Spectroscopic interferometric displacement sensing device with real-time self-calibration function and displacement measurement method

Abstract

The application discloses a spectrum interference displacement sensing device with real-time self-calibration function and a displacement measuring method, and relates to the technical field of displacement sensing devices. The device comprises an optical interference sensing system, a multi-channel spectrometer and a data analysis system. The optical interference sensing system is used for acquiring interference light signals formed by displacement of a measured object. The multi-channel spectrometer is used for processing the interference light signals, acquiring interference spectra and reference spectra. The data analysis system is used for real-time spectrum self-calibration and spectrum analysis, so as to measure the displacement under the premise of reducing the influence of environmental disturbance. The application can calibrate the spectrum analysis in real time according to environmental changes, can eliminate filtering systems and environmental noise, can improve the precision and efficiency of displacement measurement, and can solve the problems of insufficient stability and inability to calibrate in real time caused by system and environmental noise of the existing interference displacement sensing device.

Description

Technical Field

[0001] This application belongs to the field of spectroscopic instrument technology, and more specifically, relates to a spectral interferometric displacement sensing device with real-time self-calibration function and its measurement method. Background Technology

[0002] The core technology of displacement analysis using interferometric spectroscopy lies in calculating the displacement by analyzing the phase change of the interference spectrum modulated by the measured displacement. Essentially, it encodes spatial displacement information into the spectral phase of the interference light, and then accurately reconstructs the displacement change using a high-resolution spectrometer and phase demodulation algorithms. In precision manufacturing and high-end equipment, high-precision displacement measurement is a core element in ensuring process quality and control. Traditional interferometric displacement sensing devices generally face two major technical bottlenecks: first, the instability of the light source directly introduces significant measurement errors; second, environmental noise, especially disturbances in the air refractive index caused by changes in temperature, pressure, and humidity, interferes with the interference signal, affecting the accuracy and repeatability of long-term measurements. These inherent defects make it difficult for existing sensing devices to achieve high-precision, high-stability continuous operation in industrial environments. Summary of the Invention

[0003] The present invention addresses the shortcomings of the prior art by proposing a spectral interferometric displacement sensing device and its measurement method with real-time self-calibration function. This device aims to calibrate spectral analysis in real time according to environmental changes and eliminate system and environmental noise, thereby improving the accuracy and efficiency of displacement measurement. This solves the problems of insufficient stability and inability to perform real-time calibration caused by system and environmental noise in existing interferometric displacement sensing devices.

[0004] To achieve the above-mentioned objectives, the present invention adopts the following technical solution: The present invention provides a spectral interferometric displacement sensing device with real-time self-calibration function, characterized in that it includes: an optical interferometric sensing system, a multi-channel spectrometer, and a data analysis system; The optical interferometric sensing system includes: a measuring arm, a reference arm, a broadband light source, a first beam splitter, an optical fiber coupler, a second beam splitter, a third beam splitter, and a standard light source; wherein, the measuring arm includes: a first collimating mirror and a first reflecting mirror, and the reference arm includes: a circulator, a second collimating mirror, and a second reflecting mirror; The multi-channel spectrometer includes: a multi-channel fiber array, an optical system, and a photodetector; the multi-channel fiber array is a four-channel parallel fiber array; the optical system includes: a third collimating mirror, a third reflecting mirror, a transmission grating, a first focusing lens, a second focusing lens, and a concave lens. The light emitted by the broadband light source is split by the first beam splitter. 1% of the beam is coupled into channel CH1 of the multi-channel fiber array, and 99% of the beam enters the fiber coupler and is then split into two beams of equal intensity, which enter the measuring arm and the reference arm for processing. The incident beam from the measuring arm is collimated by the first collimating lens and then enters the first reflecting mirror. Its return light is connected to the 1:1 third beam splitter through the fiber coupler. The beam from the reference arm enters the circulator, is collimated by the second collimating lens, and then enters the second reflecting mirror. Its return light is emitted through the circulator and enters the second beam splitter for splitting. 1% of the beam is coupled into channel CH3 of the multi-channel fiber array, and 99% of the beam enters the third beam splitter. Together with the return light from the measuring arm, they form an interference light signal indicating the displacement of the measured object. The interference light signal is then coupled into channel CH2 of the multi-channel fiber array. The beam emitted by the standard light source is coupled into channel CH4 of the multi-channel fiber optic array. The multi-channel fiber array directs the optical signals from the four channels into the optical system in parallel. After collimation by the third collimating lens, the light is reflected by the third reflecting mirror. The reflected light is dispersed by the transmission grating and then focused by the first and second focusing lenses. Finally, the focused light is directed onto the detection surface of the area array photodetector by an achromatic concave lens. The photodetector then converts the broadband light source spectrum, interference spectrum, reference arm backlight spectrum, and standard light source spectrum generated by channels CH1, CH2, CH3, and CH4 into corresponding electrical signals. The data analysis system (50) includes: a spectral calibration self-calibration system, an interferometric spectral analysis system, and a disturbance signal processing system; The spectral calibration self-calibration system uses a third-order polynomial to fit the electrical signal converted from the standard light source spectrum, obtaining a wavenumber-pixel relationship, which is used to obtain the corresponding wavenumber of each pixel in the spectrometer at the t-th sampling time. ,in, It represents the t-th sampling time. The wavenumber corresponding to each pixel in the spectrometer The total number of pixels; The interferometric spectral analysis system converts the three electrical signals—the broadband light source spectrum, the interferometric spectrum, and the reference arm backlight spectrum—into corresponding spectral signals based on the wavenumber-pixel relationship, thereby obtaining the corresponding wavenumber at the t-th sampling time. broadband light source spectral signal Interference spectral signal Reference arm backlight spectral signal ; The disturbance signal processing system is based on and ,right After filtering and noise reduction, the noise-reduced interference spectrum signal is obtained, which is used to calculate the displacement of the measured object.

[0005] The displacement measurement method based on the aforementioned spectral interferometric displacement sensing device with real-time self-calibration function is characterized by comprising the following steps: Step S1: Connect the optical path formed by the optical interferometric sensing system, the multi-channel spectrometer, and the data analysis system, and keep the broadband light source and the standard light source on; Step S2: Replace the first reflector with the object to be measured, or fix the first reflector on the object to be measured, and make the displacement direction of the object to be measured parallel to the direction of the beam emitted by the first collimating mirror of the measuring arm. Step S3: Adjust the distance H between the second collimating mirror and the second reflecting mirror in the reference arm by moving the second reflecting mirror, so that the distance is close to the distance h1 between the object being measured and the first collimating mirror, or the distance h2 between the first reflecting mirror and the first collimating mirror fixed on the object being measured; Step S4: Based on the data analysis system, obtain the absolute displacement sequence between H and h1 or between H and h1 under the sampling period. ;in, Let H represent the absolute displacement between H and h1 or H and h2 at the t-th sampling time, and T represent the total number of sampling times. Step S5: Based on The time-displacement curve is obtained and used to output the displacement of the measured object relative to the initial sampling time at any sampling time t. ,in, This represents the absolute displacement between H and h1 or H and h2 at the initial sampling time.

[0006] The displacement measurement method of the spectral interferometric displacement sensing device with real-time self-calibration function described in this invention is also characterized in that the data analysis system in step S4 obtains the following steps: : Step 1: Use equation (1) to obtain the wavenumber corresponding to the t-th sampling time. Interference spectral signal after eliminating light source disturbance : (1) In equation (1), and These represent the effective return coefficients of the reference arm and the measuring arm, respectively. This represents the optical path difference between the measuring arm and the reference arm at the t-th sampling time. Indicates the initial phase; Represents the wavenumber corresponding to the t-th sampling time. The interference spectrum signal below, Represents the wavenumber corresponding to the t-th sampling time. Broadband light source spectral signal; Step 2: Use equation (2) to obtain the wavenumber corresponding to the t-th sampling time. Reference arm backlight spectrum signal after eliminating light source disturbance : (2) In equation (2), Represents the wavenumber corresponding to the t-th sampling time. The reference arm's backlight spectrum signal; Step 3: Use equation (3) to obtain the wavenumber corresponding to the t-th sampling time. Normalized interferometric signal to eliminate environmental disturbances : (3) Step 4: Use equation (4) to obtain the wavenumber corresponding to the t-th sampling time. Preprocessed interference signal after eliminating DC component : (4) Step 5: Use equation (5) to... Perform a Fourier transform to obtain the Fourier transform spectrum signal at the t-th sampling time. : (5) In equation (5), Indicates wave number The corresponding interference signal, where p represents the discrete frequency index after Fourier transform; i represents the imaginary unit; Step 6: Obtain the amplitude spectrum using equation (6) The index corresponding to the maximum value in the middle : (6) Step 7: Use equation (7) to obtain : (7) in, Indicates the wavenumber scan range.

[0007] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. In this invention, the optical interferometric sensing system is used to acquire the interference light formed by the displacement of the object under test and convert the physical quantity of displacement into an optical signal; the multi-channel spectrometer is used to process the interference light signal, acquire the interference spectrum and the reference spectrum, so as to calibrate the spectrometer in real time while processing the interference signal, and filter out system noise and environmental noise in real time; the data analysis system is used to perform spectral self-calibration and spectral analysis in real time, reducing the influence of environmental disturbances.

[0008] 2. The displacement measurement method in this invention uses a standard light source to calibrate the spectrometer in real time, ensuring that each spectral signal is based on the spectrometer calibration result under real-time environmental influences. By eliminating light source noise and environmental noise, the impact of environmental disturbances on the displacement measurement results is further reduced. This achieves a displacement measurement method with reliable structure, high resolution, and high accuracy, suitable for complex industrial field testing scenarios with unstable working environments and high accuracy requirements. Attached Figure Description

[0009] Figure 1 This is a schematic diagram of the real-time self-calibrating spectral interferometric displacement sensing device system of this application, used to illustrate the optical interferometric system, optical path structure, multi-channel spectrometer functional interface connection method and spectrometer internal structure; Figure 2 This is a schematic diagram of the multi-channel fiber optic array structure of this application; Figure 3 This is a simulation diagram of the optical structure of the multi-channel spectrometer in this application; Figure 4 This is a schematic diagram of the detection results of the photodetector receiving four-channel spectra in this application. Channel CH1 represents the broadband light source spectrum, channel CH2 represents the interference signal spectrum, channel CH3 represents the reference arm backlight spectrum, and channel CH4 represents the standard light source spectrum. Figure 5 This is a schematic diagram of the real-time spectral calibration results of this application; The following components are labeled in the diagram: 10 Broadband light source, 11 First beam splitter, 12 Fiber optic coupler, 13 Circulator, 14 Second beam splitter, 15 Third beam splitter, 16 Standard light source, 20 First collimating mirror, 21 First reflecting mirror, 22 Second collimating mirror, 23 Second reflecting mirror, 30 Multi-channel fiber array, 40 Third collimating mirror, 41 Third reflecting mirror, 42 Transmission grating, 43 First focusing lens, 44 Second focusing lens, 45 Concave lens, 46 Photodetector, 50 Data analysis system. Detailed Implementation

[0010] To make the technical solutions and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments.

[0011] Firstly, this application provides a spectral interferometric displacement sensing device with real-time self-calibration function, such as... Figure 1 As shown, it includes an optical interferometric sensing system, a multi-channel spectrometer based on a transmission grating, and a data analysis system; The optical interferometric sensing system is used to acquire the interference light signal formed by the displacement of the object being measured; the multi-channel spectrometer is used to process the interference light signal, acquire the interference spectrum and reference spectrum; the data analysis system is used to perform real-time spectral self-calibration and spectral analysis to achieve displacement measurement while reducing the influence of environmental disturbances.

[0012] An optical interferometric sensing system includes: a measuring arm, a reference arm, a broadband light source 10, a first beam splitter 11, an optical fiber coupler 12, a second beam splitter 14, a third beam splitter 15, and a standard light source 16; wherein, the measuring arm includes: a first collimating mirror 20 and a first reflecting mirror 21, and the reference arm includes: a circulator 13, a second collimating mirror 22, and a second reflecting mirror 23; the first collimating mirror 20 and the second collimating mirror 22 are used to collimate the input broadband light source; the first reflecting mirror 21 and the second reflecting mirror 23 are used to generate backlight interference.

[0013] The internal structure of a multichannel spectrometer is as follows: Figure 3 As shown, the system includes: a multi-channel fiber array 30, an optical system, and a photodetector 46. The multi-channel fiber array 30 is a four-channel parallel fiber array. The optical system includes: a third collimating mirror 40, a third reflecting mirror 41, a transmission grating 42, a first focusing lens 43, a second focusing lens 44, and a concave lens 45. The third collimating mirror 40 is a 60mm focal length spherical collimating mirror used to collimate the incident beam. The third reflecting mirror 40 is used to change the direction of the collimated beam's optical path, making the collimating mirror group parallel to the focusing system's lens group, so as to facilitate system integration. The 1800 groove / mm transmission grating 42 serves as a beam-splitting element, used to disperse the beam. The first focusing lens 43 and the second focusing lens 44 are two 150mm spherical mirrors, and the concave lens 45 has a focal length of 100mm. These three sets of lenses are used to converge the dispersed spectrum.

[0014] More preferably, the multi-channel fiber array 30 is a four-channel parallel fiber array, such as... Figure 2 As shown, the optical fiber is a 0.12 NA single-mode fiber with a core pitch of 250 μm, and the channels from top to bottom are CH1, CH2, CH3, and CH4.

[0015] After the light emitted by the broadband light source 10 is split by the first beam splitter 11, 1% of the beam is coupled into channel CH1 of the multi-channel fiber array 30, and 99% of the beam enters the fiber coupler 12 and is then split into two beams of the same intensity, which enter the measuring arm and the reference arm for processing. The incident beam of the measuring arm is collimated by the first collimating lens 20 and then enters the first reflecting mirror 21. Its return light is connected to the 1:1 third beam splitter 15 through the fiber coupler 12. The beam of the reference arm is connected to the circulator 13 and collimated by the second collimating lens 22 and then enters the second reflecting mirror 23. Its return light is emitted through the circulator 13 and enters the second beam splitter 14 for splitting. 1% of the beam is coupled into channel CH3 of the multi-channel fiber array 30, and 99% of the beam enters the third beam splitter 15. Together with the return light of the measuring arm, they form an interference light signal of the displacement of the measured object. The interference light signal is then coupled into channel CH2 of the multi-channel fiber array 30.

[0016] The beam emitted by the standard light source 16 is coupled into channel CH4 of the multi-channel fiber array 30; The multi-channel fiber array 30 sends the optical signals of the four channels into the optical system in parallel. After being collimated by the third collimating lens 40, the light is reflected by the third reflecting mirror 41. The reflected light is dispersed by the transmission grating 42 and then focused by the first focusing lens 43 and the second focusing lens 44. The focused light is then sent onto the detection surface of the area array photodetector 46 through the achromatic concave lens 45. The photodetector 46 then converts the broadband light source spectrum, interference spectrum, reference arm return spectrum, and standard light source spectrum generated by channels CH1, CH2, CH3, and CH4 into corresponding electrical signals.

[0017] More preferably, the spectral response range of the photodetector 46 is 810~860 nm.

[0018] The spectral detection signal acquired by photodetector 46 is as follows Figure 4 As shown, channel CH1 represents the broadband light source spectrum, channel CH2 represents the interference signal spectrum, channel CH3 represents the reference arm backlight spectrum, and channel CH4 represents the standard light source spectrum. The spectral signals from channels CH1 and CH3 are used to filter out noise from the light source itself and environmental noise caused by air disturbances or temperature changes, respectively. The spectral signal from channel CH4 is used for real-time calibration of the spectrometer using a standard light source to reduce the impact of optical path offset or jitter caused by changes in the working environment on the accuracy of the spectrometer, thereby enhancing the reliability of the spectrometer system. The calibration pattern is shown below. Figure 5 As shown.

[0019] The data analysis system 50 includes a real-time spectral calibration and self-calibration system, an interferometric spectral analysis system, and a disturbance signal processing system. The real-time spectral calibration and self-calibration system is used to calibrate the spectrum of the standard light source in real time to achieve spectral analysis self-calibration; the interferometric spectral analysis system is used to process the interferometric light signal to read the displacement data of the measured object; and the disturbance signal processing system is used to perform filtering and noise reduction to reduce the noise of the light source itself and the effects of air and ambient temperature disturbances.

[0020] More preferably, the disturbance signal processing system uses the broadband light source signal and the reference arm return signal coupled through two fiber array channels to form a corresponding spectral signal. The system then uses targeted filtering to reduce the noise of the light source itself and the noise caused by the air environment affecting the interference signal.

[0021] The spectral calibration self-calibration system uses a third-order polynomial to fit the electrical signal converted from the standard light source spectrum. It extracts the pixels corresponding to the five wavelength peaks within the spectral response range of the photodetector 46 from the standard light source 16, obtaining the wavenumber-pixel relationship. This relationship is used to determine the corresponding wavenumber of each pixel in the spectrometer at the t-th sampling time. ,in, It represents the t-th sampling time. The wavenumber corresponding to each pixel in the spectrometer The total number of pixels; The interferometric spectral analysis system, based on the wavenumber-pixel relationship, converts the three electrical signals—the broadband light source spectrum, the interferometric spectrum, and the reference arm backlight spectrum—into corresponding spectral signals, thereby obtaining the broadband light source spectral signal. Interference spectral signal Reference arm backlight spectral signal ; Disturbance signal processing system based on and ,right After filtering and noise reduction, the noise-reduced interference spectrum signal is obtained, which is used to calculate the displacement of the measured object.

[0022] Secondly, this application provides a displacement measurement method based on the above-mentioned real-time self-calibrated spectral interferometric displacement sensing device, comprising the following steps: Step S1: Connect the optical path formed by the optical interferometric sensing system, the multi-channel spectrometer, and the data analysis system, and keep the broadband light source 10 and the standard light source 16 on; Step S2: Replace the first reflector 21 with the object to be measured, or fix the first reflector 21 on the object to be measured, and make the displacement direction of the object to be measured parallel to the direction of the emitted beam of the first collimating mirror 20 of the measuring arm.

[0023] Step S3: Adjust the distance H between the second collimating mirror 22 and the second collimating mirror 23 in the reference arm by moving the second reflecting mirror 23, so that the distance is close to the distance h1 between the object being measured and the first collimating mirror 20, or the distance h2 between the first reflecting mirror 21 and the first collimating mirror 20 fixed on the object being measured.

[0024] Step S4: Based on the data analysis system 50, obtain the absolute displacement sequence between H and h1 or between H and h1 under the sampling period. ;in, Let H represent the absolute displacement between H and h1 or H and h2 at the t-th sampling time, and T represent the total number of sampling times.

[0025] Step S5: Based on The time-displacement curve is obtained and used to output the displacement of the measured object relative to the initial sampling time at any sampling time t. ,in, Indicates the initial sampling time H and h1 or H and The absolute displacement between h2.

[0026] For the t-th sampling time, the data analysis system 50 in step S4 obtains the following steps: : Step 1: Use equation (1) to obtain the wavenumber corresponding to the t-th sampling time. Interference spectral signal after eliminating light source disturbance : (1) In equation (1), and These represent the effective return coefficients of the reference arm and the measuring arm, respectively. This indicates the optical path difference between the measuring arm and the reference arm. Indicates the initial phase; Represents the interference spectrum signal. Represents the spectral signal of a broadband light source; Step 2: Use equation (2) to obtain the wavenumber corresponding to the t-th sampling time. Reference arm backlight spectrum signal after eliminating light source disturbance : (2) In equation (2), This indicates the reference arm's backlight spectrum signal; Step 3: Use equation (3) to obtain the wavenumber corresponding to the t-th sampling time. Normalized interferometric signal to eliminate environmental disturbances : (3) Step 4: Use equation (4) to obtain the wavenumber corresponding to the t-th sampling time. Preprocessed interference signal after eliminating DC component : (4) In equation (4), It represents the t-th sampling time. The number of waves corresponding to each pixel, where N represents the total number of pixels. This represents the normalized interference signal; Step 5: Use equation (5) to... Perform a Fourier transform to obtain the Fourier transform spectrum signal at the t-th sampling time. : (5) In equation (5), This represents the wavenumber corresponding to the m-th pixel at the t-th sampling time. Indicates wave number The corresponding interference signal, where p represents the discrete frequency index after Fourier transform; i represents the imaginary unit; Step 6: Obtain the amplitude spectrum using equation (6) The index corresponding to the maximum value in the middle : (6) Step 7: Use equation (7) to obtain : (7) in, Indicates the wavenumber scan range.

[0027] In summary, this application provides a highly accurate, stable, and adaptable spectral interferometric displacement sensing device method capable of real-time self-calibration in complex environments. It possesses high precision (resolution ≤ 0.5 nm) and a long reliability range (effective displacement measurement range ≤ 12 mm). This method is suitable for precision detection scenarios in complex and changing environments and can be widely applied in scientific research, industrial testing, and instrument integration.

[0028] This application provides a measurement method based on a real-time self-calibrating spectral interferometric displacement sensing device. The method uses a standard light source spectrum to calibrate the spectrometer in real time, reducing the impact of environmental or system fluctuation errors. By introducing the real-time light source spectrum and the reference arm spectrum, system noise and environmental noise and disturbances are eliminated simultaneously. Compared with interferometric ranging sensing devices based on a single fiber coupler, this method has higher accuracy, better signal-to-noise ratio, and stronger environmental adaptability.

Claims

1. A spectral interferometric displacement sensing device with real-time self-calibration function, characterized in that, include: An optical interferometric sensing system, a multi-channel spectrometer, and a data analysis system; The optical interferometric sensing system includes: a measuring arm, a reference arm, a broadband light source (10), a first beam splitter (11), an optical fiber coupler (12), a second beam splitter (14), a third beam splitter (15), and a standard light source (16); wherein, the measuring arm includes: a first collimating mirror (20) and a first reflecting mirror (21), and the reference arm includes: a circulator (13), a second collimating mirror (22), and a second reflecting mirror (23); The multi-channel spectrometer includes: a multi-channel fiber array (30), an optical system, and a photodetector (46). The multi-channel fiber array (30) is a four-channel parallel fiber array. The optical system includes: a third collimating mirror (40), a third reflecting mirror (41), a transmission grating (42), a first focusing lens (43), a second focusing lens (44), and a concave lens (45). The light emitted by the broadband light source (10) is split by the first beam splitter (11). 1% of the beam is coupled into channel CH1 of the multi-channel fiber array (30), and 99% of the beam enters the fiber coupler (12) and is then split into two beams of equal intensity for processing in the measuring arm and the reference arm. The incident beam from the measuring arm is collimated by the first collimating mirror (20) and then enters the first reflecting mirror (21). Its return light is connected to the 1:1 third beam splitter (15) through the fiber coupler (12). The reference arm... The beam is fed into the circulator (13), and after being collimated by the second collimating mirror (22), it enters the second reflecting mirror (23). Its return light is emitted through the circulator (13) and enters the second beam splitter (14) for beam splitting. 1% of the beam is coupled into channel CH3 of the multi-channel fiber array (30), and 99% of the beam enters the third beam splitter (15). Together with the return light from the measuring arm, they form an interference light signal of the displacement of the measured object. The interference light signal is then coupled into channel CH2 of the multi-channel fiber array (30). The beam emitted by the standard light source (16) is coupled into channel CH4 of the multi-channel fiber array (30); The multi-channel fiber array (30) sends the optical signals of the four channels into the optical system in parallel, and after being collimated by the third collimating lens (40), they are sent into the third reflecting mirror (41) for reflection. The reflected light is dispersed by the transmission grating (42), and then focused by the first focusing lens (43) and the second focusing lens (44). The focused light is then sent into the detection surface of the area array photodetector (46) through the achromatic concave lens (45). Thus, the photodetector (46) converts the broadband light source spectrum, interference spectrum, reference arm backlight spectrum and standard light source spectrum generated by channels CH1, CH2, CH3 and CH4 into corresponding electrical signals. The data analysis system (50) includes: a spectral calibration self-calibration system, an interferometric spectral analysis system, and a disturbance signal processing system; The spectral calibration self-calibration system uses a third-order polynomial to fit the electrical signal converted from the standard light source spectrum, obtaining a wavenumber-pixel relationship, which is used to obtain the corresponding wavenumber of each pixel in the spectrometer at the t-th sampling time. ,in, It represents the t-th sampling time. The wavenumber corresponding to each pixel in the spectrometer The total number of pixels; The interferometric spectral analysis system converts the three electrical signals—the broadband light source spectrum, the interferometric spectrum, and the reference arm backlight spectrum—into corresponding spectral signals based on the wavenumber-pixel relationship, thereby obtaining the corresponding wavenumber at the t-th sampling time. broadband light source spectral signal Interference spectral signal Reference arm backlight spectral signal ; The disturbance signal processing system is based on and ,right After filtering and noise reduction, the noise-reduced interference spectrum signal is obtained, which is used to calculate the displacement of the measured object.

2. A displacement measurement method based on the spectral interferometric displacement sensing device with real-time self-calibration function as described in claim 1, characterized in that, Includes the following steps: Step S1: Connect the optical path formed by the optical interference sensing system, the multi-channel spectrometer and the data analysis system, and keep the broadband light source (10) and the standard light source (16) on; Step S2: Replace the first reflector (21) with the object to be measured, or fix the first reflector (21) on the object to be measured, and make the displacement direction of the object to be measured parallel to the direction of the emitted beam of the first collimating mirror (20) of the measuring arm. Step S3: Adjust the distance H between the second collimating mirror (22) and the second collimating mirror (23) in the reference arm by moving the second reflecting mirror (23) so that the distance is close to the distance h1 between the object being measured and the first collimating mirror (20), or the distance h2 between the first reflecting mirror (21) fixed on the object being measured and the first collimating mirror (20). Step S4: Based on the data analysis system (50), obtain the absolute displacement sequence between H and h1 or between H and h1 under the sampling period. ;in, Let H represent the absolute displacement between H and h1 or H and h2 at the t-th sampling time, and T represent the total number of sampling times. Step S5: Based on The time-displacement curve is obtained and used to output the displacement of the measured object relative to the initial sampling time at any sampling time t. ,in, This represents the absolute displacement between H and h1 or H and h2 at the initial sampling time.

3. The displacement measurement method of the spectral interferometric displacement sensing device with real-time self-calibration function according to claim 2, characterized in that, The data analysis system (50) in step S4 is obtained according to the following steps. : Step 1: Use equation (1) to obtain the wavenumber corresponding to the t-th sampling time. Interference spectral signal after eliminating light source disturbance : (1) In equation (1), and These represent the effective return coefficients of the reference arm and the measuring arm, respectively. This represents the optical path difference between the measuring arm and the reference arm at the t-th sampling time. Indicates the initial phase; Represents the wavenumber corresponding to the t-th sampling time. The interference spectrum signal below, Represents the wavenumber corresponding to the t-th sampling time. Broadband light source spectral signal; Step 2: Use equation (2) to obtain the wavenumber corresponding to the t-th sampling time. Reference arm backlight spectrum signal after eliminating light source disturbance : (2) In equation (2), Represents the wavenumber corresponding to the t-th sampling time. The reference arm's backlight spectrum signal; Step 3: Use equation (3) to obtain the wavenumber corresponding to the t-th sampling time. Normalized interferometric signal to eliminate environmental disturbances : (3) Step 4: Use equation (4) to obtain the wavenumber corresponding to the t-th sampling time. Preprocessed interference signal after eliminating DC component : (4) Step 5: Use equation (5) to... Perform a Fourier transform to obtain the Fourier transform spectrum signal at the t-th sampling time. : (5) In equation (5), Indicates wave number The corresponding interference signal, where p represents the discrete frequency index after Fourier transform; i represents the imaginary unit; Step 6: Obtain the amplitude spectrum using equation (6) The index corresponding to the maximum value in the middle : (6) Step 7: Use equation (7) to obtain : (7) in, Indicates the wavenumber scan range.

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