Displacement measurement system, displacement measurement method and related equipment

Abstract

The invention provides a displacement measurement system, a displacement measurement method and related equipment, and belongs to the field of measurement, and the system comprises a first interference module which is used for projecting a first laser beam and a second laser beam to the surface of a measured object, the two laser beams are coplanar and have the same incident angle, and the incident plane is parallel to the axis direction of the object; the second interference module is used for projecting a third laser beam and a fourth laser beam to the surface of the measured object, the two laser beams are coplanar and equal in incident angle, and the incident plane is perpendicular to the axis direction of the object; the phase shift controller is used for performing phase shift control; the 3CCD color camera is used for carrying out speckle image acquisition on a measured object to obtain speckle images of a first wavelength and speckle images of a second wavelength; and the data processing unit is used for determining the two-dimensional displacement of the target observation point according to each speckle image. By applying the system provided by the invention, two-dimensional displacement measurement can be realized based on a phase-shift electronic speckle interference technology, the surface of an object is not damaged, and the measurement precision is high.

Description

Technical Field

[0001] The present invention relates to the field of measurement technology, and particularly to a displacement measurement system, a displacement measurement method, and related devices. Background Art

[0002] In many fields of scientific research or industrial production, it is usually necessary to perform deformation detection on various objects such as components to evaluate whether the performance of the object can meet the application requirements. Deformation detection mainly detects the deformation of the object under test when it is subjected to an external force. Usually, the two-dimensional displacement generated by the observation points on the object under test under the action of force, that is, the lateral displacement and the longitudinal displacement, is measured, and thus the deformation of the object under test is evaluated.

[0003] Currently, the measurement method for the two-dimensional displacement of an object under test when it is subjected to a force is generally to make marking points on the surface of the object under test, and then apply a corresponding force to the object under test. Before and after the object under test is subjected to the force, a mechanical micrometer is used to measure the positions of the marking points on the surface of the object under test, and the change in the position of the marking points is used as the measurement result of the two-dimensional displacement.

[0004] With the development of science and technology, the types of objects under test that need to be subjected to deformation detection are becoming more and more diverse, and the measurement requirements are also getting higher and higher. Based on the existing measurement method for two-dimensional displacement, it is necessary to make marks on the surface of the object under test and use a mechanical micrometer to measure on the surface of the object under test. In the existing measurement process, it is necessary to frequently contact the surface of the object under test, which is likely to cause damage to the object surface, and the accuracy of the mechanical micrometer is limited, and the accuracy of the measurement result is low, making it difficult to meet the requirements of non-destructive and high-precision detection. Summary of the Invention

[0005] In view of this, embodiments of the present invention provide a displacement measurement system, a displacement measurement method, and related devices to solve the problems that the existing two-dimensional displacement measurement method is likely to cause damage to the object surface, has low measurement accuracy, and is difficult to meet the requirements of non-destructive and high-precision detection.

[0006] To achieve the above object, embodiments of the present invention provide the following technical solutions:

[0007] A displacement measurement system includes:

[0008] A first interference module, a second interference module, a 3CCD color camera, a phase shift controller, and a data processing unit;

[0009] The first interference module is configured to project a first laser beam and a second laser beam with a first wavelength onto the surface of the object to be measured, so as to implement phase-shifting electronic speckle pattern interferometry associated with longitudinal displacement; the first laser beam and the second laser beam are coplanar, and the incident plane of the first laser beam is parallel to the axis direction of the object to be measured; the incident angles of the first laser beam and the second laser beam are equal;

[0010] The second interference module is configured to project a third laser beam and a fourth laser beam with a second wavelength onto the surface of the object to be measured, so as to implement phase-shifting electronic speckle pattern interferometry associated with lateral displacement; the third laser beam and the fourth laser beam are coplanar, and the incident plane of the third laser beam is perpendicular to the axis direction; the incident angles of the third laser beam and the fourth laser beam are equal;

[0011] The phase-shift controller is configured to perform phase-shift control on the first interference module and the second interference module;

[0012] The 3CCD color camera is configured to collect speckle images of the object to be measured, and obtain respective speckle images corresponding to the first wavelength and respective speckle images corresponding to the second wavelength;

[0013] The data processing unit is configured to determine the longitudinal displacement and the lateral displacement corresponding to the target observation point according to the respective speckle images corresponding to the first wavelength and the respective speckle images corresponding to the second wavelength.

[0014] For the above system, optionally, the first interference module includes: a first laser, a first fiber optic beam splitter, a first collimating lens, a first mirror, a first piezoelectric ceramic, a second collimating lens, and a second mirror; the first piezoelectric ceramic is fixedly connected to the first mirror;

[0015] The first laser is configured to generate a laser with the first wavelength;

[0016] The first fiber optic beam splitter is configured to split the laser generated by the first laser, and output a first sub-beam and a second sub-beam;

[0017] The first collimating lens is configured to collimate the first sub-beam to obtain a first parallel beam;

[0018] The first mirror is configured to reflect the first parallel beam to obtain the first laser beam;

[0019] The first piezoelectric ceramic is configured to respond to the phase-shift control operation of the phase-shift controller, drive the first mirror, and perform phase shift on the first laser beam;

[0020] The second collimating lens is configured to collimate the second sub-beam to obtain a second parallel beam;

[0021] The second mirror is configured to reflect the second parallel beam to obtain the second laser beam.

[0022] In the above system, optionally, the second interference module includes: a second laser, a second fiber optic beam splitter, a third collimating lens, a third mirror, a second piezoelectric ceramic, a fourth collimating lens, and a fourth mirror; the second piezoelectric ceramic is fixedly connected to the third mirror;

[0023] The second laser is configured to generate laser light with a wavelength of the second wavelength;

[0024] The second fiber optic beam splitter is configured to split the laser light generated by the second laser and output a third sub-beam and a fourth sub-beam;

[0025] The third collimating lens is configured to collimate the third sub-beam to obtain a third parallel beam;

[0026] The third mirror is configured to reflect the third parallel beam to obtain the third laser beam;

[0027] The second piezoelectric ceramic is configured to respond to the phase shift control operation of the phase shift controller, drive the third mirror, and perform a phase shift on the third laser beam;

[0028] The fourth collimating lens is configured to collimate the fourth sub-beam to obtain a fourth parallel beam;

[0029] The fourth mirror is configured to reflect the fourth parallel beam to obtain the fourth laser beam.

[0030] In the above system, optionally, the data processing unit is specifically configured to:

[0031] Based on the respective speckle images corresponding to the first wavelength, determine the first phase change amount corresponding to the target observation point;

[0032] Based on the respective speckle images corresponding to the second wavelength, determine the second phase change amount corresponding to the target observation point;

[0033] Determine a first sine parameter and a second sine parameter; the first sine parameter is the product of the sine value of the incident angle of the first laser beam and the constant 2π, and the second sine parameter is the product of the sine value of the incident angle of the third laser beam and the constant 2π;

[0034] Perform a multiplication operation on the first wavelength and the first phase change amount to obtain a first product;

[0035] Divide the first product by the first sine parameter, and use the quotient of the first product and the first sine parameter as the longitudinal displacement corresponding to the target observation point;

[0036] Multiply the second wavelength by the second phase change amount to obtain a second product;

[0037] Divide the second product by the second sine parameter, and use the quotient of the second product and the second sine parameter as the lateral displacement corresponding to the target observation point.

[0038] For the above system, optionally, the data processing unit is further configured to:

[0039] Determine the longitudinal displacement field and the lateral displacement field corresponding to the target observation area according to the respective speckle images corresponding to the first wavelength and the respective speckle images corresponding to the second wavelength;

[0040] Determine longitudinal displacement information based on the longitudinal displacement field; the longitudinal displacement information includes the longitudinal displacement corresponding to the first observation point and the longitudinal displacement corresponding to the second observation point;

[0041] Determine lateral displacement information based on the lateral displacement field; the lateral displacement information includes the lateral displacement corresponding to the first observation point and the lateral displacement corresponding to the second observation point;

[0042] Determine the observation distance information; the observation distance information includes the longitudinal distance and the lateral distance between the first observation point and the second observation point;

[0043] Determine the Poisson's ratio corresponding to the object to be measured according to the longitudinal displacement information, the lateral displacement information and the observation distance information.

[0044] A displacement measurement method, comprising:

[0045] Control a preset first interference module to project a first laser beam and a second laser beam with a first wavelength onto the surface of the object to be measured to achieve phase-shifting electronic speckle interferometry associated with longitudinal displacement; the first laser beam and the second laser beam are coplanar, and the incident plane of the first laser beam is parallel to the axis direction of the object to be measured; the incident angles of the first laser beam and the second laser beam are equal;

[0046] Control the preset second interference module to project a third laser beam and a fourth laser beam with a second wavelength onto the surface of the object to be measured, so as to achieve phase-shifting electronic speckle interferometry associated with lateral displacement; the third laser beam and the fourth laser beam are coplanar, and the incident plane of the third laser beam is perpendicular to the axis direction; the incident angles of the third laser beam and the fourth laser beam are equal;

[0047] Control the preset phase-shift controller to perform phase-shift control on the first interference module and the second interference module;

[0048] Collect speckle images of the object to be measured through a preset 3CCD color camera to obtain respective speckle images corresponding to the first wavelength and respective speckle images corresponding to the second wavelength;

[0049] Determine the longitudinal displacement and lateral displacement corresponding to the target observation point based on the respective speckle images corresponding to the first wavelength and the respective speckle images corresponding to the second wavelength.

[0050] For the above method, optionally, the determining the longitudinal displacement and lateral displacement corresponding to the target observation point based on the respective speckle images corresponding to the first wavelength and the respective speckle images corresponding to the second wavelength includes:

[0051] Based on the respective speckle images corresponding to the first wavelength, determine the first phase change amount corresponding to the target observation point;

[0052] Based on the respective speckle images corresponding to the second wavelength, determine the second phase change amount corresponding to the target observation point;

[0053] Determine a first sine parameter and a second sine parameter; the first sine parameter is the product of the sine value of the incident angle of the first laser beam and the constant 2π, and the second sine parameter is the product of the sine value of the incident angle of the third laser beam and the constant 2π;

[0054] Perform a multiplication operation on the first wavelength and the first phase change amount to obtain a first product;

[0055] Perform a division operation on the first product and the first sine parameter, and use the quotient of the first product and the first sine parameter as the longitudinal displacement corresponding to the target observation point;

[0056] Perform a multiplication operation on the second wavelength and the second phase change amount to obtain a second product;

[0057] Perform a division operation on the second product and the second sine parameter, and use the quotient of the second product and the second sine parameter as the lateral displacement corresponding to the target observation point.

[0058] A displacement measurement device, comprising:

[0059] A first interference unit, configured to control a preset first interference module to project a first laser beam and a second laser beam with a first wavelength onto the surface of an object to be measured, so as to implement phase-shifting electronic speckle pattern interferometry associated with longitudinal displacement; the first laser beam and the second laser beam are coplanar, and the incident plane of the first laser beam is parallel to the axis direction of the object to be measured; the incident angle of the first laser beam is equal to the incident angle of the second laser beam;

[0060] A second interference unit, configured to control a preset second interference module to project a third laser beam and a fourth laser beam with a second wavelength onto the surface of the object to be measured, so as to implement phase-shifting electronic speckle pattern interferometry associated with lateral displacement; the third laser beam and the fourth laser beam are coplanar, and the incident plane of the third laser beam is perpendicular to the axis direction; the incident angle of the third laser beam is equal to the incident angle of the fourth laser beam;

[0061] A phase-shift control unit, configured to control a preset phase-shift controller to perform phase-shift control on the first interference module and the second interference module;

[0062] An image acquisition unit, configured to acquire speckle images of the object to be measured through a preset 3CCD color camera, and obtain respective speckle images corresponding to the first wavelength and respective speckle images corresponding to the second wavelength;

[0063] A displacement calculation unit, configured to determine the longitudinal displacement and the lateral displacement corresponding to a target observation point according to the respective speckle images corresponding to the first wavelength and the respective speckle images corresponding to the second wavelength.

[0064] An electronic device, comprising a memory, and one or more instructions, wherein the one or more instructions are stored in the memory and are configured to be executed by one or more processors to perform the displacement measurement method as described above.

[0065] Based on the displacement measurement system provided by the embodiments of the present invention described above, the system includes: a first interference module, a second interference module, a 3CCD color camera, a phase shift controller, and a data processing unit; the first interference module is configured to project a first laser beam and a second laser beam with a first wavelength onto the surface of the object to be measured, so as to implement phase-shifting electronic speckle pattern interferometry associated with the longitudinal displacement; the first laser beam and the second laser beam are coplanar, and the incident plane of the first laser beam is parallel to the axis direction of the object to be measured; the incident angle of the first laser beam is equal to the incident angle of the second laser beam; the second interference module is configured to project a third laser beam and a fourth laser beam with a second wavelength onto the surface of the object to be measured, so as to implement phase-shifting electronic speckle pattern interferometry associated with the lateral displacement; the third laser beam and the fourth laser beam are coplanar, and the incident plane of the third laser beam is perpendicular to the axis direction; the incident angle of the third laser beam is equal to the incident angle of the fourth laser beam; the phase shift controller is configured to perform phase shift control on the first interference module and the second interference module; the 3CCD color camera is configured to collect speckle images of the object to be measured, and obtain respective speckle images corresponding to the first wavelength and respective speckle images corresponding to the second wavelength; the data processing unit is configured to determine the longitudinal displacement and the lateral displacement corresponding to the target observation point based on the respective speckle images corresponding to the first wavelength and the respective speckle images corresponding to the second wavelength. By applying the system provided by the embodiments of the present invention, before and after the deformation of the object to be measured, the first interference module can project laser beams with incident planes parallel to the axis direction of the object to be measured onto the surface of the object to be measured, the second interference module can project laser beams with incident planes perpendicular to the axis direction of the object to be measured onto the surface of the object to be measured, and the phase shift controller can perform phase shift control on the first interference module and the second interference module, so as to perform phase-shifting electronic speckle pattern interferometry in two directions on the surface of the object to be measured simultaneously. The 3CCD color camera can collect respective speckle images formed by the laser beam with the first wavelength and respective speckle images formed by the laser beam with the second wavelength simultaneously. The interference implemented by the first interference module is sensitive to the longitudinal displacement, and the interference implemented by the second interference module is sensitive to the lateral displacement. The data processing unit can calculate the longitudinal displacement of the corresponding observation point based on the respective speckle images corresponding to the first wavelength, and can calculate the lateral displacement of the corresponding observation point based on the respective speckle images corresponding to the second wavelength. Thus, the longitudinal displacement and the lateral displacement during the deformation of the object to be measured can be completed simultaneously. During the measurement process, no additional processing is required on the surface of the object to be measured, nor is it necessary to contact the surface of the object to be measured, which will not cause damage to the object surface, and the measurement result is obtained based on the phase-shifting electronic speckle pattern interferometry technology, and its measurement accuracy is relatively high, which is beneficial to meeting the non-destructive and high-precision detection requirements for the object to be measured. Description of the Drawings

[0066] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on the provided drawings.

[0067] Figure 1 It is a schematic structural diagram of a displacement measurement system provided by an embodiment of the present invention;

[0068] Figure 2 It is a schematic diagram of the specific architecture of a first interference module provided by an embodiment of the present invention;

[0069] Figure 3 It is a schematic diagram of the specific architecture of a second interference module provided by an embodiment of the present invention;

[0070] Figure 4 It is a schematic diagram of the specific architecture of a displacement measurement system provided by an embodiment of the present invention;

[0071] Figure 5 It is a schematic diagram of the internal structure of a 3CCD color camera provided by an embodiment of the present invention;

[0072] Figure 6 It is a flowchart of a displacement measurement method provided by an embodiment of the present invention;

[0073] Figure 7 It is a schematic diagram of the structure of a displacement measurement device provided by an embodiment of the present invention;

[0074] Figure 8 It is a schematic diagram of the structure of an electronic device provided by an embodiment of the present invention. Detailed implementation manners

[0075] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0076] In this application, the terms "comprise", "include" or any other variants thereof are intended to cover non-exclusive inclusion, such that a process, method, article or device comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising one..." does not exclude the presence of additional identical elements in the process, method, article or device comprising the said element.

[0077] An embodiment of the present invention provides a displacement measurement system, and a schematic structural diagram of the displacement measurement system can be as Figure 1 shown. The system includes:

[0078] a first interference module 101, a second interference module 102, a 3CCD color camera 103, a phase shift controller 104 and a data processing unit 105;

[0079] [[ID=**11**]]The first interference module 101 is configured to project a first laser beam and a second laser beam with a first wavelength onto the surface of the object to be measured, so as to implement phase-shifting electronic speckle pattern interferometry associated with longitudinal displacement; the first laser beam and the second laser beam are coplanar, and the incident plane of the first laser beam is parallel to the axis direction of the object to be measured; the incident angles of the first laser beam and the second laser beam are equal;

[0080] [[ID=**14**]]The second interference module 102 is configured to project a third laser beam and a fourth laser beam with a second wavelength onto the surface of the object to be measured, so as to implement phase-shifting electronic speckle pattern interferometry associated with lateral displacement; the third laser beam and the fourth laser beam are coplanar, and the incident plane of the third laser beam is perpendicular to the axis direction; the incident angles of the third laser beam and the fourth laser beam are equal;

[0081] [[ID=**17**]]The phase shift controller 104 is configured to perform phase shift control on the first interference module 101 and the second interference module 102;

[0082] [[ID=**20**]]The 3CCD color camera 103 is configured to collect speckle images of the object to be measured, and obtain respective speckle images corresponding to the first wavelength and respective speckle images corresponding to the second wavelength;

[0083] [[ID=**23**]]The data processing unit 105 is configured to determine the longitudinal displacement and the lateral displacement corresponding to the target observation point according to the respective speckle images corresponding to the first wavelength and the respective speckle images corresponding to the second wavelength.

[0084] The system provided by the embodiments of the present invention can measure the two-dimensional displacement of the object to be measured before and after deformation. In practical applications, the displacement measurement system is deployed at the relative position of the object to be measured, so that the laser beam projected by the system can be projected onto the surface of the object to be measured according to the measurement requirements, forming speckle interference on the surface of the object to be measured, and the 3CCD color camera can collect the speckle images on the surface of the object to be measured according to the requirements. Before and after the object to be measured undergoes deformation, the displacement measurement system provided by the embodiments of the present invention is used to perform phase-shifting electronic speckle pattern interferometry on the object to be measured, obtaining the respective speckle images of the object to be measured before and after deformation. Based on the respective speckle images of the object to be measured before and after deformation, the longitudinal displacement and the lateral displacement of the object to be measured before and after deformation are calculated.

[0085] In the system provided by the embodiments of the present invention, a first interference module and a second interference module are deployed. The first interference module and the second interference module are respectively used to perform phase-shifting electronic speckle pattern interferometry on the object to be measured before and after deformation, that is, before the object to be measured undergoes deformation, a phase-shifting electronic speckle pattern interferometry is first performed on the surface of the object to be measured, and after the object to be measured undergoes deformation, a phase-shifting electronic speckle pattern interferometry is performed on the surface of the object to be measured again. A laser and various optical elements are provided in the first interference module. During the operation of the system, the laser in the first interference module can emit laser light of a specified wavelength (the first wavelength), for example, it can emit laser light with a wavelength of the blue light wavelength. The laser light emitted by the laser is processed by various optical elements in the first interference module, and finally two laser beams (i.e., the first laser beam and the second laser beam) projected onto the surface of the object to be measured are formed. These two laser beams are coplanar and have equal incident angles on the surface of the object to be measured, that is, these two laser beams are symmetrically incident, and the incident plane of the first laser beam on the surface of the object to be measured is parallel to the axial direction of the object to be measured (the same is true for the second laser beam). At the same time, in response to the control operation of the phase-shift controller, the first interference module can perform phase shift on the corresponding laser beam, for example, perform phase shift on the first laser beam, so as to introduce a phase shift during the interference process and realize a phase-shifting electronic speckle pattern interferometry optical path sensitive to the longitudinal displacement of the surface of the object to be measured. For example Figure 1 As shown, the displacement measurement system measures the surface of the object to be measured from the right side, and the position is indicated by the coordinate axes x - y - z. The laser beams projected by the first interference module onto the surface of the object to be measured are the first laser beam f1 and the second laser beam f2. The incident angles of f1 and f2 on the surface of the object to be measured are equal, f1 and f2 are coplanar, and the incident planes of f1 and f2 are parallel to the axis direction of the object to be measured (i.e., the z-axis direction), which can also be understood as the plane where f1 and f2 are located is parallel to the axis direction of the object to be measured. For example Figure 1 As shown, the plane where f1 and f2 are located is the plane formed by the z-axis and the y-axis, and this plane is parallel to the z-axis direction.

[0086] The second interference module is also provided with a laser and various optical elements. During the operation of the system, the laser in the second interference module can emit laser light with a specified wavelength (a second wavelength that is not equal to the first wavelength). For example, if the first wavelength is the blue light wavelength, the second wavelength can be the green light wavelength. The laser light emitted by the laser is processed by various optical elements in the second interference module and finally forms two laser beams (i.e., the third laser beam and the fourth laser beam) projected onto the surface of the object to be measured. These two laser beams are coplanar and have equal incident angles on the surface of the object to be measured, that is, these two laser beams are symmetrically incident, and the incident plane of the third laser beam on the surface of the object to be measured is perpendicular to the axial direction of the object to be measured (the same is true for the fourth laser beam). At the same time, in response to the control operation of the phase shift controller, the second interference module can perform phase shift on the corresponding laser beam. For example, perform phase shift on the third laser beam to introduce a phase shift during the interference process and realize a phase shift electronic speckle interferometry optical path that is sensitive to the lateral displacement of the surface of the object to be measured. For example Figure 1 As shown, the laser beams projected by the second interference module onto the surface of the object to be measured are the third laser beam f3 and the fourth laser beam f4. The incident angles of f3 and f4 on the surface of the object to be measured are equal, f3 and f4 are coplanar, and the incident planes of f3 and f4 are perpendicular to the axial direction of the object to be measured. It can also be understood that the plane where f3 and f4 are located is perpendicular to the axial direction of the object to be measured. For example Figure 1 As shown, the plane where f3 and f4 are located is the plane formed by the x-axis and the y-axis, and this plane is perpendicular to the z-axis direction.

[0087] It should be noted that the wavelength (the first wavelength) of the laser beam projected by the first interference module and the wavelength (the second wavelength) of the laser beam projected by the second interference module can be configured according to actual needs. The first wavelength and the second wavelength are not equal, and as long as they can be distinguished and recognized by the 3CCD color camera. The specific internal structures of the first interference module and the second interference module can be set according to actual needs, as long as they can meet the corresponding laser beam projection requirements.

[0088] In the system provided by the embodiment of the present invention, a phase shift controller, a 3CCD color camera, and a data processing unit are deployed. The data processing unit can send corresponding phase shift control signals to the phase shift controller based on a preset phase shift algorithm. The preset phase shift algorithm can adopt existing phase shift algorithms, such as the four-step phase shift algorithm. The phase shift control signals can include data such as the time interval of phase shift and the phase shift step size. Based on the received phase shift control signals, the phase shift controller can perform phase shift control on the first interference module and the second interference module respectively during the interference process, so that the first interference module and the second interference module respectively perform phase shift on the projected laser beams, generating corresponding phase shift amounts. The 3CCD color camera is a color camera composed of three CCDs. CCD (Charge Coupled Device) refers to a charge-coupled device. Based on three independent CCD elements, when the 3CCD color camera takes pictures, it can receive images of different wavelengths respectively. The 3CCD color camera is an existing device and will not be elaborated here. In the system provided by the embodiment of the present invention, during the process of the first interference module and the second interference module performing phase shift electronic speckle interferometry on the surface of the object to be measured, the 3CCD color camera can face the surface of the object to be measured to take pictures to collect the speckle images on the surface of the object to be measured. The lasers of different wavelengths on the surface of the object to be measured will be imaged separately in the 3CCD color camera, that is, the 3CCD color camera can respectively collect the speckle images corresponding to the first wavelength and the speckle images corresponding to the second wavelength. Each of the speckle images corresponding to the first wavelength includes the speckle images formed by the first laser beam and the second laser beam during the two interference processes before and after the deformation of the object to be measured. Each of the speckle images corresponding to the second wavelength includes the speckle images formed by the third laser beam and the fourth laser beam during the two interference processes before and after the deformation of the object to be measured. Each of the speckle images collected by the 3CCD color camera can be transmitted to the data processing unit. The data processing unit can perform phase extraction on each of the speckle images based on the preset phase shift algorithm, thereby determining the phase change amount before and after the deformation of the object to be measured, and then determining the displacement before and after the deformation of the object to be measured based on the phase change amount. After the data processing unit obtains each of the speckle images before and after the deformation of the object to be measured, it can calculate the phase change amount in the direction of the phase shift step size corresponding to the deformation before and after the object to be measured based on each of the speckle images corresponding to the first wavelength obtained and the preset phase shift algorithm, and calculate the longitudinal displacement before and after the deformation of the object to be measured according to this phase change amount. The data processing unit can calculate the phase change amount in the direction of the phase shift step size corresponding to the deformation before and after the object to be measured based on each of the speckle images corresponding to the second wavelength obtained and the preset phase shift algorithm, and calculate the lateral displacement before and after the deformation of the object to be measured according to this phase change amount. Thus, the two-dimensional displacement measurement before and after the deformation of the object to be measured is realized.

[0089] By applying the system provided by the embodiments of the present invention, before and after the object under test is deformed, a laser beam with an incident plane parallel to the axis direction of the object under test can be projected onto the surface of the object under test through the first interference module, and a laser beam with an incident plane perpendicular to the axis direction of the object under test can be projected onto the surface of the object under test through the second interference module. The phase shift controller is used to perform phase shift control on the first interference module and the second interference module, so as to perform phase shift electronic speckle interferometry in two directions on the surface of the object under test at the same time. The 3CCD color camera can collect the speckle images formed by the laser beams of the first wavelength and the speckle images formed by the laser beams of the second wavelength at the same time. The interference realized by the first interference module is sensitive to the longitudinal displacement, and the interference realized by the second interference module is sensitive to the transverse displacement. The data processing unit can calculate the longitudinal displacement of the corresponding observation point based on the speckle images corresponding to the first wavelength, and can calculate the transverse displacement of the corresponding observation point based on the speckle images corresponding to the second wavelength. Thus, the longitudinal displacement and the transverse displacement of the object under test during deformation can be completed at the same time. During the measurement process, no additional treatment is required on the surface of the object under test, nor is it necessary to contact the surface of the object under test, which will not cause damage to the object surface. Moreover, the measurement result is obtained based on the phase shift electronic speckle interferometry technology, and its measurement accuracy is relatively high, which is beneficial to meeting the requirements of non-destructive and high-precision detection of the object under test.

[0090] Based on the Figure 1 system shown, in the system provided by the embodiments of the present invention, the specific architecture of the first interference module can be as Figure 2 shown. In the embodiments of the present invention, the first interference module 101 includes: a first laser 201, a first fiber optic beam splitter 202, a first collimating lens 203, a first piezoelectric ceramic 204, a first mirror 205, a second collimating lens 206, and a second mirror 207; the first piezoelectric ceramic 204 is fixedly connected to the first mirror 205;

[0091] The first laser 201 is used to generate a laser with a wavelength of the first wavelength;

[0092] The first fiber optic beam splitter 202 is used to split the laser generated by the first laser 201 and output a first sub-beam and a second sub-beam;

[0093] The first collimating lens 203 is used to collimate the first sub-beam to obtain a first parallel beam;

[0094] The first mirror 205 is used to reflect the first parallel beam to obtain the first laser beam;

[0095] The first piezoelectric ceramic 204 is used to respond to the phase shift control operation of the phase shift controller, drive the first mirror 205, and perform phase shift on the first laser beam;

[0096] The second collimating lens 206 is configured to collimate the second sub-beam to obtain a second parallel beam;

[0097] The second mirror 207 is configured to reflect the second parallel beam to obtain the second laser beam.

[0098] In the system provided by the embodiment of the present invention, one laser (the first laser), one fiber optic splitter (the first fiber optic splitter), two collimating lenses (the first collimating lens and the second collimating lens), and one piezoelectric ceramic (the first piezoelectric ceramic) are deployed in the first interference module. The first laser is connected to the first fiber optic splitter through an optical fiber. The laser emitted by the first laser enters the first fiber optic splitter after being introduced into the optical fiber. The first fiber optic splitter can split the laser emitted by the first laser into two beams of laser, namely the first sub-beam and the second sub-beam. The first sub-beam is projected onto the first collimating lens and collimated by the first collimating lens. The first sub-beam after collimation is the first parallel beam. The second sub-beam is projected onto the second collimating lens and collimated by the second collimating lens. The second sub-beam after collimation is the second parallel beam. The first parallel beam is projected onto the first mirror and reflected by the first mirror. The reflected beam of the first mirror is the first laser beam projected by the first interference module onto the surface of the object to be measured. The second parallel beam is projected onto the second mirror and reflected by the second mirror. The reflected beam of the second mirror is the second laser beam projected by the first interference module onto the surface of the object to be measured. The incident planes of the first laser beam and the second laser beam are parallel to the axial direction of the object to be measured. Therefore, the interference formed by the first laser beam and the second laser beam is sensitive to the longitudinal displacement of the object to be measured. Taking Figure 2 the shown projection scenario as an example, the displacement measurement system measures from the left side to the object to be measured. The first laser beam is the laser beam reflected and output by the first mirror 205. The second laser beam is the laser beam reflected and output by the second mirror 207. The incident angles of the first laser beam and the second laser beam on the surface of the object to be measured are the angles between the laser beams and the normal of the surface of the object to be measured. The incident angles of both of these two laser beams are θ B . The axial direction of the object to be measured is the y-axis direction. The incident planes of the first laser beam and the second laser beam are parallel to the y-axis. During the interference process, in the initial state, the first piezoelectric ceramic is located at the reset position. The phase shift controller can perform a phase shift control operation on the first piezoelectric ceramic according to the phase shift requirement. The first piezoelectric ceramic responds to the signal of the phase shift control operation and can drive the first mirror to move, and then phase-shift the first laser beam, so as to introduce a phase shift in the phase-shifting electronic speckle pattern interferometry for measuring longitudinal deformation information, and achieve high-precision longitudinal deformation measurement.

[0099] In Figure 1Based on the system shown, in the system provided by the embodiments of the present invention, the specific architecture of the second interference module may be as follows Figure 3 As shown, the second interference module 102 includes: a second laser 208, a second fiber optic beam splitter 209, a third collimating lens 210, a second piezoelectric ceramic 211, a third mirror 212, a fourth collimating lens 213, and a fourth mirror 214; the second piezoelectric ceramic 211 is fixedly connected to the third mirror 212;

[0100] The second laser 208 is used to generate laser light with a wavelength of the second wavelength;

[0101] The second fiber optic beam splitter 209 is used to split the laser light generated by the second laser 208 and output a third sub-beam and a fourth sub-beam;

[0102] The third collimating lens 210 is used to collimate the third sub-beam to obtain a third parallel beam;

[0103] The third mirror 212 is used to reflect the third parallel beam to obtain the third laser beam;

[0104] The second piezoelectric ceramic 211 is used to respond to the phase shift control operation of the phase shift controller, drive the third mirror 212, and phase shift the third laser beam;

[0105] The fourth collimating lens 213 is used to collimate the third sub-beam to obtain a fourth parallel beam;

[0106] The fourth mirror 214 is used to reflect the fourth parallel beam to obtain the fourth laser beam.

[0107] In the system provided by the embodiment of the present invention, a laser (the second laser), an optical fiber beam splitter (the second optical fiber beam splitter), two collimating lenses (the third collimating lens and the fourth collimating lens), and a piezoelectric ceramic (the second piezoelectric ceramic) are deployed in the second interference module. The second laser is connected to the second optical fiber beam splitter through an optical fiber. The laser emitted by the second laser enters the second optical fiber beam splitter after being introduced into the optical fiber. The second optical fiber beam splitter can split the laser emitted by the second laser into two beams of laser, namely the third sub-beam and the fourth sub-beam. The third sub-beam is projected onto the third collimating lens and collimated by the third collimating lens. The third sub-beam after collimation is the third parallel beam. The fourth sub-beam is projected onto the fourth collimating lens and collimated by the fourth collimating lens. The fourth sub-beam after collimation is the fourth parallel beam. The third parallel beam is projected onto the third mirror and reflected by the third mirror. The reflected beam of the third mirror is the third laser beam projected by the second interference module onto the surface of the object to be measured. The fourth parallel beam is projected onto the fourth mirror and reflected by the fourth mirror. The reflected beam of the fourth mirror is the fourth laser beam projected by the second interference module onto the surface of the object to be measured. The incident planes of the third laser beam and the fourth laser beam are perpendicular to the axial direction of the object to be measured. Therefore, the interference formed by the third laser beam and the fourth laser beam is sensitive to the lateral displacement of the object to be measured. Taking Figure 3 the projection scenario shown as an example, when the displacement measurement system measures from the left side to the object to be measured, the third laser beam is the laser beam reflected and output by the third mirror 212. The fourth laser beam is the laser beam reflected and output by the fourth mirror 214. The incident angles of the third laser beam and the fourth laser beam on the surface of the object to be measured are the angles between the laser beams and the normal of the surface of the object to be measured. The incident angles of both of these two laser beams are θ G . The axial direction of the object to be measured is the y-axis direction. The incident planes of the third laser beam and the fourth laser beam are perpendicular to the y-axis. During the interference process, in the initial state, the second piezoelectric ceramic is in the reset position. The phase shift controller can perform a phase shift control operation on the second piezoelectric ceramic according to the phase shift requirement. The second piezoelectric ceramic responds to the signal of the phase shift control operation and can drive the third mirror to move, and then phase-shift the third laser beam, so as to introduce a phase shift during the phase-shift electronic speckle pattern interferometry for measuring the lateral deformation information, and achieve high-precision lateral deformation measurement.

[0108] On the basis of the system shown in Figure 1 , in the system provided by the embodiment of the present invention, the data processing unit is specifically configured to:

[0109] Determine the first phase change amount corresponding to the target observation point based on each speckle image corresponding to the first wavelength;

[0110] In the system provided by the embodiment of the present invention, when determining the longitudinal displacement and lateral displacement of the object under test before and after deformation, the data processing unit may first select an observation point as the target observation point in the speckle image on the surface of the object under test. The data processing unit may perform image processing on the speckle images of the object under test before deformation and after deformation in each speckle image corresponding to the first wavelength, and may obtain the phase shift image of the object under test before deformation and the phase shift image of the object under test after deformation in the dimension of the first wavelength. Based on the phase shift image of the object under test before deformation in this dimension, the phase amount corresponding to the target observation point before object deformation can be extracted. Based on the phase shift image of the object under test after deformation, the phase amount corresponding to the target observation point after object deformation can be extracted. According to the phase amounts corresponding to the target observation point before and after object deformation, the phase change amount corresponding to the target observation point in the longitudinal direction can be calculated, and this phase change amount is used as the first phase change amount.

[0111] Based on each speckle image corresponding to the second wavelength, determine the second phase change amount corresponding to the target observation point;

[0112] In the system provided by the embodiment of the present invention, the data processing unit may perform image processing on the speckle images of the object under test before deformation and after deformation in each speckle image corresponding to the second wavelength, and may obtain the phase shift image of the object under test before deformation and the phase shift image of the object under test after deformation in the dimension of the second wavelength. Based on the phase shift image of the object under test before deformation in this dimension, the phase amount corresponding to the target observation point before object deformation can be extracted. Based on the phase shift image of the object under test after deformation, the phase amount corresponding to the target observation point after object deformation can be extracted. According to the phase amounts corresponding to the target observation point before and after object deformation, the phase change amount corresponding to the target observation point in the lateral direction can be calculated, and this phase change amount is used as the second phase change amount.

[0113] Determine a first sine parameter and a second sine parameter; the first sine parameter is the product of the sine value of the incident angle of the first laser beam and the constant 2π, and the second sine parameter is the product of the sine value of the incident angle of the third laser beam and the constant 2π;

[0114] In the system provided by the embodiment of the present invention, the data processing unit may obtain the incident angles of the first laser beam and the third laser beam on the surface of the object under test. Perform a sine operation on the incident angle of the first laser beam, and use the product of the sine value of the incident angle of the first laser beam and the constant 2π as the first sine parameter. Perform a sine operation on the incident angle of the third laser beam, and use the product of the sine value of the incident angle of the third laser beam and the constant 2π as the second sine parameter.

[0115] Perform a product operation on the first wavelength and the first phase change amount to obtain a first product;

[0116] Perform a division operation on the first product and the first sine parameter, and use the quotient of the first product and the first sine parameter as the longitudinal displacement corresponding to the target observation point;

[0117] In the system provided by the embodiments of the present invention, a calculation method for longitudinal displacement is preset in the data processing unit. The longitudinal displacement can be calculated based on the wavelength of the first laser beam / second laser beam (i.e., the first wavelength), the first sine parameter, and the first phase change amount. Specifically, the data processing unit can divide the product of the first wavelength and the first phase change amount by the first sine parameter, and use the quotient of the product and the first sine parameter as the longitudinal displacement corresponding to the target observation point. The calculation method of the longitudinal displacement can be shown as the following formula:

[0118] (Equation 1)

[0119] Wherein, y represents the longitudinal displacement of the target observation point, λ B represents the first wavelength, φ B (x, y) represents the first phase change amount corresponding to the target observation point, θ B represents the incident angle of the first laser beam, and sinθ B is the sine value of the incident angle of the first laser beam.

[0120] Perform a multiplication operation on the second wavelength and the second phase change amount to obtain a second product;

[0121] Perform a division operation on the second product and the second sine parameter, and use the quotient of the second product and the second sine parameter as the transverse displacement corresponding to the target observation point.

[0122] In the system provided by the embodiments of the present invention, a calculation method for transverse displacement is preset in the data processing unit. The transverse displacement can be calculated based on the wavelength of the third laser beam / fourth laser beam (i.e., the second wavelength), the second sine parameter, and the second phase change amount. Specifically, the data processing unit can divide the product of the second wavelength and the second phase change amount by the second sine parameter, and use the quotient of the product and the second sine parameter as the transverse displacement corresponding to the target observation point. The calculation method of the transverse displacement can be shown as the following formula:

[0123] (Equation 2)

[0124] Wherein, x represents the transverse displacement of the target observation point, λ G represents the second wavelength, φ G (x, y) represents the second phase change amount corresponding to the target observation point, θ GDenote the incident angle of the third laser beam as sinθ G That is, the sine value of the incident angle of the third laser beam.

[0125] Based on Figure 1 In the system provided by the embodiments of the present invention based on the system shown, the data processing unit 105 is further configured to:

[0126] Determine the longitudinal displacement field and the transverse displacement field corresponding to the target observation area according to the respective speckle images corresponding to the first wavelength and the respective speckle images corresponding to the second wavelength;

[0127] In the system provided by the embodiments of the present invention, the data processing unit can also be used to calculate the Poisson's ratio of the object under test. The data processing unit can select an observation area in the speckle image of the object under test as the target observation area, and select multiple observation points in the target observation area. Based on the respective speckle images corresponding to the first wavelength and the respective speckle images corresponding to the second wavelength, calculate the longitudinal displacement and the transverse displacement corresponding to each observation point in the target observation area. The method for calculating the longitudinal displacement and the transverse displacement corresponding to a single observation point is the same as the principle of determining the longitudinal displacement and the transverse displacement corresponding to the target observation point in the previous embodiments, which can be referred to the previous description and will not be elaborated here. The longitudinal displacements corresponding to each observation point in the target observation area form the longitudinal displacement field corresponding to the target observation area, and the transverse displacements corresponding to each observation point in the target observation area form the transverse displacement field corresponding to the target observation area.

[0128] Based on the longitudinal displacement field, determine longitudinal displacement information; the longitudinal displacement information includes the longitudinal displacement corresponding to the first observation point and the longitudinal displacement corresponding to the second observation point;

[0129] In the system provided by the embodiments of the present invention, the data processing unit can select one observation point as the first observation point and another observation point as the second observation point from each observation point in the target observation area. Obtain the longitudinal displacement corresponding to the first observation point from the longitudinal displacement field corresponding to the target observation area, and obtain the longitudinal displacement corresponding to the second observation point, and use the longitudinal displacements corresponding to these two observation points as the longitudinal displacement information.

[0130] Based on the transverse displacement field, determine transverse displacement information; the transverse displacement information includes the transverse displacement corresponding to the first observation point and the transverse displacement corresponding to the second observation point;

[0131] In the system provided by the embodiments of the present invention, the data processing unit can obtain the transverse displacement corresponding to the first observation point and the transverse displacement corresponding to the second observation point from the transverse displacement field corresponding to the target observation area, and use the transverse displacements corresponding to these two observation points as the transverse displacement information.

[0132] Determine the observation distance information; the observation distance information includes the longitudinal distance and the lateral distance between the first observation point and the second observation point;

[0133] In the system provided by the embodiment of the present invention, the data processing unit can calculate the longitudinal distance between the two observation points and the lateral distance between the two observation points based on the position coordinates of the first observation point and the position coordinates of the second observation point. The longitudinal distance and the lateral distance between the two observation points are used as the observation distance information.

[0134] Determine the Poisson's ratio corresponding to the measured object according to the longitudinal displacement information, the lateral displacement information, and the observation distance information.

[0135] In the system provided by the embodiment of the present invention, the data processing unit can calculate the Poisson's ratio of the measured object based on the longitudinal displacement information, the lateral displacement information, and the observation distance information. Specifically, a difference operation can be performed on the longitudinal displacement corresponding to the first observation point and the longitudinal displacement corresponding to the second observation point, and the difference between the longitudinal displacements of the two observation points is used as the longitudinal displacement difference. A difference operation is performed on the lateral displacement corresponding to the first observation point and the lateral displacement corresponding to the second observation point, and the difference between the lateral displacements of the two observation points is used as the lateral displacement difference. Then, calculate the product of the lateral displacement difference between the two observation points and the longitudinal distance, and use this product as the third product. Calculate the product of the longitudinal displacement difference between the two observation points and the lateral distance, and use this product as the fourth product. Calculate the quotient of the third product and the fourth product, and use the quotient of the two products as the Poisson's ratio corresponding to the measured object. The calculation method of the Poisson's ratio of the measured object can be shown as the following formula:

[0136] μ = x 12 l y / y 12 l x (Equation 3)

[0137] Where, μ represents the Poisson's ratio corresponding to the measured object, x 12 represents the lateral displacement difference between the first observation point and the second observation point, l y represents the longitudinal distance between the first observation point and the second observation point, y 12 represents the longitudinal displacement difference between the first observation point and the second observation point, l x represents the lateral distance between the first observation point and the second observation point.

[0138] Based on the system provided by the embodiment of the present invention, it is possible to further measure the Poisson's ratio of the measured object on the basis of measuring the two-dimensional displacement of the measured object before and after deformation, which is beneficial to meeting various measurement requirements and further improving the user experience.

[0139] To better illustrate the system provided by the embodiments of the present invention, based on the systems provided in the foregoing embodiments, the embodiments of the present invention provide another displacement measurement system. The specific architecture of the displacement measurement system provided by the embodiments of the present invention can be as Figure 4 shown. The system provided by the embodiments of the present invention includes a data processing unit 217, a phase shift controller 218, a 3CCD color camera 215 (imaging lens 216 of the camera), and two interference modules. The specific architecture of the two interference modules is Figure 2 and Figure 3 shown in the architecture. That is, the first interference module includes: a first laser 201, a first fiber optic beam splitter 202, a first collimating lens 203, a first piezoelectric ceramic 204, a first mirror 205, a second collimating lens 206, and a second mirror 207. The second interference module includes: a second laser 208, a second fiber optic beam splitter 209, a third collimating lens 210, a second piezoelectric ceramic 211, a third mirror 212, a fourth collimating lens 213, and a fourth mirror 214.

[0140] The specific architecture of the 3CCD color camera in the system provided by the embodiments of the present invention can be as Figure 5 shown. The 3CCD color camera is composed of a 3CCD image sensor and an imaging lens connected through a standard interface. During the shooting process, the optical axis of the 3CCD color camera is directly facing the object to be measured for shooting. The 3CCD image sensor is composed of three specially designed dichroic prisms (A, B, C) and 3 CCD elements. The camera can reflect and transmit light of a specific wavelength according to the dichroic films (F1, F2) coated on the dichroic prism. The three CCD elements are respectively used to collect images formed by light in three different wavelength bands. After the lasers of three wavelengths (λ1, λ2, λ3) enter the 3CCD color camera, the light with a wavelength of λ1 is reflected by the dichroic film F1 and undergoes total internal reflection at the interface between the prism A and the air, and finally enters CCD1. The light with a wavelength of λ2 is reflected at the dichroic film F2, and then undergoes total internal reflection at the interface between the prism B and the air (there is a small gap between the prism A and the prism B), and finally enters CCD2. The light with a wavelength of λ3 is not reflected by the dichroic film and finally reaches CCD3. Thus, the simultaneous acquisition of images of three wavelengths can be realized. In the system provided by the embodiments of the present invention, only the 3CCD color camera needs to be applied to simultaneously image the lasers of two wavelengths (the first wavelength and the second wavelength) respectively.

[0141] In the system provided by the embodiments of the present invention, the first laser is a blue laser, and the laser with the first wavelength generated by it is a laser with a blue light wavelength (blue light). The first wavelength can specifically be 473 nm. The second laser is a green laser, and the laser with the second wavelength generated by it is a laser with a green light wavelength (green light). The second wavelength can specifically be 532 nm. The phase shift algorithm configured in the data processing unit is a four-step phase shift algorithm.

[0142] To better illustrate the system provided by the embodiments of the present invention, in a specific practical scenario, the system provided by the embodiments of the present invention is applied for corresponding measurements. Specifically, the displacement measurement system can be deployed at a position where the optical axis of the camera is directly facing the measured surface of the object to be measured, and the laser beam output position is 900 mm away from the surface of the object to be measured. The object to be measured uses a standard calibration block. The object to be measured is connected to both ends of the displacer of the grating type indicating meter calibrator, and a displacement of 30.123 mm and an angle of 32.1° are applied. The corresponding displacement vector is (23.345, 19.036). Adjust the optical axis of the 3CCD color camera to be perpendicular to the surface of the object to be measured, and the distance from the object to be measured is 366 mm. Take a picture directly facing the surface of the object to be measured. The data processing unit acquires the speckle images of the object to be measured before and after deformation taken by the 3CCD color camera, and processes the data of the speckle images to obtain the phase-shifted image. According to the four-step phase-shifting algorithm, the phase change amount in the corresponding step direction is calculated from the phase-shifted image. Based on the principles shown in Equation 1 and Equation 2 above, the measured displacement vector is (23.348, 19.032). It can be seen that compared with the applied displacement vector, the error in a single direction of the measurement result does not exceed 0.005 mm.

[0143] Furthermore, the embodiments of the present invention also conduct an experiment on Poisson's ratio measurement. An alloy GH4169 tensile specimen is used as the object to be measured, and an electronic tensile testing machine is used to apply a tensile force load of 300 MPa to the object to be measured. The data processing unit controls the first piezoelectric ceramic and the second piezoelectric ceramic to generate phase shift amounts through the phase shift controller. The generated phase shift amounts are 0, π / 2, π, and 3π / 2 respectively. At the same time, the 3CCD color camera acquires the corresponding speckle images. The data processing unit calculates the longitudinal displacement field and the lateral displacement field of the observation area based on the speckle images and the four-step phase-shifting algorithm. Based on the longitudinal displacement and the lateral displacement of two observation points, Poisson's ratio is calculated according to the principle shown in Equation 3 above. The measured Poisson's ratio result is 0.301. Then, based on GB / T 22315 of the national standard, the Poisson's ratio of the same GH4169 alloy is measured by the dynamic method, and the result is 0.302. The errors between these two measurement results are small. It can be seen that the system provided by the embodiments of the present invention can effectively measure Poisson's ratio.

[0144] Based on the system provided by the embodiments of the present invention, phase-shifting electronic speckle pattern interferometry can be used as a measurement means to measure the deformation of the test piece. There is no need to process and polish the surface of the test piece, paste strain gauges, or make fiducial points, which can avoid the cumbersome process of pasting strain gauges or making fiducial points and the possibility of damaging the test piece during this process. Since the system is based on laser interferometry, its measurement accuracy depends on the laser wavelength, and by using the phase-shifting technology driven by piezoelectric ceramic PZT, the measurement accuracy can be further improved to 0.01 laser wavelengths. By adopting the dual-wavelength measurement optical path and the phase-shift map acquisition technology of the 3CCD color camera, the longitudinal and transverse strains can be measured simultaneously, which is beneficial to improving the reliability and stability of the measurement.

[0145] Corresponding to Figure 1 the displacement measurement system shown, the embodiments of the present invention further provide a displacement measurement method. The displacement measurement method can be applied to the displacement measurement system, and the execution subject of this method can be the data processing unit in the system, such as Figure 6 shown, the displacement measurement method provided by the embodiments of the present invention includes:

[0146] S301: Control the preset first interference module to project a first laser beam and a second laser beam with a first wavelength onto the surface of the object to be measured, so as to realize phase-shifting electronic speckle pattern interferometry measurement associated with the longitudinal displacement; the first laser beam and the second laser beam are coplanar, and the incident plane of the first laser beam is parallel to the axis direction of the object to be measured; the incident angles of the first laser beam and the second laser beam are equal;

[0147] The method provided by the embodiments of the present invention can be applied to a displacement measurement system. In this displacement measurement system, a first interference module, a second interference module, a phase-shift controller, a data processing unit, and a 3CCD color camera are preset in advance. During the two-dimensional displacement measurement of the object to be measured, the data processing unit can, according to the measurement requirements, control the first interference module to project a first laser beam and a second laser beam with a first wavelength onto the surface of the object to be measured before and after the deformation of the object to be measured, respectively, so as to form speckle interference on the surface of the object to be measured. The first laser beam and the second laser beam are coplanar, and the incident plane of the first laser beam is parallel to the axis direction of the object to be measured. Therefore, this interference process is sensitive to the longitudinal displacement of the object to be measured.

[0148] S302: Control the preset second interference module to project a third laser beam and a fourth laser beam with a second wavelength onto the surface of the object to be measured, so as to realize phase-shifting electronic speckle pattern interferometry measurement associated with the transverse displacement; the third laser beam and the fourth laser beam are coplanar, and the incident plane of the third laser beam is perpendicular to the axis direction; the incident angles of the third laser beam and the fourth laser beam are equal;

[0149] In the method provided by the embodiment of the present invention, the data processing unit can, based on the measurement requirements, respectively control the second interference module to project a third laser beam and a fourth laser beam of a second wavelength onto the surface of the object to be measured before and after the deformation of the object to be measured, so as to form speckle interference on the surface of the object to be measured. The third laser beam and the fourth laser beam are coplanar, and the incident plane of the third laser beam is perpendicular to the axis direction of the object to be measured. Therefore, this interference process is sensitive to the lateral displacement of the object to be measured.

[0150] It should be noted that in the specific implementation process, there is no necessary execution order between step S301 and step S302, that is, step S301 can be executed first, and then step S302 can be executed; step S302 can be executed first, and then step S301 can be executed; or step S301 and S302 can be executed simultaneously.

[0151] S303: Control a preset phase shift controller to perform phase shift control on the first interference module and the second interference module;

[0152] In the method provided by the embodiment of the present invention, during the process of projecting a laser beam onto the surface of the object to be measured to form speckle interference, a phase shift control signal can be sent to the phase shift controller based on a preset phase shift algorithm, so that the phase shift controller performs corresponding phase shift control operations on the first interference module and the second interference module, so as to introduce phase shifts respectively during the interference processes formed by the first interference module and the second interference module.

[0153] S304: Use a preset 3CCD color camera to collect speckle images of the object to be measured, and obtain each speckle image corresponding to the first wavelength and each speckle image corresponding to the second wavelength;

[0154] In the method provided by the embodiment of the present invention, during the process of performing speckle interference on the object to be measured, the 3CCD color camera can collect speckle images of the object to be measured in real time, and the data processing unit can obtain each speckle image collected by the 3CCD color camera during the interference processes before and after the deformation of the object to be measured, including each speckle image corresponding to the first wavelength and each speckle image corresponding to the second wavelength.

[0155] S305: Determine the longitudinal displacement and lateral displacement corresponding to the target observation point based on each speckle image corresponding to the first wavelength and each speckle image corresponding to the second wavelength.

[0156] In the method provided by the embodiment of the present invention, based on a preset phase shift algorithm, phase extraction can be performed on each speckle image, so as to determine the phase change amount before and after the deformation of the measured object, and then the displacement before and after the deformation of the measured object can be determined based on the phase change amount. After the data processing unit obtains each speckle image before and after the deformation of the measured object, based on each speckle image corresponding to the first wavelength obtained and the preset phase shift algorithm, the phase change amount in the phase step direction corresponding to before and after the deformation of the measured object can be calculated, and the longitudinal displacement before and after the deformation of the measured object can be calculated according to this phase change amount. Based on each speckle image corresponding to the second wavelength obtained and the preset phase shift algorithm, the phase change amount in the phase step direction corresponding to before and after the deformation of the measured object can be calculated, and the transverse displacement before and after the deformation of the measured object can be calculated according to this phase change amount. Thus, two-dimensional displacement measurement before and after the deformation of the measured object is realized.

[0157] By applying the method provided by the embodiment of the present invention, before and after the deformation of the measured object, a laser beam with an incident plane parallel to the axis direction of the measured object can be projected onto the surface of the measured object through the first interference module, and a laser beam with an incident plane perpendicular to the axis direction of the measured object can be projected onto the surface of the measured object through the second interference module, and the phase shift controller can be used to perform phase shift control on the first interference module and the second interference module, so as to perform phase shift electronic speckle interferometry in two directions on the surface of the measured object at the same time. The 3CCD color camera can simultaneously collect each speckle image formed by the laser beam of the first wavelength and each speckle image formed by the laser beam of the second wavelength. The interference realized by the first interference module is sensitive to the longitudinal displacement, and the interference realized by the second interference module is sensitive to the transverse displacement. Based on each speckle image corresponding to the first wavelength, the longitudinal displacement of the corresponding observation point can be calculated, and based on each speckle image corresponding to the second wavelength, the transverse displacement of the corresponding observation point can be calculated. Thus, the longitudinal displacement and the transverse displacement during the deformation of the measured object can be completed simultaneously. During the measurement process, no additional processing is required on the surface of the measured object, nor is it necessary to contact the surface of the measured object, which will not cause damage to the object surface, and the measurement result is obtained based on the phase shift electronic speckle interferometry technology, and its measurement accuracy is relatively high, which is beneficial to meeting the requirements for non-destructive and high-precision detection of the measured object.

[0158] On the basis of the Figure 6 method shown, in the method provided by the embodiment of the present invention, the process of determining the longitudinal displacement and the transverse displacement corresponding to the target observation point according to each speckle image corresponding to the first wavelength and each speckle image corresponding to the second wavelength mentioned in step S305 includes:

[0159] Based on each speckle image corresponding to the first wavelength, determine the first phase change amount corresponding to the target observation point;

[0160] Determine a second phase change amount corresponding to the target observation point based on each speckle image corresponding to the second wavelength;

[0161] Determine a first sine parameter and a second sine parameter; the first sine parameter is the product of the sine value of the incident angle of the first laser beam and the constant 2π, and the second sine parameter is the product of the sine value of the incident angle of the third laser beam and the constant 2π;

[0162] Perform a multiplication operation on the first wavelength and the first phase change amount to obtain a first product;

[0163] Perform a division operation on the first product and the first sine parameter, and use the quotient of the first product and the first sine parameter as the longitudinal displacement corresponding to the target observation point;

[0164] Perform a multiplication operation on the second wavelength and the second phase change amount to obtain a second product;

[0165] Perform a division operation on the second product and the second sine parameter, and use the quotient of the second product and the second sine parameter as the lateral displacement corresponding to the target observation point.

[0166] And Figure 6 Corresponding to the displacement measurement method shown, an embodiment of the present invention further provides a displacement measurement device for Figure 1 The specific implementation of the method shown in, and its structural schematic diagram is as Figure 7 Shown, including:

[0167] A first interference unit 401, configured to control a preset first interference module to project a first laser beam and a second laser beam with a first wavelength onto the surface of the object to be measured, so as to implement phase-shifting electronic speckle interferometry associated with longitudinal displacement; the first laser beam and the second laser beam are coplanar, and the incident plane of the first laser beam is parallel to the axis direction of the object to be measured; the incident angles of the first laser beam and the second laser beam are equal;

[0168] A second interference unit 402, configured to control a preset second interference module to project a third laser beam and a fourth laser beam with a second wavelength onto the surface of the object to be measured, so as to implement phase-shifting electronic speckle interferometry associated with lateral displacement; the third laser beam and the fourth laser beam are coplanar, and the incident plane of the third laser beam is perpendicular to the axis direction; the incident angles of the third laser beam and the fourth laser beam are equal;

[0169] A phase-shift control unit 403, configured to control a preset phase-shift controller to perform phase-shift control on the first interference module and the second interference module;

[0170] An image acquisition unit 404 is configured to collect speckle images of the object to be measured through a preset 3CCD color camera, so as to obtain each speckle image corresponding to the first wavelength and each speckle image corresponding to the second wavelength.

[0171] A displacement calculation unit 405 is configured to determine the longitudinal displacement and the lateral displacement corresponding to a target observation point according to each speckle image corresponding to the first wavelength and each speckle image corresponding to the second wavelength.

[0172] An embodiment of the present invention further provides a storage medium, where the storage medium includes stored instructions, and when the instructions run, the device where the storage medium is located is controlled to execute the displacement measurement method as described above.

[0173] An embodiment of the present invention further provides an electronic device, and a schematic structural diagram thereof is as Figure 8 shown, and specifically includes a memory 501 and one or more instructions 502, where one or more instructions 502 are stored in the memory 501 and are configured to be executed by one or more processors 503 to perform the following operations by the one or more instructions 502:

[0174] Control a preset first interference module to project a first laser beam and a second laser beam with a first wavelength onto the surface of the object to be measured, so as to implement phase-shifting electronic speckle interferometry associated with the longitudinal displacement; the first laser beam and the second laser beam are coplanar, and the incident plane of the first laser beam is parallel to the axis direction of the object to be measured; the incident angles of the first laser beam and the second laser beam are equal;

[0175] Control a preset second interference module to project a third laser beam and a fourth laser beam with a second wavelength onto the surface of the object to be measured, so as to implement phase-shifting electronic speckle interferometry associated with the lateral displacement; the third laser beam and the fourth laser beam are coplanar, and the incident plane of the third laser beam is perpendicular to the axis direction; the incident angles of the third laser beam and the fourth laser beam are equal;

[0176] Control a preset phase-shift controller to perform phase-shift control on the first interference module and the second interference module;

[0177] Collect speckle images of the object to be measured through a preset 3CCD color camera, so as to obtain each speckle image corresponding to the first wavelength and each speckle image corresponding to the second wavelength;

[0178] Determine the longitudinal displacement and the lateral displacement corresponding to a target observation point according to each speckle image corresponding to the first wavelength and each speckle image corresponding to the second wavelength.

[0179] Each embodiment in this specification is described in a progressive manner. For the same or similar parts among the embodiments, reference can be made to each other, and the differences between each embodiment and other embodiments are emphasized. The systems and system embodiments described above are merely illustrative. The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed to multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. Those of ordinary skill in the art can understand and implement it without creative efforts.

[0180] Those skilled in the art can further realize that the units and algorithm steps of each example described in combination with the embodiments disclosed in this article can be implemented by electronic hardware, computer software, or a combination of the two. To clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described according to functions in the above description. Whether these functions are executed in a hardware or software manner depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the present invention.

[0181] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but will be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A displacement measurement system, characterized in that, Including: A first interference module, a second interference module, a 3CCD color camera, a phase shift controller, and a data processing unit; The first interference module is configured to project a first laser beam and a second laser beam with a first wavelength onto the surface of the object to be measured, so as to achieve phase-shifted electronic speckle interferometry associated with longitudinal displacement; the first laser beam and the second laser beam are coplanar, and the incident plane of the first laser beam is parallel to the axis direction of the object to be measured; the incident angle of the first laser beam is equal to the incident angle of the second laser beam; The second interference module is configured to project a third laser beam and a fourth laser beam with a second wavelength onto the surface of the object to be measured, so as to achieve phase-shifted electronic speckle interferometry associated with lateral displacement; the third laser beam and the fourth laser beam are coplanar, and the incident plane of the third laser beam is perpendicular to the axis direction; the incident angle of the third laser beam is equal to the incident angle of the fourth laser beam; The phase shift controller is configured to perform phase shift control on the first interference module and the second interference module; The 3CCD color camera is configured to collect speckle images of the object to be measured, and obtain respective speckle images corresponding to the first wavelength and respective speckle images corresponding to the second wavelength; The data processing unit is configured to determine the longitudinal displacement and the lateral displacement corresponding to the target observation point based on the respective speckle images corresponding to the first wavelength and the respective speckle images corresponding to the second wavelength.

2. The displacement measurement system according to claim 1, wherein The first interference module includes: a first laser, a first fiber optic beam splitter, a first collimating lens, a first mirror, a first piezoelectric ceramic, a second collimating lens, and a second mirror; the first piezoelectric ceramic is fixedly connected to the first mirror; The first laser is configured to generate a laser with the first wavelength; The first fiber optic beam splitter is configured to split the laser generated by the first laser, and output a first sub-beam and a second sub-beam; The first collimating lens is configured to collimate the first sub-beam to obtain a first parallel beam; The first mirror is configured to reflect the first parallel beam to obtain the first laser beam; The first piezoelectric ceramic is configured to respond to the phase shift control operation of the phase shift controller, drive the first mirror, and perform phase shift on the first laser beam; The second collimating lens is configured to collimate the second sub-beam to obtain a second parallel beam; The second mirror is configured to reflect the second parallel beam to obtain the second laser beam.

3. The displacement measurement system according to claim 1, characterized in that, The second interference module includes: a second laser, a second fiber optic beam splitter, a third collimating lens, a third mirror, a second piezoelectric ceramic, a fourth collimating lens, and a fourth mirror; the second piezoelectric ceramic is fixedly connected to the third mirror; The second laser is configured to generate a laser with the second wavelength; The second fiber optic beam splitter is configured to split the laser generated by the second laser, and output a third sub-beam and a fourth sub-beam; The third collimating lens is configured to collimate the third sub-beam to obtain a third parallel beam; The third reflecting mirror is configured to reflect the third parallel light beam to obtain the third laser beam; The second piezoelectric ceramic is configured to drive the third reflecting mirror in response to the phase shift control operation of the phase shift controller to perform phase shift on the third laser beam; The fourth collimating lens is configured to collimate the third sub-light beam to obtain a fourth parallel light beam; The fourth reflecting mirror is configured to reflect the fourth parallel light beam to obtain the fourth laser beam.

4. The displacement measurement system according to claim 1, wherein The data processing unit is specifically configured to: Determine a first phase change amount corresponding to the target observation point based on each speckle image corresponding to the first wavelength; Determine a second phase change amount corresponding to the target observation point based on each speckle image corresponding to the second wavelength; Determine a first sine parameter and a second sine parameter; the first sine parameter is the product of the sine value of the incident angle of the first laser beam and the constant 2π, and the second sine parameter is the product of the sine value of the incident angle of the third laser beam and the constant 2π; Perform a multiplication operation on the first wavelength and the first phase change amount to obtain a first product; Perform a division operation on the first product and the first sine parameter, and use the quotient of the first product and the first sine parameter as the longitudinal displacement corresponding to the target observation point; Perform a multiplication operation on the second wavelength and the second phase change amount to obtain a second product; Perform a division operation on the second product and the second sine parameter, and use the quotient of the second product and the second sine parameter as the lateral displacement corresponding to the target observation point.

5. The displacement measurement system according to claim 1, wherein The data processing unit is further configured to: Determine a longitudinal displacement field and a lateral displacement field corresponding to the target observation area based on each speckle image corresponding to the first wavelength and each speckle image corresponding to the second wavelength; Determine longitudinal displacement information based on the longitudinal displacement field; the longitudinal displacement information includes the longitudinal displacement corresponding to the first observation point and the longitudinal displacement corresponding to the second observation point; Determine lateral displacement information based on the lateral displacement field; the lateral displacement information includes the lateral displacement corresponding to the first observation point and the lateral displacement corresponding to the second observation point; Determine observation distance information; the observation distance information includes the longitudinal distance and the lateral distance between the first observation point and the second observation point; Determine the Poisson's ratio corresponding to the measured object according to the longitudinal displacement information, the lateral displacement information, and the observation distance information.

6. A displacement measurement method, characterized in that, It includes: Controlling a preset first interference module to project a first laser beam and a second laser beam with a first wavelength onto the surface of the measured object to implement phase-shifting electronic speckle interferometry associated with longitudinal displacement; the first laser beam and the second laser beam are coplanar, and the incident plane of the first laser beam is parallel to the axis direction of the measured object; the incident angle of the first laser beam is equal to the incident angle of the second laser beam; Control the preset second interference module to project a third laser beam and a fourth laser beam with a second wavelength onto the surface of the object to be measured, so as to achieve phase-shifting electronic speckle pattern interferometry associated with lateral displacement; the third laser beam and the fourth laser beam are coplanar, and the incident plane of the third laser beam is perpendicular to the axis direction; the incident angles of the third laser beam and the fourth laser beam are equal; Control the preset phase-shifting controller to perform phase-shifting control on the first interference module and the second interference module; Collect speckle images of the object to be measured through a preset 3CCD color camera to obtain each speckle image corresponding to the first wavelength and each speckle image corresponding to the second wavelength; Determine the longitudinal displacement and lateral displacement corresponding to the target observation point based on each speckle image corresponding to the first wavelength and each speckle image corresponding to the second wavelength.

7. The displacement measurement method according to claim 6, wherein, The determining the longitudinal displacement and lateral displacement corresponding to the target observation point based on each speckle image corresponding to the first wavelength and each speckle image corresponding to the second wavelength includes: Based on each speckle image corresponding to the first wavelength, determine the first phase change amount corresponding to the target observation point; Based on each speckle image corresponding to the second wavelength, determine the second phase change amount corresponding to the target observation point; Determine a first sine parameter and a second sine parameter; the first sine parameter is the product of the sine value of the incident angle of the first laser beam and the constant 2π, and the second sine parameter is the product of the sine value of the incident angle of the third laser beam and the constant 2π; Perform a multiplication operation on the first wavelength and the first phase change amount to obtain a first product; Perform a division operation on the first product and the first sine parameter, and use the quotient of the first product and the first sine parameter as the longitudinal displacement corresponding to the target observation point; Perform a multiplication operation on the second wavelength and the second phase change amount to obtain a second product; Perform a division operation on the second product and the second sine parameter, and use the quotient of the second product and the second sine parameter as the lateral displacement corresponding to the target observation point.

8. A displacement measuring device, characterized in that, Includes: A first interference unit for controlling a preset first interference module to project a first laser beam and a second laser beam with a first wavelength onto the surface of the object to be measured, so as to achieve phase-shifting electronic speckle pattern interferometry associated with longitudinal displacement; the first laser beam and the second laser beam are coplanar, and the incident plane of the first laser beam is parallel to the axis direction of the object to be measured; the incident angles of the first laser beam and the second laser beam are equal; A second interference unit for controlling a preset second interference module to project a third laser beam and a fourth laser beam with a second wavelength onto the surface of the object to be measured, so as to achieve phase-shifting electronic speckle pattern interferometry associated with lateral displacement; the third laser beam and the fourth laser beam are coplanar, and the incident plane of the third laser beam is perpendicular to the axis direction; the incident angles of the third laser beam and the fourth laser beam are equal; A phase shift control unit for controlling a preset phase shifter to perform phase shift control on the first interference module and the second interference module; An image acquisition unit for acquiring speckle images of the object to be measured through a preset 3CCD color camera, obtaining respective speckle images corresponding to the first wavelength and respective speckle images corresponding to the second wavelength; A displacement calculation unit for determining a longitudinal displacement and a lateral displacement corresponding to a target observation point based on the respective speckle images corresponding to the first wavelength and the respective speckle images corresponding to the second wavelength.

9. A storage medium, characterized in that, The storage medium includes stored instructions, wherein when the instructions are running, the device where the storage medium is located is controlled to execute the displacement measurement method according to any one of claims 6 to 7.

10. An electronic device, characterized in that, It includes a memory, and one or more instructions, wherein one or more instructions are stored in the memory and are configured to be executed by one or more processors to execute the displacement measurement method according to any one of claims 6 to 7.

Images