A method, apparatus, device, and medium for three-dimensional reconstruction of internal strain of an object

Abstract

This invention discloses a method, apparatus, device, and medium for three-dimensional reconstruction of the internal strain of an object. When a target object is placed in three-dimensional space in a target placement manner, the strain expression for the strain to be measured inside the target object is determined. Neutron imaging is performed on the target object based on the target imaging angle to obtain the corresponding neutron imaging Bragg edge spectrum. Based on the neutron imaging Bragg edge spectrum, the average strain expression of the target object, and the strain expression for the strain to be measured, the strain information of the strain to be measured inside the target object is determined. The technical solution of this invention solves the problem that current two-dimensional Bragg edge neutron imaging can only determine the average strain value inside an object, but cannot determine the strain information at any location inside the object. It achieves the reconstruction of the three-dimensional strain inside a target object and the determination of the strain information at any location inside the target object.

Description

Technical Field

[0001] This invention relates to the field of neutron imaging technology, and in particular to a method, apparatus, device, and medium for three-dimensional reconstruction of internal strain of an object. Background Technology

[0002] With advancements in neutron sources, imaging methodologies, and detector technologies, energy-selective neutron radiography based on the Bragg edge effect has become one of the most studied research areas in neutron radiography, often referred to as Bragg edge imaging. Using methods such as time-of-flight or neutron monochromatic instruments, energy-selective neutron radiography records continuous transmission energy spectrum data for each pixel of the detector while simultaneously imaging in space. Information extraction methods can then be used to obtain strain and strain information within the material.

[0003] The strain calculated by two-dimensional Bragg edge neutron imaging is the average strain of the material along the transmission path, but the strain at a specific location within the sample is unknown. Therefore, obtaining strain information at any location within the sample is a pressing technical problem that needs to be solved. Summary of the Invention

[0004] This invention provides a method, apparatus, device, and medium for three-dimensional reconstruction of internal strain of an object, so as to determine strain information at any location inside the target object.

[0005] According to one aspect of the present invention, a method for three-dimensional reconstruction of internal strain of an object is provided, comprising:

[0006] When a target object is placed in a three-dimensional space in a target placement manner, determine the strain expression of the strain to be measured inside the target object;

[0007] Neutron imaging is performed on the target object based on the target imaging angle to obtain the neutron imaging Bragg side spectrum corresponding to the target object;

[0008] Based on the neutron imaging Bragg side spectrum, the average strain expression of the target object, and the strain expression of the strain to be measured, the strain information of the strain to be measured inside the target object is determined.

[0009] According to another aspect of the present invention, a three-dimensional reconstruction apparatus for the internal strain of an object is provided, comprising:

[0010] The target placement module is used to determine the strain expression of the internal strain to be measured of the target object when the target object is placed in a three-dimensional space in a target placement manner.

[0011] The neutron imaging module is used to perform neutron imaging on the target object based on the target imaging angle, and obtain the neutron imaging Bragg side spectrum corresponding to the target object.

[0012] The strain determination module is used to determine the strain information of the internal strain to be measured of the target object based on the neutron imaging Bragg side spectrum, the average strain expression of the target object, and the strain expression of the strain to be measured.

[0013] According to another aspect of the present invention, an electronic device is provided, the electronic device comprising:

[0014] At least one processor; and

[0015] A memory communicatively connected to the at least one processor; wherein,

[0016] The memory stores a computer program that can be executed by the at least one processor, which enables the at least one processor to perform the three-dimensional reconstruction method for internal strain of an object as described in any embodiment of the present invention.

[0017] According to another aspect of the present invention, a computer-readable storage medium is provided, the computer-readable storage medium storing computer instructions for causing a processor to execute and implement the three-dimensional reconstruction method for internal strain of an object as described in any embodiment of the present invention.

[0018] The technical solution of this invention, when a target object is placed in a three-dimensional space in a target placement manner, determines the strain expression of the strain to be measured inside the target object; performs neutron imaging on the target object based on the target imaging angle to obtain the corresponding neutron imaging Bragg edge spectrum of the target object; and determines the strain information of the strain to be measured inside the target object based on the neutron imaging Bragg edge spectrum, the average strain expression of the target object, and the strain expression of the strain to be measured. The technical solution of this invention solves the problem that current two-dimensional Bragg edge neutron imaging can only determine the average strain value inside an object, but cannot determine the strain information at any location inside the object, thus realizing the reconstruction of the three-dimensional strain inside the target object and the determination of the strain information at any location inside the target object.

[0019] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a flowchart of a three-dimensional reconstruction method for the internal strain of an object according to Embodiment 1 of the present invention;

[0022] Figure 2 A spatial schematic diagram of the strain to be measured inside the target object;

[0023] Figure 3 This is a schematic diagram of the Bragg transmission imaging information of the sample;

[0024] Figure 4 This is a schematic diagram of three-dimensional strain nondestructive testing sample acquisition provided in Embodiment 2 of the present invention;

[0025] Figure 5 This is a schematic diagram of the structure of a three-dimensional reconstruction device for the internal strain of an object according to Embodiment 3 of the present invention;

[0026] Figure 6 This is a schematic diagram of the structure of an electronic device that implements a three-dimensional reconstruction method for the internal strain of an object according to Embodiment 4 of the present invention. Detailed Implementation

[0027] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0028] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0029] Example 1

[0030] Figure 1 This is a flowchart of a three-dimensional reconstruction method for the internal strain of an object according to Embodiment 1 of the present invention. This embodiment is applicable to the situation of three-dimensional reconstruction of the internal strain of a target object. This method can be executed by a three-dimensional reconstruction device for the internal strain of an object. This device can be implemented in hardware and / or software and can be configured in an electronic device. Figure 1 As shown, the method includes:

[0031] S110. When the target object is placed in a three-dimensional space in a target placement manner, determine the strain expression of the strain to be measured inside the target object.

[0032] In this embodiment, the target object refers to the object whose internal strain needs to be determined. Optionally, the target object is a metal sample. The target placement method can be understood as the placement posture of the target object in three-dimensional space, that is, the target object is placed in three-dimensional space according to the target placement method, and the expression of the internal strain to be measured is further determined. The strain to be measured can be understood as the strain at a certain position inside the target object. The strain expression is a mathematical expression of the strain to be measured.

[0033] Based on the above embodiments, the target placement method includes a first placement method, a second placement method, and a third placement method. The three-dimensional space is a Cartesian space. In the first placement method, the extension direction of the target object is parallel to the Z-axis of the Cartesian coordinate system. In the second placement method, the extension direction of the target object is parallel to the Y-axis of the Cartesian coordinate system. In the third placement method, the extension direction of the target object is parallel to the X-axis of the Cartesian coordinate system.

[0034] In this embodiment, the three-dimensional space is represented by a Cartesian coordinate system. The target object is placed in the three-dimensional space in different ways. For example, the extension direction of the target object is parallel to the Z-axis in the Cartesian coordinate system, or the extension direction of the target object is parallel to the Y-axis, or the extension direction of the target object is parallel to the X-axis. The target object is placed in different ways to perform neutron imaging of the target object from multiple angles.

[0035] Based on the above technical solution, determining the strain expression of the strain to be measured inside the target object includes: determining the initial strain expression of the strain to be measured in the Cartesian coordinate system, and determining the angle value in the initial strain expression based on the target placement method; substituting the angle value into the initial strain expression to obtain the strain expression of the strain to be measured inside the target object.

[0036] It should be noted that strain is a second-order tensor, containing nine components in three-dimensional space: three normal stress components and six shear stress components. In a static state of equilibrium (no torque), the shear stress is diagonally symmetric, and only six of the nine components are independent. To calculate the strain tensor at a standard location, at least six independent strain measurements are required in different ε{φ,ψ} directions. Figure 2 The figure shows a spatial diagram of the strain to be measured inside the target object. In the coordinate system of the sample, the strain to be measured consists of six components: principal strain and shear strain. The initial strain expression for the strain to be measured is:

[0037] ε{φ,ψ}=ε 11 cos 2 φsin 2 φ+ε 12 sin 2 φsin 2 ψ+ε 22 sin 2 φsin 2 ψ+ε 33 cos 2 ψ+ε 13 cosφsin2ψ+ε 23 sinφsin2ψ (1)

[0038] If it is necessary to determine the specific magnitude of the strain to be measured, it is necessary to solve the initial strain expression for the strain to be measured. In this embodiment, firstly, the angle value in the initial strain expression is determined according to the target placement method, that is, different placement methods correspond to different angle values. Then, the determined angle value is substituted into the initial strain expression to obtain the strain expression for the strain to be measured inside the target object. In a preferred embodiment scenario, if the target placement method is the first placement method, it means that the extension direction of the target object is parallel to the Z-axis. Since 2θ reaches 180° during transmission, that is, when the Bragg edge is imaged, ψ is equal to 90°. At this time, formula (1) can be written as formula (2).

[0039] ε φ90° ε 11 cos 2 φ+ε 22 sin 2 φ+ε12 sin2φ (2)

[0040] At this point, the six quantities that need to be rebuilt can be reduced to three quantities ε. 11 ,ε 22 ,ε 12 The first thing to achieve is the reconstruction of these three quantities. If the target is placed in the second way, it means that the extension direction of the target object is parallel to the Y-axis, which means that φ is equal to 90°. Substituting into formula (1), we can obtain the strain expression corresponding to the second placement method.

[0041] S120. Perform neutron imaging on the target object based on the target imaging angle to obtain the neutron imaging Bragg side spectrum corresponding to the target object.

[0042] In this embodiment, the target imaging angle refers to the angle at which neutron imaging is performed on the target object. A neutron beam is emitted toward the target object according to the target imaging angle, and then the neutrons passing through the target object are detected by a corresponding neutron detector. Finally, the Bragg side spectrum of the neutron imaging is obtained.

[0043] Based on the above embodiments, the step of performing neutron imaging on the target object based on the target imaging angle to obtain the neutron imaging Bragg side spectrum corresponding to the target object includes: determining multiple target imaging angles based on an initial angle, a termination angle, and a set step size; performing neutron imaging on the target object based on the multiple target imaging angles; and obtaining the neutron imaging Bragg side spectrum at each target imaging angle.

[0044] In this embodiment, during neutron imaging, the neutron emitting device can adjust the emission angle, i.e., the target imaging angle. For example, the initial angle can be 0 degrees, the ending angle can be 360 ​​degrees, and the step size can be 1 degree. Specifically, when the target is placed in the first placement mode, the extension direction of the target object is parallel to the Z-axis. During neutron imaging of the target object, the neutron emitting device is rotated using the Z-axis as the rotation axis. 0 degrees is taken as the angle at the start of rotation, and 360 degrees is taken as the angle at the stop of rotation. Bragg side spectrum imaging data is collected every 1 degree, thus obtaining neutron imaging Bragg side spectra at multiple target imaging angles.

[0045] S130. Based on the neutron imaging Bragg edge spectrum, the average strain expression of the target object, and the strain expression of the strain to be measured, determine the strain information of the strain to be measured inside the target object.

[0046] like Figure 3 The image shown is a schematic diagram of the Bragg transmission imaging information of the sample. The average strain obtained through Bragg edge imaging can be written in the following form:

[0047]

[0048] Neutron along direction The internal strain at the point through which the sample passes through thickness L is averaged by 1 / L to obtain Γ. ε , Γ ε That is, the value obtained by Bragg imaging, Γ ε In (p,θ), θ refers to the projection angle, and p refers to the position. The strain information within the target object refers to the magnitude and direction of the strain being measured.

[0049] Based on the above embodiments, determining the strain information of the strain to be measured inside the target object based on the neutron imaging Bragg side spectrum, the average strain expression of the target object, and the strain expression of the strain to be measured includes: determining the average strain value based on the neutron imaging Bragg side spectrum, and updating the average strain expression of the target object based on the average strain value; converting the updated average strain expression of the target object into a discrete expression, and iteratively solving based on the discrete expression and the strain expression of the strain to be measured to determine the strain information of the strain to be measured.

[0050] It should also be noted that the precise location of the Bragg edge (interplanar spacing d) extracted from a single-angle two-dimensional image is... hkl Comparative analysis of interplanar spacing d under stress conditions hkl The elastic strain can be calculated by considering the change in interplanar spacing d0 under stress-free conditions.

[0051] ε=(d hkl -d0) / d0=(t hkl -t0) / t0 (4)

[0052] d0 is the stress-free interplanar spacing, and t0 is the flight time of the neutron in the stress-free sample.

[0053] Specifically, after neutron imaging of the target object, the Bragg side spectrum is obtained. The neutron flight time can be determined through the Bragg side spectrum. Then, according to the above formula (4), the strain value can be obtained, that is, the average strain value of the target object with thickness L, which is Γ in formula (3). ε The specific values ​​of (p,θ) are then substituted into formula (3) to obtain the updated expression for the average strain. Furthermore, according to Huke's law, the elastic stress equilibrium satisfies the following constraints:

[0054]

[0055]

[0056] Where v is Poisson's ratio. Formula (4) can be written in discrete form:

[0057]

[0058] Formula (6) is the discrete expression mentioned above.

[0059] Optionally, the iterative solution based on the discrete expression and the strain expression of the strain to be measured includes: decomposing the discrete expression based on the strain expression and converting it into a total variation expression; and iteratively solving based on the total variation expression to obtain the normal stress value and shear stress value corresponding to the strain to be measured.

[0060] In this embodiment, ε in formula (6) ij It can be decomposed according to formula (2), and also due to the prior condition of formula (5). For two-dimensional strain reconstruction, the system matrix M and the measured average strain Γ can be derived by projecting the sample from different angles. ε For simple samples, the penetration thickness L (p, Θ) can be measured directly or obtained from traditional CT reconstruction. The reconstruction problem then becomes the simple problem of ε = M. -1 Γ ε In actual reconstruction, direct matrix inversion is extremely difficult due to the massive computational load, the underdeterminacy of the equations, and the effects of measurement errors and noise. In such cases, iterative methods can be used to solve this problem.

[0061] It can be written in the form of a total variational solution:

[0062] ε=argmin||ε|| TV

[0063]

[0064] Here, ζ represents a very small numerical error.

[0065] Following the above solution process, based on the strain expression and mean stress expression corresponding to the first placement method, and the above solution process, the values ​​of the normal stress and shear stress of the strain to be measured, i.e., ε, can finally be obtained. 11 ,ε 22 ,ε 12 It should also be noted that, based on the strain and mean stress expressions corresponding to other placement methods, the values ​​of other normal stresses and shear stresses, i.e., ε, can be obtained. 23 ,ε 33 ,ε 13 The value.

[0066] Based on the above embodiments, determining the strain information of the strain to be measured inside the target object includes: calculating the strain information of the strain to be measured inside the target object based on the normal stress and shear stress values ​​corresponding to the strain to be measured. Specifically, the above steps have already obtained the values ​​of each normal stress and shear stress and their corresponding angles, and the specific magnitude and direction of the strain to be measured can be obtained through stress synthesis.

[0067] The technical solution of this invention, when a target object is placed in a three-dimensional space in a target placement manner, determines the strain expression of the strain to be measured inside the target object; performs neutron imaging on the target object based on the target imaging angle to obtain the corresponding neutron imaging Bragg edge spectrum of the target object; and determines the strain information of the strain to be measured inside the target object based on the neutron imaging Bragg edge spectrum, the average strain expression of the target object, and the strain expression of the strain to be measured. The technical solution of this invention solves the problem that current two-dimensional Bragg edge neutron imaging can only determine the average strain value inside an object, but cannot determine the strain information at any location inside the object, thus realizing the reconstruction of the three-dimensional strain inside the target object and the determination of the strain information at any location inside the target object.

[0068] Example 2

[0069] Figure 4 This is a schematic diagram of three-dimensional strain nondestructive testing sample acquisition according to Embodiment 2 of the present invention. This embodiment is a preferred embodiment among the above embodiments. Figure 4 As shown, the method includes:

[0070] The three-dimensional reconstruction method for the internal strain of an object according to embodiments of the present invention is achieved through the following steps:

[0071] First, the precise location of the Bragg edge (interplanar spacing d) is extracted from a single-angle two-dimensional image. h kl Comparative analysis of interplanar spacing d under stress conditions h kl The elastic strain can be calculated by considering the change in interplanar spacing d0 under stress-free conditions.

[0072] ε=(d h kl -d0) / d0=(t h kl -t0) / t0 (8)

[0073] d0 is the stress-free interplanar spacing, and t0 is the flight time of the neutron in the stress-free sample.

[0074] The second-order strain tensor requires nine components (three normal stress components and six shear stress components) to determine in three-dimensional space. In static equilibrium (no moment), the shear stress is diagonally symmetric, and only six of the nine components are independent. To calculate the strain tensor at a standard location, at least six independent strain measurements are required in different ε{φ, ψ} directions.

[0075] In the coordinate system of the sample, continue as follows Figure 2 As shown, strain ε φψ From principal strain ε 11 , ε 22 , ε 33 and shear strain ε 12 , ε 13 , ε 23 These six components are expressed as follows:

[0076] ε{φ,ψ}=ε 11 cos 2 φsin 2 φ+ε 12 sin 2 φsin 2 ψ+ε 22 sin 2 φsin 2 ψ+ε 33 cos 2 ψ+ε 13 cosφsin2ψ+ε 23 sinφsin2ψ (9)

[0077] During transmission, i.e., when imaging along the Bragg edge, 2θ reaches 180°, and ψ equals 90°. Strain reconstruction requires data acquisition from different angles. While ensuring the rotation axis remains constant at Axis3, formula (9) can be written as:

[0078] ε φ90° =ε 11 cos 2 φ+ε 22 sin 2 φ+ε 12 sin2φ (10)

[0079] At this point, the six quantities that need to be rebuilt can be reduced to three quantities ε. 11 , ε 22 , ε 12 The first thing to achieve is the reconstruction of these three quantities.

[0080] The average strain obtained by Bragg edge imaging can be written in the following form:

[0081]

[0082] Neutron along direction The internal strain at the point through which the sample passes through thickness L is averaged by 1 / L to obtain Γ. ε , Γ ε That is, the value obtained by Bragg imaging, Γ ε In (p, θ), θ refers to the projection angle, and p refers to the position.

[0083] According to Huke's law, elastic stress equilibrium satisfies the following constraints:

[0084]

[0085]

[0086] Where v is Poisson's ratio.

[0087] Formula (11) can be written in discrete form:

[0088]

[0089] ε in formula (13) ij It can be decomposed according to formula (10), and also due to the prior condition of formula (12). For two-dimensional strain reconstruction, the system matrix M and the measured average strain Γ can be derived by projecting the sample from different angles. ε For simple samples, the penetration thickness L (p, Θ) can be directly measured or obtained from traditional CT reconstruction. The reconstruction problem then becomes a simple ε = . In actual reconstruction, due to the huge computational load, the underdeterminacy of the equation, and the influence of measurement errors and noise, direct matrix inversion is very difficult. At this time, an iterative method can be used to solve this problem.

[0090] It can be written in the form of a total variational solution:

[0091] ε=argmin||ε|| TV

[0092]

[0093] Here, ζ represents a very small numerical error.

[0094] The above description illustrates the solution process; specific data collection can be done using... Figure 4 This means that the sample is first rotated 360° along the system coordinate system Z, and Bragg edge imaging data is collected at 1° intervals. After collecting 360° of data, ε is obtained according to the above solution process. 11 ,ε 22 ,ε 12 .

[0095] Furthermore, taking the y-axis of the coordinate system as the rotation axis, rotate the sample by 90° (lay the sample in the above figure upside down), and then formula (9) can be written as:

[0096] ε φ90° =ε 11 cos 2 φ+ε 33 sin 2 φ+ε 13 sin2φ (15)

[0097] Then, rotate 360° along the Z-axis, collecting Bragg edge imaging data at 1° intervals. After collecting 360° of data, obtain ε according to the above solution process. 11 ,ε 33 ,ε 13 .

[0098] Following this method, the principal strain ε can eventually be solved. 11 ,ε 22 ,ε 33 and shear strain ε 12 ,ε 13 ,ε 23 These six components.

[0099] The technical solution of this invention utilizes Bragg edge neutron imaging technology to accurately measure the distribution of two-dimensional residual strain within a material. However, many scientific problems remain to be studied in order to accurately characterize the three-dimensional stress tensor field within a material. This invention obtains the three-dimensional strain distribution of a material through data acquisition at 4π angles and tensor CT reconstruction.

[0100] The technical solution of this invention, when a target object is placed in a three-dimensional space in a target placement manner, determines the strain expression of the strain to be measured inside the target object; performs neutron imaging on the target object based on the target imaging angle to obtain the corresponding neutron imaging Bragg edge spectrum of the target object; and determines the strain information of the strain to be measured inside the target object based on the neutron imaging Bragg edge spectrum, the average strain expression of the target object, and the strain expression of the strain to be measured. The technical solution of this invention solves the problem that current two-dimensional Bragg edge neutron imaging can only determine the average strain value inside an object, but cannot determine the strain information at any location inside the object, thus realizing the reconstruction of the three-dimensional strain inside the target object and the determination of the strain information at any location inside the target object.

[0101] Example 3

[0102] Figure 5 This is a schematic diagram of a three-dimensional reconstruction device for the internal strain of an object according to Embodiment 3 of the present invention. Figure 5 As shown, the device includes:

[0103] The target placement module 310 is used to determine the strain expression of the internal strain to be measured of the target object when the target object is placed in a three-dimensional space in a target placement manner.

[0104] Neutron imaging module 320 is used to perform neutron imaging on the target object based on the target imaging angle to obtain the neutron imaging Bragg side spectrum corresponding to the target object.

[0105] The strain determination module 330 is used to determine the strain information of the internal strain to be measured of the target object based on the neutron imaging Bragg side spectrum, the average strain expression of the target object, and the strain expression of the strain to be measured.

[0106] The technical solution of this invention, when a target object is placed in a three-dimensional space in a target placement manner, determines the strain expression of the strain to be measured inside the target object; performs neutron imaging on the target object based on the target imaging angle to obtain the corresponding neutron imaging Bragg edge spectrum of the target object; and determines the strain information of the strain to be measured inside the target object based on the neutron imaging Bragg edge spectrum, the average strain expression of the target object, and the strain expression of the strain to be measured. The technical solution of this invention solves the problem that current two-dimensional Bragg edge neutron imaging can only determine the average strain value inside an object, but cannot determine the strain information at any location inside the object, thus realizing the reconstruction of the three-dimensional strain inside the target object and the determination of the strain information at any location inside the target object.

[0107] Optionally, the target placement method includes a first placement method, a second placement method, and a third placement method. The three-dimensional space is a Cartesian space. In the first placement method, the extension direction of the target object is parallel to the Z-axis of the Cartesian coordinate system. In the second placement method, the extension direction of the target object is parallel to the Y-axis of the Cartesian coordinate system. In the third placement method, the extension direction of the target object is parallel to the X-axis of the Cartesian coordinate system.

[0108] Optionally, the target placement module 310 includes:

[0109] An angle value determination module is used to determine the initial strain expression of the strain to be measured in the Cartesian coordinate system, and to determine the angle value in the initial strain expression based on the target placement method.

[0110] The expression determination module is used to substitute the angle value into the initial strain expression to obtain the strain expression of the strain to be measured inside the target object.

[0111] Optionally, the neutron imaging module 320 includes:

[0112] An imaging unit is used to determine multiple target imaging angles based on an initial angle, a termination angle, and a set step size, and to perform neutron imaging on the target object based on the multiple target imaging angles to obtain the neutron imaging Bragg side spectrum at each target imaging angle.

[0113] Optionally, the strain determination module 330 includes:

[0114] The average strain expression determination unit is used to determine the average strain value based on the neutron imaging Bragg side spectrum, and update the average strain expression of the target object based on the average strain value.

[0115] The strain information determination unit is used to convert the updated average strain expression of the target object into a discrete expression, and to perform iterative solution based on the discrete expression and the strain expression of the strain to be measured, so as to determine the strain information of the strain to be measured.

[0116] Optionally, the strain information determination unit includes: a transformation subunit, used to decompose the discrete expression based on the strain expression and convert it into a total variation expression; and to perform iterative solution based on the total variation expression to obtain the normal stress value and shear stress value corresponding to the strain to be measured.

[0117] Optionally, the strain information determination unit includes:

[0118] The strain determination subunit calculates the strain information of the target object based on the normal stress value and shear stress value corresponding to the strain to be measured.

[0119] The three-dimensional reconstruction device for internal strain of an object provided in the embodiments of the present invention can execute the three-dimensional reconstruction method for internal strain of an object provided in any embodiment of the present invention, and has the corresponding functional modules and beneficial effects of executing the method.

[0120] Example 4

[0121] Figure 6This is a schematic diagram of an electronic device that implements a three-dimensional reconstruction method for the internal strain of an object according to Embodiment 4 of the present invention. The electronic device is intended to represent various forms of digital computers, such as laptop computers, desktop computers, workbenches, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The electronic device can also represent various forms of mobile devices, such as personal digital processors, cellular phones, smartphones, wearable devices (e.g., helmets, glasses, watches, etc.), and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely illustrative and are not intended to limit the implementation of the invention described and / or claimed herein.

[0122] like Figure 6 As shown, the electronic device 10 includes at least one processor 11 and a memory, such as a read-only memory (ROM) 12 or a random access memory (RAM) 13, communicatively connected to the at least one processor 11. The memory stores computer programs executable by the at least one processor. The processor 11 can perform various appropriate actions and processes based on the computer program stored in the ROM 12 or loaded from storage unit 18 into the RAM 13. The RAM 13 may also store various programs and data required for the operation of the electronic device 10. The processor 11, ROM 12, and RAM 13 are interconnected via a bus 14. An input / output (I / O) interface 15 is also connected to the bus 14.

[0123] Multiple components in electronic device 10 are connected to I / O interface 15, including: input unit 16, such as keyboard, mouse, etc.; output unit 17, such as various types of displays, speakers, etc.; storage unit 18, such as disk, optical disk, etc.; and communication unit 19, such as network card, modem, wireless transceiver, etc. Communication unit 19 allows electronic device 10 to exchange information / data with other devices through computer networks such as the Internet and / or various telecommunications networks.

[0124] Processor 11 can be a variety of general-purpose and / or special-purpose processing components with processing and computing capabilities. Some examples of processor 11 include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various special-purpose artificial intelligence (AI) computing chips, various processors running machine learning model algorithms, a digital signal processor (DSP), and any suitable processor, controller, microcontroller, etc. Processor 11 performs the various methods and processes described above, such as the three-dimensional reconstruction method of internal strain of an object.

[0125] In some embodiments, the method for three-dimensional reconstruction of the internal strain of an object may be implemented as a computer program tangibly contained in a computer-readable storage medium, such as storage unit 18. In some embodiments, part or all of the computer program may be loaded and / or mounted on electronic device 10 via ROM 12 and / or communication unit 19. When the computer program is loaded into RAM 13 and executed by processor 11, one or more steps of the three-dimensional reconstruction method for the internal strain of an object described above may be performed. Alternatively, in other embodiments, processor 11 may be configured to perform the three-dimensional reconstruction method for the internal strain of an object by any other suitable means (e.g., by means of firmware).

[0126] Various embodiments of the systems and techniques described above herein can be implemented in digital electronic circuit systems, integrated circuit systems, field-programmable gate arrays (FPGAs), application-specific integrated circuits (ASICs), application-specific standard products (ASSPs), systems-on-a-chip (SoCs), payload-programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various embodiments may include implementations in one or more computer programs that can be executed and / or interpreted on a programmable system including at least one programmable processor, which may be a dedicated or general-purpose programmable processor, capable of receiving data and instructions from a storage system, at least one input device, and at least one output device, and transmitting data and instructions to the storage system, the at least one input device, and the at least one output device.

[0127] Computer programs used to implement the methods of the present invention may be written in any combination of one or more programming languages. These computer programs may be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device, such that when executed by the processor, the computer programs cause the functions / operations specified in the flowcharts and / or block diagrams to be performed. The computer programs may be executed entirely on a machine, partially on a machine, or as a standalone software package, partially on a machine and partially on a remote machine, or entirely on a remote machine or server.

[0128] In the context of this invention, a computer-readable storage medium can be a tangible medium that may contain or store a computer program for use by or in conjunction with an instruction execution system, apparatus, or device. A computer-readable storage medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination thereof. Alternatively, a computer-readable storage medium may be a machine-readable signal medium. More specific examples of machine-readable storage media include electrical connections based on one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof.

[0129] To provide interaction with a user, the systems and techniques described herein can be implemented on an electronic device having: a display device (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to the user; and a keyboard and pointing device (e.g., a mouse or trackball) through which the user provides input to the electronic device. Other types of devices can also be used to provide interaction with the user; for example, feedback provided to the user can be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user can be received in any form (including sound input, voice input, or tactile input).

[0130] The systems and technologies described herein can be implemented in computing systems that include backend components (e.g., as data servers), or computing systems that include middleware components (e.g., application servers), or computing systems that include frontend components (e.g., user computers with graphical user interfaces or web browsers through which users can interact with implementations of the systems and technologies described herein), or any combination of such backend, middleware, or frontend components. The components of the system can be interconnected via digital data communication of any form or medium (e.g., communication networks). Examples of communication networks include local area networks (LANs), wide area networks (WANs), blockchain networks, and the Internet.

[0131] A computing system can include clients and servers. Clients and servers are generally located far apart and typically interact through communication networks. The client-server relationship is created by computer programs running on the respective computers and having a client-server relationship with each other. The server can be a cloud server, also known as a cloud computing server or cloud host, which is a hosting product within the cloud computing service system to address the shortcomings of traditional physical hosts and VPS services, such as high management difficulty and weak business scalability.

[0132] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and this is not limited herein.

[0133] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A method for three-dimensional reconstruction of internal strain of an object, characterized in that, include: When a target object is placed in a three-dimensional space in a target placement manner, determine the strain expression of the strain to be measured inside the target object; Neutron imaging is performed on the target object based on the target imaging angle to obtain the neutron imaging Bragg side spectrum corresponding to the target object; Based on the neutron imaging Bragg edge spectrum, the average strain expression of the target object, and the strain expression of the strain to be measured, the strain information of the strain to be measured inside the target object is determined. The target placement method includes a first placement method, a second placement method, and a third placement method. The three-dimensional space is a Cartesian space. In the first placement method, the extension direction of the target object is parallel to the Z-axis of the Cartesian coordinate system. In the second placement method, the extension direction of the target object is parallel to the Y-axis of the Cartesian coordinate system. In the third placement method, the extension direction of the target object is parallel to the X-axis of the Cartesian coordinate system. The determination of the strain expression for the strain to be measured inside the target object includes: In the Cartesian coordinate system, the initial strain expression of the strain to be measured is determined, and the angle value in the initial strain expression is determined based on the target placement method. Substituting the angle value into the initial strain expression, the strain expression for the strain to be measured inside the target object is obtained; The process of determining the strain information of the target object's internal strain based on the neutron imaging Bragg edge spectrum, the average strain expression of the target object, and the strain expression of the strain to be measured includes: The average strain value is determined based on the neutron imaging Bragg side spectrum, and the average strain expression of the target object is updated based on the average strain value. The updated average strain expression of the target object is converted into a discrete expression. Based on the discrete expression and the strain expression of the strain to be measured, the strain information of the strain to be measured is determined by iterative solution.

2. The method according to claim 1, characterized in that, The step of performing neutron imaging on the target object based on the target imaging angle to obtain the neutron imaging Bragg side spectrum corresponding to the target object includes: Multiple target imaging angles are determined based on the initial angle, the termination angle, and the set step size. Neutron imaging is performed on the target object based on the multiple target imaging angles to obtain the neutron imaging Bragg side spectrum at each target imaging angle.

3. The method according to claim 1, characterized in that, The iterative solution based on the discrete expression and the strain expression of the strain to be measured includes: The discrete expression is decomposed based on the strain expression and converted into a total variation expression; Based on the total variational expression, the normal stress and shear stress values ​​corresponding to the strain to be measured are obtained by iterative solution.

4. The method according to claim 3, characterized in that, The determination of strain information for the internal strain of the target object includes: Based on the normal stress and shear stress values ​​corresponding to the strain to be measured, the strain information of the strain to be measured inside the target object is calculated.

5. A three-dimensional reconstruction device for the internal strain of an object, characterized in that, The apparatus for performing a three-dimensional reconstruction method for the internal strain of an object as described in any one of claims 1-4, the apparatus comprising: The target placement module is used to determine the strain expression of the internal strain to be measured of the target object when the target object is placed in a three-dimensional space in a target placement manner. The neutron imaging module is used to perform neutron imaging on the target object based on the target imaging angle, and obtain the neutron imaging Bragg side spectrum corresponding to the target object. The strain determination module is used to determine the strain information of the internal strain to be measured of the target object based on the neutron imaging Bragg side spectrum, the average strain expression of the target object, and the strain expression of the strain to be measured.

6. An electronic device, characterized in that, The electronic device includes: At least one processor; and A memory communicatively connected to the at least one processor; wherein, The memory stores a computer program that can be executed by the at least one processor, the computer program being executed by the at least one processor to enable the at least one processor to perform the three-dimensional reconstruction method of the internal strain of an object according to any one of claims 1-4.

7. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer instructions that, when executed by a processor, implement the three-dimensional reconstruction method for the internal strain of an object as described in any one of claims 1-4.

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