Common phase error detection method, device and medium

Abstract

The present invention relates to the field of optical measurement technology, and specifically discloses a common-phase error detection method, device, and medium. The method comprises the following steps: S1: combining two sub-aperture pupil surfaces to be detected using a Mach-Zehnder interference configuration; S2: selecting one of the combined beam outputs of the Mach-Zehnder interference configuration and capturing the combined beam output light intensity in real time using a detection camera; S3: performing digital image processing on the combined beam output light intensity to obtain an image processing result; S4: locating the coordinates of the amplitude maximum in the frequency domain information based on the image processing result, and inversely solving the tilt error between the two sub-aperture pupil surfaces; S5: obtaining the phase value at the coordinates of the amplitude maximum in the frequency domain information based on the coordinates, and inversely solving the piston error between the two sub-aperture pupil surfaces. The method of the present invention is an optical detection method based on pupil interferometry, does not require an iterative algorithm, has a high detection frequency, and is suitable for common-phase application scenarios requiring real-time performance, such as combating atmospheric turbulence.

Description

Technical Field

[0001] The present invention relates to the field of optical measurement technology, and in particular to a common phase error detection method, device and medium. Background Art

[0002] Optical synthetic apertures are the mainstream development direction for high-resolution imaging in the future of astronomy. However, due to phase mismatches between subapertures caused by factors such as atmospheric turbulence and mechanical instability, the actual improvement in imaging resolution is far lower than the theoretical value, defeating the purpose of optical synthetic apertures. Currently, mainstream large-scale ground-based telescope arrays and spliced ​​sub-mirror space telescopes such as the James Webb telescope rely primarily on methods such as dispersion fringe sensing to achieve common phase correction for low-order, slowly varying errors such as tilt error and piston error, but are unable to achieve precise common phase below half a wavelength.

[0003] In summary, there is an urgent need for a high-precision and fast common-phase error detection method, device and medium to solve the problems in the existing technology. Summary of the Invention

[0004] The present invention aims to provide a common phase error detection method, device and medium. The specific technical solutions are as follows:

[0005] A common phase error detection method comprises the following steps:

[0006] S1: Use Mach-Zehnder interferometer configuration to combine the two sub-aperture pupils to be detected;

[0007] S2: Select one of the combined beam outputs of the Mach-Zehnder interferometer configuration in S1 and use a detection camera to capture the combined beam output intensity of the pupil interferometer in real time;

[0008] S3: Use discrete two-dimensional Fourier transform to perform digital image processing on the combined beam output intensity of S2 to obtain the frequency domain signal;

[0009] S4: Based on the frequency domain signal of S3, locate the coordinates of the maximum amplitude in the frequency domain information, and inversely solve the tilt error between the two sub-aperture pupil surfaces in S1;

[0010] S5: Based on the coordinates of the maximum amplitude in the frequency domain information of S4, the phase value at that coordinate in the frequency domain is obtained, and the piston error between the two sub-aperture pupil surfaces in S1 is inversely solved.

[0011] Preferably, in S1, the pupil planes of the first sub-aperture and the second sub-aperture to be detected are combined using the Mach-Zehnder interference configuration, and physical modeling is performed, specifically:

[0012] The pupil function P1(x,y) of the first sub-aperture is expressed as follows:

[0013]

[0014] Where, circ() is the circular domain function, D1 is the pupil diameter of the first sub-aperture, and x and y are the pupil coordinate systems;

[0015] Taking the pupil plane of the first sub-aperture as the reference plane, the expression of the pupil function P2(x,y) of the second sub-aperture is as follows:

[0016]

[0017] Where D2 is the pupil diameter of the second subaperture, λ is the wavelength of the electromagnetic wave; δ is the piston error; α and β are the tilt errors;

[0018] The combined output light intensity of the Mach-Zehnder interference configuration is the modulus square of the sum of the two sub-aperture light fields, which can be expressed as follows:

[0019] I(x,y)=|P1(x,y)+P2(x,y)| 2 3)

[0020] Where I(x,y) is the combined output light intensity.

[0021] Preferably, in S2, the expanded expressions of P1(x, y) and P2(x, y) are substituted into equation 3) to obtain the combined beam output intensity captured in real time by the detection camera, which is specifically expressed as follows:

[0022]

[0023] Where D is the pupil diameter after beam combining.

[0024] Preferably, in S3, discrete two-dimensional Fourier transform is used to perform digital image processing on the combined beam output light intensity I(x, y), and the frequency domain signal related to the common phase error is calculated as:

[0025]

[0026] Where G(f) represents the frequency domain signal, f is the spatial frequency vector coordinate; f0 represents the parameter related to the tilt error between the two sub-apertures, is the phase corresponding to the piston error, and the specific expression is shown in Equation 6):

[0027]

[0028] The frequency domain resolution of the frequency domain signal is at the pixel level.

[0029] Preferably, in S3, the frequency domain resolution of the frequency domain signal is further improved by:

[0030] The actual geometric size of each pixel unit of the detection camera is N μ ×N μ , and the region of interest is set to N d ×N d pixel matrix; the matrix to be demodulated for digital image processing N d ×N d Widen to N by padding around with zeros L ×N L ;

[0031] According to formula 6), the maximum frequency domain amplitude f corresponding to the inclination angle α along the x-axis is x0 Number of pixels occupied N x for:

[0032] N x =(α / λ) / (1 / (N μ ·N L )) 7)

[0033] The maximum frequency domain amplitude f corresponding to the inclination angle β along the y-axis y0 Number of pixels occupied N y for:

[0034] N y =(α / λ) / (1 / (N μ ·N L )) 8)

[0035] Among them, 1 / (N μ ·N L ) represents the frequency domain resolution.

[0036] Preferably, in S4, the coordinates of the maximum amplitude in the frequency domain information are located, and the tilt error between the pupil planes of the two sub-apertures in S1 is inversely solved as follows:

[0037] According to formula 5), ​​the coordinate positions of the maximum amplitude are symmetrical about the zero-frequency origin. The information used to inversely solve the error is exactly the same. After the discrete two-dimensional Fourier transform, the maximum coordinate N with a positive horizontal coordinate is found. x :Due to the actual geometric size N of the detection camera pixel unit μ It is known that the size N of the matrix to be demodulated in S3 is L Known, the maximum value is located to get N x Then, according to formula 7) we can get α;

[0038] Similarly, the maximum value is located to obtain N y Then, β can be obtained according to formula 8).

[0039] Preferably, in S5, the phase value at the coordinate in the frequency domain is obtained according to the positioning coordinate of the maximum amplitude in the frequency domain information of S4, and the piston error between the two sub-aperture pupil surfaces in S1 is inversely solved, and the expression is as follows:

[0040]

[0041] Where Arg represents the argument of the complex number to be solved, and M is the complex matrix after discrete two-dimensional Fourier transform;

[0042] Combining with formula (6), the piston error δ can be obtained.

[0043] Additionally, the present invention also includes a computer device comprising a memory and a processor;

[0044] The memory is used to store a computer program that can be executed on the processor;

[0045] The processor is configured to implement the steps of the common phase error detection method described above when executing the computer program.

[0046] In addition, the present invention also includes a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the steps of the common-phase error detection method as described above are implemented.

[0047] The application of the technical solution of the present invention has the following beneficial effects:

[0048] The present invention proposes a common-phase error detection method, device, and medium. This method, based on an optical detection method called pupil-plane interferometry, does not require an iterative algorithm and offers a high detection frequency, making it ideal for common-phase applications with high real-time requirements, such as combating atmospheric turbulence. The present invention demodulates tilt error and piston error using a two-dimensional discrete Fourier transform, exhibiting strong noise immunity and adaptability to common-phase applications with low signal-to-noise ratios. The present invention's common-phase solution can simultaneously detect tilt error and piston error with high precision.

[0049] In addition to the above-described objects, features and advantages, the present invention has other objects, features and advantages. The present invention will be further described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] In order to more clearly illustrate the embodiments of the present invention or the technical solutions of the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0051] Figure 1 is a flowchart of the steps of the common phase error detection method in a preferred embodiment of the present invention;

[0052] Figure 2 Schematic diagram of an optical system of a common phase error detection method in a preferred embodiment of the present invention;

[0053] Figure 3 is the intensity distribution captured by the detection camera in the simulation case;

[0054] Figure 4 It is the pre-processed matrix to be demodulated for two-dimensional discrete Fourier transform in the simulation case;

[0055] Figure 5 is the frequency domain amplitude after 2D discrete Fourier transform in the simulation case;

[0056] Figure 6 is the phase corresponding to the piston error after 2D discrete Fourier transform in the simulation case. DETAILED DESCRIPTION

[0057] In order to enable those skilled in the art to better understand the present invention, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0058] like Figure 1 As shown, this embodiment discloses a common phase error detection method, specifically a common phase error precision detection method based on pupil plane interference. The optical path part of the common phase error detection method implemented in this embodiment is as follows: Figure 2 As shown, the method of this embodiment includes the following steps:

[0059] S1: Use Mach-Zehnder interferometer configuration to combine the two sub-aperture pupils to be detected;

[0060] S2: Select one of the combined beam outputs of the Mach-Zehnder interferometer configuration in S1 and use a detection camera to capture the combined beam output light intensity in real time;

[0061] S3: Use discrete two-dimensional Fourier transform to perform digital image processing on the combined beam output intensity of S2 to obtain the frequency domain signal;

[0062] S4: Based on the frequency domain signal of S3, locate the coordinates of the maximum amplitude in the frequency domain information, and inversely solve the tilt error between the two sub-aperture pupil surfaces in S1;

[0063] S5: Based on the coordinates of the maximum amplitude in the frequency domain information of S4, the phase value at that coordinate in the frequency domain is obtained, and the piston error between the two sub-aperture pupil surfaces in S1 is inversely solved.

[0064] Preferably, in S1, the pupil planes of the first sub-aperture and the second sub-aperture to be detected are combined using the Mach-Zehnder interference configuration, and physical modeling is performed, specifically:

[0065] The pupil function P1(x,y) of the first sub-aperture is expressed as follows:

[0066]

[0067] Where, circ() is the circular domain function, D1 is the pupil diameter of the first sub-aperture, and x and y are the pupil coordinate systems;

[0068] Taking the pupil plane of the first sub-aperture as the reference plane, the expression of the pupil function P2(x,y) of the second sub-aperture is as follows:

[0069]

[0070] Where D2 is the pupil diameter of the second subaperture, λ is the wavelength of the electromagnetic wave; δ is the piston error; α and β are the tilt errors;

[0071] Considering that the amplitude intensities of the sub-apertures are equal, the combined output light intensity of the Mach-Zehnder interference configuration can be expressed as the modulus square of the sum of the two sub-aperture light fields, specifically:

[0072] I(x,y)=|P1(x,y)+P2(x,y)| 2 3)

[0073] Where I(x,y) is the combined output light intensity.

[0074] Preferably, in S2, assuming that the pupil diameters of the first sub-aperture and the second sub-aperture are the same, one of the combined beam outputs of the Mach-Zehnder interference configuration is selected, and the combined beam output intensity is captured in real time by a detection camera. Substituting the expanded expressions of P1(x, y) and P2(x, y) into equation 3), the combined beam output intensity captured in real time by the detection camera can be obtained, and its specific expression is:

[0075]

[0076] Where D represents the pupil diameter. It can be seen that tilt errors in the x- and y-axis directions will cause fringes within the circular function. The number of fringes is related to the tilt errors α and β, while the piston error δ manifests as a lateral shift of the fringes within the circular function. Due to the periodicity of the Fourier transform phase, the fine common phase detection in this embodiment limits the detection range of the piston error to ±λ / 2. Errors outside the dynamic range of this embodiment can be detected using the dispersion fringe method.

[0077] Preferably, in S3, discrete two-dimensional Fourier transform is used to perform digital image processing on the combined beam output light intensity I(x, y), and the frequency domain signal related to the common phase error is calculated as:

[0078]

[0079] Where G(f) represents the frequency domain signal, f is the spatial frequency vector coordinate; f0 represents the parameter related to the tilt error between the two sub-apertures, is the phase corresponding to the piston error, and the specific expression is shown in Equation 6):

[0080]

[0081] It should be noted that the digital image processing in this embodiment adopts discrete two-dimensional Fourier transform, so the frequency domain resolution is at the pixel level.

[0082] Preferably, in S3, this embodiment provides a method for improving frequency domain resolution, specifically:

[0083] The actual geometric size of each pixel unit of the detection camera is N μ ×N μ , and the region of interest is set to N d ×N d pixel matrix, the corresponding superimposed pupil diameter is N d pixels; the matrix N to be demodulated for digital image processing d ×N d Widen to N by padding around with zeros L ×N L ;

[0084] According to formula 6), the maximum frequency domain amplitude f corresponding to the inclination angle α along the x-axis is x0 Number of pixels occupied N x for:

[0085] N x =(α / λ) / (1 / (N μ ·N L )) 7)

[0086] The maximum frequency domain amplitude f corresponding to the inclination angle β along the y-axisy0 Number of pixels occupied N y for:

[0087] N y =(α / λ) / (1 / (N μ ·N L )) 8)

[0088] Among them, 1 / (N μ ·N L ) represents the frequency domain resolution.

[0089] Preferably, in S4, the coordinates of the maximum amplitude in the frequency domain information (the frequency domain signal related to the common phase error) are located, and the tilt error between the pupil planes of the two sub-apertures in S1 is inversely solved as follows:

[0090] According to formula 5), ​​the coordinate positions of the maximum amplitude are symmetrical about the zero-frequency origin, and the information used to inversely solve the error is exactly the same; only the coordinate value f with a positive horizontal coordinate is considered. L , then the locked coordinates after discrete two-dimensional Fourier transform are:

[0091] f L =f0=(f x0 ,f y0 )=(N x ,N y ) 9)

[0092] Since the actual geometric size N of the detection camera pixel unit μ It is known that the size N of the matrix to be demodulated in S3 is L Known, the maximum value is located to get N x Then, according to formula 7) we can get α;

[0093] Similarly, the maximum value is located to obtain N y Then, β can be obtained according to formula 8).

[0094] Preferably, in S5, the phase value at the coordinate in the frequency domain is obtained according to the positioning coordinate of the maximum amplitude in the frequency domain information of S4, and the piston error between the two sub-aperture pupil surfaces in S1 is inversely solved, and the expression is as follows:

[0095]

[0096] Where Arg represents the argument of the complex number to be solved, and M is the complex matrix after discrete two-dimensional Fourier transform;

[0097] Combining with formula (6), the piston error δ can be obtained.

[0098] The simulation case of this embodiment is as follows:

[0099] The first step is to combine the two sub-apertures in pupil plane by Mach-Zehnder interference configuration;

[0100] The intensity information actually obtained by the detection camera is a matrix caused by pixels. Specifically, the discrete form of the pupil function of the first sub-aperture is:

[0101]

[0102] Where m and n are integers, Δx=Δy=N μ , D1=NN μ is the pupil diameter of sub-aperture 1, N μ is the actual pixel size. In this embodiment, N=360, N μ =5μm. Taking the pupil plane of the first sub-aperture as the reference plane, the discrete form of the generalized pupil function of the second sub-aperture is:

[0103]

[0104] Where D1 = NN μ represents the pupil diameter of the second sub-aperture. In this embodiment, λ=1000 nm, δ=300 nm, α=2.22 mrad, and β=1.11 mrad.

[0105] Considering that the amplitude intensities of the sub-apertures are equal, the combined beam output intensity of the superimposed pupil surface is:

[0106] I(mΔx,nΔy)=|P1(mΔx,nΔy)+P2(mΔx,nΔy)| 2 ;

[0107] In the second step, the detection camera obtains the combined output light intensity distribution in real time. Its interference intensity matrix is:

[0108]

[0109] Where M and N are integers. Since the closed-loop speed needs to be considered in the end, under the premise of ensuring that the demodulation information is not excessively lost, I(M,N) is downsampled by 10 times to reduce the amount of calculation, that is, the size matrix becomes 36×36. In addition, in accordance with the actual situation, strong Gaussian white noise with a standard deviation of 0.3 is added to the normalized I(M,N). The detection camera intensity results of this embodiment are as follows Figure 3 shown.

[0110] The third step is to perform digital image processing on I(M,N) using a two-dimensional discrete Fourier transform. Before the transformation, matrix preprocessing is performed on I(M,N), which includes two steps: 1) padding the matrix with zeros to a size of 800×800 to increase the resolution of the frequency domain; 2) removing zero-frequency signals that do not contain demodulation information. In this embodiment, all elements of the normalized matrix I(M,N) can be subtracted by 0.5. The matrix used for error demodulation after preprocessing in this embodiment is as follows: Figure 4 As shown, the frequency domain amplitude after two-dimensional discrete Fourier transform is as follows Figure 5 As shown, the phase corresponding to the piston error is as follows Figure 6 shown.

[0111] The fourth step is to locate the maximum amplitude in the frequency domain and then demodulate the tilt error using the algorithm. Specifically:

[0112] Figure 5 The given frequency domain amplitude maximum position is two symmetrical positions about the zero-frequency origin. The information used to inversely solve the error is exactly the same. Only the coordinate value N with a positive horizontal coordinate is considered. x ,Right now Figure 4 For the circular spot on the right side, the row and column of the matrix of the locked frequency domain amplitude maximum value are (355, 489).

[0113] Then, the number of pixels N occupied by the maximum frequency domain amplitude corresponding to the inclination angle α along the x-axis is x It is 89.

[0114] According to the following relationship:

[0115] N x =(α / λ) / (1 / (N μ ·N L ));

[0116] Among them, λ, N μ and N L It is known that, and taking into account the operation of downsampling the detection intensity by a factor of 10 in the second step, it is calculated that α=2.225 mrad.

[0117] Similarly, according to the following relationship:

[0118] N y =(α / λ) / (1 / (N μ ·N L ));

[0119] The maximum value is located and the number of pixels N along the y-axis is obtained at the same time y is 45.

[0120] According to the following relationship and taking into account the 10-fold downsampling operation in the second step:

[0121] Ny =(β / λ) / (1 / (N μ ·N L ));

[0122] Calculation yields β = 1.125 mrad.

[0123] The fifth step is to obtain the phase value at the coordinate in the frequency domain based on the image processing results of the third step and the coordinate of the maximum amplitude in the frequency domain information of the fourth step, and inversely solve the piston error between the two sub-aperture pupil surfaces in the first step.

[0124]

[0125] Where M is the complex matrix after discrete two-dimensional Fourier transform.

[0126] According to the following relationship:

[0127]

[0128] The piston error δ is obtained to be 305.2 nm.

[0129] By applying the method of this embodiment, the tilt error and the piston error can be demodulated simultaneously with high precision under the conditions of strong detection noise, low signal-to-noise ratio, and on the basis of meeting high-frequency detection.

[0130] In addition, this embodiment also discloses a computer device, including a memory and a processor;

[0131] The memory is used to store a computer program that can be executed on the processor;

[0132] The processor is configured to implement the steps of the above-mentioned common-phase error detection method when executing the computer program.

[0133] Exemplarily, the computer program may be divided into one or more modules / units, which are stored in the memory and executed by the processor to implement the present invention. The one or more modules / units may be a series of computer program instruction segments capable of implementing specific functions, and the instruction segments are used to describe the execution process of the computer program in the computer device.

[0134] The computer device may be a mobile phone, desktop computer, laptop, PDA, cloud server, or other computing device. The computer device may include, but is not limited to, a processor and memory. For example, the computer device may also include input and output devices, network access devices, buses, etc.

[0135] The processor may be a central processing unit (CPU), other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor, etc. The processor is the control center of the computer device and connects various parts of the entire computer device using various interfaces and lines.

[0136] The memory can be used to store the computer program and / or module, and the processor implements the computer program by running or executing the computer program and / or module stored in the memory, and calling the data stored in the memory. The memory can mainly include a program storage area and a data storage area, wherein the program storage area can store an operating system, at least one application required for a function (such as a sound playback function, an image playback function, etc.); the data storage area can store data created based on the use of the mobile phone (such as audio data, a phone book, etc.). In addition, the memory can include a high-speed random access memory, and can also include a non-volatile memory, such as a hard disk, a memory, a plug-in hard disk, a smart memory card (Smart Media Card, SMC), a secure digital (Secure Digital, SD) card, a flash card (Flash Card), at least one disk storage device, a flash memory device, or other volatile solid-state storage device.

[0137] Wherein, if the module / unit integrated in the computer device is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the present invention implements all or part of the process in the above-mentioned embodiment method, and can also be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium, and when the computer program is executed by the processor, it can implement the steps of the above-mentioned various method embodiments. Wherein, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. The computer-readable medium may include: any entity or device that can carry the computer program code, recording medium, U disk, mobile hard disk, magnetic disk, optical disk, computer memory, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), electrical carrier signal, telecommunication signal and software distribution medium, etc.

[0138] In addition, an embodiment of the present invention further provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the steps of the common-phase error detection method described above are implemented.

[0139] Compared to the prior art, the present invention proposes a common-phase error detection method, device, and medium. The method is based on an optical detection method based on pupil-plane interferometry. It does not require an iterative algorithm and has a high detection frequency, making it very suitable for common-phase application scenarios with high real-time requirements, such as combating atmospheric turbulence. The present invention demodulates the tilt error and piston error through a two-dimensional discrete Fourier transform, has strong noise interference resistance, and can be applied to common-phase application scenarios with low signal-to-noise ratios. The common-phase scheme of the present invention can simultaneously detect tilt error and piston error with high precision.

[0140] It should be noted that the device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of the modules may be selected based on actual needs to achieve the objectives of this embodiment.

[0141] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A common phase error detection method, characterized in that: The steps include: S1: Use Mach-Zehnder interferometer configuration to combine the two sub-aperture pupils to be detected; S2: Select one of the combined beam outputs of the Mach-Zehnder interferometer configuration in S1 and use a detection camera to capture the combined beam output intensity of the pupil interferometer in real time; S3: Use discrete two-dimensional Fourier transform to perform digital image processing on the combined beam output intensity of S2 to obtain the frequency domain signal; S4: Based on the frequency domain signal of S3, locate the coordinates of the maximum amplitude in the frequency domain information, and inversely solve the tilt error between the two sub-aperture pupil surfaces in S1; S5: Based on the coordinates of the maximum amplitude in the frequency domain information of S4, the phase value at that coordinate in the frequency domain is obtained, and the piston error between the two sub-aperture pupil surfaces in S1 is inversely solved.

2. The common phase error detection method according to claim 1, wherein: In S1, the pupil planes of the first and second sub-apertures to be detected are combined using the Mach-Zehnder interference configuration, and physical modeling is performed. Specifically, The pupil function P1(x,y) of the first sub-aperture is expressed as follows: Where, circ() is the circular domain function, D1 is the pupil diameter of the first sub-aperture, and x and y are the pupil coordinate systems; Taking the pupil plane of the first sub-aperture as the reference plane, the expression of the pupil function P2(x,y) of the second sub-aperture is as follows: Where D2 is the pupil diameter of the second subaperture, λ is the wavelength of the electromagnetic wave; δ is the piston error; α and β are the tilt errors; The combined output light intensity of the Mach-Zehnder interference configuration is the modulus square of the sum of the two sub-aperture light fields, which can be expressed as follows: I(x,y)=|P1(x,y)+P2(x,y)| 2 3) Where I(x,y) is the combined output light intensity.

3. The common phase error detection method according to claim 2, characterized in that: In S2, the expanded expressions of P1(x, y) and P2(x, y) are substituted into equation 3) to obtain the combined beam output intensity captured in real time by the detection camera. The specific expression is: Where D is the pupil diameter after beam combining.

4. The common phase error detection method according to claim 3, characterized in that: In S3, discrete two-dimensional Fourier transform is used to perform digital image processing on the combined beam output intensity I(x,y), and the frequency domain signal related to the common phase error is calculated as: Where G(f) represents the frequency domain signal, f is the spatial frequency vector coordinate; f0 represents the parameter related to the tilt error between the two sub-apertures, is the phase corresponding to the piston error, and the specific expression is shown in Equation 6): The frequency domain resolution of the frequency domain signal is at the pixel level.

5. The common phase error detection method according to claim 4, characterized in that: In S3, the frequency domain resolution of the frequency domain signal is also improved by the following methods: The actual geometric size of each pixel unit of the detection camera is N μ ×N μ , and the region of interest is set to N d ×N d A pixel matrix; The matrix N to be demodulated for digital image processing d ×N d Widen to N by padding around with zeros L ×N L ; According to formula 6), the maximum frequency domain amplitude f corresponding to the inclination angle α along the x-axis is x0 Number of pixels occupied N x for: N x =(a / λ) / (1 / (N μ ·N L )) 7) The maximum frequency domain amplitude f corresponding to the inclination angle β along the y-axis y0 Number of pixels occupied N y for: N y =(a / λ) / (1 / (N μ ·N L )) 8) Among them, 1 / (N μ ·N L ) represents the frequency domain resolution.

6. The common phase error detection method according to claim 5, characterized in that: In S4, the coordinates of the maximum amplitude in the frequency domain information are located, and the tilt error between the pupil planes of the two sub-apertures of S1 is inversely solved as follows: According to formula 5), ​​the coordinate positions of the maximum amplitude are symmetrical about the zero-frequency origin. The information used to inversely solve the error is exactly the same. After the discrete two-dimensional Fourier transform, the maximum coordinate N with a positive horizontal coordinate is found. x :Due to the actual geometric size N of the detection camera pixel unit μ It is known that the size N of the matrix to be demodulated in S3 is L Known, the maximum value is located to get N x Then, according to formula 7) we can get α; Similarly, the maximum value is located to obtain N y Then, β can be obtained according to formula 8).

7. The common phase error detection method according to claim 6, characterized in that: In S5, according to the positioning coordinates of the maximum amplitude in the frequency domain information of S4, the phase value at the coordinates in the frequency domain is obtained, and the piston error between the two sub-aperture pupil surfaces in S1 is inversely solved. The expression is as follows: Where Arg represents the argument of the complex number to be solved, and M is the complex matrix after discrete two-dimensional Fourier transform; Combining with formula (6), the piston error δ can be obtained.

8. A computer device, characterized in that: including memory and processor; The memory is used to store a computer program that can be executed on the processor; The processor is configured to implement the steps of the common phase error detection method according to any one of claims 1 to 7 when executing the computer program.

9. A computer-readable storage medium, characterized in that The computer-readable storage medium stores a computer program, which, when executed by a processor, implements the steps of the common-phase error detection method according to any one of claims 1 to 7.

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