A deep-robust speckle generation method and device

Abstract

The application provides a kind of depth robust speckle generation method and device, comprising: A1, based on speckle generation optical path establishes the intensity correlation transmission model between initial phase field correlation and three-dimensional space in speckle intensity correlation;A2, utilize intensity correlation transmission model and the intensity correlation of target speckle to solve the correlation of initial phase field, and further obtain initial phase field;A3, load initial phase field to phase modulation device, obtain speckle with target intensity correlation in three-dimensional space after speckle generation optical path.The application can be based on the required speckle intensity correlation to customize generation speckle;The correlation of generated speckle does not change with propagation, can be kept in three-dimensional space, expands the range of customized speckle;The application can obtain speckle with different correlations using the same optical path, effectively avoids the problem of replacing illumination optical path to obtain speckle with different correlations;It has important application value.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of light beam customization, and in particular to a deep-robust speckle generation method and device. BACKGROUND

[0002] Speckle is widely present in nature, for example, when a coherent light beam such as laser is reflected or transmitted by rough objects such as walls, paper, frosted glass, etc., a speckle pattern with light and dark alternation will be observed on the reflected or transmitted light path. In the laboratory, phase-type spatial light modulators, amplitude-type spatial light modulators, rotating frosted glass, diffusers, digital micro-mirrors, etc. are usually used to modulate the coherent light beam, and then the modulated light beam is passed through the illumination light path to generate speckle.

[0003] Speckle patterns are widely used in fields such as microscopic super-resolution imaging based on speckle illumination, microscopic optical sectioning imaging based on speckle illumination, photoacoustic imaging based on dynamic speckle illumination, imaging through scattering media based on speckle correlation characteristics, digital speckle correlation measurement, and correlation imaging. In many applications of speckle, the speckle intensity correlation in three-dimensional space has a particularly significant impact on performance. For example, in the field of photoacoustic imaging based on dynamic speckle illumination, studies have shown that the greater the speckle intensity correlation in the three-dimensional space of the illuminated three-dimensional sample, the higher the visibility of the three-dimensional sample imaging by the photoacoustic system. Secondly, in the field of microscopic super-resolution imaging based on speckle illumination, studies have shown that the speckle intensity correlation in three-dimensional space gradually increases from the system diffraction limit, and the super-resolution capability that the system can obtain will gradually decrease. Therefore, it has important application value to control the speckle intensity correlation in three-dimensional space and generate speckle with specific intensity correlation required by specific applications.

[0004] Because the intensity correlation of the generated three-dimensional speckle pattern is limited by the diffraction limit of the illumination light path, some works have achieved control of the three-dimensional speckle intensity correlation by replacing the illumination light path, but the process is very complex.

[0005] The existing speckle generation method has the problems of being unable to maintain the required speckle intensity correlation in three-dimensional space and needing to replace the illumination light path to generate speckle with different intensity correlations.

[0006] The disclosure of the above background art content is only used to assist in understanding the concept and technical solutions of the present application, and it does not necessarily belong to the prior art of the present patent application. In the absence of explicit evidence that the above content has been disclosed on the filing date of the present patent application, the above background art should not be used to evaluate the novelty and inventiveness of the present application. SUMMARY

[0007] The present application aims at solving the problems that speckle generation methods cannot maintain the required speckle intensity correlation in three-dimensional space and different intensity correlations of speckles require changing the illumination light path, and provides a deep robust speckle generation method and device.

[0008] To achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0009] A deep robust speckle generation method comprises the following steps: A1, establishing an intensity correlation transmission model between an initial phase field correlation and a speckle intensity correlation in three-dimensional space based on a speckle generation light path; A2, solving the initial phase field correlation by using the intensity correlation transmission model and a target speckle intensity correlation, and further obtaining an initial phase field; A3, loading the initial phase field to a phase modulation device to obtain speckles with a target intensity correlation in three-dimensional space after the speckle generation light path.

[0010] In some embodiments of the present application, step A1 comprises the following steps: A11, convolving a three-dimensional impulse response function of the speckle generation light path with the initial phase field to obtain a three-dimensional speckle field; A12, performing autocorrelation operation on the three-dimensional speckle field to obtain a field correlation transmission model between the initial phase field correlation and a three-dimensional speckle field correlation; A13, normalizing and taking the modulus of the field correlation transmission model to obtain the intensity correlation transmission model between the initial phase field correlation and the speckle intensity correlation in three-dimensional space.

[0011] In some embodiments of the present application, in step A11, the three-dimensional speckle field is specifically expressed by the following formula:

[0012]

[0013] wherein h(x, y, z) is a three-dimensional impulse response function, is an initial phase field, is a convolution operator, (x, y, z) is a three-dimensional coordinate of a space where the three-dimensional speckle field is located, and the speckle generation light path is a 4f system, is a magnification or reduction factor of the 4f system, f is a focal length of an objective lens in the 4f system, and f1 is a focal length of a lens in the 4f system; the expression of the three-dimensional impulse response function is as follows:

[0014]

[0015] wherein P(x b ,y b ) is a pupil function of the objective lens in the 4f system, (x b ,y b ) is a coordinate of an objective lens pupil plane, j is an imaginary unit, and z is a distance of a speckle plane from the objective lens, is the wave vector, and λ is the wavelength of light.

[0016] In some embodiments of the present application, in step A12, the field correlation transmission model is Specifically expressed by the following formula:

[0017]

[0018] wherein the initial phase field correlation is The three-dimensional speckle field correlation is T A (Δx,Δy,z), (Δx,Δy) is the increment between two different coordinates in space where the speckle field is located, μ is a constant independent of (Δx,Δy), D is the pupil diameter of the objective pupil P, and J1 is the first-order Bessel function of the first kind.

[0019] In some embodiments of the present application, in step A13, the intensity correlation transmission model is Specifically expressed by the following formula:

[0020]

[0021] wherein g is a function symbol with the independent variable C A (Δx,Δy,z) is the speckle intensity correlation in three-dimensional space.

[0022] In some embodiments of the present application, step A2 specifically comprises the following steps: A21 determining the intensity correlation of the target speckle; A22 deconvolving to solve the initial phase field correlation according to the intensity correlation of the target speckle and in combination with the intensity correlation transmission model; and A23 solving the initial phase field based on the initial phase field correlation.

[0023] In some embodiments of the present application, in step A21, the intensity correlation of the target speckle comprises the particle size of the speckle and the sparseness of the speckle.

[0024] In some embodiments of the present application, in step A22, the deconvolution solving method comprises a Fourier transform-based deconvolution method, which is expressed by the following formula:

[0025]

[0026] wherein is the initial phase field correlation, and C A(Δx, Δy, z) is the intensity correlation of the target speckle, (Δx, Δy) is the increment between two different coordinates in space where the speckle field is located, D is the pupil diameter of the objective pupil P, J1 is the first-order Bessel function of the first kind, z is the distance of the speckle plane from the objective, λ is the wavelength of light, is a two-dimensional Fourier transform, is a two-dimensional inverse Fourier transform.

[0027] In some embodiments of the present application, in step A23, the initial phase field correlation The relationship between the initial phase field and the initial phase field correlation is expressed by the following formula:

[0028]

[0029] wherein, is the initial phase field.

[0030] In some embodiments of the present application, the speckle generation optical path comprises a 4f optical path or a Fourier optical path or a Fresnel optical path.

[0031] In some embodiments of the present application, in step A11, the three-dimensional impulse response function of the speckle generation optical path is established by using the Debye approximation or the paraxial approximation method.

[0032] The present application also provides a depth-robust speckle generation device, which comprises a processor, a memory, and a computer program stored in the memory and executed by the processor, wherein the processor executes the computer program to implement the depth-robust speckle generation method described above.

[0033] The present application also provides a computer readable storage medium, which stores a computer program, wherein the computer program is executed by a processor to implement the steps of the depth-robust speckle generation method described above.

[0034] The present application has the following beneficial effects:

[0035] The application establishes the intensity correlation transmission model between the initial phase field correlation and the speckle intensity correlation in the three-dimensional space, thereby obtaining the initial phase field correlation required for generating the target speckle intensity correlation; and further solving the initial phase field; and loading the modulation phase to the phase modulation device, thereby obtaining the speckle with the target intensity correlation in the three-dimensional space after the speckle generation light path. The application can generate the speckle according to the required speckle intensity correlation in specific applications, and ensure that the customized intensity correlation does not change with the propagation, and maintains the required speckle intensity correlation in the three-dimensional space, has the depth robustness, and improves the application ability in the three-dimensional scene. Meanwhile, the application uses the same light path to obtain the speckle with different intensity correlations required in specific applications, effectively avoids the limitation that the speckle with different correlations needs to replace the illumination light path, and has important application value. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 is a flow chart of a depth-robust speckle generation method in the embodiment of the application;

[0037] Figure 2 is a schematic diagram of a speckle generation light path in the embodiment of the application;

[0038] Figure 3 is a flow chart of establishing the intensity correlation transmission model in the embodiment of the application;

[0039] Figure 4 is a flow chart of obtaining the required initial phase field in the embodiment of the application;

[0040] Figure 5a is a schematic diagram of the target speckle intensity correlation with the half-height width of 1 micrometer in the embodiment of the application;

[0041] Figure 5b is a schematic diagram of the target speckle intensity correlation with the half-height width of 1.4 micrometers in the embodiment of the application;

[0042] Figure 5c is a schematic diagram of the target speckle intensity correlation with the half-height width of 1.8 micrometers in the embodiment of the application;

[0043] Figure 6a is a schematic diagram of the initial phase field obtained based on the target speckle intensity correlation with the half-height width of 1 micrometer in the embodiment of the application;

[0044] Figure 6b is a schematic diagram of the initial phase field obtained based on the target speckle intensity correlation with the half-height width of 1.4 micrometers in the embodiment of the application;

[0045] Figure 6cis a schematic diagram of the initial phase field based on the target speckle intensity correlation with a half-width of 1.8 microns in the embodiment of the application;

[0046] Figure 7a is a schematic diagram of the speckle intensity graph and the corresponding speckle intensity correlation obtained within a range of 1000 microns near the focusing plane of the speckle generation optical path by using the initial phase field in Figure 6a

[0047] Figure 7b is a schematic diagram of the speckle intensity graph and the corresponding speckle intensity correlation obtained within a range of 1000 microns near the focusing plane of the speckle generation optical path by using the initial phase field in Figure 6b

[0048] Figure 7c is a schematic diagram of the speckle intensity graph and the corresponding speckle intensity correlation obtained within a range of 1000 microns near the focusing plane of the speckle generation optical path by using the initial phase field in Figure 6c

[0049] Wherein, 1-laser, 2-beam expander, 3-polarizer, 4-phase spatial light modulator, 5-lens, 6-objective lens, 7-detector. DETAILED DESCRIPTION

[0050] In order to make the technical problems, technical solutions and beneficial effects to be solved by the embodiments of the application more clear and explicit, the application will be further described in detail below in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the application and do not limit the application.

[0051] The size of the speckle intensity correlation can be represented by the half-width of the speckle intensity correlation, and the larger the half-width, the larger the speckle intensity correlation. Most existing attempts to control the speckle intensity correlation, i.e. the half-width of the speckle intensity correlation, are to control the speckle intensity correlation in a single plane, and as the propagation distance increases, the speckle intensity correlation will deviate from the expected intensity correlation size, which is not conducive to the application of photoacoustic imaging, microscopic imaging and other fields in three-dimensional samples.

[0052] ​​​The speckle generation method in the prior art cannot keep the required speckle particle size in a three-dimensional space in part, which is not conducive to the application of photoacoustic imaging, microscopic imaging and the like in a three-dimensional sample, and another part needs to replace the illumination light path to generate speckles of different particle sizes, which is very complex. In contrast, the embodiment of the present application can customize and generate speckle particle sizes in a three-dimensional space without replacing the illumination light path on the basis of complete modeling of the transmission process of speckle intensity correlation, so that the embodiment of the present application effectively avoids the complex process of replacing the light path and expands the application in a three-dimensional scene.

[0053] As Figure 1 indicated, the following embodiment of the present application provides a deep robust speckle generation method, comprising the following steps:

[0054] A1: establishing an intensity correlation transmission model between the initial phase field correlation and the speckle intensity correlation in a three-dimensional space based on a speckle generation light path;

[0055] A2: using the intensity correlation transmission model and the intensity correlation of a target speckle to solve the correlation of the required initial phase field and further obtain the initial phase field;

[0056] A3: loading the initial phase field to a phase modulation device, so that speckles with a target intensity correlation can be obtained in a three-dimensional space after the speckle generation light path.

[0057] Unlike the method of generating speckles with different intensity correlations by using pure optimization or changing the illumination light path, the embodiment of the present application completely models the transmission process of speckle intensity correlation, can customize and generate speckles based on the required speckle intensity correlation (half-width of speckle intensity correlation) in specific applications, and ensures that the customized speckle intensity correlation does not change with propagation, keeps in a three-dimensional space, and improves the application capability in a three-dimensional scene. Secondly, the embodiment of the present application can use the same light path to obtain speckles with different intensity correlations required in specific applications, effectively avoiding the limitation that the speckles with different correlations need to replace the illumination light path, and has important application value.

[0058] Step A1 is as shown in Figure 2 , Figure 3 indicated, wherein Figure 2is a schematic diagram of a speckle generating optical path in an embodiment of the present application. Specifically, the light beam emitted by the laser 1 is first expanded by the beam expander 2 to obtain a uniform light beam with a larger diameter, then passes through the polarizer 3 to convert it into linearly polarized light, and then is modulated by the phase spatial light modulator 4. The modulated light beam passes through the 4f illumination optical path composed of the lens 5 with focal length f1 and the objective lens 6 with focal length fobj to generate a speckle pattern, and finally the speckle intensity pattern is collected by the detector 7. Specifically, the distance between the lens 5 and the objective lens 6 is f1+f, and the distance between the lens and the center of the phase spatial light modulator 4 is f1.

[0059] Figure 3 is a flowchart for establishing an intensity correlation transmission model between the initial phase field correlation and the speckle intensity correlation in three-dimensional space based on the speckle generating optical path, which describes the relationship between the initial phase field correlation of the phase spatial light modulator and the speckle intensity correlation generated in the three-dimensional space after the illumination optical path. The model elements include but are not limited to the correlation of the initial phase field, the pupil of the illumination optical path, the magnification of the illumination optical path, and the speckle correlation. The following steps are included:

[0060] A11: convolve the three-dimensional impulse response function of the speckle generating optical path with the initial phase field to obtain a three-dimensional speckle field;

[0061] A12: autocorrelate the three-dimensional speckle field to obtain a field correlation transmission model between the initial phase field correlation and the three-dimensional speckle field correlation;

[0062] A13: normalize and take the modulus of the field correlation transmission model to obtain an intensity correlation transmission model between the initial phase field correlation and the speckle intensity correlation in three-dimensional space.

[0063] Specifically, in step A11, the three-dimensional impulse response function h(x, y, z) of the speckle generating optical path is convolved with the initial phase field to obtain a three-dimensional speckle field A(x, y, z), which is specifically expressed by the following formula:

[0064]

[0065] where (x, y, z) is the three-dimensional coordinate of the space where the three-dimensional speckle field is located, is the convolution operator.

[0066] Specifically, the speckle generating optical path is a 4f system, and its three-dimensional impulse response function where P(x b ,y b ) is the pupil function of the objective lens in the 4f system, (x b ,y b() represents the coordinates of the objective lens pupil plane, j is the imaginary unit, and λ is the wavelength of light. f is the wave vector, z is the distance from the speckle plane to the objective lens, f is the focal length of the objective lens in the 4f system, and f1 is the focal length of the lens in the 4f system. This is the magnification (reduction) factor of the 4f system. The three-dimensional impulse response function of the speckle generation optical path is established using methods such as the Debye approximation and paraxial approximation.

[0067] In step A12, the three-dimensional speckle field A(x,y,z) is autocorrelated to obtain the initial phase field correlation. Correlation T with three-dimensional speckle field A Field-related transmission model between (Δx, Δy, z) Specifically, this can be expressed by the following formula:

[0068]

[0069] Where (Δx,Δy) is the increment between two different coordinates of the speckle field in space, is the independent variable of the correlation function, μ is a constant independent of (Δx,Δy), D is the pupil diameter of the objective pupil P, and J1 is the first-order Bessel function of the first kind.

[0070] In step A13, the field-related transmission model is... Normalization and modulus squared are performed to obtain the initial phase field correlation. Correlation C with speckle intensity in three-dimensional space A Intensity-dependent transmission model between (Δx, Δy, z) g is the independent variable. The function symbol is specifically expressed by the following formula:

[0071]

[0072] like Figure 4 As shown, in step A2, the correlation of the required initial phase field is solved using the intensity correlation transmission model and the intensity correlation of the target speckle, and the initial phase field is further obtained, including the following steps:

[0073] A21: Determine the intensity correlation of the target speckle based on specific needs;

[0074] A22: Based on the intensity correlation of the target speckle, and combined with the intensity correlation transmission model, the correlation of the initial phase field is solved by deconvolution;

[0075] A23: Based on the correlation of the initial phase field, solve for the required initial phase field.

[0076] Specifically, in step A21, the intensity correlation C of the target speckle is determined according to specific requirements A (Δx,Δy,z), the intensity correlation of the speckle can be manifested as the particle size of the speckle, the sparseness of the speckle and the like, which can be determined according to specific requirements.

[0077] In step A22, the intensity correlation C of the target speckle is determined according to the intensity correlation of the target speckle A (Δx,Δy,z), combined with the intensity correlation transmission model The correlation of the initial phase field is solved by deconvolution The deconvolution method includes but is not limited to the Fourier transform-based deconvolution method, and specifically, the Fourier transform-based deconvolution method is expressed by the following formula:

[0078]

[0079] Wherein, is a two-dimensional Fourier transform, is a two-dimensional inverse Fourier transform.

[0080] In step A23, the correlation of the initial phase field is determined based on the correlation of the initial phase field The required initial phase field is solved Specifically, the correlation of the initial phase field The relationship between the required initial phase field can be expressed by the following formula:

[0081]

[0082] The process of solving includes but is not limited to the phase recovery algorithm based on the Gerchberg-Saxton algorithm.

[0083] In step A3, the initial phase field is loaded onto the phase modulation device, and the speckle with the target intensity correlation can be obtained in the three-dimensional space after the speckle generation light path.

[0084] The embodiment of the present application can generate customized speckle based on the required speckle intensity correlation in specific applications through the above steps; and ensure that the customized speckle intensity correlation does not change with propagation, and remains in three-dimensional space, has depth robustness, and improves the application ability in three-dimensional scene; secondly, the speckle with different intensity correlations required in specific applications is obtained by using the same light path, which effectively avoids the limitation of replacing the illumination light path to obtain speckle with different correlations; has important application value.

[0085] An experimental example is provided as follows.

[0086] As shown in Figure 5a , Figure 5b , Figure 5c , it is a schematic diagram of intensity correlation of three different target speckles, Figure 5a The full width at half maximum of the target intensity correlation is 1 microns, Figure 5b The full width at half maximum of the target intensity correlation is 1.4 microns, Figure 5c The full width at half maximum of the target intensity correlation is 1.8 microns.

[0087] As shown in Figure 6a , Figure 6b , Figure 6c , it is three initial phase fields respectively solved based on Figure 5a , Figure 5b , Figure 5c Three different target intensity correlations.

[0088] As shown in Figure 7a , it is the initial phase field shown in Figure 6a Load on the phase type spatial light modulator, the speckle intensity diagram obtained after the illumination light path and the speckle intensity correlation schematic diagram obtained; as shown in Figure 7b , it is the initial phase field shown in Figure 6b Load on the phase type spatial light modulator, the speckle intensity diagram obtained after the illumination light path and the speckle intensity correlation schematic diagram obtained; as shown in Figure 7c , it is the initial phase field shown in Figure 6c Load on the phase type spatial light modulator, the speckle intensity diagram obtained after the illumination light path and the speckle intensity correlation schematic diagram obtained. Each set of experiments shows the speckle diagram and the intensity correlation of the speckle in the depth layer within 1000 microns near the focusing plane of the illumination light path with a depth interval of 100 microns. As shown in Figure 7a , Figure 7b , Figure 7c , the speckle intensity correlation obtained in the range of 1000 microns in depth respectively coincides with the intensity correlation of the target speckle in Figure 5a , Figure 5b , Figure 5c , which proves the effectiveness of the method of the embodiment. The embodiment can generate customized speckle intensity correlation through the above steps, effectively avoiding the limitation of replacing the illumination light path to obtain speckles with different correlations; and the customized speckle intensity correlation does not change with propagation, can be maintained in three-dimensional space, has depth robustness, and has important application value.

[0089] The embodiment of the application also provides a depth-robust speckle generation device, comprising a processor, a memory and a computer program stored in the memory and executed by the processor, wherein the processor executes the computer program to realize the depth-robust speckle generation method according to any one of the above embodiments.

[0090] The embodiment of the present application further provides a computer readable storage medium, which stores a computer program. The computer program is executed by a processor to implement the deep robust speckle generation method.

[0091] The storage medium can be implemented by any type of volatile or nonvolatile storage devices, or a combination thereof. Among them, the nonvolatile memory can be a Read Only Memory (ROM), a Programmable Read-Only Memory (PROM), an Erasable Programmable Read-Only Memory (EPROM), an Electrically Erasable Programmable Read-Only Memory (EEPROM), a Ferromagnetic Random Access Memory (FRAM), a Flash Memory, a magnetic surface memory, an optical disc, or a Compact Disc Read-Only Memory (CD-ROM). The magnetic surface memory can be a disk memory or a tape memory. The volatile memory can be a Random Access Memory (RAM) used as an external cache. By way of example and not limitation, many forms of RAM are available, such as Static Random Access Memory (SRAM), Synchronous Static Random Access Memory (SSRAM), Dynamic Random Access Memory (DRAM), Synchronous Dynamic Random Access Memory (SDRAM), Double Data Rate Synchronous Dynamic Random Access Memory (DDR SDRAM), Enhanced Synchronous Dynamic Random Access Memory (ESDRAM), Sync Link Dynamic Random Access Memory (SLDRAM), and Direct Rambus Random Access Memory (DRRAM). The storage medium described in the embodiments of the present application is intended to include but not limited to these and any other suitable types of memory.

[0092] In several embodiments provided in the present application, it should be understood that the disclosed system and method can be implemented in other manners. The described device embodiments are merely illustrative, for example, the division of the units is only a logical function division, and there can be another division manner in actual implementation, for example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the displayed or discussed coupling, or direct coupling or communication connection between the components can be indirect coupling or communication connection through some interfaces, devices or units, and can be electrical, mechanical or other forms.

[0093] The units described as separate components can or can not be physically separate, and the components shown as units can or can not be physical units, that is, can be located in one place, or can be distributed on a plurality of network units; part or all of the units can be selected according to actual needs to achieve the purpose of the embodiment.

[0094] In addition, each functional unit in each embodiment of the present application can be integrated into one processing unit, or each unit can be a separate unit, or two or more units can be integrated into one unit; the integrated unit can be realized in the form of hardware, or in the form of hardware plus software functional unit.

[0095] Those of ordinary skill in the art can understand that all or part of the steps of the above method embodiments can be completed by a program instructing related hardware, and the foregoing program can be stored in a computer readable storage medium, and when the program is executed, the steps of the method embodiments are executed; and the foregoing storage medium includes: mobile storage equipment, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), magnetic disk or optical disk, and various media that can store program codes.

[0096] Alternatively, the integrated units described above in the embodiments of the present application, if realized in the form of software function modules and sold or used as independent products, can also be stored in a computer readable storage medium. Based on such understanding, the technical solutions of the embodiments of the present application can be embodied in the form of a software product, and the computer software product is stored in a storage medium, includes several instructions to make a computer device (which can be a personal computer, a server, or a network device, etc.) execute all or part of the methods described in the embodiments of the present application. The foregoing storage medium includes: mobile storage devices, ROM, RAM, magnetic disks or optical disks, and various media that can store program codes.

[0097] The methods disclosed in the several method embodiments provided by the present application can be combined arbitrarily without conflict, to obtain new method embodiments.

[0098] The features disclosed in the several product embodiments provided by the present application can be combined arbitrarily without conflict, to obtain new product embodiments.

[0099] The features disclosed in the several method or device embodiments provided by the present application can be combined arbitrarily without conflict, to obtain new method or device embodiments.

[0100] The above is a further detailed description of the present application in combination with specific preferred embodiments, and the specific implementation of the present application cannot be limited to these descriptions. For those skilled in the art to which the present application belongs, without departing from the concept of the present application, a number of equivalent substitutions or obvious modifications can be made, and the performance or use is the same, which should be regarded as belonging to the protection scope of the present application.

Claims

1. A method for generating deep-robust speckles, characterized in that, The method comprises the following steps: A1: establishing an intensity correlation transmission model between the initial phase field correlation and the speckle intensity correlation in the three-dimensional space based on the speckle generation optical path; A2: solving the initial phase field correlation by using the intensity correlation transmission model and the intensity correlation of the target speckle, and further obtaining the initial phase field; A3: loading the initial phase field to the phase modulation device to obtain the speckle with the target intensity correlation in the three-dimensional space after the speckle generation optical path; Step A1 comprises the following steps: A11: convolving the three-dimensional impulse response function of the speckle generation optical path with the initial phase field to obtain a three-dimensional speckle field; A12: performing autocorrelation operation on the three-dimensional speckle field to obtain a field correlation transmission model between the initial phase field correlation and the three-dimensional speckle field correlation; A13: normalizing and taking the modulus of the field correlation transmission model to obtain the intensity correlation transmission model between the initial phase field correlation and the speckle intensity correlation in the three-dimensional space.

2. The depth-robust speckle generation method of claim 1, wherein, In step A11, the three-dimensional speckle field is A(x, y, z) and is expressed by the following formula: where h(x, y, z) is a three-dimensional impulse response function, is an initial phase field, is a convolution operator, (x, y, z) is a three-dimensional coordinate of a three-dimensional speckle field, and a speckle generation optical path is a 4f system, is a magnification or reduction factor of the 4f system, f is a focal length of an objective lens in the 4f system, and f1 is a focal length of a lens in the 4f system; The expression of the three-dimensional impulse response function is as follows: where P(x b ,y b ) is the pupil function of the objective lens in the 4f system, (x b ,y b ) are the coordinates of the objective pupil plane, j is the imaginary unit, z is the distance of the speckle plane from the objective, is the wave vector, and λ is the wavelength of the light.

3. The depth-robust speckle generation method of claim 2, wherein, In step A12, the field-dependent transport model is This is expressed by the following equation: where the initial phase field correlation is The three-dimensional speckle field correlation is T A (Δx,Δy,z), (Δx,Δy) is the increment between two different coordinates in space of the speckle field, μ is a constant independent of (Δx,Δy), D is the pupil diameter of the objective pupil P, and J1 is the first-order Bessel function of the first kind.

4. The depth-robust speckle generation method of claim 3, wherein, In step A13, the intensity-dependent transmission model is This is expressed by the following equation: where g is a function symbol with the argument C A (Δx,Δy,z) is the speckle intensity correlation in three-dimensional space.

5. The depth-robust speckle generation method of claim 1, wherein, Step A2 specifically comprises the following steps: A21: determining the intensity correlation of the target speckle; A22: deconvolving to solve the initial phase field correlation according to the intensity correlation of the target speckle in combination with the intensity correlation transmission model; A23: solving the initial phase field based on the initial phase field correlation.

6. The depth-robust speckle generation method of claim 5, wherein, In step A21, the intensity correlation of the target speckle comprises the particle size of the speckle and the sparseness of the speckle.

7. The depth-robust speckle generation method of claim 6, wherein, In step A22, the deconvolution solving method comprises a Fourier transform-based deconvolution method, which is expressed by the following formula: wherein, is the initial phase field correlation, C A (Δx,Δy,z) is the intensity correlation of the target speckle, (Δx,Δy) is the increment between two different coordinates in space where the speckle field is located, D is the pupil diameter of the objective pupil P, J1 is the first-order Bessel function of the first kind, z is the distance of the speckle plane from the objective, λ is the wavelength of light, is the two-dimensional Fourier transform, is the two-dimensional inverse Fourier transform.

8. The depth-robust speckle generation method of claim 7, wherein, In step A23, the initial phase field correlation The relationship between the initial phase field and the phase field is expressed by the following equation: wherein is the initial phase field.

9. The depth-robust speckle generation method of claim 1, wherein, The speckle generation optical path comprises a 4f optical path, a Fourier optical path or a Fresnel optical path.

10. The method of claim 1, wherein, In step A11, the three-dimensional impulse response function of the speckle generation optical path is established by using the Debye approximation or the paraxial approximation method.

11. A deep-robust speckle generating device, characterized by The computer program is stored in the memory and executed on the processor, and the processor executes the computer program to implement the depth-robust speckle generation method according to any one of claims 1-10.

12. A computer-readable storage medium, characterized in that, The computer readable storage medium stores a computer program, and the computer program is executed by the processor to implement the steps of the depth-robust speckle generation method according to any one of claims 1-10.

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