Stacked Imaging Method and Device for Reducing Data Sampling Rate

Abstract

The present application relates to a ptychography method and apparatus for reducing data sampling rate. Among them, the method includes: scanning a sample with a particle beam to collect diffraction data that meets a preset sampling rate condition; initializing a sample potential function and a beam spot function using an inverse space matrix that meets a first preset condition and an inverse space pixel size that meets a second preset condition; merging pixels of the diffraction data obtained by the algorithm, and then calculating a loss function with the experimental diffraction data; if the loss function does not converge to a target value, optimizing the initialized sample potential function and beam spot function to obtain optimized sample potential function and beam spot function. Repeat the above operations, and obtain a high-quality ptychography result through calculation of the iterative process. Thereby, the problem of significantly longer data acquisition time of the ptychography method compared to other imaging methods is solved.

Description

Technical Field

[0001] This application relates to the field of microscopy technology, and particularly to a ptychography imaging method and device for reducing the data sampling rate. Background Art

[0002] The ptychography imaging method has very significant advantages compared with other microscopy imaging methods. While providing ultra-high resolution, it can finely and quantitatively analyze the microstructure of materials.

[0003] In related technologies, the traditional ptychography imaging method is usually regarded as a kind of coherent diffraction imaging, called scanning coherent diffraction imaging. The basic principle of coherent diffraction imaging to achieve phase retrieval is oversampling in the reciprocal space. The traditional ptychography imaging method inherits this feature, and there is oversampling to varying degrees when recording diffraction patterns. Therefore, the experimental data set usually has a large size.

[0004] However, in related technologies, often more than ten thousand pixels are required for each scanning position, which also results in a significantly longer data acquisition time for the traditional ptychography imaging method compared with other imaging methods. The long data acquisition time will cause changes in the experimental state and sample position, etc. These changes have a non-negligible impact on the imaging quality. As the amount of data collected at each scanning position increases, this impact becomes more significant, bringing great difficulties to accurate quantitative analysis and urgently needing improvement. Summary of the Invention

[0005] This application provides a ptychography imaging method and device for reducing the data sampling rate to solve the problem of significantly longer data acquisition time of the ptychography imaging method compared with other imaging methods.

[0006] The first aspect of the embodiments of this application provides a ptychography imaging method for reducing the data sampling rate, including the following steps: scanning a sample with a particle beam to collect diffraction data that meets the preset sampling rate condition; during the reconstruction process of the ptychography imaging algorithm, using a reciprocal space matrix that meets the first preset condition and a reciprocal space pixel size that meets the second preset condition to initialize the sample potential function and the beam spot function, obtaining the initialized sample potential function and beam spot function; merging the pixels of the diffraction data obtained by the algorithm, matching the target matrix size that meets the preset condition, calculating the loss function according to the target matrix size and the experimental diffraction data, and determining whether the loss function converges to the target value; if the loss function does not converge to the target value, optimizing the initialized sample potential function and beam spot function until reaching the preset convergence stop condition, obtaining the optimized sample potential function and beam spot function, and obtaining the ptychography imaging result according to the optimized sample potential function and beam spot function.

[0007] Optionally, in an embodiment of the present application, the merging of the pixels of the diffraction data to match the target matrix size that meets the preset conditions includes: obtaining the scanning position of the sample and obtaining the diffraction data according to the scanning position; merging the pixels of the diffraction data to obtain a matrix with the same size as the experimental diffraction data.

[0008] Optionally, in an embodiment of the present application, the calculation formula of the loss function is:

[0009]

[0010] where B(·) represents merging the pixels of the matrix to obtain a matrix with the same size as the experimental diffraction data, j represents the serial number of the scanning position, u and v both represent the coordinates of the experimental diffraction intensity matrix, |·| represents calculating the modulus of each element in the matrix respectively, represents calculating the two-dimensional Fourier transform of the matrix, ψ j is the outgoing wave function to be optimized, and I j is the diffraction intensity matrix collected experimentally.

[0011] Optionally, in an embodiment of the present application, the calculation formula of the outgoing wave function is:

[0012]

[0013] where P(r - r j ) represents the electron beam scanned to the jth position, and O l (r) represents the sample transmission function of the lth layer, represents Fresnel diffraction or other effects.

[0014] An embodiment of the second aspect of the present application provides a ptychography imaging device for reducing the data sampling rate, including: an acquisition module for scanning a sample with a particle beam to acquire diffraction data that meets the preset sampling rate conditions; an initialization module for initializing the sample potential function and the beam spot function using the reciprocal space matrix that meets the first preset condition and the reciprocal space pixel size that meets the second preset condition during the reconstruction process of the ptychography algorithm to obtain the initialized sample potential function and beam spot function; a judgment module for merging the pixels of the diffraction data obtained by the algorithm to match the target matrix size that meets the preset conditions, calculating the loss function according to the target matrix size and the experimental diffraction data, and judging whether the loss function converges to the target value; an optimization module for optimizing the initialized sample potential function and beam spot function when the loss function converges to the target value until the preset convergence stop condition is reached to obtain the optimized sample potential function and beam spot function, so as to obtain the ptychography imaging result according to the optimized sample potential function and beam spot function.

[0015] Optionally, in an embodiment of the present application, the determination module includes: an acquisition unit configured to acquire the scanning position of the sample and obtain the diffraction data according to the scanning position; and a merging unit configured to merge the pixels of the diffraction data to obtain a matrix having the same size as the experimental diffraction data.

[0016] Optionally, in an embodiment of the present application, the calculation formula of the loss function is:

[0017]

[0018] wherein, B(·) represents merging the pixels of the matrix to obtain a matrix having the same size as the experimental diffraction data, j represents the serial number of the scanning position, both u and v represent the coordinates of the experimental diffraction intensity matrix, |·| represents calculating the modulus of each element in the matrix, represents calculating the two-dimensional Fourier transform of the matrix, ψ j is the outgoing wave function to be optimized, and I j is the diffraction intensity matrix collected experimentally.

[0019] Optionally, in an embodiment of the present application, the calculation formula of the outgoing wave function is:

[0020]

[0021] wherein, P(r - r j ) represents the electron beam scanned to the j-th position, and O l (r) represents the sample transmission function of the l-th layer, represents Fresnel diffraction or other effects.

[0022] An embodiment of the third aspect of the present application provides an electronic device, including: a memory, a processor, and a computer program stored on the memory and executable on the processor, wherein the processor executes the program to implement the ptychographic imaging method for reducing the data sampling rate as described in the above embodiments.

[0023] An embodiment of the fourth aspect of the present application provides a computer-readable storage medium storing a computer program, which when executed by a processor, implements the ptychographic imaging method for reducing the data sampling rate as described above.

[0024] An embodiment of the fifth aspect of the present application provides a computer program product storing a computer program, which when executed by a processor, implements the ptychographic imaging method for reducing the data sampling rate as described above.

[0025] When recording experimental data in the embodiments of the present application, it is not required to oversample the diffraction pattern, and only low-sampling-rate experimental data is needed. However, during reconstruction, the sample potential function and the beam spot function are finely sampled to reduce the experimental data sampling rate, minimize the size of the experimental data, reduce the experimental acquisition time, and minimize the reduction in imaging quality caused by overly long data acquisition time, while obtaining a high-quality reconstruction result using a small amount of experimental data. Thus, the problem of significantly longer data acquisition time of the ptychography method compared to other imaging methods is solved.

[0026] Additional aspects and advantages of the present application will be given in part in the following description, become apparent in part from the following description, or be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The above and / or additional aspects and advantages of the present application will become apparent and be readily understood from the following description of the embodiments in conjunction with the drawings, wherein:

[0028] Figure 1 FIG. is a flowchart of a ptychography method for reducing data sampling rate according to an embodiment of the present application;

[0029] Figure 2 FIG. is a schematic diagram of the crystal structure of BiFeO3 according to an embodiment of the present application;

[0030] Figure 3 FIG. is a schematic diagram of the diffraction pattern at the first scanning position collected by a detector according to an embodiment of the present application;

[0031] Figure 4 FIG. is a schematic diagram of the average of the diffraction patterns at all scanning positions collected by a detector according to an embodiment of the present application;

[0032] Figure 5 FIG. is a schematic diagram of the sample potential function obtained by initializing the algorithm according to an embodiment of the present application;

[0033] Figure 6 FIG. is a schematic diagram of the beam spot function obtained by initializing the algorithm according to an embodiment of the present application;

[0034] Figure 7 FIG. is a schematic diagram of the diffraction pattern at the first scanning position obtained by initializing the algorithm according to an embodiment of the present application;

[0035] Figure 8 FIG. is a schematic diagram of the average of the diffraction patterns at all scanning positions obtained by initializing the algorithm according to an embodiment of the present application;

[0036] Figure 9Schematic diagram of the diffraction pattern at the first scanning position initialized by the algorithm obtained after pixel merging according to an embodiment of the present application;

[0037] Figure 10 Schematic diagrams of the diffraction patterns at all scanning positions initialized by the algorithm obtained after pixel merging according to an embodiment of the present application;

[0038] Figure 11 Schematic diagram of the sample potential function reconstructed by the algorithm according to an embodiment of the present application;

[0039] Figure 12 Schematic diagram of the beam spot function reconstructed by the algorithm according to an embodiment of the present application;

[0040] Figure 13 Schematic diagram of the diffraction pattern at the first scanning position reconstructed by the algorithm according to an embodiment of the present application;

[0041] Figure 14 Schematic diagram of the average of the diffraction patterns at all scanning positions reconstructed by the algorithm according to an embodiment of the present application;

[0042] Figure 15 Schematic diagram of the diffraction pattern at the first scanning position reconstructed after pixel merging according to an embodiment of the present application;

[0043] Figure 16 Schematic diagram of the average of the diffraction patterns at all scanning positions reconstructed after pixel merging according to an embodiment of the present application;

[0044] Figure 17 Schematic diagram of the algorithm flow according to an embodiment of the present application;

[0045] Figure 18 Schematic diagram of the structure of a ptychographic imaging device for reducing the data sampling rate according to an embodiment of the present application;

[0046] Figure 19 Schematic diagram of the structure of an electronic device according to an embodiment of the present application. Detailed implementation manners

[0047] The embodiments of the present application will be described in detail below. The examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to explain the present application, and should not be construed as limiting the present application.

[0048] The following describes a stacked imaging method and apparatus for reducing the data sampling rate according to an embodiment of the present application. Aiming at the problem of significantly longer data acquisition time of the stacked imaging method compared with other imaging methods in the above-mentioned background art, the present application provides a stacked imaging method for reducing the data sampling rate. In this method, when recording experimental data, it is not required to perform oversampling on the diffraction pattern, and only low-sampling-rate experimental data is needed. However, during reconstruction, the sample potential function and the beam spot function are finely sampled to ensure that without losing the information of the sample potential function, the experimental data sampling rate is reduced, the size of the experimental data is reduced, the experimental acquisition time is reduced, and the reduction of the imaging quality caused by the overly long data acquisition time is minimized, and high-quality reconstruction results are obtained using a small amount of experimental data. Thus, the problem of significantly longer data acquisition time of the stacked imaging method compared with other imaging methods is solved.

[0049] Specifically, Figure 1 FIG. is a schematic flowchart of a stacked imaging method for reducing the data sampling rate provided by an embodiment of the present application.

[0050] As Figure 1 shown, the stacked imaging method for reducing the data sampling rate includes the following steps:

[0051] In step S101, a particle beam is used to scan the sample to collect diffraction data that meets the preset sampling rate condition.

[0052] It can be understood that the preset sampling rate condition in the embodiment of the present application can be a low sampling rate condition. What needs to be observed in the embodiment of the present application is the projection of BiFeO3 along the

[001] direction, and its structure is as Figure 2 shown.

[0053] In the actual execution process, the embodiment of the present application can use a particle beam to scan the sample and record low-sampling-rate diffraction data. Among them, when the particle beam scans the sample, the size of the diffraction data matrix collected by the detector at each scanning position is S x = 8, S y = 8, the reciprocal space pixel size is The adopted convergence semi-angle is 24.3 mrad, and the defocus amount is 20 nm. The diffraction pattern of the first scanning position collected by the detector is as Figure 3 shown, and the average of the diffraction patterns of all scanning positions collected by the detector is as Figure 4 shown.

[0054] It should be noted that the preset sampling rate condition can be set by those skilled in the art according to the actual situation, and no specific limitation is made here.

[0055] In step S102, during the reconstruction process of the ptychography algorithm, the sample potential function and the beam spot function are initialized using the reciprocal space matrix that satisfies the first preset condition and the reciprocal space pixel size that satisfies the second preset condition, so as to obtain the initialized sample potential function and beam spot function.

[0056] It can be understood that the reciprocal space matrix that satisfies the first preset condition in the embodiments of the present application can be a reciprocal space matrix larger than the experimental diffraction data, and the reciprocal space pixel size that satisfies the second preset condition can be a reciprocal space pixel size smaller than the experimental diffraction data.

[0057] During the actual execution process, in the embodiments of the present application, during the reconstruction process of the ptychography algorithm, a reciprocal space matrix larger than the experimental diffraction data and a smaller reciprocal space pixel size can be used to initialize the sample potential function and the beam spot function, so as to obtain the initialized sample potential function and beam spot function. The size of the original diffraction data matrix in the embodiments of the present application is S x *S y , the reciprocal space pixel size is dk, and the initialization parameters with a matrix size of S x ′*S y ′ and a reciprocal space pixel size of dk′ are used to initialize the sample potential function and the beam spot function, where S′ x >S x , S′ y >S y , and dk′ < dk.

[0058] For example, in the embodiments of the present application, the initialization parameters with a matrix size of S′ x = 128, S′ y = 128 and a reciprocal space pixel size of are used to initialize the sample potential function and the beam spot function. The sample potential function obtained by algorithm initialization is as Figure 5 shown, and the beam spot function obtained by algorithm initialization is as Figure 6 shown. The diffraction pattern at the first scanning position obtained by algorithm initialization is as Figure 7 shown, and the average of the diffraction patterns at all scanning positions obtained by algorithm initialization is as Figure 8 shown. The diffraction pattern at the first scanning position of the algorithm initialization obtained after pixel merging is as Figure 9 shown, and the average of the diffraction patterns at all scanning positions of the algorithm initialization obtained after pixel merging is as Figure 10 shown.

[0059] In the embodiments of the present application, a reciprocal space matrix larger than the experimental diffraction data and a smaller reciprocal space pixel size can be used to initialize the sample potential function and the beam spot function, thereby significantly improving the resolution, accuracy, and stability of the analysis, and facilitating subsequent data processing and optimization.

[0060] It should be noted that the first preset condition and the second preset condition can be set by those skilled in the art according to the actual situation, and no specific limitation is made here.

[0061] In step S103, the pixels of the diffraction data obtained by the algorithm are merged to match the target matrix size that meets the preset condition. The loss function is calculated according to the target matrix size and the experimental diffraction data, and it is determined whether the loss function converges to the target value.

[0062] It can be understood that the preset condition in the embodiment of the present application can be a matrix condition with the same size as the experimental diffraction data.

[0063] In the actual execution process, in the embodiment of the present application, the pixels of the diffraction data obtained by the algorithm can be merged. After obtaining the required matrix size, the loss function is calculated together with the experimental diffraction data, and it is determined whether the loss function converges to the target value, so that in the process of iteration, the reconstructed sample potential function is finally obtained, as Figure 11 shown, and the reconstructed spot function is as Figure 12 shown.

[0064] It should be noted that the preset condition can be set by those skilled in the art according to the actual situation, and no specific limitation is made here.

[0065] Among them, in an embodiment of the present application, the calculation formula of the loss function is:

[0066]

[0067] Among them, B(·) represents merging the pixels of the matrix to obtain a matrix with the same size as the experimental diffraction data. j represents the serial number of the scanning position. Both u and v represent the coordinates of the experimental diffraction intensity matrix. |·| represents calculating the modulus of each element in the matrix respectively. represents calculating the two-dimensional Fourier transform of the matrix, and ψ j is the outgoing wave function to be optimized, and I j is the diffraction intensity matrix collected experimentally.

[0068] Among them, in an embodiment of the present application, the calculation formula of the outgoing wave function is:

[0069]

[0070] Among them, P(r - r j ) represents the electron beam scanned to the jth position, and O l (r) represents the sample transmission function of the lth layer. represents Fresnel diffraction or other effects.

[0071] Optionally, in an embodiment of the present application, the pixels of the diffraction data are merged to match the target matrix size that meets the preset conditions, including: obtaining the scanning position of the sample, and obtaining the diffraction data of the sample according to the scanning position; merging the pixels of the diffraction data to obtain a matrix with the same size as the experimental diffraction data.

[0072] It can be understood that the diffraction data in the embodiments of the present application is the diffraction intensity.

[0073] In the actual execution process, the embodiments of the present application can move the beam spot to scan on the sample. For each scanning position, a diffraction intensity matrix is obtained, that is, the diffraction data is obtained, and the pixels of the diffraction data are merged to obtain a matrix with the same size as the experimental diffraction data. Among them, the diffraction pattern of the first scanning position reconstructed according to the above steps in the embodiments of the present application is as Figure 13 shown, and the average of the diffraction patterns of all scanning positions reconstructed is as Figure 14 shown. The diffraction pattern of the first scanning position reconstructed after pixel merging is as Figure 15 shown, and the average of the diffraction patterns of all scanning positions reconstructed after pixel merging is as Figure 16 shown.

[0074] It should be noted that the preset conditions can be set by those skilled in the art according to the actual situation, and no specific limitation is made here.

[0075] In step S104, if the loss function does not converge to the target value, the initialized sample potential function and beam spot function are optimized until the preset convergence stop condition is reached, and the optimized sample potential function and beam spot function are obtained, so as to obtain the ptychography result according to the optimized sample potential function and beam spot function.

[0076] It can be understood that the preset convergence stop condition in the embodiments of the present application can be the condition that the loss function converges to the target value.

[0077] In the actual execution process, when the loss function does not converge to the target value in the embodiments of the present application, the initialized sample potential function and beam spot function are optimized through the calculation iteration process until the loss function converges to the target value, and the optimized sample potential function and beam spot function are obtained, so as to obtain the ptychography result according to the optimized sample potential function and beam spot function. When the embodiments of the present application record experimental data, oversampling of the diffraction pattern is not required, and only low-sampling-rate experimental data is needed. However, during reconstruction, the sample potential function and beam spot function are finely sampled. In this way, without losing the information of the sample potential function, the experimental data sampling rate is reduced, the size of the experimental data is reduced, the experimental acquisition time is reduced, the reduction of the imaging quality caused by the too long experimental data acquisition time is minimized, and high-quality reconstruction results are obtained using a small amount of experimental data.

[0078] It should be noted that the preset convergence stop condition can be set by those skilled in the art according to the actual situation, and no specific limitation is made here.

[0079] Specifically, it can be combined with Figure 17 As shown, the working principle of the ptychography method for reducing the data sampling rate in the embodiments of the present application will be elaborated in detail with a specific embodiment.

[0080] As Figure 17 shown, the embodiments of the present application may include the following steps:

[0081] Step S1701: Initialize the sample potential function and the beam spot function using a reciprocal space matrix larger than the experimental diffraction data and a smaller reciprocal space pixel size.

[0082] Step S1702: Obtain the sample potential function and the beam spot function at all scanning positions.

[0083] Step S1703: Move the beam spot to scan on the sample.

[0084] Step S1704: For each scanning position, obtain a diffraction intensity matrix.

[0085] Step S1705: For all the obtained diffraction intensity matrices, merge the pixels to obtain a matrix of the same size as the experimental diffraction data.

[0086] Step S1706: Calculate the loss function L.

[0087] Step S1707: Determine whether the loss function converges to the target value. If so, execute Step S1708; if not, execute Step S1709.

[0088] Step S1708: Output the reconstruction result.

[0089] Step S1709: Solve the gradient of the parameter to be optimized.

[0090] Step S1710: Update the sample potential function and the beam spot function.

[0091] According to the ptychography method for reducing the data sampling rate proposed in the embodiments of the present application, when recording experimental data, it is not required to over-sample the diffraction pattern, and only low-sampling-rate experimental data is needed. However, during reconstruction, the sample potential function and the beam spot function are finely sampled to ensure that without losing the information of the sample potential function, the experimental data sampling rate is reduced, the size of the experimental data is reduced, the experimental acquisition time is reduced, and the reduction of the imaging quality caused by the too long experimental data acquisition time is minimized, and high-quality reconstruction results can be obtained using a small amount of experimental data. Thus, the problem that the ptychography method has a significantly longer data acquisition time compared to other imaging methods is solved.

[0092] Next, a stacked imaging device for reducing the data sampling rate according to an embodiment of the present application will be described with reference to the accompanying drawings.

[0093] Figure 18 It is a schematic structural diagram of a stacked imaging device for reducing the data sampling rate according to an embodiment of the present application.

[0094] As Figure 18 shown, the stacked imaging device 10 for reducing the data sampling rate includes: an acquisition module 100, an initialization module 200, a judgment module 300, and an optimization module 400.

[0095] Specifically, the acquisition module 100 is configured to scan a sample with a particle beam to acquire diffraction data that meets a preset sampling rate condition.

[0096] The initialization module 200 is configured to use an inverse space matrix that meets a first preset condition and an inverse space pixel size that meets a second preset condition to initialize the sample potential function and the beam spot function during the reconstruction process of the stacked imaging algorithm, and obtain the initialized sample potential function and beam spot function.

[0097] The judgment module 300 is configured to merge the pixels of the diffraction data obtained by the algorithm, match the target matrix size that meets the preset condition, calculate a loss function based on the target matrix size and the experimental diffraction data, and judge whether the loss function converges to a target value.

[0098] The optimization module 400 is configured to optimize the initialized sample potential function and beam spot function until a preset convergence stop condition is reached when the loss function converges to the target value, and obtain the optimized sample potential function and beam spot function, so as to obtain a stacked imaging result based on the optimized sample potential function and beam spot function.

[0099] Optionally, in an embodiment of the present application, the judgment module 300 includes: an acquisition unit and a merging unit.

[0100] Among them, the acquisition unit is configured to acquire the scanning position of the sample and obtain diffraction data according to the scanning position.

[0101] The merging unit is configured to merge the pixels of the diffraction data to obtain a matrix with the same size as the experimental diffraction data.

[0102] Optionally, in an embodiment of the present application, the calculation formula of the loss function is:

[0103]

[0104] Among them, B(·) represents merging the pixels of the matrix to obtain a matrix of the same size as the experimental diffraction data, j represents the serial number of the scanning position, both u and v represent the coordinates of the experimental diffraction intensity matrix, |·| represents calculating the modulus of each element in the matrix respectively. represents calculating the two-dimensional Fourier transform of the matrix, ψ j is the outgoing wave function to be optimized, I j is the diffraction intensity matrix collected experimentally.

[0105] Optionally, in an embodiment of the present application, the calculation formula of the outgoing wave function is:

[0106]

[0107] Among them, P(r - r j ) represents the electron beam scanned to the j-th position, O l (r) represents the sample transmission function of the l-th layer. represents Fresnel diffraction or other effects.

[0108] It should be noted that the foregoing explanation of the ptychography method embodiment for reducing the data sampling rate also applies to the ptychography device for reducing the data sampling rate in this embodiment, and will not be elaborated here.

[0109] The ptychography device for reducing the data sampling rate proposed according to the embodiments of the present application can, when recording experimental data, not require over-sampling of the diffraction pattern, only require low-sampling-rate experimental data. However, during reconstruction, the sample potential function and the beam spot function are finely sampled to ensure that without losing the information of the sample potential function, the experimental data sampling rate is reduced, the size of the experimental data is reduced, the experimental acquisition time is reduced, and the reduction of the imaging quality caused by the too long data acquisition time is minimized, and high-quality reconstruction results are obtained using a small amount of experimental data. Thus, the problem of significantly longer data acquisition time of the ptychography method compared with other imaging methods is solved.

[0110] Figure 19 is a schematic structural diagram of an electronic device provided by an embodiment of the present application. The electronic device may include:

[0111] A memory 1901, a processor 1902, and a computer program stored on the memory 1901 and executable on the processor 1902.

[0112] When the processor 1902 executes the program, it implements the ptychography method for reducing the data sampling rate provided in the foregoing embodiment.

[0113] Further, the electronic device further includes:

[0114] A communication interface 1903 for communication between the memory 1901 and the processor 1902.

[0115] A memory 1901 for storing a computer program that can run on the processor 1902.

[0116] The memory 1901 may include a high-speed RAM memory and may also include non-volatile memory, such as at least one disk memory.

[0117] If the memory 1901, the processor 1902, and the communication interface 1903 are implemented independently, the communication interface 1903, the memory 1901, and the processor 1902 can be interconnected through a bus and communicate with each other. The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, an Extended Industry Standard Architecture (EISA) bus, etc. The bus can be divided into an address bus, a data bus, a control bus, etc. For the sake of simplicity of representation, Figure 19 only a thick line is used to represent it in the figure, but it does not mean that there is only one bus or one type of bus.

[0118] Optionally, in a specific implementation, if the memory 1901, the processor 1902, and the communication interface 1903 are integrated on a single chip, the memory 1901, the processor 1902, and the communication interface 1903 can communicate with each other through an internal interface.

[0119] The processor 1902 may be a Central Processing Unit (CPU), or an Application Specific Integrated Circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of the present application.

[0120] This embodiment also provides a computer-readable storage medium having a computer program stored thereon, and when the program is executed by a processor, the stacked imaging method for reducing the data sampling rate as described above is implemented.

[0121] The embodiments of the present application also provide a computer program product having a computer program stored thereon, and when the program is executed by a processor, the stacked imaging method for reducing the data sampling rate as described above is implemented.

[0122] In the description of this specification, the descriptions referring to terms such as "one embodiment", "some embodiments", "examples", "specific examples", or "some examples", etc., mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of this application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any one or N embodiments or examples in a suitable manner. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0123] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of this application, the meaning of "N" is at least two, such as two, three, etc., unless otherwise specifically defined.

[0124] Any process or method description shown in a flowchart or described in other ways herein can be understood to represent a module, segment, or portion of code including one or N executable instructions for implementing a customized logical function or process, and the scope of the preferred embodiments of this application includes additional implementations, where the functions can be executed in a manner that is not in the order shown or discussed, including in a substantially simultaneous manner according to the functions involved or in a reverse order, which should be understood by those skilled in the art to which the embodiments of this application belong.

[0125] The logic and / or steps represented in the flowchart or otherwise described herein can be considered, for example, as a definitional sequence list of executable instructions for implementing logical functions, which can be embodied specifically in any computer-readable medium for use by an instruction execution system, apparatus, or device (such as a computer-based system, a system including a processor, or other systems that can fetch and execute instructions from the instruction execution system, apparatus, or device), or in connection with these instruction execution systems, apparatuses, or devices. For the purposes of this specification, a "computer-readable medium" can be any device that can contain, store, communicate, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device. More specific examples (non-exhaustive list) of computer-readable media include the following: an electrical connection portion (electronic device) having one or N wirings, a portable computer diskette (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disc read-only memory (CDROM). Additionally, the computer-readable medium can even be paper or other suitable media on which the program can be printed, because the program can be obtained electronically by optically scanning the paper or other media, followed by editing, interpretation, or otherwise processing as appropriate, and then stored in a computer memory.

[0126] It should be understood that various parts of the present application can be implemented using hardware, software, firmware, or a combination thereof. In the above-described embodiments, the N steps or methods can be implemented using software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented using hardware, as in another embodiment, any one or a combination of the following techniques well known in the art can be used: discrete logic circuits having logic gate circuits for implementing logical functions on data signals, application-specific integrated circuits having suitable combinational logic gate circuits, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), and the like.

[0127] Those of ordinary skill in the art of this technology can understand that all or part of the steps carried out in implementing the above-described example methods can be completed by a program instructing relevant hardware. The program can be stored in a computer-readable storage medium, and when executed, includes one or a combination of the steps of the method embodiments.

[0128] In addition, each functional unit in various embodiments of the present application may be integrated into one processing module, may exist separately as individual physical units, or two or more units may be integrated into one module. The above-mentioned integrated module may be implemented in the form of hardware or in the form of a software functional module. When the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it may also be stored in a computer-readable storage medium.

[0129] The above-mentioned storage medium may be a read-only memory, a magnetic disk or an optical disc, etc. Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present application. Those of ordinary skill in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present application.

Claims

1. A stacked imaging method for reducing the data sampling rate, characterized in that, It includes the following steps: Scanning the sample with a particle beam to collect diffraction data that meets the preset sampling rate condition; During the reconstruction process of the ptychography algorithm, initializing the sample potential function and the beam spot function using the reciprocal space matrix that meets the first preset condition and the reciprocal space pixel size that meets the second preset condition to obtain the initialized sample potential function and beam spot function; Merging the pixels of the diffraction data obtained by the algorithm to match the target matrix size that meets the preset condition, calculating the loss function based on the target matrix size and the experimental diffraction data, and determining whether the loss function converges to the target value. Among them, the merging of the pixels of the diffraction data obtained by the algorithm to match the target matrix size that meets the preset condition includes: Obtaining the scanning position of the sample and obtaining the diffraction data according to the scanning position; Merging the pixels of the diffraction data to obtain a matrix with the same size as the experimental diffraction data; The calculation formula of the loss function is: Among them, B(·) represents the merging of the pixels of the matrix to obtain a matrix of the same size as the experimental diffraction data, j represents the serial number of the scanning position, both u and v represent the coordinates of the experimental diffraction intensity matrix, and |·| represents calculating the modulus of each element in the matrix respectively. represents the calculation of the two-dimensional Fourier transform of the matrix, ψ j is the outgoing wave function to be optimized, I j is the diffraction intensity matrix collected experimentally; If the loss function does not converge to the target value, optimizing the initialized sample potential function and beam spot function until the preset convergence stop condition is reached to obtain the optimized sample potential function and beam spot function, so as to obtain the ptychography result according to the optimized sample potential function and beam spot function.

2. The method according to claim 1, wherein The calculation formula of the outgoing wave function is: Among them, P(r - r j ) represents the electron beam scanned to the j-th position, and O l (r) represents the sample transmission function of the l-th layer, represents Fresnel diffraction or other effects.

3. A stacked imaging device for reducing data sampling rate, characterized in that, It includes: An acquisition module for scanning the sample with a particle beam to collect diffraction data that meets the preset sampling rate condition; An initialization module for initializing the sample potential function and the beam spot function using the reciprocal space matrix that meets the first preset condition and the reciprocal space pixel size that meets the second preset condition during the reconstruction process of the ptychography algorithm to obtain the initialized sample potential function and beam spot function; A judgment module for merging the pixels of the diffraction data obtained by the algorithm to match the target matrix size that meets the preset condition, calculating the loss function based on the target matrix size and the experimental diffraction data, and determining whether the loss function converges to the target value. Among them, the judgment module includes: an acquisition unit for obtaining the scanning position of the sample and obtaining the diffraction data according to the scanning position; a merging unit for merging the pixels of the diffraction data to obtain a matrix with the same size as the experimental diffraction data; The calculation formula of the loss function is: Among them, B(·) represents the merging of the pixels of the matrix to obtain a matrix of the same size as the experimental diffraction data, j represents the serial number of the scanning position, both u and v represent the coordinates of the experimental diffraction intensity matrix, and |·| represents calculating the modulus of each element in the matrix respectively. represents the calculation of the two-dimensional Fourier transform of the matrix, ψ j is the outgoing wave function to be optimized, I j is the diffraction intensity matrix collected experimentally; An optimization module for optimizing the initialized sample potential function and beam spot function when the loss function does not converge to the target value until the preset convergence stop condition is reached to obtain the optimized sample potential function and beam spot function, so as to obtain the ptychography result according to the optimized sample potential function and beam spot function.

4. The device according to claim 3, characterized in that, The calculation formula of the outgoing wave function is: Among them, P(r - r j ) represents the electron beam scanned to the j-th position, and O l (r) represents the sample transmission function of the l-th layer, represents Fresnel diffraction or other effects.

5. An electronic device, characterized in that, It includes: A memory, a processor, and a computer program stored on the memory and executable on the processor. The processor executes the program to implement the ptychography method for reducing the data sampling rate as described in any one of claims 1-2.

6. A computer-readable storage medium having a computer program stored thereon, characterized in that, The program is executed by the processor to be used to implement the ptychography method for reducing the data sampling rate as described in any one of claims 1-2.

7. A computer program product, comprising a computer program, characterized in that, The computer program is executed to implement the stacked imaging method for reducing the data sampling rate as described in any one of claims 1-2.

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