Roll angle measuring method and device

Abstract

The invention discloses a roll angle measuring method and device. The method comprises the following steps: measuring phase change caused by rolling of an object plane by adopting a point shearing speckle interference method; and determining the roll angle of the object plane according to the phase change. According to the technical scheme provided by the invention, the roll angle error of the object plane can be measured, the measurement speed of the roll angle is effectively improved, and the method can adapt to the requirement of timely feedback of the roll angle error in an industrial field.

Description

Technical Field

[0001] The present application relates to the field of optical measurement technology, and in particular to a roll angle measurement method and device. Background Art

[0002] Nowadays, my country's traditional manufacturing industry is developing in a more precise direction, and precision CNC machine tools are the key and basic equipment of the manufacturing industry. CNC machine tools will produce geometric motion errors when they are in motion. Accurate and rapid error measurement to achieve compensation is conducive to improving the machining accuracy of machine tools and improving the production level of the manufacturing industry. Taking linear guides as an example, six-degree-of-freedom errors will be generated during operation. These errors are important factors affecting the quality of parts processed by this type of equipment. Therefore, measuring the errors of this type of equipment in six degrees of freedom has significant engineering significance.

[0003] As one of the six-degree-of-freedom errors, roll angle error is inevitable during machine tool motion and is difficult to measure. Therefore, it is necessary to measure the roll motion error to achieve higher motion control accuracy.

[0004] In the existing roll angle error measurement methods, it is usually necessary to install the sensor or cooperative target mirror on the surface of the object to be measured. This measurement mode has many inconveniences in engineering applications and will bring additional errors to the measurement results. In non-contact measurement, it takes a certain amount of time to process image information when calculating the roll angle, and it is impossible to achieve rapid measurement of angle error. Summary of the invention

[0005] A brief overview of the present application is provided below in order to provide a basic understanding of certain aspects of the present application. It should be understood that this overview is not an exhaustive overview of the present application. It is not intended to identify the key or important parts of the present application, nor is it intended to limit the scope of the present application. Its purpose is merely to present certain concepts in a simplified form as a prelude to a more detailed description discussed later.

[0006] Embodiments of the present application provide a method and device for measuring a roll angle.

[0007] In a first aspect, an embodiment of the present application provides a roll angle measurement method, comprising:

[0008] The phase change caused by the object plane roll is measured by point shearing speckle interferometry.

[0009] A roll angle of the object plane is determined according to the phase change.

[0010] Optionally, the phase is measured by point shearing speckle interferometry, including:

[0011] Using a first beam expanding laser and a second beam expanding laser to irradiate the object plane from symmetrical angles to generate a first diffuse reflection light and a second diffuse reflection light, wherein the first beam expanding laser and the second beam expanding laser have the same or different wavelengths;

[0012] A beam splitting multiplexing method is used to realize the separate irradiation of the first beam expanding laser and the second beam expanding laser, wherein the beam splitting multiplexing method includes at least one of the following: time division multiplexing, wavelength division multiplexing, polarization state division multiplexing, time division frequency multiplexing, and space division frequency multiplexing;

[0013] The first diffusely reflected light and the second diffusely reflected light enter a shearing module simultaneously or in different time periods, directly or after passing through a lens, to generate two pairs of mutually displaced but partially overlapping light beams;

[0014] The two pairs of mutually offset but partially overlapping light beams interfere with each other on a photodetector surface after passing through a phase modulation module, forming a first point shearing speckle interference and a second point shearing speckle interference;

[0015] The signals of the first point shearing speckle interferometry and the second point shearing speckle interferometry are received by the photodetector, then processed by a signal acquisition and processing module, and finally phases are extracted by a phase determination module.

[0016] Optionally, a shearing direction of the shearing module is perpendicular to a plane formed by a center line of the first beam expanding laser and a center line of the second beam expanding laser.

[0017] Optionally, the measuring the phase change caused by the object plane rolling by using the point shearing speckle interferometry method includes:

[0018] Measuring the first phase information and the second phase information of the object plane at time i by using the point shearing speckle interferometry method;

[0019] Measuring the third phase information and the fourth phase information of the object plane at time j by using the point shearing speckle interferometry, wherein j is greater than i;

[0020] Determine, according to the first phase information and the third phase information, a first phase change corresponding to the first beam expansion laser caused by the rolling of the object plane within a time period ji;

[0021] A second phase change corresponding to the second beam expansion laser caused by the rolling of the object plane within the ji time period is determined according to the second phase information and the fourth phase information.

[0022] Optionally, the first phase change and the second phase change caused by the rolling of the object plane within a time period ji are within a range of (-π, π).

[0023] Optionally, the method further comprises:

[0024] When the phase change caused by the roll exceeds 2π, the ji period is divided into a plurality of sub-periods, and the first phase change and the second phase change caused by the object plane roll in each sub-period are within the range of (-π, π);

[0025] The first phase change and the second phase change caused by the rolling in each sub-period are accumulated respectively to obtain a first total phase change and a second total phase change.

[0026] Optionally, determining the roll angle of the object plane according to the phase information includes:

[0027] Determine the roll angle of the object plane using the following formula according to the first total phase change and the second total phase change;

[0028]

[0029] The roll axis of the object plane is the Z axis, Δθ is the roll angle of the object plane, Δφ1 and Δφ2 are the first total phase change and the second total phase change, λ1 and λ2 are the wavelengths of the first beam expanding laser and the second beam expanding laser, α is the illumination angle of the first beam expanding laser and the second beam expanding laser irradiated on the object plane, and δy is the shear amount of the shear module.

[0030] In a second aspect, an embodiment of the present application further provides a roll angle measurement device, comprising:

[0031] Point shearing speckle interferometry module, used to measure the phase change caused by the object surface roll using point shearing speckle interferometry;

[0032] A roll angle determination module is used to determine the roll angle of the object plane according to the phase change.

[0033] Optionally, the point shearing speckle interferometry measurement module comprises:

[0034] A first measurement submodule, configured to measure a first total phase change of the object plane corresponding to the first beam expansion laser by using the point shearing speckle interferometry method;

[0035] The second measurement submodule is used to measure a second total phase change of the object plane corresponding to the second beam expansion laser by using the point shearing speckle interferometry method.

[0036] Optionally, the roll angle determination module is specifically used to:

[0037] According to the first total phase change and the second total phase change caused by the object plane rolling, the roll angle of the object plane is determined by using the following formula:

[0038]

[0039] Among them, the roll axis of the object plane is the Z axis, Δθ is the roll angle of the object plane, Δφ1 and Δφ2 are the first total phase change and the second total phase change, λ1 and λ2 are the wavelengths of the first beam expanding laser and the second beam expanding laser, α is the illumination angle of the first beam expanding laser and the second beam expanding laser irradiated on the object plane, and δy is the shear amount of the shear module.

[0040] By using the point shear speckle interferometry method to measure the phase change caused by the roll of the object surface, and then determining the roll angle of the object surface based on the phase change, it is possible to achieve non-contact measurement of the roll angle of the object surface while effectively reducing the measurement time, and increasing the measurement speed to more than fifty times that of the original shear speckle interferometry roll angle measurement method.

[0041] These and other advantages of the present application will become more apparent through the following detailed description of the optional embodiments of the present application in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The present application can be better understood by referring to the following description given in conjunction with the accompanying drawings, wherein the same or similar reference numerals are used throughout the drawings to represent the same or similar components. The accompanying drawings, together with the following detailed description, are included in and form a part of this specification, and are used to further illustrate the optional embodiments of the present application and explain the principles and advantages of the present application. In the accompanying drawings:

[0043] Figure 1 A flow chart of a roll angle measurement method provided in an embodiment of the present application;

[0044] Figure 2 An optional example of measuring a roll angle based on a point shearing speckle interferometry method provided in an embodiment of the present application;

[0045] Figure 3 An optional example of measuring a roll angle based on a point shearing speckle interferometry method provided in an embodiment of the present application;

[0046] Figure 4 A block diagram of a roll angle measurement device provided in an embodiment of the present application;

[0047] Figure 5 A logic block diagram of a measurement system provided in an embodiment of the present application.

[0048] Those skilled in the art will appreciate that the elements in the drawings are shown only for simplicity and clarity and are not necessarily drawn to scale. For example, the size of some elements in the drawings may be enlarged relative to other elements to help improve the understanding of the embodiments of the present application. DETAILED DESCRIPTION

[0049] Hereinafter, exemplary embodiments of the present application will be described in detail in conjunction with the accompanying drawings. For the sake of clarity and conciseness, not all features of the actual implementation are described in the specification. However, it should be understood that many implementation-specific decisions must be made in the process of developing any such actual implementation in order to achieve the developer's specific goals, such as meeting those constraints related to the system and business, and these constraints may vary from implementation to implementation. In addition, it should be understood that although the development work may be very complex and time-consuming, it is only a routine task for those skilled in the art who benefit from the present disclosure.

[0050] It is also necessary to explain here that, in order to avoid obscuring the present application due to unnecessary details, only the device structure and / or processing steps closely related to the scheme according to the present application are described in the drawings and descriptions, while the representation and description of components and processes that are not closely related to the present application and are known to ordinary technicians in the field are omitted.

[0051] The specific implementation methods of the present application are further described in detail below in conjunction with the accompanying drawings (the same reference numerals in several drawings represent the same elements) and embodiments. The following embodiments are used to illustrate the present application, but are not used to limit the scope of the present application.

[0052] Those skilled in the art will understand that the terms "first" and "second" in this application are only used to distinguish different steps, devices or modules, etc., and do not represent any specific technical meanings, nor do they indicate the necessary logical order between them.

[0053] Generally speaking, in-plane deformation is insensitive to the rolling motion of the object surface, but the rolling motion of the object surface will cause a large phase change. Point shear speckle interferometry is a non-contact optical measurement technology that can measure the deformation and strain of engineering materials. It has the characteristics of short measurement time, high accuracy, high stability and non-contact measurement. Since point shear speckle interferometry is a deformation-sensitive technology, it establishes the relationship between phase and deformation. Compared with other non-contact roll angle measurement methods such as digital shear speckle interferometry, which requires processing of the full-field phase distribution information of the object surface, point shear speckle interferometry only processes the phase value of a point on the object surface, which greatly improves the roll angle measurement speed and meets the needs of fast measurement in industry.

[0054] Based on a large number of studies and experimental demonstrations, the applicant proposed a point shearing speckle interferometry technique and applied it to roll angle measurement to achieve rapid measurement. Based on this discovery, the present application first introduced the point shearing speckle interferometry technique, which is extremely sensitive to the in-plane deformation of an object, into the measurement of the roll angle, providing a new solution for measuring the roll angle. The technical solution of the exemplary embodiment of the present application is described in detail below in conjunction with the accompanying drawings.

[0055] Figure 1 A flow chart of a roll angle measurement method provided in an embodiment of the present application. Figure 1 As shown, the roll angle measurement method provided in the embodiment of the present application includes:

[0056] S101: Use point shearing speckle interferometry to measure the phase change caused by object plane roll.

[0057] S102: Determine the roll angle of the object plane according to the phase change.

[0058] Different from the traditional roll angle measurement method, the embodiment of the present application determines the roll angle of the object plane based on the point shearing speckle interferometry method, uses a photoelectric detector to collect the shearing speckle interference signal at a point on the object plane, effectively avoids the full-field signal processing, and can achieve non-contact measurement of the roll angle of the object plane, reducing the measurement error. In addition, the roll angle measurement method based on the point shearing speckle interferometry technology of the embodiment of the present application has few components, simple structure, and intuitive and real-time measurement results.

[0059] Optionally, point shearing speckle interferometry is used to measure the phase change caused by object plane roll, including: using the point shearing speckle interferometry to measure a first total phase change of the object plane corresponding to a first beam expanding laser; using the point shearing speckle interferometry to measure a second total phase change of the object plane corresponding to a second beam expanding laser.

[0060] Optionally, determining the roll angle of the object plane according to the phase change includes: utilizing a geometric relationship between the roll angle and the phase change, substituting the first total phase change and the second total phase change into each other to solve the roll angle.

[0061] The theoretical basis and specific exemplary methods of the solution for measuring the roll angle based on the point shearing speckle interferometry technology of the present application are further described below.

[0062] Figure 2 An optional example of measuring a roll angle based on point shearing speckle interferometry is provided in an embodiment of the present application. Figure 2 The point shear interferometry optical path shown can be used for in-plane deformation measurement. Figure 2In the point shearing speckle interferometry optical path shown, the light emitted by the laser 1 is divided into two beams by the beam splitter prism 2. One beam of light passes through the first aperture 3, the first reflector 4, and the first beam expander 5 to enter the object surface, and the other beam of light passes through the second aperture 7, the second reflector 8, the third reflector 9, and the second beam expander 10 to enter the object surface. The reflected light reflected by the object surface passes through the lens 11 and enters the shearing system. After passing through the lens, the reflected light is divided into object light and reference light by the beam splitter prism 15. The object light passes through the reflector 14 to enter the photodetector 16, and the reference light passes through the reflector 12 to irradiate the sensor surface of the photodetector 16 to form interference, that is, point shearing speckle interferometry. A piezoelectric ceramic tube 13 is arranged on the back of the reflector 12. By controlling the elongation of the piezoelectric ceramic tube, multiple additional optical paths are introduced into the optical path where the reference light is located (the specific value of each additional optical path depends on the time phase shift algorithm adopted, which can be a quarter of the wavelength of light or other values). Among them, the Z axis is the rolling axis of the object plane, and the optical path is set on the XOY plane.

[0063] Figure 3 An optional example of measuring a roll angle based on point shearing speckle interferometry is provided in an embodiment of the present application. Figure 3 The point shearing speckle interferometry optical path shown can be used for in-plane deformation measurement. Figure 3 In the point shearing speckle interferometry measurement optical path shown, the light emitted by the laser 1 passes through the first reflector 2 and the first beam expander 3 and is incident on the object plane 4. Another beam of light emitted by the laser 13 passes through the second reflector 12 and the second beam expander 11 and is incident on the object plane symmetrically along the Z axis. The diffusely reflected light reflected by the object plane passes through the aperture 5 and the convex lens 6 and enters the shearing system. After passing through the lens, the reflected light is divided into object light and reference light by the beam splitter prism 7. The object light passes through the reflector 9 and enters the photodetector 8. The reference light passes through the reflector 10 and is irradiated onto the sensor surface of the photodetector 8 to form speckle interference, namely point shearing speckle interference. Among them, the Z axis is the roll axis of the object plane, and the optical path is set on the XOY plane.

[0064] It should be noted that the point shearing speckle interferometry measurement optical path can be used in addition to the above Figure 2 , Figure 3 In addition to the optical path form, other optical path deformations and component replacements that can perform point shearing speckle interferometry also fall within the protection scope of this application. In order to simplify the calculation process, a symmetrical illumination optical path structure can be used, that is, the two light paths incident on the object surface are symmetrically distributed relative to the roll axis, that is, the incident angles are both α. The following specific description is based on the incident angle of the two light paths being α.

[0065] In a possible implementation, a first beam expanding laser and a second beam expanding laser are used to irradiate the object plane from symmetrical angles to generate a first diffuse reflection light and a second diffuse reflection light, wherein the first beam expanding laser and the second beam expanding laser have the same or different wavelengths;

[0066] like Figure 2 As shown, the light beam emitted by the laser 1 is split into two beams by the beam splitter prism 2, and then passes through the aperture, the reflector and the beam expander to generate the first beam expansion laser and the second beam expansion laser with the same wavelength, which are symmetrically irradiated to the object plane 6 to generate the first diffuse reflection light and the second diffuse reflection light;

[0067] like Figure 3 As shown, the light beam emitted by laser 1 passes through reflector 2 and beam expander 3 to generate a first beam expanded laser that irradiates object surface 4. The light beam emitted by laser 13 passes through reflector 12 and beam expander 11 to generate a second beam expanded laser that irradiates object surface 4. Two beams of expanded lasers with different wavelengths irradiate the object surface, generating a first diffuse reflection light and a second diffuse reflection light.

[0068] In a possible implementation, a beam splitting multiplexing method is used to implement the separate irradiation of the first beam expanding laser and the second beam expanding laser, wherein the beam splitting multiplexing method includes at least one of the following: time division multiplexing, wavelength division multiplexing, polarization state division multiplexing, time division frequency multiplexing, and space division frequency multiplexing;

[0069] like Figure 2 As shown, apertures 3 and 7 are used to switch the optical paths. During each measurement, only one side of the optical path is incident. The first beam expansion laser and the second beam expansion laser are irradiated separately by time division multiplexing.

[0070] like Figure 3 As shown, lasers with different wavelengths are used to respectively implement point shearing speckle interference, that is, wavelength division multiplexing is used to implement the separate irradiation of the first beam expansion laser and the second beam expansion laser.

[0071] In a possible implementation, the first diffusely reflected light and the second diffusely reflected light enter a shearing module simultaneously or in different time periods, directly or after passing through a lens, to generate two pairs of mutually offset but partially overlapping light beams;

[0072] like Figure 2 As shown, the first diffusely reflected light and the second diffusely reflected light enter a shearing module after passing through a convex lens 11 in a time-division manner, generating two pairs of mutually offset but partially overlapping light beams;

[0073] like Figure 3 As shown, the first diffusely reflected light and the second diffusely reflected light simultaneously pass through an aperture 5 and a convex lens 6 and then enter a shearing module, generating two pairs of mutually offset but partially overlapping light beams.

[0074] In a possible implementation, the two pairs of mutually offset but partially overlapping light beams interfere with each other on a photodetector surface after passing through a phase modulation module, forming a first point shearing speckle interference and a second point shearing speckle interference;

[0075] like Figure 2 As shown, the phase shift is introduced by changing the interference phase difference by the deformation of the piezoelectric ceramic 13. The two pairs of mutually offset but partially overlapping light beams interfere on the surface of a photodetector 16 after passing through a phase modulation module based on time phase shift, forming a first point shearing speckle interference and a second point shearing speckle interference.

[0076] like Figure 3 As shown, a spatial carrier is introduced by using an inclined incident light beam, and the two pairs of mutually offset but partially overlapping light beams interfere on the surface of a photodetector 8 after passing through a phase modulation module based on a spatial carrier, forming a first point shearing speckle interference and a second point shearing speckle interference;

[0077] In a possible implementation, the signals of the first point shearing speckle interferometry and the second point shearing speckle interferometry are received by the photodetector, then processed by a signal acquisition and processing module, and finally a phase determination module is used to extract the phase;

[0078] like Figure 2 As shown, the signals of the first point shearing speckle interferometry and the second point shearing speckle interferometry are received by the photodetector 16, then processed by a signal acquisition processing module, and finally the phase is extracted by a phase determination module based on time phase shift. The following formula is used to determine the wrapping phase:

[0079]

[0080] Wherein, I1, I2, I3, and I4 respectively represent the point shear speckle interference light intensities corresponding to different telescopic steps generated by the piezoelectric ceramic 16.

[0081] like Figure 3 As shown, the signals of the first point shearing speckle interference and the second point shearing speckle interference are received by the photodetector 8, then processed by a signal acquisition processing module, and finally the phase is extracted by the phase determination module based on the spatial carrier. The carrier is introduced by using an oblique incident light beam. After Fourier transforming the point shearing speckle interference light intensity signal, a high-pass filter is used to extract the signal U, and the wrapping phase is determined by the following formula:

[0082]

[0083] In a possible implementation, the shearing direction of the shearing module is perpendicular to a plane formed by a center line of the first beam expanding laser and a center line of the second beam expanding laser;

[0084] like Figure 2 or Figure 3 As shown, the shearing direction of the shearing module is along the Y axis and is perpendicular to the plane XOZ plane formed by the center line of the first beam expanding laser and the center line of the second beam expanding laser.

[0085] In a possible implementation, the measuring of the phase change caused by the rolling of the object plane by using the point shearing speckle interferometry method includes: measuring first phase information and second phase information of the object plane at time i by using the point shearing speckle interferometry method; measuring third phase information and fourth phase information of the object plane at time j by using the point shearing speckle interferometry method, wherein j is greater than i; determining a first phase change corresponding to the first beam expanding laser caused by the rolling of the object plane in a time period ji according to the first phase information and the third phase information; determining a second phase change corresponding to the second beam expanding laser caused by the rolling of the object plane in a time period ji according to the second phase information and the fourth phase information;

[0086] like Figure 2 As shown, the left and right incident lights are controlled by an aperture. At time i, aperture 7 is closed. After the laser is incident on the left optical path from one side and passes through the first beam expansion to the object plane, the first phase information is measured using point shearing speckle interferometry. The optical path is switched by closing aperture 8 and opening aperture 7. After the laser is incident on the right optical path from one side and passes through the second beam expansion to the object plane, the second phase information is measured using point shearing speckle interferometry. After the same operation is performed at time j, the third phase information and the fourth phase information of the first beam expansion laser and the second beam expansion laser are measured. According to the phase information of the first beam expansion laser at times i and j and the phase information of the second beam expansion laser at times i and j, the phase change corresponding to the first beam expansion laser and the second beam expansion laser caused by the rolling of the object plane in the (ji) time period is determined;

[0087] like Figure 3 As shown, lasers of different wavelengths are used to be incident on the object surface symmetrically relative to the roll axis. At time i, after the signal acquisition system receives the light intensity signal, it uses bandpass filters of different frequency domain ranges to separate the point shear interference light intensity signals corresponding to the two wavelengths, and obtains the corresponding phase information of the first beam expansion laser and the second beam expansion laser according to the phase extraction algorithm. At time j, the received light intensity signal is processed in the same way to obtain the corresponding phase information of the first beam expansion laser and the second beam expansion laser, and the phase change corresponding to the first beam expansion laser and the second beam expansion laser caused by the roll of the object surface in the (ji) time period can be determined.

[0088] In a possible implementation manner, the first phase change and the second phase change caused by the rolling of the object plane within a time period ji are within a range of (-π, π).

[0089] like Figure 2 or Figure 3 As shown, the first phase change and the second phase change caused by the rolling of the object plane within the ji time period are within the range of (-π, π).

[0090] In a possible implementation manner, when the phase change caused by the roll exceeds 2π, the ji period is divided into a plurality of sub-periods, and the first phase change and the second phase change caused by the roll of the object plane in each sub-period are within a range of (-π, π); the first phase change and the second phase change caused by the roll in each sub-period are respectively accumulated to obtain a first total phase change and a second total phase change;

[0091] like Figure 2 or Figure 3 As shown, when the phase change caused by the roll exceeds 2π, the ji period is divided into a plurality of sub-periods, and the first phase change and the second phase change caused by the roll of the object plane in each sub-period are within the range of (-π, π); the first phase change and the second phase change caused by the roll in each sub-period are accumulated respectively to obtain a first total phase change and a second total phase change.

[0092] In a possible implementation manner, the roll angle of the object plane is determined by using the following formula according to the first total phase change and the second total phase change:

[0093]

[0094] The roll axis of the object plane is the Z axis, Δθ is the roll angle of the object plane, Δφ1 and Δφ2 are the first total phase change and the second total phase change, λ1 and λ2 are the wavelengths of the first beam expanding laser and the second beam expanding laser, α is the illumination angle of the first beam expanding laser and the second beam expanding laser irradiated on the object plane, and δy is the shearing amount of the shearing module;

[0095] like Figure 2 As shown, the wavelengths of the first beam expansion laser and the second beam expansion laser are the same, and the roll angle of the object plane is determined by the following formula according to the first total phase change and the second total phase change:

[0096]

[0097] wherein the roll axis of the object plane is the Z axis, Δθ is the roll angle of the object plane, Δφ1 and Δφ2 are the first total phase change and the second total phase change, respectively, λ is the wavelength of the first beam expanding laser and the second beam expanding laser, α is the illumination angle of the first beam expanding laser and the second beam expanding laser irradiated onto the object plane, and δy is the shearing amount of the shearing module;

[0098] like Figure 3 As shown, according to the first total phase change and the second total phase change, the roll angle of the object plane is determined by using the following formula;

[0099]

[0100] The roll axis of the object plane is the Z axis, Δθ is the roll angle of the object plane, Δφ1 and Δφ2 are the first total phase change and the second total phase change, λ1 and λ2 are the wavelengths of the first beam expanding laser and the second beam expanding laser, α is the illumination angle of the first beam expanding laser and the second beam expanding laser irradiated on the object plane, and δy is the shear amount of the shear module.

[0101] Those skilled in the art will understand that, in any of the above methods of the specific implementation methods of the present application, the serial number of each step does not mean the order of execution, and the execution order of each step should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the specific implementation methods of the present application.

[0102] Figure 4 A block diagram of a roll angle measurement device provided in an embodiment of the present application. Figure 4 As shown, a roll angle measurement device provided in an embodiment of the present application includes: a point shearing speckle interferometry measurement module 41 and a roll angle determination module 42 .

[0103] The point shearing speckle interferometry measurement module 41 is used to measure the phase information caused by the object surface roll by using the point shearing speckle interferometry method.

[0104] The roll angle determination module 42 is used to determine the roll angle of the object plane according to the geometric relationship between the phase change and the roll angle.

[0105] Optionally, the point shearing speckle interferometry measurement module 41 includes:

[0106] A first measurement submodule, configured to measure a first total phase change of the object plane corresponding to the first beam expansion laser by using the point shearing speckle interferometry method;

[0107] The second measurement submodule is used to measure a second total phase change of the object plane corresponding to the second beam expansion laser by using the point shearing speckle interferometry method.

[0108] Optionally, the roll angle determination module 42 is specifically configured to:

[0109] According to the first total phase change and the second total phase change caused by the object plane rolling, the roll angle of the object plane is determined by using the following formula:

[0110]

[0111] The roll axis of the object plane is the Z axis, Δθ is the roll angle, Δφ1 and Δφ2 are the first total phase change and the second total phase change, λ1 and λ2 are the wavelengths of the first beam expanding laser and the second beam expanding laser, α is the illumination angle of the first beam expanding laser and the second beam expanding laser irradiated on the object plane, and δy is the shearing amount of the shearing module.

[0112] The roll angle measurement device provided in the embodiment of the present application can be used to implement the above Figure 1 The various steps of the method embodiment of the roll angle measurement method shown in the figure (for various further preferred implementations, they are not described in detail in the embodiment of the roll angle measurement device, and can be specifically referred to in Figure 1 The roll angle measurement method shown in the embodiment of the invention is used to determine the roll angle of an object surface, has a wide range of applications, a simple structure, a fast measurement speed and intuitive measurement results.

[0113] Figure 5 This is a logic block diagram of a measurement system provided in an embodiment of the present application. Figure 5 As shown, the measurement system provided in the embodiment of the present application includes: a roll angle measurement device 501, a processor 502 and a memory 503; the processor 502 is connected to the roll angle measurement device 501 and the memory 503 respectively, and optionally, the processor 502 can be communicatively connected to the roll angle measurement device 501 via a bus and a communication interface, and the processor 502 and the memory 503 can be communicatively connected via a bus.

[0114] The processor 502 is used to execute a program, and specifically can execute the relevant steps in the above-mentioned roll angle measurement method embodiment; for example, the program may include a program code, and the program code includes a computer operation instruction. The memory 503 is used to store at least one instruction, and the stored instruction enables the processor 502 to perform the following operations: control the roll angle measurement device 501 to measure the phase information caused by the roll of the object plane, and determine the roll angle of the object plane according to the phase information; or control the roll angle measurement device 501 to measure the phase information caused by the roll of the object plane, and determine the roll angle of the object plane according to the phase information.

[0115] The processor 502 may be a central processing unit (CPU), or an application specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of the present application.

[0116] The memory 503 may include a random access memory (RAM), and may also include a non-volatile memory (Non-volatile memory), such as at least one disk memory.

[0117] The specific implementation of each step in the program executed by the processor can refer to the corresponding description of the corresponding steps, modules, submodules, and units in the above embodiments, which will not be repeated here. Those skilled in the art can clearly understand that for the convenience and simplicity of description, the specific working process of the above-described devices and modules can refer to the corresponding process description in the above-mentioned method embodiment, which will not be repeated here.

[0118] In the above-mentioned embodiments of the present application, the serial number and / or the order of the embodiments are only for the convenience of description and do not represent the advantages and disadvantages of the embodiments. The description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, please refer to the relevant description of other embodiments. For the relevant description of the implementation principle or process of the device, equipment or system embodiment, please refer to the record of the corresponding method embodiment, which will not be repeated here.

[0119] Those of ordinary skill in the art will appreciate that the units and method steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0120] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application can be essentially or partly embodied in the form of a software product that contributes to the prior art. The computer software product is stored in a storage medium and includes several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods described in each embodiment of the present application. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0121] In the embodiments of the device, method, system, etc. of the present application, it is obvious that each component (system, subsystem, module, submodule, unit, subunit, etc.) or each step can be decomposed, combined and / or recombined after decomposition. These decompositions and / or recombinations should be regarded as equivalent schemes of the present application. At the same time, in the above description of the specific embodiments of the present application, the features described and / or shown for one embodiment can be used in one or more other embodiments in the same or similar manner, combined with the features in other embodiments, or replace the features in other embodiments.

[0122] It should be emphasized that the term “include / comprises” when used herein refers to the presence of features, elements, steps or components, but does not exclude the presence or addition of one or more other features, elements, steps or components.

[0123] Finally, it should be noted that the above implementation modes are only used to illustrate the present application, and are not intended to limit the present application. Ordinary technicians in the relevant technical field may make various changes and modifications without departing from the spirit and scope of the present application. Therefore, all equivalent technical solutions also belong to the scope of the present application, and the scope of patent protection of the present application shall be limited by the claims.

Claims

1. A method for measuring a rolling angle, characterized in that: include: The phase change caused by the object plane roll is measured by point shearing speckle interferometry. A roll angle of the object plane is determined according to the phase change.

2. The method according to claim 1, characterized in that Point shearing speckle interferometry measures phase, including: Using a first beam expanding laser and a second beam expanding laser to irradiate the object plane from symmetrical angles to generate a first diffuse reflection light and a second diffuse reflection light, wherein the first beam expanding laser and the second beam expanding laser have the same or different wavelengths; A beam splitting multiplexing method is used to realize the separate irradiation of the first beam expanding laser and the second beam expanding laser, wherein the beam splitting multiplexing method includes at least one of the following: time division multiplexing, wavelength division multiplexing, polarization state division multiplexing, time division frequency multiplexing, and space division frequency multiplexing; The first diffusely reflected light and the second diffusely reflected light enter a shearing module simultaneously or in different time periods, directly or after passing through a lens, to generate two pairs of mutually displaced but partially overlapping light beams; The two pairs of mutually offset but partially overlapping light beams interfere with each other on a photodetector surface after passing through a phase modulation module, forming a first point shearing speckle interference and a second point shearing speckle interference; The signals of the first point shearing speckle interferometry and the second point shearing speckle interferometry are received by the photodetector, then processed by a signal acquisition and processing module, and finally phases are extracted by a phase determination module.

3. The method according to claim 2, characterized in that The shearing direction of the shearing module is perpendicular to a plane formed by a center line of the first beam expanding laser and a center line of the second beam expanding laser.

4. The method according to claim 1 or 2, characterized in that: The method of measuring the phase change caused by the object plane rolling by using the point shearing speckle interferometry method comprises: Measuring the first phase information and the second phase information of the object plane at time i by using the point shearing speckle interferometry method; Measuring the third phase information and the fourth phase information of the object plane at time j by using the point shearing speckle interferometry, wherein j is greater than i; Determine, according to the first phase information and the third phase information, a first phase change corresponding to the first beam expansion laser caused by the rolling of the object plane within a time period ji; A second phase change corresponding to the second beam expansion laser caused by the rolling of the object plane within the ji time period is determined according to the second phase information and the fourth phase information.

5. The method according to claim 4, characterized in that The first phase change and the second phase change caused by the rolling of the object plane within a time period ji are within the range of (-π, π).

6. The method according to claim 4 or 5, characterized in that: The method further comprises: When the phase change caused by the roll exceeds 2π, the ji period is divided into a plurality of sub-periods, and the first phase change and the second phase change caused by the object plane roll in each sub-period are within the range of (-π, π); The first phase change and the second phase change caused by the rolling in each sub-period are accumulated respectively to obtain a first total phase change and a second total phase change.

7. The method according to claim 6, characterized in that Determining the roll angle of the object plane according to the phase change includes: Determine the roll angle of the object plane using the following formula according to the first total phase change and the second total phase change; Among them, the roll axis of the object plane is the Z axis, Δθ is the roll angle of the object plane, Δφ1 and Δφ2 are the first total phase change and the second total phase change, λ1 and λ2 are the wavelengths of the first beam expanding laser and the second beam expanding laser, α is the illumination angle of the first beam expanding laser and the second beam expanding laser irradiated on the object plane, and δy is the shear amount of the shear module.

8. A rolling angle measuring device, characterized in that: include: Point shearing speckle interferometry module, used to measure the phase change caused by the object surface roll using point shearing speckle interferometry; The roll angle determination module is used to determine the roll angle of the object plane according to the phase change.

9. The device according to claim 8, characterized in that The point shearing speckle interferometry measurement module comprises: A first measurement submodule, configured to measure a first total phase change of the object plane corresponding to the first beam expansion laser by using the point shearing speckle interferometry method; The second measurement submodule is used to measure a second total phase change of the object plane corresponding to the second beam expansion laser by using the point shearing speckle interferometry method.

10. The device according to claim 8, characterized in that The roll angle determination module is specifically used for: According to the first total phase change and the second total phase change caused by the object plane rolling, the roll angle of the object plane is determined by using the following formula: Among them, the roll axis of the object plane is the Z axis, Δθ is the roll angle of the object plane, Δφ1 and Δφ2 are the first total phase change and the second total phase change, λ1 and λ2 are the wavelengths of the first beam expanding laser and the second beam expanding laser, α is the illumination angle of the first beam expanding laser and the second beam expanding laser irradiated on the object plane, and δy is the shear amount of the shear module.

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