A calibration system, method and device for physical parameters of a wavefront sensor

Abstract

The present application discloses a calibration system, method and device for physical parameters of a wavefront sensor, including: a spherical wave generating device, a wavefront sensor to be calibrated and a data processor. First, a high-precision spherical wave is generated by the spherical wave generating device, and the wavefront sensor to be calibrated generates a corresponding spot array image based on the spherical wave; the data processor obtains the proportional relationship between the sub-lens size of the microlens array and the pixel size of the detector, and then iteratively solves each physical parameter of the wavefront sensor based on this proportional relationship, the spot array image and the constraint relationship between the physical parameters to obtain approximate values of each physical parameter. Finally, the final calibration values of each physical parameter are determined through the analysis of the wavefront restoration accuracy. It solves the technical problem that due to the lack of existing technical means, the physical parameters of the wavefront sensor cannot be calibrated with high precision, converges each physical parameter to the target accuracy range, and improves the measurement accuracy of the wavefront sensor.

Description

Technical Field

[0001] The present application relates to the technical field of optical measurement, and particularly relates to a calibration system, method and device for physical parameters of a wavefront sensor. Background Art

[0002] A wavefront sensor is a relative wavefront measurement instrument that can detect the wavefront shape and is widely used in fields such as astronomy, high-energy lasers, fundus imaging, optical communication, and optical detection.

[0003] In order to obtain a high-precision wavefront sensor, it is necessary to calibrate its physical parameters. The physical parameters have a great influence on its measurement accuracy. Since manufacturers are bound to introduce some errors during the production process, there will be a certain difference between the factory design value and the true value of the physical parameters. Directly using the factory design value as its true value cannot achieve high-precision measurement of the wavefront.

[0004] Therefore, due to the lack of existing technical means, there is an urgent need for an effective calibration method and device for physical parameters of a wavefront sensor to calibrate the physical parameters of the wavefront sensor with high precision. Summary of the Invention

[0005] The present application provides a calibration system, method and device for physical parameters of a wavefront sensor, which solves the technical problem that due to the lack of existing technical means, the physical parameters of the wavefront sensor cannot be calibrated with high precision.

[0006] On the one hand, a calibration system for physical parameters of a wavefront sensor is provided. The system includes: a spherical wave generating device, a wavefront sensor to be calibrated, and a data processor. The spherical wave generating device includes: a laser, a converging lens, and a spherical wave generator;

[0007] The laser is used to output laser light, and the output laser light is focused on the spherical wave generator through the converging lens;

[0008] The spherical wave generator is used to generate a spherical wave when receiving the laser light, and the spherical wave generator coincides with the focal point of the converging lens;

[0009] The wavefront sensor to be calibrated is used to detect the spherical wave and generate a spot array image corresponding to the spherical wave;

[0010] The data processor is configured to obtain the proportional relationship between the sub-lens size of the microlens array in the wavefront sensor and the pixel size of the detector in the wavefront sensor, obtain the constraint relationship between the spot array image and the physical parameters of the wavefront sensor based on the proportional relationship, and perform step-by-step iterative solution on the constraint relationship to obtain an approximate value of the physical parameters; the physical parameters include: the focal length of the microlens array, the sub-lens size of the microlens array, the pixel size of the detector, and the number of pixels.

[0011] The data processor is further configured to obtain the measured wavefront of the wavefront sensor based on the approximate value of the physical parameters, and obtain the wavefront restoration accuracy of the measured wavefront based on the original wavefront. When the wavefront restoration accuracy meets the target restoration accuracy requirement, the approximate value is determined as the final calibration value.

[0012] In a possible implementation, the spherical wave generating device further includes: a glass substrate;

[0013] The glass substrate is disposed on the focal plane of the converging lens, and the spherical wave generator is fixed on the glass substrate and coincides with the focal point of the converging lens;

[0014] The spherical wave generator is nanoparticles.

[0015] In a possible implementation, the system further includes: a displacement platform, the displacement platform includes a slider, a linear guide rail and a grating scale, and the displacement platform is configured to realize the alignment operation between the spherical wave and the wavefront sensor;

[0016] Wherein, the spherical wave generating device is fixed on the slider, and the wavefront sensor to be calibrated is fixed on the linear guide rail;

[0017] The grating scale is disposed on the side of the linear guide rail, and the grating reading head is fixed on the slider.

[0018] In another aspect, a method for calibrating the physical parameters of a wavefront sensor is provided. The method is executed by a data processor in a calibration system for the physical parameters of a wavefront sensor. The system includes: a spherical wave generating device, a wavefront sensor to be calibrated, and the data processor. The spherical wave generating device includes: a laser, a converging lens, and a spherical wave generator. Wherein, the laser is configured to output laser, and the output laser is focused on the spherical wave generator through the converging lens; the spherical wave generator is configured to generate a spherical wave when receiving the laser, and the spherical wave generator coincides with the focal point of the converging lens; the wavefront sensor to be calibrated is configured to detect the spherical wave and generate a spot array image corresponding to the spherical wave;

[0019] The method includes:

[0020] Obtaining the proportional relationship between the sub-lens size of the microlens array in the wavefront sensor and the pixel size of the detector in the wavefront sensor;

[0021] Based on the proportional relationship, obtaining the constraint relationship between the spot array image and the physical parameters of the wavefront sensor;

[0022] Performing step-by-step iterative solution on the constraint relationship to obtain an approximate value of the physical parameters; the physical parameters include: the focal length of the microlens array, the sub-lens size of the microlens array, the pixel size of the detector, and the number of pixels;

[0023] Based on the approximate value of the physical parameters, obtaining the measured wavefront of the wavefront sensor, and obtaining the wavefront reconstruction accuracy of the measured wavefront based on the original wavefront. When the wavefront reconstruction accuracy meets the target reconstruction accuracy requirement, the approximate value is determined as the final calibration value.

[0024] In a possible implementation manner, the obtaining the constraint relationship between the spot array image and the physical parameters of the wavefront sensor based on the proportional relationship includes:

[0025] Obtaining the initial constraint relationship between the spot array image and the physical parameters of the wavefront sensor through the following formula:

[0026]

[0027]

[0028] where Q represents the array pitch in the spot array image, R represents the radius of curvature of the spherical wave, P represents the sub-lens size of the microlens array, f represents the focal length of the microlens array, N represents the number of pixels of the detector, S represents the pixel size of the detector, N i represents the different spot pitches corresponding to the nanoparticles at different positions, i ∈ [1, k], L i represents the distance between the nanoparticles at different positions and the target reference point on the linear guide, L0 represents the distance between the detector and the target reference point, and P, f, N, and S are all the physical parameters;

[0029] Based on the initial constraint relationship and the proportional relationship, obtaining the target constraint relationship between the spot array image and the physical parameters of the wavefront sensor.

[0030] In a possible implementation manner, the target constraint relationship is represented by the following formula:

[0031]

[0032] Wherein, w represents the ratio between the size of the sub-lenses of the microlens array and the pixel size of the detector.

[0033] In a possible implementation, the step-by-step iterative solution of the constraint relationship to obtain an approximate value of the physical parameter includes:

[0034] Step-by-step representation of the target constraint relationship through the first sub-goal constraint relational expression and the second sub-goal constraint relational expression;

[0035] The first sub-goal constraint relational expression is represented by the following formula:

[0036]

[0037] The second sub-goal constraint relational expression is represented by the following formula:

[0038]

[0039] Iteratively solve the first sub-goal constraint relational expression and the second sub-goal constraint relational expression respectively to obtain an approximate value of the physical parameter.

[0040] On the other hand, a calibration device for the physical parameters of a wavefront sensor is provided. The device includes:

[0041] A ratio relationship acquisition module, configured to acquire the ratio relationship between the size of the sub-lenses of the microlens array and the pixel size of the detector;

[0042] A constraint relational expression acquisition module, configured to acquire the constraint relationship between the spot array image and the physical parameters of the wavefront sensor based on the ratio relationship;

[0043] An approximate value acquisition module, configured to perform step-by-step iterative solution on the constraint relationship to obtain an approximate value of the physical parameter; the physical parameters include: the focal length of the microlens array, the size of the sub-lenses of the microlens array, the pixel size of the detector, and the number of pixels;

[0044] A final calibration value acquisition module, configured to acquire the measured wavefront of the wavefront sensor based on the approximate value of the physical parameter, and acquire the wavefront restoration accuracy of the measured wavefront based on the original wavefront. When the wavefront restoration accuracy meets the target restoration accuracy requirement, the approximate value is determined as the final calibration value.

[0045] In a possible implementation, the constraint relational expression acquisition module includes:

[0046] An initial constraint relationship acquisition sub-module, configured to obtain an initial constraint relationship between the spot array image and the physical parameters of the wavefront sensor through the following formula:

[0047]

[0048]

[0049] Where Q represents the array pitch in the spot array image, R represents the radius of curvature of the spherical wave, P represents the sub-lens size of the microlens array, f represents the focal length of the microlens array, N represents the number of pixels of the detector, S represents the pixel size of the detector, N i represents the different spot pitches corresponding to the nanoparticles at different positions, i ∈ [1, k], L i represents the distance between the nanoparticles at different positions and the target reference point on the linear guide, L0 represents the distance between the detector and the target reference point, and P, f, N, and S are all the physical parameters;

[0050] A target constraint relationship acquisition sub-module, configured to obtain a target constraint relationship between the spot array image and the physical parameters of the wavefront sensor based on the initial constraint relationship and the proportional relationship.

[0051] In a possible implementation manner, the target constraint relationship acquisition sub-module is further configured to: represent the target constraint relationship through the following formula:

[0052]

[0053] Where w represents the ratio between the sub-lens size of the microlens array and the pixel size of the detector.

[0054] In a possible implementation manner, the approximation value acquisition module is further configured to:

[0055] Represent the target constraint relationship step by step through a first sub-target constraint relationship formula and a second sub-target constraint relationship formula;

[0056] Represent the first sub-target constraint relationship formula through the following formula:

[0057]

[0058] Represent the second sub-target constraint relationship formula through the following formula:

[0059]

[0060] Iteratively solve the first sub-target constraint relationship formula and the second sub-target constraint relationship formula respectively to obtain an approximate value of the physical parameter.

[0061] In another aspect, a computer device is provided, which includes a data processor and a memory. At least one instruction is stored in the memory, and the at least one instruction is loaded and executed by the data processor to implement a calibration method for physical parameters of a wavefront sensor as described above.

[0062] In still another aspect, a computer-readable storage medium is provided. At least one instruction is stored in the storage medium, and the at least one instruction is loaded and executed by a processor to implement a calibration method for physical parameters of a wavefront sensor as described above.

[0063] The technical solution provided by this application may include the following beneficial effects:

[0064] A high-precision spherical wave is generated as a reference wave by a spherical wave generating device. The wavefront sensor to be calibrated detects the spherical wave and generates a corresponding spot array image. The data processor obtains the proportional relationship between the two through the tight coupling relationship between the sub-lens size of the microlens array and the pixel size of the detector, which well overcomes the non-linear problem between various physical parameters. Then, based on this proportional relationship, the spot array image, and the constraint relationship between various physical parameters, the physical parameters of the wavefront sensor are iteratively solved, and the various physical parameters are converged to the target accuracy range, greatly improving the measurement accuracy of the calibrated wavefront sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0066] Figure 1 is a schematic structural diagram of a calibration system for physical parameters of a wavefront sensor shown according to an exemplary embodiment.

[0067] Figure 2 is a schematic structural diagram of a calibration system for physical parameters of a wavefront sensor shown according to an exemplary embodiment.

[0068] Figure 3 is a flowchart of a calibration method for physical parameters of a wavefront sensor shown according to an exemplary embodiment.

[0069] Figure 4 A block diagram of the structure of a calibration device for physical parameters of a wavefront sensor shown according to an exemplary embodiment.

[0070] Figure 5 The block diagram of the computer device shown in an exemplary embodiment of the present application is shown. Detailed implementation manners

[0071] The technical solution of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts shall fall within the protection scope of the present application.

[0072] It should be understood that in the description of the embodiments of the present application, the term "corresponding" may represent a direct or indirect corresponding relationship between two, may also represent an associated relationship between two, or may be an indication and being indicated, configuration and being configured, etc. relationships.

[0073] Figure 1 It is a schematic structural diagram of a calibration system for physical parameters of a wavefront sensor shown according to an exemplary embodiment. The system includes a spherical wave generating device 110, a wavefront sensor 120 to be calibrated, and a data processor 130.

[0074] Optionally, the spherical wave generating device 110 includes: a laser 111, a converging lens 112, and a spherical wave generator 113.

[0075] Optionally, the laser 111 is used to output laser, and the output laser is focused on the spherical wave generator 113 through the converging lens 112.

[0076] Optionally, the laser 111 is used to emit laser. The emitting end of the laser 111 is connected to a single-mode optical fiber through an optical fiber coupler. The central glass core of the single-mode optical fiber is very thin (the core diameter is generally 8μm - 10μm) and is used to transmit an optical fiber of one mode.

[0077] Optionally, the spherical wave generator 113 is used to generate a spherical wave when receiving the laser, and the spherical wave generator 113 coincides with the focal point of the converging lens 112.

[0078] Optionally, the spherical wave generator 113 can be a nanoparticle, and the nanoparticle will generate a spherical wave with ultra-high precision when receiving the laser.

[0079] Currently, when generating spherical waves, the following two methods are often used: The first is to couple a laser into a single-mode fiber to generate spherical waves; the second is to utilize pinhole diffraction to generate spherical waves. In the first method, since the core diameter of a standard single-mode fiber is 8μm - 10μm, this method is limited by the size of the fiber core diameter and cannot generate high-precision spherical waves, thus affecting the calibration accuracy of the physical parameters of the wavefront sensor to be calibrated. Compared with the first method, in the second method, the diameter of the pinhole is smaller than the core diameter of the single-mode fiber. According to the pinhole diffraction theory, the smaller the diameter of the pinhole, the smaller the wavefront error of the generated spherical wave. However, the processing difficulty of the pinhole increases as the diameter of the pinhole decreases, and the energy loss of the spherical wave will also be more serious, which may cause the wavefront sensor to be calibrated to be unresponsive and ultimately unable to complete high-precision calibration.

[0080] The size of the nanoparticle is much smaller than the core diameter of the optical fiber and the aperture diameter of the pinhole, which well solves the problems brought by factors such as the size of the optical fiber core diameter, the processing difficulty of the pinhole, and the energy loss, thereby improving the calibration accuracy of the physical parameters of the wavefront sensor.

[0081] Optionally, the wavefront sensor 120 to be calibrated is used to detect the spherical wave and generate a spot array image corresponding to the spherical wave.

[0082] Optionally, the wavefront sensor 120 to be calibrated can be a Hartmann-Shack wavefront sensor. The Hartmann-Shack wavefront sensor consists of a microlens array and a detector. Each microlens serves as a sub-aperture. When a light beam (i.e., the spherical wave) is incident on the Hartmann-Shack wavefront sensor, the microlens array divides the light beam into multiple sub-beams (i.e., sub-apertures) that are spatially independent of each other, and focuses them on the focal points of the sub-apertures respectively, and forms a spot array image at the corresponding positions on the detector. According to the offset of the centroid positions of the individual sub-spots on the spot array image relative to the centroid position of the aberration-free wavefront reference, the wavefront slope of each sub-beam is calculated, and then the wavefront is reconstructed and the aberration is obtained from the wavefront slopes of all sub-beams.

[0083] Optionally, the data processor 130 is used to obtain the proportional relationship between the sub-lens size of the microlens array in the wavefront sensor and the pixel size of the detector in the wavefront sensor, obtain the constraint relationship between the spot array image and the physical parameters of the wavefront sensor based on this proportional relationship, and perform step-by-step iterative solution on this constraint relationship to obtain an approximate value of the physical parameters; the physical parameters include: the focal length of the microlens array, the sub-lens size of the microlens array, the pixel size of the detector, and the number of pixels.

[0084] Optionally, the data processor 130 is further configured to obtain the measured wavefront of the wavefront sensor based on the approximation of the physical parameters, and obtain the wavefront restoration accuracy of the measured wavefront based on the original wavefront. When the wavefront restoration accuracy meets the target restoration accuracy requirement, the approximation is determined as the final calibration value.

[0085] As Figure 1 shown, a calibration system for physical parameters of a wavefront sensor can output laser light through the laser 111 in the spherical wave generating device 110. The output laser light is focused onto the spherical wave generator 113 through the converging lens 112. When the spherical wave generator 113 receives the laser light, it generates a spherical wave. The wavefront sensor 120 to be calibrated generates a spot array image corresponding to the spherical wave. The data processor 130 obtains the proportional relationship between the two through the tight coupling relationship between the sub-lens size of the microlens array and the pixel size of the detector, and then iteratively solves the physical parameters of the wavefront sensor based on the proportional relationship, the spot array image, and the constraint relationship between the physical parameters, converges each physical parameter to the target accuracy range, and finally obtains the actual values of each physical parameter, achieving high-precision calibration of each physical parameter.

[0086] In summary, a high-precision spherical wave is generated by the spherical wave generating device as a reference wave, the wavefront sensor to be calibrated detects the spherical wave and generates a corresponding spot array image. The data processor obtains the proportional relationship between the two through the tight coupling relationship between the sub-lens size of the microlens array and the pixel size of the detector, well overcomes the non-linear problem between the physical parameters, and then iteratively solves the physical parameters of the wavefront sensor based on the proportional relationship, the spot array image, and the constraint relationship between the physical parameters, converges each physical parameter to the target accuracy range, and greatly improves the measurement accuracy of the calibrated wavefront sensor.

[0087] Figure 2 is a schematic structural diagram of a calibration system for physical parameters of a wavefront sensor shown according to an exemplary embodiment. The system includes a spherical wave generating device 210, a wavefront sensor 220 to be calibrated, a data processor 230, and a displacement platform 240.

[0088] Optionally, the spherical wave generating device 210 includes: a laser 211, a converging lens 212, a spherical wave generator 213, and a glass substrate 214.

[0089] Optionally, the laser 211 is configured to output laser light, and the output laser light is focused onto the spherical wave generator 213 through the converging lens 212.

[0090] Optionally, the spherical wave generator 213 is configured to generate a spherical wave when receiving the laser, and the spherical wave generator 213 coincides with the focal point of the converging lens 212.

[0091] Optionally, the spherical wave generator 213 can be nanoparticles. When the nanoparticles receive the laser, they will generate a spherical wave with ultra-high precision. The size of the nanoparticles is much smaller than the core diameter of the optical fiber and the aperture of the pinhole, which can well solve the problems caused by factors such as the core diameter of the optical fiber, the processing difficulty of the pinhole, and energy loss, thereby improving the calibration accuracy of the physical parameters of the wavefront sensor.

[0092] Optionally, the glass substrate 214 is disposed on the focal plane of the converging lens 212, and the spherical wave generator 213 is fixed on the glass substrate 214 and coincides with the focal point of the converging lens 212.

[0093] Optionally, the nanoparticles (i.e., the spherical wave generator 213) are fixed on the glass substrate 214 to coincide with the focal point of the converging lens 212. The laser output by the laser 211 is focused on the nanoparticles (i.e., the spherical wave generator 213) through the converging lens 212. The nanoparticles (i.e., the spherical wave generator 213) have a relatively strong dipole response and can simultaneously suppress higher-order multipoles. Under the impact of the laser, dipole radiation can be generated, and then an ultra-high-precision spherical wave can be generated.

[0094] Optionally, the wavefront sensor 220 to be calibrated is configured to detect the spherical wave and generate a spot array image corresponding to the spherical wave.

[0095] Optionally, the wavefront sensor 220 to be calibrated can be a Hartmann-Shack wavefront sensor.

[0096] Optionally, the displacement platform 240 includes a slider 241, a linear guide 242, and a grating scale 243. The displacement platform 240 is configured to align the spherical wave with the wavefront sensor. Among them, the spherical wave generating device 210 is fixed on the slider 241, and the wavefront sensor 220 to be calibrated is fixed on the linear guide 242. The grating scale 243 is disposed on the side of the linear guide 242, and the grating reading head is fixed on the slider.

[0097] Optionally, the grating scale 243 is one of the gratings and is a measurement feedback device that works based on the optical principle of the grating. It is commonly used for the detection of linear displacement or angular displacement, and the signal output by its measurement is a digital pulse. The key part of the grating scale 243 is the grating reading head, which is composed of a light source, a converging lens, an indicating grating, a photoelectric element, and an adjustment mechanism, etc.

[0098] Optionally, the slider 241 drives the spherical wave generating device 210 to move. When the spherical wave generating device 210 is at any position, the displacement platform 240 realizes the alignment operation between the spherical wave and the wavefront sensor through the grating scale 243 and the grating reading head.

[0099] Optionally, the data processor 230 is configured to obtain the proportional relationship between the sub-lens size of the microlens array in the wavefront sensor and the pixel size of the detector in the wavefront sensor, obtain the constraint relationship between the spot array image and the physical parameters of the wavefront sensor based on the proportional relationship, and perform step-by-step iterative solution on the constraint relationship to obtain an approximate value of the physical parameters; the physical parameters include: the focal length of the microlens array, the sub-lens size of the microlens array, the pixel size of the detector, and the number of pixels.

[0100] Optionally, the data processor 230 is further configured to obtain the measured wavefront of the wavefront sensor based on the approximate value of the physical parameters, and obtain the wavefront restoration accuracy of the measured wavefront based on the original wavefront. When the wavefront restoration accuracy meets the target restoration accuracy requirement, the approximate value is determined as the final calibration value.

[0101] In summary, a high-precision spherical wave is generated by the spherical wave generating device as a reference wave, the wavefront sensor to be calibrated detects the spherical wave and generates a corresponding spot array image. The data processor obtains the proportional relationship between the two through the tight coupling relationship between the sub-lens size of the microlens array and the pixel size of the detector, which well overcomes the non-linear problem between the physical parameters. Then, based on the proportional relationship, the spot array image, and the constraint relationship between the physical parameters, iterative solution is performed on the physical parameters of the wavefront sensor to converge the physical parameters to the target accuracy range, greatly improving the measurement accuracy of the wavefront sensor after calibration.

[0102] Figure 3 is a flowchart of a method for calibrating physical parameters of a wavefront sensor shown according to an exemplary embodiment. This method is executed by a data processor in a calibration system for physical parameters of a wavefront sensor, and the data processor can be, for example, Figure 1 the data processor 130 shown in Figure 5 As shown, the method may include the following steps:

[0103] Step S301, obtain the proportional relationship between the sub-lens size of the microlens array in the wavefront sensor and the pixel size of the detector in the wavefront sensor.

[0104] In a possible implementation manner, the proportional relationship is obtained through the following formula:

[0105]

[0106] Wherein, w represents the ratio between the size of the sub-lens of the microlens array and the pixel size of the detector, w is a specific value, S represents the pixel size of the detector, and the above formula is obtained from the tight coupling relationship between the size P of the sub-lens of the microlens array and the pixel size S of the detector.

[0107] Step S302, obtain the constraint relationship between the spot array image and the physical parameters of the wavefront sensor based on this ratio relationship.

[0108] In a possible implementation manner, the initial constraint relationship between the spot array image and the physical parameters of the wavefront sensor is obtained through the following formula:

[0109]

[0110]

[0111] Wherein, Q represents the array pitch in the spot array image, R represents the radius of curvature of the spherical wave, P represents the size of the sub-lens of the microlens array, f represents the focal length of the microlens array, N represents the number of pixels of the detector, S represents the pixel size of the detector, N i represents the different spot pitches corresponding to the nanoparticles at different positions, i ∈ [1, k], L i represents the distance between the nanoparticles at different positions and the target reference point (this reference point can be obtained arbitrarily) on the linear guide, L0 represents the distance between the detector and the target reference point (this reference point can be obtained arbitrarily) on the linear guide. Therefore, L i -L0 is the distance between the nanoparticles at different positions and the detector (i.e., the length of the spherical wave generated by the nanoparticles), and P, f, N, and S are all the physical parameters;

[0112] Based on this initial constraint relationship and this ratio relationship, obtain the target constraint relationship between the spot array image and the physical parameters of the wavefront sensor.

[0113] Furthermore, formula (1) can be obtained from the constraint relationship between the spot array image obtained by the wavefront detector and the physical parameters. Formula (2) shows the initial constraint relationship between the different spot pitches measured when the nanoparticles are at different positions and the physical parameters. Therefore, the calibration process of the system can be transformed into a problem of solving the four physical parameters: the focal length f of the microlens array, the size P of the sub-lens of the microlens array, the pixel size S of the detector, and the distance L0 between the detector and the target reference point.

[0114] Furthermore, the problem of solving the above four physical parameters can be transformed into the following least squares problem:

[0115]

[0116] In theory, at least four equations are required to solve the above formula (3), that is, the spot pitch needs to be measured at least at four different positions of the nanoparticles. To reduce the influence of the system's non-linearity and measurement noise, we can select 20 different positions of the nanoparticles for image sampling.

[0117] In a possible implementation, the target constraint relationship is represented by the following formula:

[0118]

[0119] where w represents the ratio between the size of the sub-lenses of the microlens array and the pixel size of the detector.

[0120] Furthermore, since the spot pitch Ni corresponding to the nanoparticles at different positions is not linearly related to other parameters and cannot be directly fitted by least squares, the introduction of the ratio w solves this problem.

[0121] Step S303: Solve the constraint relationship by stepwise iteration to obtain an approximate value of the physical parameter; the physical parameter includes: the focal length of the microlens array, the size of the sub-lenses of the microlens array, the pixel size of the detector, and the number of pixels.

[0122] In a possible implementation, the target constraint relationship is represented step by step through a first sub-target constraint relationship formula and a second sub-target constraint relationship formula;

[0123] The first sub-target constraint relationship formula is represented by the following formula:

[0124]

[0125] The second sub-target constraint relationship formula is represented by the following formula:

[0126]

[0127] Iteratively solve the first sub-target constraint relationship formula and the second sub-target constraint relationship formula respectively to obtain an approximate value of the physical parameter.

[0128] Further, the ratio w can be fixed first (i.e., the initial value of the ratio w is obtained first). The initial value of the ratio w is the ratio between the factory design value of the sub-lens size of the microlens array and the factory design value of the pixel size of the detector. The focal length f of the microlens array and the distance L0 between the detector and the target reference point are solved by formula (5). Then, the focal length f of the microlens array and the distance L0 between the detector and the target reference point are fixed, and the ratio w is solved by formula (6). After iterating 3 times in this way, w, f, and L0 will converge to an acceptable accuracy range. Also, since the ratio w represents the ratio relationship between the sub-lens size P of the microlens array and the pixel size s of the detector, if an approximate value of the ratio w is obtained, the sub-lens size P of the microlens array and the pixel size s of the detector will also obtain approximate values accordingly.

[0129] Further, it is also possible to fix the focal length f of the microlens array or the distance L0 between the detector and the target reference point first (i.e., obtain the initial value of f or L0 first). The initial value of f is the factory design value of the focal length of the microlens array, and the initial value of L0 is the pre-measured distance between the detector and the target reference point. When the focal length f of the microlens array is fixed first, then w and L0 are solved first by formula (5) and formula (6), and then the approximate values of w, f, and L0 are iteratively obtained; when the distance L0 between the detector and the target reference point is fixed first, then w and f are solved first by formula (5) and formula (6), and then the approximate values of w, f, and L0 are iteratively obtained.

[0130] Step S304: Based on the approximate values of the physical parameters, obtain the measured wavefront of the wavefront sensor, and obtain the wavefront restoration accuracy of the measured wavefront based on the original wavefront. When the wavefront restoration accuracy meets the target restoration accuracy requirement, the approximate value is determined as the final calibration value.

[0131] In a possible implementation, the approximate values of each physical parameter (the focal length f of the microlens array, the distance L0 between the detector and the target reference point, and the ratio w) obtained in step S303 are substituted into the existing wavefront restoration program to obtain the measured wavefront of the wavefront sensor, and the original wavefront of the spherical wave (reference wave) is measured. The measured wavefront and the original wavefront are analyzed for wavefront restoration accuracy to obtain the wavefront restoration accuracy of the measured wavefront. When the wavefront restoration accuracy meets the target restoration accuracy requirement, the approximate value is determined as the final calibration value; when the wavefront restoration accuracy does not meet the target restoration accuracy requirement, the operations of S301 to S303 are repeated until the wavefront restoration accuracy meets the target restoration accuracy requirement, and the calibration process ends.

[0132] Further, if the nanoparticles are selected for image sampling at 20 different positions, there will be 20 corresponding approximate values for each physical parameter (the focal length f of the microlens array, the distance L0 between the detector and the target reference point, and the ratio w) obtained in step S303. Analyze the wavefront reconstruction accuracy of these 20 approximate values, and obtain the final calibration value that meets the requirements of the target reconstruction accuracy. The requirements for the target reconstruction accuracy are preset according to the actual application scenario and actual needs.

[0133] In summary, a high-precision spherical wave is generated by a spherical wave generating device as a reference wave. The wavefront sensor to be calibrated detects the spherical wave and generates a corresponding spot array image. The data processor obtains the proportional relationship between the two through the tight coupling relationship between the sub-lens size of the microlens array and the pixel size of the detector, which well overcomes the non-linear problem between the physical parameters. Then, based on this proportional relationship, the spot array image, and the constraint relationship between the physical parameters, the physical parameters of the wavefront sensor are iteratively solved, and the physical parameters are converged to the target accuracy range, greatly improving the measurement accuracy of the calibrated wavefront sensor.

[0134] Figure 4 is a schematic diagram of a calibration device for physical parameters of a wavefront sensor shown according to an exemplary embodiment. The device includes: The device includes:

[0135] A proportional relationship acquisition module 401, configured to acquire the proportional relationship between the sub-lens size of the microlens array and the pixel size of the detector;

[0136] A constraint relation acquisition module 402, configured to acquire the constraint relation between the spot array image and the physical parameters of the wavefront sensor based on the proportional relationship;

[0137] An approximate value acquisition module 403, configured to perform step-by-step iterative solution on the constraint relation to acquire the approximate value of the physical parameter; the physical parameter includes: the focal length of the microlens array, the sub-lens size of the microlens array, the pixel size of the detector, and the number of pixels;

[0138] A final calibration value acquisition module 404, configured to acquire the measured wavefront of the wavefront sensor based on the approximate value of the physical parameter, and acquire the wavefront reconstruction accuracy of the measured wavefront based on the original wavefront. When the wavefront reconstruction accuracy meets the requirements of the target reconstruction accuracy, the approximate value is determined as the final calibration value.

[0139] In a possible implementation manner, the constraint relation acquisition module 402 includes:

[0140] An initial constraint relationship acquisition sub-module, configured to obtain an initial constraint relationship between the spot array image and the physical parameters of the wavefront sensor through the following formula:

[0141]

[0142]

[0143] where Q represents the array pitch in the spot array image, R represents the curvature radius of the spherical wave, P represents the size of the sub-lenses of the microlens array, f represents the focal length of the microlens array, N i represents the different spot pitches corresponding to the nanoparticles at different positions, i ∈ [1, k], L i represents the distance between the nanoparticles at different positions and the target reference point on the linear guide, L0 represents the distance between the detector and the target reference point, and P, f, N, and S are all the physical parameters;

[0144] A target constraint relationship acquisition sub-module, configured to obtain a target constraint relationship between the spot array image and the physical parameters of the wavefront sensor based on the initial constraint relationship and the proportional relationship.

[0145] In a possible implementation, the target constraint relationship acquisition sub-module is further configured to: represent the target constraint relationship through the following formula:

[0146]

[0147] where w represents the ratio between the size of the sub-lenses of the microlens array and the pixel size of the detector.

[0148] In a possible implementation, the approximation value acquisition module 403 is further configured to:

[0149] stepwise represent the target constraint relationship through a first sub-target constraint relationship formula and a second sub-target constraint relationship formula;

[0150] represent the first sub-target constraint relationship formula through the following formula:

[0151]

[0152] represent the second sub-target constraint relationship formula through the following formula:

[0153]

[0154] iteratively solve the first sub-target constraint relationship formula and the second sub-target constraint relationship formula respectively to obtain an approximation value of the physical parameter.

[0155] In summary, a high-precision spherical wave is generated as a reference wave by a spherical wave generating device. The wavefront sensor to be calibrated detects the spherical wave and generates a corresponding spot array image. The data processor obtains the proportional relationship between the two through the tight coupling relationship between the sub-lens size of the microlens array and the pixel size of the detector, which well overcomes the non-linear problem between various physical parameters. Then, based on this proportional relationship, the spot array image, and the constraint relationship between various physical parameters, the physical parameters of the wavefront sensor are iteratively solved, and each physical parameter is converged to the target accuracy range, greatly improving the measurement accuracy of the calibrated wavefront sensor.

[0156] Please refer to Figure 5 , which is a schematic diagram of a computer device provided according to an exemplary embodiment of the present application. The computer device includes a memory and a processor. The memory is used to store a computer program. When the computer program is executed by the processor, the above-described method for calibrating the physical parameters of a wavefront sensor is implemented.

[0157] Among them, the processor can be a Central Processing Unit (CPU). The processor can also be other general-purpose processors, Digital Signal Processors (DSPs), Application Specific Integrated Circuits (ASICs), Field-Programmable Gate Arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. chips, or a combination of the above types of chips.

[0158] As a non-transitory computer-readable storage medium, the memory can be used to store non-transitory software programs, non-transitory computer-executable programs, and modules, such as the program instructions / modules corresponding to the method in the embodiment of the present invention. The processor executes various functional applications and data processing of the processor by running the non-transitory software programs, instructions, and modules stored in the memory, that is, the method in the above method embodiment is implemented.

[0159] The memory may include a program storage area and a data storage area. The program storage area may store an operating system and application programs required for at least one function. The data storage area may store data created by the processor and the like. In addition, the memory may include a high-speed random access memory and may also include a non-transitory memory, such as at least one magnetic disk storage device, a flash memory device, or other non-transitory solid-state storage devices. In some embodiments, the memory may optionally include a memory remotely disposed relative to the processor, and these remote memories may be connected to the processor through a network. Examples of the above network include but are not limited to the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0160] In an exemplary embodiment, a computer-readable storage medium is also provided, which stores at least one computer program, and the at least one computer program is loaded and executed by a processor to implement all or part of the steps in the above method. For example, the computer-readable storage medium may be a read-only memory (ROM), a random access memory (RAM), a compact disc read-only memory (CD-ROM), magnetic tape, a floppy disk, and an optical data storage device, etc.

[0161] Those skilled in the art will readily conceive of other embodiments of the present application after considering the specification and practicing the invention disclosed herein. The present application is intended to cover any variations, uses, or adaptations of the present application, which follow the general principles of the present application and include common general knowledge or conventional technical means in the technical field not disclosed in the present application. The specification and embodiments are only regarded as exemplary, and the true scope and spirit of the present application are pointed out by the following claims.

[0162] It should be understood that the present application is not limited to the exact structures described above and shown in the drawings, and various modifications and changes can be made without departing from its scope. The scope of the present application is only limited by the appended claims.

Claims

1. A calibration system for physical parameters of a wavefront sensor, characterized in that, The system includes: a spherical wave generating device, a wavefront sensor to be calibrated, and a data processor. The spherical wave generating device includes: a laser, a converging lens, and a spherical wave generator; The laser is configured to output laser light, and the output laser light is focused onto the spherical wave generator through the converging lens; The spherical wave generator is configured to generate a spherical wave when receiving the laser light, and the spherical wave generator coincides with the focal point of the converging lens; The wavefront sensor to be calibrated is configured to detect the spherical wave and generate a spot array image corresponding to the spherical wave; The data processor is configured to obtain the proportional relationship between the sub-lens size of the microlens array in the wavefront sensor and the pixel size of the detector in the wavefront sensor, obtain the constraint relationship between the spot array image and the physical parameters of the wavefront sensor based on the proportional relationship, and perform step-by-step iterative solution on the constraint relationship to obtain an approximate value of the physical parameters; the physical parameters include: the focal length of the microlens array, the sub-lens size of the microlens array, the pixel size and the number of pixels of the detector; The data processor is further configured to obtain the measured wavefront of the wavefront sensor based on the approximate value of the physical parameters, and obtain the wavefront reconstruction accuracy of the measured wavefront based on the original wavefront. When the wavefront reconstruction accuracy meets the target reconstruction accuracy requirement, the approximate value is determined as the final calibration value.

2. The system according to claim 1, characterized in that, The spherical wave generating device further includes: a glass substrate; The glass substrate is disposed on the focal plane of the converging lens, and the spherical wave generator is fixed on the glass substrate and coincides with the focal point of the converging lens; The spherical wave generator is nanoparticles.

3. The system according to claim 1 or 2, characterized in that, The system further includes: a displacement platform, which includes a slider, a linear guide rail, and a grating scale. The displacement platform is configured to perform the alignment operation between the spherical wave and the wavefront sensor; Wherein, the spherical wave generating device is fixed on the slider, and the wavefront sensor to be calibrated is fixed on the linear guide rail; The grating scale is disposed on the side of the linear guide rail, and the grating reading head is fixed on the slider.

4. A calibration method for physical parameters of a wavefront sensor, characterized in that The method is executed by the data processor in the calibration system of the wavefront sensor physical parameters. The system includes: a spherical wave generating device, a wavefront sensor to be calibrated, and the data processor. The spherical wave generating device includes: a laser, a converging lens, and a spherical wave generator; wherein, the laser is configured to output laser light, and the output laser light is focused onto the spherical wave generator through the converging lens; the spherical wave generator is configured to generate a spherical wave when receiving the laser light, and the spherical wave generator coincides with the focal point of the converging lens; the wavefront sensor to be calibrated is configured to detect the spherical wave and generate a spot array image corresponding to the spherical wave; The method includes: Obtaining the proportional relationship between the sub-lens size of the microlens array in the wavefront sensor and the pixel size of the detector in the wavefront sensor; Obtaining the constraint relationship between the spot array image and the physical parameters of the wavefront sensor based on the proportional relationship; Perform step - by - step iterative solution of the constraint relationship to obtain an approximate value of the physical parameters; the physical parameters include: the focal length of the microlens array, the size of the sub - lenses of the microlens array, the pixel size and the number of pixels of the detector; Based on the approximate value of the physical parameters, it is also used to obtain the measured wavefront of the wavefront sensor based on the approximate value of the physical parameters, and obtain the wavefront reconstruction accuracy of the measured wavefront based on the original wavefront. When the wavefront reconstruction accuracy meets the target reconstruction accuracy requirement, the approximate value is determined as the final calibration value.

5. The method according to claim 4, characterized in that, The obtaining of the constraint relationship between the spot array image and the physical parameters of the wavefront sensor based on the proportional relationship includes: Obtain the initial constraint relationship between the spot array image and the physical parameters of the wavefront sensor through the following formula: Wherein, Q represents the array pitch in the spot array image, R represents the radius of curvature of the spherical wave, P represents the size of the sub-lenses of the microlens array, f represents the focal length of the microlens array, N represents the number of pixels of the detector, S represents the pixel size of the detector, N i represents the different spot pitches corresponding to the nanoparticles at different positions, i ∈ [1, k], L i represents the distance between the nanoparticles at different positions and the target reference point on the linear guide, L0 represents the distance between the detector and the target reference point, and P, f, N, and S are all physical parameters; Based on the initial constraint relationship and the proportional relationship, obtain the target constraint relationship between the spot array image and the physical parameters of the wavefront sensor.

6. The method according to claim 5, wherein Represent the target constraint relationship through the following formula: where w represents the ratio between the size of the sub - lenses of the microlens array and the pixel size of the detector.

7. The method according to any one of claims 4 to 6, characterized in that The performing step - by - step iterative solution of the constraint relationship to obtain an approximate value of the physical parameters includes: Represent the target constraint relationship step - by - step through the first sub - target constraint relation formula and the second sub - target constraint relation formula; Represent the first sub - target constraint relation formula through the following formula: Represent the second sub - target constraint relation formula through the following formula: Perform iterative solution on the first sub - target constraint relation formula and the second sub - target constraint relation formula respectively to obtain an approximate value of the physical parameters.

8. A calibration device for physical parameters of a wavefront sensor, characterized in that The device includes: A proportional - relationship acquisition module, configured to acquire the proportional relationship between the size of the sub - lenses of the microlens array and the pixel size of the detector; A constraint - relation formula acquisition module, configured to acquire the constraint relationship between the spot array image and the physical parameters of the wavefront sensor based on the proportional relationship; An approximate - value acquisition module, configured to perform step - by - step iterative solution of the constraint relationship to obtain an approximate value of the physical parameters; the physical parameters include: the focal length of the microlens array, the size of the sub - lenses of the microlens array, the pixel size and the number of pixels of the detector; A final - calibration - value acquisition module, configured to obtain the measured wavefront of the wavefront sensor based on the approximate value of the physical parameters, and obtain the wavefront reconstruction accuracy of the measured wavefront based on the original wavefront. When the wavefront reconstruction accuracy meets the target reconstruction accuracy requirement, the approximate value is determined as the final calibration value.

9. A computer device, characterized in that, The computer device includes a data processor and a memory. At least one instruction is stored in the memory, and the at least one instruction is loaded and executed by the data processor to implement a calibration method for the physical parameters of a wavefront sensor as described in any one of claims 4 to 7.

10. A computer-readable storage medium, characterized in that, At least one instruction is stored in the storage medium, and the at least one instruction is loaded and executed by the processor to implement a calibration method for the physical parameters of a wavefront sensor as described in any one of claims 4 to 7.

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