, the second lens 146, the mask 149, the third lens 147, the fourth lens 148, and the sixth reflector 144 are optically connected in sequence. The spatial light first enters the spatial disperser 141, where the pulse spectrum of the spatial light is mapped into a 1D or 2D rainbow beam, achieving spatial separation of the spatial light, thereby illuminating the dynamic sample 200. The dynamic sample 200 is located between the spatial disperser 141 and the fourth reflector 142. Encoding is achieved by utilizing the different pulse frequency components of spatial light, corresponding to different spatial coordinates on the dynamic sample. The encoded rainbow light beam first passes through the fourth reflector 142 and the fifth reflector 143 to ensure the accuracy of the light transmission direction of the encoded rainbow light beam. It then passes through the first optical 4f system composed of the first lens 145 and the second lens 146, so that the rainbow light beam is focused on the mask plate 149. The mask plate 149 is pre-loaded with a random matrix to ensure efficient encoding. The encoded image enters the second optical 4f system composed of the third lens 147 and the fourth lens 148 along the optical path to filter the encoded image, improve the image quality of the encoded image, reduce data redundancy, and effectively improve the temporal resolution of ultrafast imaging. It then passes through the sixth reflector 144 and arrives at the image acquisition module 150.

[0063] Reference Figure 3 , Figure 3 This is a flowchart of a method for compressive ultrafast imaging based on time stretching provided by an embodiment of the present application. The method for compressive ultrafast imaging based on time stretching is applied to the control processing module 160 of the above-mentioned compressive ultrafast imaging device 100 based on time stretching. The method includes but is not limited to the following steps:

[0064] Step 310, acquiring the observation image sent by the image acquisition module;

[0065] Step 320, processing the observed image using the underdetermined equations to obtain the original signal corresponding to the observed image;

[0066] Step 330 : reconstruct the original signal according to a two-step iterative shrinkage / thresholding algorithm to obtain a target image sequence frame.

[0067] It can be understood that obtaining the observation image sent by the image acquisition module and then processing the observation image using the underdetermined equations to obtain the original signal corresponding to the observation image can effectively improve the computing efficiency. The original signal is then reconstructed according to the two-step iterative shrinkage / threshold algorithm to ensure accurate reconstruction of the original signal and obtain the target image sequence frame, which can effectively improve the temporal resolution of ultrafast imaging.

[0068] In some embodiments of the present application, the underdetermined system of equations is y=Φx=Φψs=As,

[0069] Where y represents the known measurement value, y∈R m , Φ represents the measurement matrix, the size of Φ is M×N, x represents the original signal, x∈R n , ψ represents the sparse basis matrix, s represents the sparse coefficient, the number of non-zero elements in s is c, and c <m<n,A表示感知矩阵,A=Φψ,A的大小为M×N。

[0070] It's understandable that compressed sensing can sample sparse or compressible signals at a frequency lower than the Nyquist sampling rate, reducing data transmission and accurately reconstructing the signal. However, natural signals are not sparse and require sparsification on a sparse basis. For example, let x = ψs to obtain a sparse representation of the signal, resulting in the underdetermined system of equations y = Φx = Φψs = As.

[0071] In addition, refer to Figure 4 In one embodiment, Figure 3 Step 320 in the illustrated embodiment also includes but is not limited to the following steps:

[0072] Step 410: When the sensing matrix satisfies the restricted equidistance characteristic criterion, a preset signal reconstruction algorithm is used to obtain a target sparse coefficient;

[0073] Step 420: Determine the original signal based on the target sparse coefficients and the underdetermined equations.

[0074] It is understandable that the preset signal reconstruction algorithm may be min||S||0.sty=As, and the restricted isometry characteristic criterion is defined as the restricted isometry characteristic criterion parameter δ of the matrix B. k , 0<δ k <1, and satisfies Among them, c represents the sparse signal of k, if δ k <1, then the matrix B satisfies the k-order restricted isometry criterion.

[0075] It's understandable that, given known measurements and a perception matrix, solving for the sparse coefficients or original signal is equivalent to solving a system of linear equations. In an underdetermined system, since the number of equations is far less than the number of unknowns, the problem becomes solving an underdetermined system, but there are infinite solutions to underdetermined systems. When the perception matrix satisfies the restricted isometry criterion, a preset signal reconstruction algorithm can be used to calculate a unique solution to the underdetermined system, resulting in the target sparse coefficients. The original signal can then be determined based on the target sparse coefficients and the underdetermined system.

[0076] In some embodiments of the present application, the two-step iterative shrinkage / thresholding algorithm is

[0077]

[0078] Among them, ‖·‖2 is the l2 norm, ‖·‖ TV is the TV function, r represents the weight ratio of the adjustment regularization parameter to the measurement fidelity, I represents the dynamic scene data, T represents the time-space integration operator, S represents the time shear operator in the vertical direction, C represents the encoding operator, and E represents the image data of the observed image.

[0079] It is understandable that the initial guess can be set as a point in n-dimensional space and recorded as I0, and the search for the target point I0 can be started from the initial point I0. L , update the intermediate point I in each iteration i , until the middle point I i Approaching target point I L The search path should follow the preset signal reconstruction algorithm to improve the accuracy of the target image sequence frames. A two-step iterative shrinkage / thresholding algorithm is used to reconstruct the original signal to obtain the target image sequence frames, which can effectively improve the temporal resolution of ultrafast imaging.

[0080] Reference Figure 5 , Figure 5 This is a flowchart of a method for compressive ultrafast imaging based on time stretching provided by another embodiment of the present application. The method for compressive ultrafast imaging based on time stretching is applied to the control processing module 160 of the above-mentioned compressive ultrafast imaging device 100 based on time stretching. The method may also include but is not limited to the following steps:

[0081] Step S510, obtaining a coded image of the dynamic light beam;

[0082] Step S520, obtaining the compressed dynamic scene graph sent by the image acquisition module;

[0083] Step S530 : Inputting the compressed dynamic scene graph and the encoded image into a preset reconstruction algorithm model to obtain a dynamic scene image sequence frame.

[0084] It is understood that when the encoded image of the dynamic light beam is transmitted to the image acquisition module, the image acquisition module cuts the dynamic scene and captures the cut scene to obtain a compressed dynamic scene image. The encoded image of the dynamic light beam and the compressed dynamic scene image are obtained, and the compressed dynamic scene image and the encoded image are input into a preset reconstruction algorithm model to obtain a sequence of dynamic scene image frames. This can fully capture the dynamic process, achieve observation of ultrafast dynamic scenes, and ensure the temporal resolution of ultrafast imaging.

[0085] In addition, an embodiment of the present application further provides a computer-readable storage medium, wherein the computer-readable storage medium stores computer-executable instructions. The computer-executable instructions are executed by a processor or a controller, so that the processor can execute the time-stretching-based compressive ultrafast imaging method applied to the control processing module 160 of the time-stretching-based compressive ultrafast imaging device 100 in the above embodiment, for example, executing the above-described Figure 3 Method steps 310 to 330, Figure 4 Method steps 410 to 420 and Figure 5 Method step S510 to method step S530. It will be appreciated by those skilled in the art that all or some of the steps and systems in the method disclosed above can be implemented as software, firmware, hardware, and appropriate combinations thereof. Some physical components or all physical components can be implemented as software executed by a processor, such as a central processing unit, a digital signal processor, or a microprocessor, or implemented as hardware, or implemented as an integrated circuit, such as an application-specific integrated circuit. Such software can be distributed on a computer-readable medium, which can include computer storage media (or non-transitory media) and communication media (or temporary media). As known to those skilled in the art, the term computer storage media includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information (such as computer-readable instructions, data structures, program modules, or other data). Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tapes, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to store desired information and can be accessed by a computer. Furthermore, as is well known to those skilled in the art, communication media typically embodies computer-readable instructions, data structures, program modules, or other data in a modulated data signal such as a carrier wave or other transport mechanism, and may include any information delivery media.

[0086] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0087] The above is a specific description of the preferred implementation of the present application, but the present application is not limited to the above implementation mode. Technical personnel familiar with the field can also make various equivalent modifications or substitutions without violating the spirit of the present application. These equivalent modifications or substitutions are all included in the scope defined by the claims of the present application.

Claims

1. A time-stretching-based compressed ultrafast imaging device, characterized in that: include: a laser generating module, wherein the laser generating module is configured to emit laser light; A collimation module, the collimation module being optically connected to the laser generating module and configured to collimate the laser; A laser conversion module, the laser conversion module being optically connected to the collimation module and configured to convert the collimated laser into spatial light; an encoding module, the encoding module being optically connected to the laser conversion module and configured to perform encoding according to the spatial light; An image acquisition module, connected to the encoding module; a control processing module, the control processing module being in communication with the laser generating module and the image acquisition module, respectively, and configured to obtain a target image sequence frame based on the observation image sent by the image acquisition module; The laser generating module includes a laser and an attenuator, and the laser is optically connected to the attenuator; The collimating module includes a first reflector, a second reflector and a third reflector, wherein the first reflector, the second reflector and the third reflector are optically connected in sequence; The laser conversion module includes a first collimator, a second collimator and a time disperser, and the time disperser is optically connected to the first collimator and the second collimator respectively; The encoding module includes a spatial disperser, a fourth reflector, a fifth reflector, a sixth reflector, a first lens, a second lens, a third lens, a fourth lens and a mask plate. The spatial disperser, the fourth reflector, the fifth reflector, the first lens, the second lens, the mask plate, the third lens, the fourth lens and the sixth reflector are optically connected in sequence.

2. A method for compressive ultrafast imaging based on time stretching, applied to the control processing module of the compressive ultrafast imaging device based on time stretching according to claim 1, characterized in that: include: Acquiring the observation image sent by the image acquisition module; Processing the observed image using an underdetermined set of equations to obtain an original signal corresponding to the observed image; The original signal is reconstructed according to a two-step iterative shrinkage / thresholding algorithm to obtain the target image sequence frames.

3. The method for compressive ultrafast imaging based on time stretching according to claim 2, characterized in that: The underdetermined system of equations is y=Φx=Φψs=As, where \(y\) represents the known measurement value, \(y\in\mathbb{R}\). m , \(\varPhi\) represents the measurement matrix, the size of \(\varPhi\) is \(M\times N\), \(x\) represents the original signal, \(x\in\mathbb{R}\). n , \(\varPsi\) represents the sparse basis matrix, \(s\) represents the sparse coefficient, the number of non-zero elements in \(s\) is \(c\), and \(c\lt m\lt n\), \(A\) represents the sensing matrix, \(A = \varPhi\varPsi\), the size of \(A\) is \(M\times N\).

4. The method for compressive ultrafast imaging based on time stretching according to claim 3, characterized in that: The method of processing the observed image by using an underdetermined set of equations to obtain an original signal corresponding to the observed image includes: When the sensing matrix satisfies the restricted equidistance characteristic criterion, a target sparse coefficient is obtained by using a preset signal reconstruction algorithm; The original signal is determined according to the target sparse coefficient and the underdetermined equation group.

5. The method for compressive ultrafast imaging based on time stretching according to claim 2, characterized in that: The two-step iterative shrinkage / thresholding algorithm is Among them, ‖·‖2 is the l2 norm, ‖·‖ TV is the TV function, r represents the weight ratio of the adjustment regularization parameter to the measurement fidelity, I represents the dynamic scene data, T represents the time-space integration operator, S represents the time shear operator in the vertical direction, C represents the encoding operator, and E represents the image data of the observed image.

6. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer-executable instructions, and the computer-executable instructions are used to enable a computer to execute the time-stretching-based compressive ultrafast imaging method according to any one of claims 2 to 5.

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