Dual-path error dynamic correction method and laser displacement measurement system

Abstract

This invention relates to a dual-optical-path error dynamic correction method and a laser displacement measurement system, comprising: acquiring interference signals from a measurement optical path and a reference optical path; extracting features from the two interference signals to obtain feature data for the measurement optical path and the reference optical path; dynamically estimating the frequency based on the feature data of the measurement and reference optical paths to obtain the precise beat frequencies of the measurement and reference optical paths; calculating a proportionality coefficient based on the precise beat frequencies of the measurement and reference optical paths; performing dynamic phase correction based on the proportionality coefficient to obtain a corrected phase; and calculating the displacement based on the corrected phase to obtain the corrected displacement. This invention can achieve phase compensation under optical path mismatch conditions in the traditional laser heterodyne interferometry dual-optical-path structure, effectively avoiding errors introduced by optical path mismatch and significantly improving measurement accuracy and real-time performance.

Description

Technical Field

[0001] This invention relates to the field of laser measurement technology, and more specifically, to a dual-optical-path error dynamic correction method and a laser displacement measurement system. Background Technology

[0002] Frequency-modulated continuous wave (FMCW) laser interferometry has been widely used in precision displacement measurement, topography measurement, and vibration analysis due to its advantages such as high precision, high resolution, and strong anti-interference capability. Traditional FMCW laser displacement measurement systems typically employ a dual-path structure, consisting of a measurement optical path and a reference optical path. These paths are used to detect the interference signal reflected from the target object and the internal reference signal of the system, respectively. By comparing the phase difference between the two interference signals, the displacement of the target object can be calculated.

[0003] However, in practical engineering applications, there is often a mismatch in the optical path difference between the measurement optical path and the reference optical path, i.e. When the center wavelength of the system shifts, two optical paths with different optical path differences will experience phase shifts of different amplitudes. According to the phase shift formula: ,in For optical path difference, For wavelength shift, The center wavelength. When In such cases, the traditional method of directly using "measured phase - reference phase" cannot effectively compensate for phase drift error, resulting in a significant decrease in measurement accuracy.

[0004] To address the aforementioned issues, existing compensation methods typically assume that the measurement optical path and the reference optical path have the same center wavelength drift (i.e., However, this is often difficult to achieve in practical engineering, resulting in limited compensation effects. Therefore, how to achieve high-precision dual-optical-path phase correction under the condition of optical path difference mismatch has become an urgent problem to be solved in FMCW laser displacement measurement technology. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a dual-optical-path error dynamic correction method and a laser displacement measurement system, which address the problems existing in the prior art.

[0006] The technical solution adopted by this invention to solve its technical problem is: a dual-optical-path error dynamic correction method, comprising the following steps: Step S1: Acquire the interference signal of the measurement optical path and the interference signal of the reference optical path; Step S2: Perform feature extraction on the interference signal of the measurement optical path and the interference signal of the reference optical path respectively to obtain the feature data of the measurement optical path and the feature data of the reference optical path; Step S3: Based on the characteristic data of the measurement optical path and the characteristic data of the reference optical path, perform dynamic frequency estimation to obtain the precise beat frequency of the measurement optical path and the precise beat frequency of the reference optical path; Step S4: Calculate the proportionality coefficient based on the precise beat frequency of the measurement optical path and the precise beat frequency of the reference optical path; Step S5: Perform dynamic phase correction based on the scaling factor to obtain the corrected phase; Step S6: Calculate the displacement based on the corrected phase to obtain the corrected displacement amount.

[0007] In the dual-optical-path error dynamic correction method of the present invention, the characteristic data of the measurement optical path includes: coarse estimates of the phase and frequency of the measurement optical path; the characteristic data of the reference optical path includes: coarse estimates of the phase and frequency of the reference optical path. Step S2 includes: Step S201: Perform a Fourier transform on the interference signal of the measurement optical path to obtain a coarse estimate of the phase and frequency of the measurement optical path; Step S202: Perform a Fourier transform on the reference optical path interference to obtain a coarse estimate of the phase and frequency of the reference optical path; Steps S201 and S202 are executed simultaneously.

[0008] In the dual-optical-path error dynamic correction method of the present invention, the characteristic data of the measurement optical path further includes: the initial amplitude and initial offset of the measurement optical path; the characteristic data of the reference optical path further includes: the initial amplitude and initial offset of the reference optical path. Step S2 further includes: Obtain the average value and peak-to-peak value of the interference signal of the measurement optical path, and the average value and peak-to-peak value of the interference signal of the reference optical path; The initial amplitude of the measurement optical path is obtained by calculating the peak-to-peak value of the interference signal of the measurement optical path. The initial offset of the measurement optical path is obtained by calculating based on the average value of the interference signal of the measurement optical path; The initial amplitude of the reference optical path is obtained by calculating based on the peak-to-peak value of the interference signal of the reference optical path; The initial offset of the reference optical path is obtained by calculating based on the average value of the interference signal of the reference optical path.

[0009] In the dual-optical-path error dynamic correction method of the present invention, step S3 includes: Step S301: Select the target data segment; Step S302: Based on the feature data of the measurement optical path and the feature data of the reference optical path, the least squares method is used for fitting calculation to obtain the precise beat frequency of the measurement optical path and the precise beat frequency of the reference optical path.

[0010] In the dual-optical-path error dynamic correction method of the present invention, step S302 includes: The least squares method is used to iteratively optimize the initial values ​​of the initial amplitude and initial offset of the measurement optical path, the coarse estimate of the phase and frequency of the measurement optical path, the initial amplitude and initial offset of the reference optical path, and the coarse estimate of the phase and frequency of the reference optical path, respectively, to obtain the precise beat frequency of the measurement optical path and the precise beat frequency of the reference optical path.

[0011] In the dual-optical-path error dynamic correction method of the present invention, in step S5, proportional compensation is performed based on the proportional coefficient using the frequency-optical path difference coupling relationship to obtain the correction phase.

[0012] In the dual-optical-path error dynamic correction method of the present invention, the correction phase satisfies: ; in, To correct the phase; To measure the phase of the optical path; The phase of the reference optical path; This is the proportionality coefficient.

[0013] In the dual-optical-path error dynamic correction method described in this invention, the correction displacement is calculated using the following formula: ; in, To correct the displacement; The center wavelength; This represents the corrected phase change.

[0014] This invention also provides a laser displacement measurement system applied to the above-described dual-optical-path error dynamic correction method, comprising: A laser source used to generate a triangular wave modulated laser signal; A dual-optical-path interference structure is used to receive the laser signal and generate a measurement optical path interference signal and a reference optical path interference signal based on the laser signal, respectively. A photodetector is used to receive the interference signal of the measurement optical path and the interference signal of the reference optical path, respectively. The signal preprocessing module is used to preprocess the measurement optical path interference signal and the reference optical path interference signal respectively. The frequency dynamic correction module is used to perform dynamic frequency estimation and calculation based on the preprocessed measurement optical path interference signal and the reference optical path interference signal to obtain the correction phase. The displacement calculation module is used to calculate the displacement based on the correction phase and obtain the correction displacement amount.

[0015] In the laser displacement measurement system of the present invention, the dual-optical-path interference structure includes: a measurement optical path and a reference optical path; The laser signal is irradiated onto the target object of the measurement optical path, and the laser signal reflected by the collimating lens end face and the laser signal reflected by the target object generate the measurement optical path interference signal; The laser signal is split and combined by two fiber couplers in the reference optical path to generate the reference optical path interference signal.

[0016] The dual-optical-path error dynamic correction method and laser displacement measurement system of the present invention have the following beneficial effects: They include: acquiring interference signals from the measurement optical path and the reference optical path; extracting features from the two interference signals to obtain feature data for the measurement optical path and the reference optical path; dynamically estimating the frequency based on the feature data of the measurement optical path and the reference optical path to obtain the precise beat frequency of the measurement optical path and the precise beat frequency of the reference optical path; calculating a proportionality coefficient based on the precise beat frequency of the measurement optical path and the precise beat frequency of the reference optical path; performing dynamic phase correction based on the proportionality coefficient to obtain the corrected phase; and calculating the displacement based on the corrected phase to obtain the corrected displacement. This invention can achieve phase compensation under optical path difference mismatch conditions in the traditional laser heterodyne interferometry dual-optical-path structure, effectively avoiding errors introduced by optical path difference mismatch and significantly improving measurement accuracy and real-time performance. Attached Figure Description

[0017] The present invention will be further described below with reference to the accompanying drawings and embodiments. In the accompanying drawings: Figure 1 This is a flowchart illustrating the dual-optical-path error dynamic correction method provided by the present invention; Figure 2 This is a signal flow diagram of the dual-optical-path error dynamic correction provided by the present invention; Figure 3 This is a flowchart of the frequency dynamic estimation method provided by the present invention; Figure 4 This is a schematic diagram of the phase correction principle provided by the present invention; Figure 5 This is a schematic diagram comparing the measurement accuracy provided by the present invention; Figure 6 This is a schematic diagram of the laser displacement measurement system provided by the present invention. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] The dual-optical-path error dynamic correction method provided by this invention can eliminate the phase drift error introduced by traditional dual-optical-path compensation methods under optical path difference mismatch conditions, reducing the requirements for hardware computing power and sampling rate. It belongs to a dual-optical-path error elimination method for FMCW laser displacement measurement based on frequency dynamic correction, which combines dynamic frequency estimation with proportional compensation technology. Specifically, by performing phase extraction and dynamic frequency estimation on the measurement optical path and the reference optical path, and using the beat frequency ratio as a proportional coefficient, phase compensation under non-common-mode conditions is achieved, thereby suppressing center wavelength drift error. Compared with existing dual-optical-path compensation algorithms for FMCW laser displacement measurement, this invention overcomes the optical path difference mismatch problem inherent in previous compensation algorithms that rely on the common-mode assumption, while also eliminating the impact of phase drift on measurement accuracy. It not only achieves effective compensation under optical path difference mismatch conditions but also maintains high measurement accuracy. Finally, while maintaining high accuracy, this invention ensures shorter computation time and less computational load through a low-frequency refresh strategy. Therefore, this invention has advantages such as high precision, strong adaptability, and strong real-time performance, and can greatly improve the performance of FMCW laser displacement measurement.

[0020] refer to Figure 1 In a preferred embodiment, the dual-optical-path error dynamic correction method includes the following steps: step S1, step S2, step S3, step S4, step S5 and step S6.

[0021] Step S1: Acquire the interference signal of the measurement optical path and the interference signal of the reference optical path.

[0022] The measurement optical path interference signal can be expressed as: The reference optical path interference signal can be represented as: .

[0023] Step S2: Extract features from the interference signals of the measurement optical path and the reference optical path respectively to obtain the feature data of the measurement optical path and the feature data of the reference optical path.

[0024] In this embodiment of the invention, the characteristic data of the measurement optical path includes: coarse estimates of the phase and frequency of the measurement optical path; the characteristic data of the reference optical path includes: coarse estimates of the phase and frequency of the reference optical path.

[0025] In some embodiments, step S2 includes: Step S201: Perform Fourier transform on the interference signal of the measurement optical path to obtain a rough estimate of the phase and frequency of the measurement optical path.

[0026] Step S202: Perform a Fourier transform on the reference optical path interference to obtain a rough estimate of the phase and frequency of the reference optical path.

[0027] Steps S201 and S202 are executed simultaneously.

[0028] Specifically, phase extraction of the two interference signals can be performed using a windowed FFT (Fourier Transform) method. This involves: applying a Hanning window to each frame of interference data to eliminate spectral leakage; performing an FFT to extract a coarse estimate of the beat frequency; and obtaining the initial phase. The phase of the measurement optical path (i.e., the initial phase) can be expressed as: The coarse estimate of the frequency can be expressed as: The phase of the reference optical path (i.e., the initial phase) can be expressed as: The coarse estimate of the frequency can be expressed as: .

[0029] Furthermore, the characteristic data of the measurement optical path also includes: the initial amplitude and initial offset of the measurement optical path; the characteristic data of the reference optical path also includes: the initial amplitude and initial offset of the reference optical path.

[0030] Step S2 further includes: obtaining the average value and peak-to-peak value of the interference signal of the measurement optical path, and the average value and peak-to-peak value of the interference signal of the reference optical path; calculating the initial amplitude of the measurement optical path based on the peak-to-peak value of the interference signal of the measurement optical path; calculating the initial offset of the measurement optical path based on the average value of the interference signal of the measurement optical path; calculating the initial amplitude of the reference optical path based on the peak-to-peak value of the interference signal of the reference optical path; and calculating the initial offset of the reference optical path based on the average value of the interference signal of the reference optical path.

[0031] Step S3: Based on the characteristic data of the measurement optical path and the characteristic data of the reference optical path, perform dynamic frequency estimation to obtain the accurate beat frequency of the measurement optical path and the accurate beat frequency of the reference optical path.

[0032] In this embodiment of the invention, the frequency dynamic estimation employs the least squares method. Specifically: Step S301: Select the target data segment.

[0033] The target data segment can be a representative data segment, such as the first modulation period.

[0034] Step S302: Based on the characteristic data of the measurement optical path and the characteristic data of the reference optical path, the least squares method is used for fitting calculation to obtain the accurate beat frequency of the measurement optical path and the accurate beat frequency of the reference optical path.

[0035] In some embodiments, step S302 includes: using the least squares method to iteratively optimize the initial amplitude and initial offset of the measurement optical path, the coarse estimates of the phase and frequency of the measurement optical path, the initial amplitude and initial offset of the reference optical path, and the coarse estimates of the phase and frequency of the reference optical path as initial values, to obtain the precise beat frequency of the measurement optical path and the precise beat frequency of the reference optical path, respectively. The initial amplitude of the measurement optical path is expressed as... A obj The initial offset is represented as B obj The initial amplitude of the reference optical path is expressed as... A ref The initial offset is represented as B ref The precise beat frequency of the measuring optical path can be expressed as: The precise beat frequency of the reference optical path can be expressed as: .

[0036] In step S3, the dynamic frequency estimation includes: performing precise frequency calculation only on the target data segment within a fixed time window; applying the obtained scaling factor to all modulation cycles within the fixed time window; and dynamically adjusting the refresh interval according to the application scenario. Specifically, the dynamic frequency estimation principle of this invention is as follows: within a fixed time window, performing precise frequency estimation only on a representative data segment (such as the first modulation cycle); applying the obtained scaling factor to all modulation cycles within the fixed time window; and dynamically adjusting the refresh interval according to the application scenario to balance calculation accuracy and real-time performance.

[0037] Step S4: Calculate the proportionality coefficient based on the precise beat frequency of the measurement optical path and the precise beat frequency of the reference optical path.

[0038] Specifically, after obtaining the precise beat frequency of the measurement optical path... and the precise beat frequency of the reference optical path Then, the proportionality constant can be calculated. The proportionality constant can be calculated using the following formula: ; in, This represents the proportionality coefficient.

[0039] Step S5: Perform dynamic phase correction based on the scaling factor to obtain the corrected phase.

[0040] In step S5, proportional compensation is performed using the frequency-optical path difference coupling relationship based on the scaling factor to obtain the corrected phase. Specifically, phase correction involves scaling the reference optical path phase using the scaling factor, and then subtracting the scaled value from the measured optical path phase to obtain the corrected phase. The underlying principle is based on the linear relationship between the optical path difference and the beat frequency (i.e., the frequency-optical path difference coupling relationship), using the scaling factor to achieve phase matching compensation of the reference optical path at the same scale.

[0041] The frequency-optical path difference coupling relationship is as follows: ; in, The beat frequency, For optical path difference, For the modulation wave frequency, For wavelength modulation width, The center wavelength is .

[0042] ; To measure the optical path difference, The reference optical path difference.

[0043] In this embodiment of the invention, the corrected phase satisfies: ; in, To correct the phase; To measure the phase of the optical path; The phase of the reference optical path; This is the proportionality coefficient.

[0044] Step S6: Calculate the displacement based on the correction phase to obtain the correction displacement amount.

[0045] In this embodiment of the invention, the correction displacement is calculated using the following formula: ; in, To correct the displacement; The center wavelength (i.e., the center wavelength of the laser). This represents the corrected phase change.

[0046] Specifically, after calculating the corrected phase according to formula (4), step S5 is repeated for each modulation period in the time series to construct the corrected phase sequence. ; then with the first cycle phase Using the zero point as the reference, solve the phase change sequence. Finally, the corrected displacement is calculated based on the phase change sequence obtained from the solution and in combination with formula (5).

[0047] The dual-optical-path error dynamic correction method of the present invention can achieve effective phase error cancellation under optical path difference mismatch conditions, and significantly improve measurement accuracy. Figure 2 The signal flow for dynamic error correction in dual optical paths according to the present invention is illustrated. For example... Figure 2 As shown, the FMCW laser source employs triangular wave modulation, with the laser frequency changing linearly with time to generate an FMCW laser signal. This FMCW laser signal passes through a dual-path interference structure, where two photodetectors receive the interference signals from the measurement and reference paths, respectively, yielding two analog interference signals. These analog interference signals are then preprocessed, including amplification, filtering, and analog-to-digital conversion, to obtain two digital interference signals. Phase extraction and frequency estimation are then performed on these two digital interference signals in real time to obtain the precise estimated beat frequencies of each signal. and Based on accurate estimation of beat frequency and Calculate the proportionality coefficient Then use the obtained proportionality coefficient The phase of the reference optical path is scaled and subtracted to obtain the corrected phase. Finally, the displacement is calculated based on the corrected phase.

[0048] Figure 3 The flowchart of the frequency dynamic estimation method provided by the present invention is shown.

[0049] like Figure 3 As shown, a windowed FFT transform is performed on the interference signals of the measurement optical path and the reference optical path to obtain a coarse estimate of the beat frequency. and Select a representative data segment (such as the first modulation period) to obtain the initial amplitude and initial offset of the two signals respectively; then use the least squares method to iteratively optimize with coarse estimates (phase, frequency coarse estimates, initial amplitude and initial offset) as initial values ​​to obtain accurate frequency and phase estimation results for the two signals.

[0050] Figure 4 The phase correction principle provided by this invention is illustrated.

[0051] like Figure 4 As shown, the principle of phase correction is as follows: Measuring optical path phase Includes displacement information and phase drift introduced by light source drift; Reference optical path phase It primarily characterizes the phase drift introduced by the light source drift; By calculating the proportionality coefficient The phase of the reference optical path is scaled proportionally to the scale of the measurement optical path. Corrected phase Phase with the measurement optical path The responses are of the same scale, thus effectively suppressing drift errors.

[0052] The dual-optical-path error dynamic correction method of the present invention can achieve phase compensation under the condition of optical path difference mismatch in the traditional laser heterodyne interference dual-optical-path structure. Therefore, compared with other dual-optical-path compensation algorithms, the present invention can effectively avoid the error introduced by optical path difference mismatch and has stronger adaptability.

[0053] This invention can effectively and dynamically estimate the frequency and utilize the frequency-optical path difference coupling relationship for proportional compensation, thereby effectively suppressing wavelength drift errors and improving the system's measurement accuracy. The low-frequency refresh strategy significantly reduces computational overhead and lowers the hardware computing power requirements. By first coarsely solving for the frequency using the Discrete Fourier Transform algorithm and then precisely solving for the frequency using fitting and other methods, the frequency estimation can remain relatively stable in a system that maintains the same sampling time interval, improving measurement accuracy and real-time performance. Figure 5 A comparison of the measurement accuracy of this invention with that of conventional methods is presented. Figure 5 It can be seen that the measurement accuracy of the present invention is significantly higher than that of the traditional method.

[0054] refer to Figure 6 The present invention also provides a laser displacement measurement system, which is applied to the above-mentioned dual-optical-path error dynamic correction method.

[0055] like Figure 6 As shown, the laser displacement measurement system includes: Laser source 601 is used to generate a triangular wave modulated laser signal.

[0056] The dual-path interference structure 602 is used to receive laser signals and generate measurement optical path interference signals and reference optical path interference signals based on the laser signals. In this embodiment of the invention, both interference signals are rising edge signals and falling edge signals of the beat frequency signal. Several segments of the rising edge signal and several segments of the falling edge signal are synchronized with the triangular wave digital signal.

[0057] In some embodiments, the dual-path interference structure includes: a measurement optical path and a reference optical path; a laser signal is irradiated onto the target object in the measurement optical path, and the laser signal reflected by the collimating lens end face and the laser signal reflected by the target object generate a measurement optical path interference signal; the laser signal is split and combined by two fiber couplers in the reference optical path to generate a reference optical path interference signal.

[0058] The photodetector 603 is used to receive the interference signal of the measurement optical path and the interference signal of the reference optical path, respectively.

[0059] The signal preprocessing module 604 is used to preprocess the measurement optical path interference signal and the reference optical path interference signal respectively.

[0060] The frequency dynamic correction module 605 is used to perform frequency dynamic estimation and calculation based on the preprocessed measurement optical path interference signal and the reference optical path interference signal to obtain the correction phase.

[0061] The displacement calculation module 606 is used to calculate the displacement based on the correction phase and obtain the correction displacement amount.

[0062] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0063] Those skilled in the art will further recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0064] The steps of the methods or algorithms described in conjunction with the embodiments disclosed herein can be implemented directly by hardware, a software module executed by a processor, or a combination of both. The software module can be located in random access memory (RAM), main memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, removable disk, CD-ROM, or any other form of storage medium known in the art.

[0065] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They do not limit the scope of protection of the present invention. All equivalent changes and modifications made within the scope of the claims of the present invention should fall within the scope of the claims of the present invention.

Claims

1. A method for dynamic error correction in dual optical paths, characterized in that, Includes the following steps: Step S1: Acquire the interference signal of the measurement optical path and the interference signal of the reference optical path; Step S2: Perform feature extraction on the interference signal of the measurement optical path and the interference signal of the reference optical path respectively to obtain the feature data of the measurement optical path and the feature data of the reference optical path; Step S3: Based on the characteristic data of the measurement optical path and the characteristic data of the reference optical path, perform dynamic frequency estimation to obtain the precise beat frequency of the measurement optical path and the precise beat frequency of the reference optical path; Step S4: Calculate the proportionality coefficient based on the precise beat frequency of the measurement optical path and the precise beat frequency of the reference optical path; Step S5: Perform dynamic phase correction based on the scaling factor to obtain the corrected phase; Step S6: Calculate the displacement based on the corrected phase to obtain the corrected displacement amount.

2. The dual-optical-path error dynamic correction method according to claim 1, characterized in that, The characteristic data of the measurement optical path includes: coarse estimates of the phase and frequency of the measurement optical path; the characteristic data of the reference optical path includes: coarse estimates of the phase and frequency of the reference optical path. Step S2 includes: Step S201: Perform a Fourier transform on the interference signal of the measurement optical path to obtain a coarse estimate of the phase and frequency of the measurement optical path; Step S202: Perform a Fourier transform on the reference optical path interference to obtain a coarse estimate of the phase and frequency of the reference optical path; Steps S201 and S202 are executed simultaneously.

3. The dual-optical-path error dynamic correction method according to claim 2, characterized in that, The characteristic data of the measurement optical path also includes: the initial amplitude and initial offset of the measurement optical path; the characteristic data of the reference optical path also includes: the initial amplitude and initial offset of the reference optical path; Step S2 further includes: Obtain the average value and peak-to-peak value of the interference signal of the measurement optical path, and the average value and peak-to-peak value of the interference signal of the reference optical path; The initial amplitude of the measurement optical path is obtained by calculating the peak-to-peak value of the interference signal of the measurement optical path. The initial offset of the measurement optical path is obtained by calculating based on the average value of the interference signal of the measurement optical path; The initial amplitude of the reference optical path is obtained by calculating based on the peak-to-peak value of the interference signal of the reference optical path; The initial offset of the reference optical path is obtained by calculating based on the average value of the interference signal of the reference optical path.

4. The dual-optical-path error dynamic correction method according to claim 3, characterized in that, Step S3 includes: Step S301: Select the target data segment; Step S302: Based on the feature data of the measurement optical path and the feature data of the reference optical path, the least squares method is used for fitting calculation to obtain the precise beat frequency of the measurement optical path and the precise beat frequency of the reference optical path.

5. The dual-optical-path error dynamic correction method according to claim 4, characterized in that, Step S302 includes: The least squares method is used to iteratively optimize the initial values ​​of the initial amplitude and initial offset of the measurement optical path, the coarse estimate of the phase and frequency of the measurement optical path, the initial amplitude and initial offset of the reference optical path, and the coarse estimate of the phase and frequency of the reference optical path, respectively, to obtain the precise beat frequency of the measurement optical path and the precise beat frequency of the reference optical path.

6. The dual-optical-path error dynamic correction method according to claim 1, characterized in that, In step S5, proportional compensation is performed using the frequency-optical path difference coupling relationship based on the proportional coefficient to obtain the corrected phase.

7. The dual-optical-path error dynamic correction method according to any one of claims 1-6, characterized in that, The correction phase satisfies: ； in, To correct the phase; To measure the phase of the optical path; The phase of the reference optical path; This is the proportionality coefficient.

8. The dual-optical-path error dynamic correction method according to claim 1, characterized in that, The corrected displacement is calculated using the following formula: ； in, To correct the displacement; The center wavelength; This represents the corrected phase change.

9. A laser displacement measurement system, applied to the dual-optical-path error dynamic correction method according to any one of claims 1-8, characterized in that, include: A laser source used to generate a triangular wave modulated laser signal; A dual-optical-path interference structure is used to receive the laser signal and generate a measurement optical path interference signal and a reference optical path interference signal based on the laser signal, respectively. A photodetector is used to receive the interference signal of the measurement optical path and the interference signal of the reference optical path, respectively. The signal preprocessing module is used to preprocess the measurement optical path interference signal and the reference optical path interference signal respectively. The frequency dynamic correction module is used to perform dynamic frequency estimation and calculation based on the preprocessed measurement optical path interference signal and the reference optical path interference signal to obtain the correction phase. The displacement calculation module is used to calculate the displacement based on the correction phase and obtain the correction displacement amount.

10. The laser displacement measurement system according to claim 9, characterized in that, The dual-optical-path interference structure includes: a measurement optical path and a reference optical path; The laser signal is irradiated onto the target object of the measurement optical path, and the laser signal reflected by the collimating lens end face and the laser signal reflected by the target object generate the measurement optical path interference signal; The laser signal is split and combined by two fiber couplers in the reference optical path to generate the reference optical path interference signal.

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