Multi-depth diffraction field calculation method and device based on phase initialization and medium

Abstract

The invention discloses a multi-depth diffraction field calculation method and device based on phase initialization and a medium, and relates to the field of computer data processing.The method comprises the steps that on the basis of laser wavelengths, integral multiple processing is conducted on an initial diffraction interval and an initial depth interval to achieve initialization, and an optimized diffraction interval and an optimized depth interval are obtained; and performing diffraction simulation based on the optimized diffraction spacing, the laser wavelength and the optimized depth spacing, determining an optical transfer function according to the optimized depth spacing, and then multiplexing the optical transfer function to determine a multi-depth diffraction field. According to the invention, the multi-depth diffraction field can be rapidly and accurately determined, and a data basis is provided for subsequent three-dimensional scene reproduction.

Description

Technical Field

[0001] The present application relates to the field of computer data processing, and in particular, to a multi-depth diffraction field calculation method, device, and medium based on phase initialization. Background Art

[0002] Computer-Generated Holograms (CGH) generate holographic images by calculating and simulating the propagation of object light waves. In computer-generated holograms, traditional phase initialization methods are difficult to meet the requirements of real-time 3D display due to high computational complexity or poor reconstruction effects. For example, random phase initialization introduces speckle noise and reduces the reconstruction quality; in constant phase initialization, in order to ensure the consistency of position and phase, the optical transfer function (OTF) needs to be calculated multiple times in a 3D scene, but since the calculation speed is related to the number of layers, the speed is slow. Summary of the Invention

[0003] The purpose of the present application is to provide a multi-depth diffraction field calculation method, device, and medium based on phase initialization, which can quickly and accurately determine the multi-depth diffraction field and provide a data basis for subsequent three-dimensional scene reproduction.

[0004] To achieve the above purpose, the present application provides the following solutions:

[0005] In the first aspect, the present application provides a multi-depth diffraction field calculation method based on phase initialization, including:

[0006] Obtain an initial diffraction spacing, a laser wavelength, and an initial depth spacing;

[0007] Based on the laser wavelength, perform integer multiple processing on the initial diffraction spacing and the initial depth spacing respectively to achieve initialization, and obtain an optimized diffraction spacing and an optimized depth spacing;

[0008] Perform diffraction simulation based on the optimized diffraction spacing, the laser wavelength, and the optimized depth spacing, determine the optical transfer function according to the optimized depth spacing, and then reuse the optical transfer function to determine the multi-depth diffraction field.

[0009] In the second aspect, the present application provides a computer device, including: a memory, a processor, and a computer program stored on the memory and executable on the processor, where the processor executes the computer program to implement the multi-depth diffraction field calculation method based on phase initialization.

[0010] In a third aspect, the present application provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, it implements a method for calculating multi-depth diffraction fields based on phase initialization.

[0011] In a fourth aspect, the present application provides a computer program product, including a computer program. When the computer program is executed by a processor, it implements a method for calculating multi-depth diffraction fields based on phase initialization.

[0012] According to the specific embodiments provided by the present application, the present application has the following technical effects: The present application provides a method, device, and medium for calculating multi-depth diffraction fields based on phase initialization. By performing integer multiple processing on the initial diffraction spacing and the initial depth spacing based on the laser wavelength, it can ensure that during the diffraction simulation process in the generation of computer holograms, a unified optical transfer function is generated. That is, for different depth layers at the same wavelength obtained from the diffraction simulation, since the corresponding depth intervals are the same, the optical transfer functions for information transmission between different depth layers are the same. During the determination of the multi-depth diffraction field, the above optical transfer function can be directly reused without the need to calculate it for each depth layer, avoiding repeated calculation of the optical transfer function, significantly reducing the amount of calculation, and without introducing speckle noise. The multi-depth diffraction field can be quickly and accurately determined, providing a data basis for subsequent three-dimensional scene reproduction. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0014] Figure 1 It is an application environment diagram of a method for calculating multi-depth diffraction fields based on phase initialization in an embodiment of the present application.

[0015] Figure 2 It is a flowchart of a method for calculating multi-depth diffraction fields based on phase initialization provided by an embodiment of the present application.

[0016] Figure 3 It is a schematic diagram of integer multiple processing provided by an embodiment of the present application.

[0017] Figure 4 It is a schematic diagram of the structure of a computer device provided by an embodiment of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0018] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts shall fall within the protection scope of the present application.

[0019] The present application optimizes the relationship between the diffraction pitch, depth interval, and laser wavelength, and proposes an efficient and consistent phase initialization method to solve the problems of low calculation efficiency and data inconsistency in the prior art.

[0020] To make the above objects, features, and advantages of the present application more obvious and understandable, the present application will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0021] The multi-depth diffraction field calculation method based on phase initialization provided by the embodiments of the present application can be applied to an application environment as Figure 1 shown. Among them, the terminal 102 communicates with the server 104 through the network. The data storage system can store the data that the server 104 needs to process. The data storage system can be set up separately, integrated on the server 104, or placed on the cloud or other servers. The terminal 102 can send the initial diffraction pitch, laser wavelength, and initial depth interval to the server 104. After receiving them, the server 104 performs an integer multiple process on the initial diffraction pitch and the initial depth interval respectively based on the laser wavelength to achieve initialization, obtaining the optimized diffraction pitch and the optimized depth interval, and then performing diffraction simulation. During this process, the optical transfer function is determined according to the optimized depth interval, and then the optical transfer function is reused to determine the multi-depth diffraction field. On this basis, the server 104 can continue to reproduce the three-dimensional scene with the help of a neural network, and then feedback the reproduced three-dimensional scene to the terminal 102. In addition, in some embodiments, the multi-depth diffraction field calculation method based on phase initialization can also be implemented independently by the server 104 or the terminal 102.

[0022] Among them, the terminal 102 can be, but is not limited to, various desktop computers, laptop computers, smartphones, tablet computers, etc. The server 104 can be implemented by an independent server or a server cluster composed of multiple servers, and can also be a cloud server.

[0023] For computer-generated holograms, the processing process includes: inside the computer, the target object is represented by shape data or mathematical formulas; according to the preset laser source and the optical characteristics of the target object, the complex amplitude distribution of the light wave emitted or reflected by the target object on the object plane is calculated; the complex amplitude contains the amplitude and phase information of the light wave; based on the complex amplitude, angular spectrum propagation calculation, Fourier transform, etc. are performed to obtain a two-dimensional hologram recording the three-dimensional scene information where the target object is located; by processing the two-dimensional hologram, the three-dimensional scene where the target object is located can be reproduced.

[0024] In an exemplary embodiment, as Figure 2 shown, a method for calculating a multi-depth diffraction field based on phase initialization is provided. This method is executed by a computer device, and specifically can be executed alone by a computer device such as a terminal or a server, or can be jointly executed by a terminal and a server. In the embodiments of the present application, taking this method applied to Figure 1 server 104 therein as an example for illustration, it includes the following steps 201 to step 203.

[0025] Step 201, obtain the initial diffraction spacing, laser wavelength, and initial depth spacing. Among them, the initial diffraction spacing and the initial depth spacing can be set by relevant technicians according to experience, or can be calculated as needed.

[0026] Step 202, based on the laser wavelength, perform integer multiple processing on the initial diffraction spacing and the initial depth spacing respectively to achieve initialization, and obtain the optimized diffraction spacing and the optimized depth spacing.

[0027] Among them, as Figure 3 shown, the step of performing integer multiple processing on the initial diffraction spacing based on the laser wavelength to achieve data initialization and obtain the optimized diffraction spacing includes:

[0028] Use the following formula to calculate the optimized diffraction spacing: where z is the initial diffraction spacing, λ is the laser wavelength, is the floor function, and z′ is the optimized diffraction spacing.

[0029] The integer multiple processing of the initial depth interval is the same as the above integer multiple processing of the initial diffraction spacing, and will not be elaborated here.

[0030] Step 203, perform diffraction simulation based on the optimized diffraction spacing, the laser wavelength, and the optimized depth spacing, determine the optical transfer function according to the optimized depth spacing, and then reuse the optical transfer function to determine the multi-depth diffraction field.

[0031] Among them, the optical transfer function is: where R Δz′ (fx ,f y ) is the optical transfer function, j is the imaginary unit; k = 2π / λ, where k is the wave number and λ is the laser wavelength; Δz′ is the optimized depth spacing; f x 、f y are frequency domain coordinates, |F x |, |f y | < 1 / 2Δp, where Δp is the pixel pitch of the spatial light modulator used in the diffraction simulation process.

[0032] By adjusting the diffraction spacing and depth spacing to integer multiples of the wavelength, a unified optical transfer function can be generated and reused in the diffraction simulation process, avoiding repeated calculations, reducing the amount of calculation, and significantly improving the calculation efficiency.

[0033] The iteration of the multi-depth diffraction process can be extended to more general scenarios without sacrificing generality. Assuming that the target scene is evenly divided into N depth layers and the optimized depth spacing is Δz′, then the determination process of the multi-depth diffraction field includes:

[0034] (1) For the depth layer in the diffraction simulation process, according to the optical transfer function, the angular spectrum method is used to calculate the complex amplitude to describe the diffraction field of the depth layer; the calculation formula for the complex amplitude of the depth layer is:

[0035]

[0036] where ASM{·} Δz′ is the angular spectrum method calculation function for diffraction, Δz′ is the optimized depth spacing, U n (x,y) is the complex amplitude of the nth depth layer; F{·} is the Fourier transform function, F -1 {·} is the inverse Fourier transform function, H Δz′ (f x ,f y ) is the optical transfer function; Λ{·} is the angular spectrum diffraction processing, U n-1 (x,y) is the complex amplitude of the (n - 1)th depth layer; is the amplitude of the intensity image, j is the imaginary unit, satisfying j 2 = -1, φ0 is a constant phase, M n (x, y) is the Boolean mask corresponding to the nth depth layer S n , n ∈ [0, N - 1], n is an integer, and N is the total number of depth layers in the diffraction simulation process.

[0037] (2) According to the complex amplitude of the depth layer, recursively calculate the complex amplitude of the next depth layer to finally obtain the complex amplitude of the hologram plane, which is used to describe the multi-depth diffraction field. The calculation formula for the complex amplitude of the hologram plane is:

[0038]

[0039] Among them, U h (x, y) is the complex amplitude of the hologram plane S h The reverse distance from the (-z h ′-(N - 1)Δz′) to the hologram plane S is from the (N - 1)th depth layer h The distance from z h to the hologram plane S is from the 1st depth layer h The distance from z h ′ is the optimized distance for z h Optimized distance.

[0040] After determining the multi-depth diffraction field, with the help of a neural network, the complex amplitude U h (x, y) of the hologram plane will be used to encode the multi-depth hologram. The phase initialization method for calculating the multi-depth diffraction field described in this application can also be named the position-period-dependent phase initialization method (PPD-PIM), which is used for the rapid generation of multi-depth holograms.

[0041] In summary, for scenes of different depth layers at the same wavelength, this application directly reuses a unified optical transfer function and accelerates the calculation of the diffraction fields of each depth layer through fast Fourier transform. Among them, through strict adjustment of integer multiples of the wavelength, while ensuring the accuracy required by the human eye, the reuse rate of the optical transfer function is maximized, realizing the rapid calculation of the multi-depth diffraction field. While ensuring the hologram reconstruction quality, the hologram generation efficiency is significantly improved. And the unified optical transfer function can ensure the statistical consistency of the diffraction fields in scenes of different depth layers, improving the training effect of the machine learning model in subsequent three-dimensional scene reconstruction steps. In addition, this application is applicable to holographic display devices based on the angular spectrum method (such as spatial light modulator SLM) without additional hardware modification.

[0042] In an exemplary embodiment, a computer device is provided. The computer device can be a server or a terminal, and its internal structure diagram can be as shown in Figure 4As shown in the figure. The computer device includes a processor, a memory, an input / output interface (Input / Output, abbreviated as I / O), and a communication interface. Among them, the processor, the memory, and the input / output interface are connected through a system bus, and the communication interface is connected to the system bus through the input / output interface. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program, and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The input / output interface of the computer device is used to exchange information between the processor and external devices. The communication interface of the computer device is used to communicate with external terminals through a network connection. When the computer program is executed by the processor, it implements a multi-depth diffraction field calculation method based on phase initialization.

[0043] Those skilled in the art can understand that Figure 4 the structure shown in the figure is only a block diagram of some structures related to the solution of this application, and does not constitute a limitation on the computer device to which the solution of this application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine some components, or have different component arrangements. In an exemplary embodiment, a computer device is provided, including a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the computer program, it implements the steps in the above method embodiments.

[0044] In an exemplary embodiment, a computer-readable storage medium is provided, storing a computer program, which when executed by a processor implements the steps in the above method embodiments.

[0045] In an exemplary embodiment, a computer program product is provided, including a computer program, which when executed by a processor implements the steps in the above method embodiments.

[0046] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use, and processing of relevant data need to comply with relevant regulations.

[0047] Those of ordinary skill in the art can understand that all or part of the processes in the methods of the above embodiments can be completed by instructing relevant hardware through a computer program. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above methods. Among them, any reference to a memory, database, or other medium used in the embodiments provided in the present application can include at least one of non-volatile and volatile memories. Non-volatile memories can include read-only memory (ROM), magnetic tapes, floppy disks, flash memories, optical memories, high-density embedded non-volatile memories, resistive random access memories (ReRAMs), magnetoresistive random access memories (MRAMs), ferroelectric random access memories (FRAMs), phase change memories (PCMs), graphene memories, etc. Volatile memories can include random access memory (RAM) or external cache memories, etc. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc.

[0048] The databases involved in the embodiments provided in the present application can include at least one of relational databases and non-relational databases. Non-relational databases can include distributed databases based on blockchain, etc., without limitation. The processors involved in the embodiments provided in the present application can be general-purpose processors, central processors, graphics processors, digital signal processors, programmable logics, data processing logics based on quantum computing, etc., without limitation.

[0049] The technical features of the above embodiments can be combined arbitrarily. For the sake of concise description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0050] Specific examples are used in this article to elaborate on the principles and implementation manners of the present application. The description of the above embodiments is only used to help understand the method and its core idea of the present application; at the same time, for those of ordinary skill in the art, according to the idea of the present application, there will be changes in the specific implementation manners and application scopes. In summary, the content of this specification should not be construed as a limitation to the present application.

Claims

1. A multi-depth diffraction field calculation method based on phase initialization, characterized in that: The method comprises: Obtaining initial diffraction spacing, laser wavelength, and initial depth spacing; Based on the laser wavelength, the initial diffraction spacing and the initial depth spacing are respectively processed by integer multiples to achieve initialization, thereby obtaining an optimized diffraction spacing and an optimized depth spacing; A diffraction simulation is performed based on the optimized diffraction spacing, the laser wavelength and the optimized depth spacing, and an optical transfer function is determined according to the optimized depth spacing, and then the optical transfer function is multiplexed to determine a multi-depth diffraction field.

2. The multi-depth diffraction field calculation method based on phase initialization according to claim 1 is characterized in that: Based on the laser wavelength, the initial diffraction spacing is processed by integer multiples to achieve initialization and obtain the step of optimizing the diffraction spacing, including: The optimized diffraction spacing is calculated using the following formula: Where z is the initial diffraction spacing, λ is the laser wavelength, is the floor rounding function, and z′ is the optimized diffraction spacing.

3. The multi-depth diffraction field calculation method based on phase initialization according to claim 1 is characterized in that: The optical transfer function is: Among them, H Δz′ (f x , f y ) is the optical transfer function, j is the imaginary unit; k = 2π / λ, k is the wave number, λ is the laser wavelength; Δz′ is the optimized depth spacing; f x 、f y is the frequency domain coordinate.

4. The multi-depth diffraction field calculation method based on phase initialization according to claim 1 is characterized in that: The process of determining the multi-depth diffraction field includes: For the depth layer in the diffraction simulation process, the complex amplitude is calculated using the angular spectrum method according to the optical transfer function to describe the diffraction field of the depth layer; According to the complex amplitude of the depth layer, the complex amplitude of the next depth layer is recursively calculated to finally obtain the complex amplitude of the hologram plane for describing the multi-depth diffraction field.

5. The multi-depth diffraction field calculation method based on phase initialization according to claim 4 is characterized in that: The calculation formula of the complex amplitude of the depth layer is: Among them, ASM{·} Δz′ is the angular spectrum calculation function of diffraction, Δz′ is the optimized depth spacing, U n (x, y) is the complex amplitude of the nth depth layer; F{·} is the Fourier transform function, F -1 {·} is the inverse Fourier transform function, H Δz′ (f x , f y ) is the optical transfer function; Λ{·} is the angular spectrum diffraction processing, U n-1 (x,y) is the complex amplitude of the n-1th depth layer; is the amplitude of the intensity image, j is the imaginary unit, φ0 is the constant phase, M n (x,y) is the Boolean mask corresponding to the nth depth layer, n∈[0,N-1], and N is the total number of depth layers during the diffraction simulation.

6. The multi-depth diffraction field calculation method based on phase initialization according to claim 5 is characterized in that: The calculation formula of the complex amplitude of the hologram plane is: Among them, U h (x,y) is the hologram plane S h The complex amplitude, (-z h ′-(N-1)Δz′) is the reverse distance from the N-1th depth layer to the hologram plane, z h From the first depth layer to the hologram plane S h The distance, z h ′ is the pair z h Optimized distance.

7. A computer device comprising: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the multi-depth diffraction field calculation method based on phase initialization as described in any one of claims 1 to 6.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the multi-depth diffraction field calculation method based on phase initialization described in any one of claims 1 to 6 is implemented.

9. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the multi-depth diffraction field calculation method based on phase initialization described in any one of claims 1 to 6 is implemented.

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