Fourier infrared spectrum online self-checking diagnosis control method and system

Abstract

The application discloses a Fourier infrared spectrum online self-checking diagnosis control method and system, and relates to the technical field of spectrometer diagnosis. The method comprises the following steps: S1, collecting an interferogram amplitude sequence of a spectrum instrument in each scan, carrying out pretreatment, identifying a zero optical path difference position, and constructing a center-symmetry analysis interval of the interferogram; S2, analyzing a mirror image symmetry characteristic, and evaluating current scan stability; S3, extracting an envelope amplitude sequence, analyzing a disturbance separation characteristic, and determining a current scan abnormal source; S4, identifying a disturbance intensity, combining a scan time interval, evaluating a current disturbance recovery trend, and generating a disposal control strategy. The method solves the problems that it is difficult to identify the stability abnormality of the interferogram in the Fourier infrared spectrum instrument online operation process, invalid scans are easily generated, and the spectrum quality and measurement reliability are affected.

Description

Technical Field

[0001] This invention relates to the field of spectrometer diagnostic technology, specifically to a Fourier transform infrared spectroscopy online self-testing diagnostic control method and system. Background Technology

[0002] Spectrometers are important analytical and testing devices widely used in industrial manufacturing, pharmaceutical testing, food safety, environmental monitoring, materials analysis, and scientific research. With the continuous expansion of testing scenarios and the constant improvement of instrument hardware and software integration, spectrometers have evolved from traditional standalone testing equipment into data acquisition and analysis platforms that can work collaboratively with computers, playing an increasingly important role in applications such as continuous detection, process monitoring, laboratory automation, and online quality control.

[0003] For example, Chinese patent CN112578728B discloses a switching device and method for switching gases in an ICP spectrometer, comprising: a power supply, a torque stepper motor, a positionable stepper motor driver, a PLC controller, a user terminal, a two-way stainless steel valve, and a coupling; the two-way stainless steel valve is mounted on a connecting pipeline; one end of the coupling is connected to the two-way stainless steel valve, and the other end is connected to the torque stepper motor; the positionable stepper motor driver is mounted on the torque stepper motor and electrically connected to it; the PLC controller is electrically connected to the positionable stepper motor driver, the power supply, and the two-way stainless steel valve; the PLC controller is remotely connected to the user terminal via long-distance communication.

[0004] For example, Chinese patent CN105676725A discloses a signal acquisition and control system for a spark spectrometer, belonging to the field of spark spectrometer technology. It includes a PC, a network cable, a data acquisition, transmission, and processing module, a serial port cable, and a negative high-voltage control module. The PC communicates with the data acquisition, transmission, and processing module via Ethernet. The negative high-voltage control module outputs multiple negative high-voltage control signals, and the data acquisition, transmission, and processing module acquires, processes, and transmits the output signals from the multi-channel photodetector. Its advantages include: using high-resolution, high-speed parallel AD to acquire elemental spectral line intensities, resulting in fast acquisition speed and high accuracy; using multi-channel DA to set the negative high voltage applied to the photodetector, achieving real-time digital control of the multi-channel negative high voltage; using an FPGA as the main controller to achieve parallel real-time processing of various system functions; using the FPGA's built-in FIFO for storage, realizing real-time storage and processing of spectral line intensity signals; and communicating with the PC via Ethernet to improve communication reliability.

[0005] However, during the operation of a Fourier transform infrared spectrometer, the interferogram generated by the interferometer scan is the fundamental data for spectral calculations, and its stability directly affects the final spectral quality. In actual online operation scenarios, the interferogram is easily affected by various dynamic factors, such as instrument platform vibration, transient fluctuations in the light source, changes in scanning speed, and environmental airflow disturbances. These factors may cause the interferogram's central peak to shift, symmetry to be disrupted, or periodic structure to be distorted. When the anomaly is minor, traditional systems often still complete the scan and output the spectrum, but the resulting spectrum's signal-to-noise ratio decreases or the baseline is distorted; when the anomaly is severe, scan failures or inability to calculate the spectrum may occur. Since interferogram anomalies are often only detected after the spectral calculation is completed, the consumed scanning time and computational resources cannot be utilized, resulting in a large amount of invalid scan data in continuous monitoring or online analysis scenarios, affecting measurement efficiency and data reliability.

[0006] Therefore, in order to address the above problems, there is an urgent need for a Fourier transform infrared spectroscopy online self-testing diagnostic control method and system. Summary of the Invention

[0007] Technical problems to be solved

[0008] To address the shortcomings of existing technologies, this invention provides a self-diagnostic control method and system for online Fourier transform infrared spectroscopy, which solves the problems of difficulty in timely identification of abnormal interferogram stability during online operation of Fourier transform infrared spectrometers, easy generation of invalid scans, and impact on spectral quality and measurement reliability.

[0009] Technical solution

[0010] To achieve the above objectives, the present invention provides the following technical solution: a Fourier transform infrared spectroscopy online self-diagnostic control method, comprising the following steps: S1, real-time acquisition of the interferogram amplitude sequence of each scan by the spectrometer, preprocessing the interferogram amplitude sequence, identifying the zero optical path difference position based on the interferogram amplitude sequence, and constructing a central symmetry analysis interval for the interferogram; S2, analyzing the mirror symmetry features using the interferogram amplitude sequence within the central symmetry analysis interval, and evaluating the current scan stability based on the mirror symmetry features; S3, extracting the envelope amplitude sequence based on the interferogram amplitude sequence, combining the envelope amplitude sequence and the interferogram amplitude sequence to extract perturbation separation features, and determining the source of the current scan anomaly based on the perturbation separation features; S4, identifying the perturbation intensity by combining the mirror symmetry features and the perturbation separation features, evaluating the current perturbation recovery trend based on the perturbation intensity and the scan time interval, and generating a corresponding handling control strategy based on the evaluation results.

[0011] Furthermore, the interferogram amplitude sequence of each scan of the spectrometer is acquired in real time. The specific process of preprocessing the interferogram amplitude sequence is as follows: During the operation of the Fourier transform infrared spectrometer, the spectrometer online data of each scan is acquired in real time through the acquisition driver and instrument control interface. The spectrometer online data includes: scan start time, scan end time, and interferogram amplitude sequence; by calculating the average value of the interferogram amplitude sequence and subtracting the average value from the original sequence, the DC removal processing is performed on the interferogram amplitude sequence; by dividing the DC removal interferogram amplitude sequence by the maximum absolute interferogram amplitude, the normalization processing is performed on the interferogram amplitude sequence; an infrared spectroscopy online self-test database is established to store the original and preprocessed spectrometer online data.

[0012] Furthermore, the specific process of identifying the zero optical path difference position based on the interferogram amplitude sequence and constructing the centrally symmetric analysis interval of the interferogram is as follows: In the interferogram amplitude sequence, the sampling point corresponding to the largest absolute value of the interferogram amplitude is selected to obtain the zero optical path difference position; with the zero optical path difference position as the center, the interferogram amplitude is traversed along the left and right sides respectively, and the number of sampling points whose interferogram amplitude is continuously greater than or equal to the central peak amplitude ratio threshold is calculated, and the number of the most sampling points on the left and right sides is taken as the length of the central analysis window; with the zero optical path difference position as the center, the extension range on the left and right sides is determined by the length of the central analysis window to construct the centrally symmetric analysis interval of the interferogram.

[0013] Furthermore, the specific process of analyzing the mirror symmetry features using the interferogram amplitude sequence within the central symmetry analysis interval of the interferogram is as follows: Read the central symmetry analysis interval of the interferogram; multiply the interferogram amplitudes of the left sampling points and their corresponding right sampling points pairwise within the interval, and sum all the multiplications within the interval to obtain the mirror product value; calculate and sum the squares of the interferogram amplitudes corresponding to the left sampling points within the central symmetry analysis interval to obtain the left sum of squares; calculate and sum the squares of the interferogram amplitudes corresponding to the right sampling points within the central symmetry analysis interval to obtain the right sum of squares; multiply the square roots of the left sum of squares and the right sum of squares to obtain the normalized product value; subtract the ratio of the mirror product value to the normalized product value from one to obtain the mirror symmetry deviation value.

[0014] Furthermore, the specific process for evaluating the stability of the current scan based on the mirror symmetry feature is as follows: the mirror symmetry deviation value is compared with the deviation threshold to determine the stability: when the mirror symmetry deviation value is less than or equal to the deviation threshold, the current scan is determined to be stable; when the mirror symmetry deviation value is greater than the deviation threshold, the current scan is determined to be abnormal; the mirror symmetry deviation value and the stability determination result are written into the infrared spectroscopy online self-test database.

[0015] Furthermore, the specific process of extracting the envelope amplitude sequence based on the interferogram amplitude sequence and combining the envelope amplitude sequence with the interferogram amplitude sequence to extract perturbation separation features is as follows: Read the interferogram amplitude sequence within the central symmetric analysis interval of the interferogram; perform a Hilbert transform on the interferogram amplitude sequence to obtain the imaginary part sequence; use the interferogram amplitude sequence as the real part of a complex number and the corresponding imaginary part sequence as the imaginary part of a complex number to construct a complex sequence; perform a modulo operation on each sampling point in the complex sequence to obtain the interferogram envelope amplitude sequence; perform a second-order difference operation on each interferogram amplitude within the central symmetric analysis interval of the interferogram to obtain the interferogram amplitude sequence. Figure 2 The step difference fraction represents all interference within the interval. Figure 2 The first difference values ​​are squared and summed, then divided by the number of sampling points in the interval minus two. The square root of the divisor is taken to obtain the second difference standard value. For each interferogram envelope amplitude in the centrally symmetric analysis interval of the interferogram, the first difference operation is performed to obtain the first difference value of the envelope. The first difference values ​​of the envelope in the interval are squared and summed, then divided by the number of sampling points in the interval minus one. The square root of the divisor is taken to obtain the first difference standard value of the envelope. The second difference standard value is divided by the sum of the first difference standard value of the envelope and the smallest positive number to obtain the vibration envelope disturbance separation value.

[0016] Furthermore, the specific process for determining the source of the current scan anomaly based on the disturbance separation characteristics is as follows: when the current scan is determined to be abnormal, if the vibration envelope disturbance separation value is greater than or equal to the separation determination threshold, the source of the current scan anomaly is determined to be a mechanical vibration anomaly; if the vibration envelope disturbance separation value is less than the separation determination threshold, the source of the current scan anomaly is determined to be a light source and environmental disturbance anomaly; when the current scan is determined to be stable, only the vibration envelope disturbance separation value is recorded; the vibration envelope disturbance separation value and the anomaly type are written into the infrared spectroscopy online self-test database.

[0017] Furthermore, the disturbance intensity is identified by combining mirror symmetry features and disturbance separation features. Based on the disturbance intensity and the scanning time interval, the specific process for evaluating the current disturbance recovery trend is as follows: multiply the mirror symmetry deviation value by the sum of the vibration envelope disturbance separation value and one to obtain the scan disturbance intensity value; subtract the natural logarithm of the current scan disturbance intensity value from the natural logarithm of the previous scan disturbance intensity value to obtain the disturbance change amplitude; subtract the previous scan end time from the current scan end time to obtain the scanning time interval; divide the disturbance change amplitude by the scanning time interval to obtain the disturbance decay rate; read the scan disturbance intensity values ​​corresponding to the historical scan stability, take the median and calculate the median absolute deviation, and add three times the median absolute deviation to the median to obtain the normal disturbance reference value; subtract the natural logarithm of the normal disturbance reference value from the natural logarithm of the current scan disturbance intensity value and divide by the disturbance decay rate to obtain the recovery waiting time.

[0018] Furthermore, the specific process of generating the corresponding handling control strategy based on the evaluation results is as follows: When the current scan is determined to be abnormal, the disturbance attenuation rate and recovery waiting time are calculated, and the handling control strategy is generated: If the disturbance attenuation rate is greater than zero, a delay waiting is performed according to the recovery waiting time, and the scan is re-examined after the waiting period ends; If the disturbance attenuation rate is less than or equal to zero, the abnormality is determined to have not attenuated, and the recovery strategy is triggered: the scan is stopped and a control command to restart the Fourier transform infrared spectrometer is generated, and prompts to check the equipment and environmental status and re-acquire the background are generated at the same time.

[0019] A second aspect of this invention provides an online self-diagnostic control system for Fourier transform infrared spectroscopy, comprising: an online data acquisition and processing module for real-time acquisition of interferogram amplitude sequences from each scan of the spectrometer, preprocessing the interferogram amplitude sequences, identifying the zero optical path difference position based on the interferogram amplitude sequences, and constructing a central symmetry analysis interval for the interferogram; an interferogram quality assessment module for analyzing mirror symmetry features using the interferogram amplitude sequences within the central symmetry analysis interval, and assessing the stability of the current scan based on the mirror symmetry features; an anomaly diagnosis and discrimination module for extracting envelope amplitude sequences based on the interferogram amplitude sequences, extracting disturbance separation features by combining the envelope amplitude sequences and the interferogram amplitude sequences, and determining the source of the current scan anomaly based on the disturbance separation features; and a recovery control and handling module for identifying disturbance intensity by comprehensively considering mirror symmetry features and disturbance separation features, assessing the current disturbance recovery trend based on the disturbance intensity and the scan time interval, and generating a corresponding handling control strategy based on the assessment results.

[0020] Beneficial effects

[0021] The present invention has the following beneficial effects:

[0022] (1) The present invention analyzes the central symmetry features of the interferogram and evaluates the current scanning stability before spectral calculation. It can identify interferogram anomalies in advance and reduce the situation where abnormal interferograms directly enter subsequent spectral calculations, thereby improving the scanning quality control capability in the online detection process.

[0023] (2) By combining the amplitude sequence of the interferogram and the amplitude sequence of the envelope to extract the disturbance separation features, the present invention can further distinguish the current scanning anomalies, refine the source of the anomalies into mechanical vibration anomalies and light source and environmental disturbance anomalies, improve the pertinence of anomaly judgment, and provide a basis for subsequent differentiated treatment.

[0024] (3) The present invention identifies the scanning disturbance intensity by combining the mirror symmetry feature and the disturbance separation feature, and evaluates the disturbance recovery trend by combining the time interval between consecutive scans. It can determine whether the current abnormality is in the decay process, thereby improving the continuity and dynamism of the online self-test diagnosis process.

[0025] (4) The present invention can improve the automation level of self-diagnosis during the online operation of the spectrometer by generating delayed rescanning, suspending scanning, generating restart control commands, and generating prompts for checking equipment and environmental status and re-acquiring background based on the disturbance recovery trend, thereby reducing invalid scans and improving online detection efficiency and operational stability.

[0026] Of course, any product implementing this invention does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description

[0027] Figure 1 A flowchart of an online self-testing diagnostic control method for Fourier transform infrared spectroscopy;

[0028] Figure 2 This is a structural diagram of an online self-testing diagnostic control system for Fourier transform infrared spectroscopy.

[0029] Figure 3 A diagram illustrating the changes in the recovery waiting time response;

[0030] Figure 4 This is a flowchart of a Fourier transform infrared spectroscopy online self-testing diagnostic control process. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. As those skilled in the art will understand, 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.

[0032] Please see Figures 1-4 This invention provides a technical solution: a Fourier transform infrared spectroscopy online self-testing diagnostic control method, such as... Figure 1 As shown, the process includes the following steps: S1, real-time acquisition of the interferogram amplitude sequence for each scan of the spectrometer, preprocessing the interferogram amplitude sequence, identifying the zero optical path difference position based on the interferogram amplitude sequence, and constructing a central symmetry analysis interval for the interferogram; S2, analysis of mirror symmetry features using the interferogram amplitude sequence within the central symmetry analysis interval, and assessment of the current scan stability based on the mirror symmetry features; S3, extraction of the envelope amplitude sequence based on the interferogram amplitude sequence, extraction of perturbation separation features by combining the envelope amplitude sequence and the interferogram amplitude sequence, and determination of the source of the current scan anomaly based on the perturbation separation features; S4, identification of perturbation intensity by combining the mirror symmetry features and the perturbation separation features, assessment of the current perturbation recovery trend based on the perturbation intensity and the scan time interval, and generation of corresponding handling and control strategies based on the assessment results.

[0033] Specifically, the real-time acquisition of the interferogram amplitude sequence for each scan of the spectrometer and the preprocessing of the interferogram amplitude sequence are as follows: During the operation of the Fourier transform infrared spectrometer, the spectrometer online data for each scan is acquired in real time through the acquisition driver and instrument control interface. The spectrometer online data includes: scan start time, scan end time, and interferogram amplitude sequence. The acquisition driver and instrument control interface can be deployed on the host computer software side to complete the issuance of scan commands, scan status monitoring, data reception, and data caching, thereby ensuring that the data corresponding to each scan can be independently acquired according to the scan batch and a one-to-one correspondence can be established. The acquisition driver and instrument control interface preferably establish an online communication connection with the spectrometer through a USB device driver interface. The instrument control interface is used to issue scan start commands, scan stop commands, status query commands, and data read commands to the spectrometer. The acquisition driver is used to receive the scan status data and interferogram amplitude data returned by the spectrometer and write the received data into the host computer buffer. The scan status data includes at least the scan task identifier, scan start timestamp, scan end timestamp, and scan completion identifier. The scan start and end times can be timestamped by the spectrometer's online control software at the trigger and completion of each scan task. The interferogram amplitude sequence is a discrete amplitude data sequence formed by continuous acquisition by the detector and analog-to-digital conversion during a single scan. The sampling points in the interferogram amplitude sequence are arranged in the acquisition order and are used to characterize the changes in the interferogram signal corresponding to the current scan. DC removal processing is performed on the interferogram amplitude sequence by calculating the average value and subtracting it from the original sequence. The average value is the arithmetic mean of the amplitudes of all sampling points in the entire interferogram amplitude sequence corresponding to the current single scan. Subtracting the average value from the original sequence involves performing a point-by-point subtraction operation on the amplitudes of each sampling point in the same scan to eliminate the influence of DC bias, background baseline drift, or fixed offset in the sampling link on subsequent mirror symmetry analysis and differential analysis. This makes the preprocessed interferogram amplitude sequence more reflective of the relative change characteristics of the actual interferometric signal. The interferogram amplitude sequence is normalized by dividing the DC-free interferogram amplitude sequence by the effective maximum absolute interferogram amplitude. The effective maximum absolute interferogram amplitude is the amplitude of the largest absolute sampling point in the DC-free interferogram amplitude sequence after removing saturation points and abnormal peaks. Normalization involves dividing the amplitude of each sampling point after DC removal by the effective maximum absolute interferogram amplitude to unify the amplitude scale under different scanning conditions to a similar range, reducing the impact of differences in absolute energy levels on subsequent mirror symmetry deviation analysis, envelope amplitude extraction, and disturbance separation determination. When the amplitude of a sampling point exceeds the upper or lower limit of the acquisition system's range, the sampling point is determined to be a saturation point; when the difference between the amplitude of a sampling point and its adjacent sampling points exceeds a preset abrupt change threshold, the sampling point is determined to be an abnormal peak.For identified saturation points and abnormal peaks, these are not used as the normalization reference. Instead, the amplitude with the largest absolute value is selected from the remaining sampling points as the effective maximum absolute interferogram amplitude. Preferably, when the maximum absolute interferogram amplitude is less than a preset minimum positive number, the preset minimum positive number can be used as the normalization divisor to avoid calculation instability caused by a zero denominator or an excessively small value. An infrared spectroscopy online self-test database is established to store the raw and preprocessed spectrometer online data, and records and indexes it according to a single scan unit. This ensures that subsequent diagnostic steps are processed based on data corresponding to the same scan, avoiding data mixing between different scan batches.

[0034] In this implementation plan, by real-time acquisition, preprocessing and standardized management of scanning data during the online operation of the spectrometer, a unified and reliable data foundation is provided for subsequent stability assessment, anomaly diagnosis and handling control, thereby improving the consistency of interferogram analysis results, the accuracy of subsequent diagnostic processes, and the feasibility and engineering implementation capability of the overall online self-test of the system.

[0035] Specifically, the process of identifying the zero optical path difference position based on the interferogram amplitude sequence and constructing the central symmetric analysis interval of the interferogram is as follows: In the preprocessed interferogram amplitude sequence, the sampling point corresponding to the largest absolute value of the interferogram amplitude is selected to obtain the zero optical path difference position, which corresponds to the location of the central main peak of the interferogram. In order to avoid misjudgment of the zero optical path difference position due to abnormal peaks, pseudo-peaks and saturation points in abnormal online scenarios, a candidate peak set can be formed first for the peak sampling points with absolute amplitude values ​​greater than the threshold. Consistency screening is performed by combining the amplitude continuity, peak width range, peak shape symmetry and whether it exceeds the upper and lower limits of the acquisition range of the sampling points in the neighborhood of the candidate peak. After removing the candidate peaks that do not meet the preset neighborhood consistency conditions, peak width conditions, peak shape conditions or saturation conditions, the zero optical path difference position is determined from the remaining candidate peaks. The neighborhood consistency condition characterizes whether the amplitude changes of adjacent sampling points on both sides of a candidate peak are continuous; the peak width condition characterizes whether the span of continuous sampling points corresponding to the candidate peak falls within the effective range under a preset amplitude ratio; the peak shape condition characterizes whether the local morphology on both sides of the candidate peak conforms to the characteristics of the central main peak; and the saturation condition is used to eliminate distorted peaks that exceed the range boundary of the sampling system. Through these constraints, the stability of zero optical path difference position identification can be improved in the presence of local abnormal peaks, sudden interference, and amplitude saturation. If the same maximum interferogram amplitude exists, the sampling point closest to the center can be selected as the zero optical path difference position to ensure the uniqueness and stability of subsequent left and right mirror analyses. Centered on the zero optical path difference position, the interferogram amplitude is traversed along both sides. The number of sampling points whose interferogram amplitude is continuously greater than or equal to the central peak amplitude ratio threshold is calculated, and the maximum number of sampling points on both sides is taken as the length of the central analysis window. The central peak amplitude ratio threshold is used to limit the effective analysis range near the central peak. Traversing the interferogram amplitude along both sides means starting from the sampling point corresponding to the zero optical path difference position, checking point by point on both the left and right sides whether the amplitude of the current sampling point continuously satisfies the condition of being greater than or equal to the central peak amplitude ratio threshold. When a sampling point that does not meet the condition appears for the first time on a certain side, the traversal on that side is stopped, and the number of sampling points that previously continuously met the condition is recorded as the number of sampling points on that side. Taking the maximum number of sampling points on both sides as the length of the central analysis window ensures complete coverage of the effective central region even when the attenuation rates on both sides of the interferogram center are not completely consistent, thereby enhancing the robustness of subsequent mirror symmetry feature extraction. Centered on the zero optical path difference position, the extension range on both sides is determined by the length of the central analysis window, constructing the central symmetry analysis interval of the interferogram. The interferogram center-symmetric analysis interval is represented as a continuous sampling interval centered at the zero optical path difference position, extending to the left and right by one central analysis window length. It is used for subsequent mirror symmetry deviation analysis, envelope difference analysis, and perturbation separation feature extraction.By pre-constructing a unified centrally symmetric analysis interval for the interferogram, subsequent feature calculations can be limited to the same effective central range, thereby avoiding result deviations caused by inconsistent analysis intervals and improving the consistency and comparability of subsequent scanning stability assessments and abnormal diagnosis results.

[0036] This implementation scheme can stably identify the zero optical path difference position under abnormal online scenarios. By constructing a unified interferogram center symmetry analysis interval, it provides a consistent data range for subsequent mirror symmetry deviation analysis, envelope difference analysis, and perturbation separation feature extraction, thereby improving the accuracy of center positioning results, the robustness of subsequent feature analysis, and the consistency and reliability of scanning stability assessment and anomaly diagnosis results.

[0037] Specifically, the process of analyzing the mirror symmetry features using the interferogram amplitude sequence within the central symmetry analysis interval of the interferogram is as follows: The central symmetry analysis interval of the interferogram is read. This interval is the aforementioned continuously symmetrical sampling interval constructed with the zero optical path difference position as the center. Within the interval, the left and right sampling points correspond one-to-one with the same offset relative to the zero optical path difference position. The interferogram amplitudes of the left and right sampling points are multiplied pairwise within the interval, and all multiplications within the interval are summed to obtain the mirror product value. The mirror product value is used to characterize the overall consistency of the amplitude direction of the corresponding sampling points on both sides of the center of the interferogram. When the amplitude change trends of the corresponding sampling points on the left and right sides are consistent, the mirror product value increases accordingly. The squares of the interferogram amplitudes corresponding to the left sampling points within the central symmetry analysis interval of the interferogram are calculated and summed to obtain the left-side sum of squares. Similarly, the squares of the interferogram amplitudes corresponding to the right sampling points within the same interval are calculated and summed to obtain the right-side sum of squares. The square roots of both the left and right sums of squares are then multiplied to obtain the normalized product. This normalized product is used to scale the mirror product, reducing the impact of absolute amplitude differences between different scanning batches on the mirror symmetry analysis results. The normalized product, formed by multiplying the square roots of the left and right sums of squares, essentially reflects the joint scale of the effective energy on both sides of the interferogram center, ensuring that subsequent mirror symmetry deviations are within a comparable, uniform dimensional range. Furthermore, when the normalized product is less than a preset minimum value, it can be set to this minimum value before subsequent ratio calculations to avoid instability caused by zero denominators or excessively small values ​​in cases of extremely weak signals, local distortion, or abnormal sampling on both sides of the center. Preferably, the preset minimum value can be a very small positive number, and the preferred value for the very small positive number is [value missing]. arrive This process ensures the numerical stability and engineering feasibility of the mirror symmetry deviation calculation. The mirror symmetry deviation is obtained by subtracting the ratio of the mirror product to the normalized product from one. The mirror symmetry deviation characterizes the degree of deviation of the mirror consistency on both sides of the interferogram center from the ideal symmetry state. When the amplitudes of corresponding sampling points on the left and right sides are more consistent, the ratio of the mirror product to the normalized product is closer to one, and the mirror symmetry deviation is smaller. Conversely, when the amplitude difference between corresponding sampling points on the left and right sides increases, the ratio decreases, and the mirror symmetry deviation increases. Through this process, the mirror symmetry of the currently scanned interferogram can be quantitatively characterized within the unified center analysis interval, providing a directly usable feature basis for subsequent scanning stability determination.

[0038] The specific formula for the mirror symmetry deviation value is as follows: ;

[0039] In the formula, The value represents the mirror symmetry deviation, which characterizes the degree of mirror symmetry between the amplitudes on both sides of the center of the interferogram. The smaller the mirror symmetry deviation value, the more symmetrical the left and right sides of the current interferogram are and the more stable the scan is. The larger the mirror symmetry deviation value, the more obvious the deviation between the left and right sides of the current interferogram is and the higher the possibility of scanning abnormality. Indicates the length of the central analysis window, used to limit the sampling range on both sides of the center of the interferogram for symmetrical analysis; This represents the interferogram amplitude corresponding to the sampling point on the left, used to characterize the local signal on the left. This represents the interferogram amplitude corresponding to the sampling point on the right, used to characterize the corresponding signal on the right. This indicates the position of zero optical path difference, used to determine the center position of the interferogram; This represents the offset from the zero optical path difference position to the left and right sides, used to establish a mirror matching relationship between corresponding sampling points on the left and right.

[0040] This implementation scheme can stably quantify the mirror consistency of corresponding sampling points on the left and right sides within a unified interferogram center symmetry analysis interval. By setting protection measures for cases where the normalized product value is too small, the numerical stability and engineering feasibility of mirror symmetry deviation analysis are improved, thereby enhancing the accuracy, robustness, and consistency of the scanning stability assessment results.

[0041] Specifically, the process of assessing the stability of the current scan based on mirror symmetry characteristics is as follows: The mirror symmetry deviation value is compared with a deviation threshold to determine stability. The deviation threshold characterizes the boundary at which the mirror symmetry of the interferogram transitions from a stable to an abnormal state. It can be adaptively set based on the statistical results of mirror symmetry deviation values ​​corresponding to historical normal scan samples. When the mirror symmetry deviation value is less than or equal to the deviation threshold, the current scan is considered stable, indicating that the mirror consistency on both sides of the center of the interferogram is within the allowable range, meeting the basic data requirements for subsequent envelope analysis, disturbance separation analysis, and online self-diagnosis. When the mirror symmetry deviation value is greater than the deviation threshold, the current scan is considered abnormal, indicating that the mirror consistency deviation on both sides of the center of the interferogram exceeds a preset allowable range, and the current scan may be affected by local vibrations, optical path disturbances, abnormal peaks, or other online operation interference factors. By writing the mirror symmetry deviation value and stability judgment result into the infrared spectroscopy online self-test database, the stability result of a single scan can be traced and recorded. By storing the mirror symmetry deviation value and stability judgment result, a judgment basis that can be directly called can be provided for subsequent anomaly source identification, disturbance recovery trend assessment and disposal control strategy generation, and the continuity, consistency and engineering feasibility of the online self-test process can be improved.

[0042] In this implementation plan, the stability of the current scan can be clearly determined based on the mirror symmetry deviation value, and the determination result and corresponding feature data are uniformly written into the database, providing a reliable basis for subsequent anomaly source identification, recovery trend assessment and handling control, thereby improving the accuracy, continuity and traceability of the online self-testing and diagnosis process.

[0043] Specifically, the process of extracting the envelope amplitude sequence based on the interferogram amplitude sequence and extracting the perturbation separation features by combining the envelope amplitude sequence and the interferogram amplitude sequence is as follows: The interferogram amplitude sequence within the central symmetric analysis interval of the interferogram is read. This central local sequence is extracted from the preprocessed interferogram amplitude sequence and used as the input for the Hilbert transform to ensure consistency between the envelope amplitude extraction and the aforementioned central symmetric analysis interval. To reduce the boundary effect of the Hilbert transform under finite-length sequence conditions, boundary processing can be performed before performing the Hilbert transform on the interferogram amplitude sequence within the central symmetric analysis interval. Mirror extension is preferred for boundary processing to maintain the continuity of local waveforms at both ends of the interval and reduce the impact of endpoint truncation on the Hilbert transform result. After performing the Hilbert transform on the extended sequence after boundary processing, the imaginary part sequence corresponding to the original central symmetric analysis interval of the interferogram is extracted as the subsequent calculation object. A Hilbert transform is performed on the interferogram amplitude sequence to obtain the imaginary part sequence. This imaginary part sequence corresponds one-to-one with the interferogram amplitude sequence within the central symmetric analysis interval of the interferogram in terms of the number and order of sampling points, and is used to jointly construct the analytic signal. By using the central local sequence as input to the Hilbert transform, the envelope amplitude sequence can be kept consistent with the analysis interval used in the subsequent second-order difference analysis, thus avoiding result deviations caused by inconsistencies between the Hilbert transform's effective range and the difference analysis range. A complex sequence is constructed by using the interferogram amplitude sequence as the real part of a complex number and the corresponding imaginary part sequence as the imaginary part of a complex number. A modulo operation is performed on each sampling point in the complex sequence to obtain the interferogram envelope amplitude sequence. This modulo operation involves squaring the real and imaginary parts of the complex number corresponding to each sampling point, summing the sums, and then taking the square root of the sum to obtain the envelope amplitude corresponding to the sampling point. The interferogram envelope amplitude sequence has the same length as the interferogram amplitude sequence within the central symmetric analysis interval of the interferogram, and is used to characterize the changing trend of the overall energy envelope of the interferogram within the current analysis interval. A second-order difference operation is performed on each interferogram amplitude within the central symmetric analysis interval of the interferogram to obtain the interferogram amplitude. Figure 2 The step difference fraction represents all interference within the interval. Figure 2 The first-order difference values ​​are squared and summed, then divided by the number of sampling points in the interval minus two. The square root of the divisor is taken to obtain the standard value of the second-order difference. The second-order difference operation characterizes the curvature change intensity of the interferogram amplitude at local sampling points, and the number of sampling points in the interval minus two corresponds to the number of effective sampling points that can form the second-order difference. Interference Figure 2The first-order difference value is calculated using the discrete second-order difference form of three adjacent sampling points, thus reflecting the sharpness of local amplitude fluctuations. A larger second-order difference standard value indicates more pronounced local vibrations, distortions, or high-frequency disturbances within the current central analysis interval. A first-order difference operation is performed on the envelope amplitude of each interferogram within the centrally symmetrical analysis interval to obtain the envelope first-order difference value. All envelope first-order difference values ​​within the interval are squared, summed, and divided by the number of sampling points in the interval minus one. The square root of the divisor is then used to obtain the envelope first-order difference standard value. The first-order difference operation characterizes the intensity of envelope amplitude variation along the sampling point direction; the number of sampling points in the interval minus one corresponds to the number of effective sampling points that can form a first-order difference. A larger envelope first-order difference standard value indicates more pronounced overall envelope fluctuations within the current central analysis interval. By constructing second-order difference standard values ​​and envelope first-order difference standard values ​​separately, local high-frequency fluctuation characteristics can be distinguished from overall envelope variation characteristics. The vibration envelope disturbance separation value is obtained by dividing the second-order difference standard value by the sum of the first-order difference standard value of the envelope and the minimum positive number. The minimum positive number is used to avoid numerical divergence or calculation instability caused by an excessively small denominator when the first-order difference standard value of the envelope is too small or close to zero. Preferably, this minimum positive number is used. arrive Positive numbers between these ranges. The vibration envelope disturbance separation value is used to characterize the proportion of local vibration fluctuation features relative to the overall envelope fluctuation features. When this value increases, it indicates that the local vibration disturbance component is relatively more prominent; when this value decreases, it indicates that the overall envelope fluctuation component is relatively more obvious. By extracting the envelope amplitude sequence within a unified centrally symmetric analysis interval and further constructing the vibration envelope disturbance separation value, a quantifiable and comparable disturbance separation basis can be provided for subsequent anomaly source determination.

[0044] The specific formula for the vibration envelope disturbance separation value is as follows:

[0045] ;

[0046] In the formula, The vibration envelope perturbation separation value represents the relative strength of local vibration perturbation and overall envelope fluctuation in the current scan. The larger the vibration envelope perturbation separation value, the more prominent the local vibration characteristics are; the smaller the vibration envelope perturbation separation value, the higher the proportion of envelope fluctuation components. This indicates the number of sampling points within the central symmetry analysis interval of the interferogram, used for normalizing the difference results within the interval; Indicates interference Figure 2 The step difference value is used to characterize the intensity of curvature change in the interferogram amplitude at local locations; This represents the first-order difference value of the envelope, used to characterize the intensity of the change in the envelope amplitude along the sampling point direction; This represents a very small positive number, used to avoid zero denominators and ensure the stability of the formula calculation; the preferred value is [value missing]. arrive .

[0047] In this implementation scheme, the envelope amplitude sequence can be stably extracted within a unified interferogram center-symmetric analysis interval. By introducing boundary processing and protection against minimal positive numbers, the stability and feasibility of the Hilbert transform and subsequent difference calculations are improved, thereby enhancing the accuracy, robustness, and consistency of the perturbation separation feature extraction results and the subsequent anomaly source determination results.

[0048] Specifically, the process of determining the source of the current scan anomaly based on the disturbance separation characteristics is as follows: When the current scan is determined to be abnormal, the stability determination result obtained by the aforementioned mirror symmetry deviation value being greater than the deviation threshold is used as a prerequisite. If the vibration envelope disturbance separation value is greater than or equal to the separation determination threshold, the source of the current scan anomaly is determined to be a mechanical vibration anomaly. The separation determination threshold is used to distinguish between anomalies where local vibration disturbance components dominate and anomalies where overall envelope fluctuation components dominate. Mechanical vibration anomalies are used to characterize situations where the current scan anomaly is mainly caused by local vibration fluctuations, mechanical impacts, structural shaking, or abnormal scan rhythm. If the vibration envelope disturbance separation value is less than the separation determination threshold, the source of the current scan anomaly is determined to be a light source and environmental disturbance anomaly. Light source and environmental disturbance anomalies are used to characterize situations where the current scan anomaly is mainly caused by light source output fluctuations, environmental airflow disturbances, insufficient thermal stability, or abnormal overall envelope changes. By comparing the vibration envelope disturbance separation value with the separation determination threshold, the source of the anomaly can be further subdivided under the premise that the current scan has been determined to be abnormal, thereby providing a basis for the differentiated generation of subsequent recovery control strategies. When the current scan is determined to be stable, only the vibration envelope disturbance separation value is recorded. This means that without triggering the anomaly source classification results, the vibration envelope disturbance separation value corresponding to the current scan is written into the database as a reference feature under stable scan conditions for subsequent analysis. By continuously recording the vibration envelope disturbance separation value under stable scan conditions, a data foundation can be provided for subsequently constructing a normal disturbance reference range. The vibration envelope disturbance separation value and anomaly type are written into the infrared spectroscopy online self-test database. For scan records determined to be mechanical vibration anomalies and light source and environmental disturbance anomalies, corresponding anomaly category identifiers can be established in the database to support the subsequent recovery control and handling module in calling different control strategies according to the anomaly type. By uniformly storing the vibration envelope disturbance separation value and anomaly type, the continuity, traceability, and engineering feasibility of the online anomaly diagnosis process can be improved.

[0049] This implementation plan can further distinguish the source of anomalies based on the identification of scan anomalies, and simultaneously record the disturbance separation characteristics when the scan is stable, providing a unified basis for anomaly classification, normal disturbance statistics and subsequent handling strategy generation, thereby improving the pertinence, continuity and traceability of online anomaly diagnosis.

[0050] Specifically, the process of identifying disturbance intensity by combining mirror symmetry features and disturbance separation features, and evaluating the current disturbance recovery trend based on the disturbance intensity and scanning time interval, is as follows: The scanning disturbance intensity value is obtained by multiplying the mirror symmetry deviation value by the sum of the vibration envelope disturbance separation value and one. The mirror symmetry deviation value characterizes the degree of deviation from the mirror consistency on both sides of the interferogram center, while the vibration envelope disturbance separation value characterizes the proportion of local vibration fluctuations relative to the overall envelope fluctuations. Both together reflect the comprehensive disturbance level of the current scanning anomaly. By multiplying the mirror symmetry deviation value by the sum of the vibration envelope disturbance separation value and one, the degree of mirror symmetry anomaly and the disturbance source features can be coupled into a single scanning disturbance intensity value while maintaining the non-negative amplification effect of the vibration envelope disturbance separation value. This value is used to uniformly characterize the comprehensive anomaly intensity of the current scan. Preferably, when the scanning disturbance intensity value is less than a preset minimum positive number, it can be set to a preset minimum positive number before subsequent natural logarithmic calculations to avoid undefined logarithms or numerical instability. The perturbation variation amplitude is obtained by subtracting the natural logarithm of the current scan perturbation intensity value from the natural logarithm of the previous scan perturbation intensity value. The previous scan perturbation intensity value is the perturbation intensity value corresponding to the scan preceding the current scan. Both the current scan perturbation intensity value and the previous scan perturbation intensity value are derived from continuous scan records in the infrared spectroscopy online self-test database. By taking the natural logarithm and differing the perturbation intensity values ​​of two adjacent scans, the relative change relationship of the perturbation level can be converted into a comparable variation amplitude, thereby enhancing the consistency of recovery trend analysis under different perturbation intensity levels. The scan time interval is obtained by subtracting the previous scan end time from the current scan end time. Both the current scan end time and the previous scan end time are determined by the timestamp recorded by the online control software when the corresponding scan task is completed. The scan time interval is the actual time difference between the completion of two adjacent scans, used to reflect the time span experienced by the system during waiting, recovery, and re-acquisition between two scans. The disturbance decay rate is obtained by dividing the disturbance change amplitude by the scan time interval. The disturbance decay rate characterizes the degree of decay of the scan disturbance intensity per unit time. A positive disturbance decay rate indicates that the current disturbance is generally weakening; a rate less than or equal to zero indicates that the current disturbance does not show a weakening trend or is in a persistent abnormal state. Normalizing the disturbance change amplitude by introducing the scan time interval avoids bias caused by directly comparing disturbance changes at different scan intervals. The scan disturbance intensity values ​​corresponding to historical stable scans are read, the median is taken, and the median absolute deviation is calculated. The median plus three times the median absolute deviation yields the normal disturbance reference value. The scan disturbance intensity values ​​corresponding to historical stable scans are the set of scan disturbance intensity values ​​corresponding to the historical records judged as stable in the aforementioned stability assessment. The median characterizes the central level of historical stable scan disturbance intensity, and the median absolute deviation characterizes the dispersion of historical stable scan disturbance intensity relative to the central level.By constructing a normal perturbation reference value using the median and median absolute deviation, the impact of extreme outliers, local drift samples, or occasional perturbation samples on the normal reference range can be reduced, thereby improving the robustness and engineering applicability of the normal perturbation reference value. The recovery waiting time is obtained by subtracting the natural logarithm of the normal perturbation reference value from the natural logarithm of the current scan perturbation intensity value and dividing by the perturbation decay rate. The recovery waiting time characterizes the estimated waiting time required for the current scan perturbation intensity to decay from the current level to the normal perturbation reference level.

[0051] The specific formula for restoring the waiting time is as follows:

[0052] ;

[0053] In the formula, This represents the recovery waiting time, used to assess the waiting time required for the current scan disturbance to decay to a normal level. By comparing the current scan disturbance intensity with historical normal disturbance reference values ​​and taking into account the disturbance decay rate, the delay waiting time is determined to guide the recovery operation. This indicates the current scan disturbance intensity value, used to reflect the disturbance level of the current scan; This represents the disturbance intensity value of the previous scan, used to calculate the disturbance decay rate; This represents the normal disturbance reference value, used to indicate the disturbance level when the historical scan is stable; This indicates the current scan end time, used to calculate the scan time interval; This indicates the end time of the previous scan, used to calculate the scan time interval.

[0054] In this embodiment, Table 1 is a recovery waiting time data table. The normal disturbance reference value is 0.08. The table details the disturbance intensity value of the previous scan, the disturbance intensity value of the current scan, the scan time interval, and the recovery waiting time for five abnormal scans. Specifically, for abnormal scan 1, the previous scan disturbance intensity value is 0.72, the current scan disturbance intensity value is 0.36, the scan time interval is 15, and the recovery waiting time is [missing value]. For abnormal scan 2, the previous scan disturbance intensity value is 0.64, the current scan disturbance intensity value is 0.30, the scan time interval is 14, and the recovery waiting time is 24.42 [missing value]. The disturbance intensity value of the previous scan for abnormal scan 3 is 0.58, the disturbance intensity value of the current scan is 0.26, the scan interval is 14, and the recovery waiting time is 20.57. The disturbance intensity value of the previous scan for abnormal scan 4 is 0.47, the disturbance intensity value of the current scan is 0.21, the scan interval is 12, and the recovery waiting time is 14.38. The disturbance intensity value of the previous scan for abnormal scan 5 is 0.36, the disturbance intensity value of the current scan is 0.16, the scan interval is 10, and the recovery waiting time is 8.55.

[0055] Table 1 Recovery Waiting Time Data Table

[0056]

[0057] like Figure 3 The figure shows a schematic diagram illustrating the changes in recovery waiting time. It illustrates the corresponding changes in the disturbance intensity value of the previous scan, the disturbance intensity value of the current scan, and the recovery waiting time across five anomaly scans. The bars represent the disturbance intensity values ​​between consecutive scans, the line represents the recovery waiting time, and the values ​​below the line indicate the specific recovery waiting time, along with the corresponding scan time interval for each anomaly scan. (Refer to Table 1 and...) Figure 3 As can be seen, as the abnormal scan number increases, the current scan disturbance intensity value continues to decrease and is always lower than the corresponding previous scan disturbance intensity value, indicating that the disturbance is in the process of decay. At the same time, the recovery waiting time gradually decreases from 32.55 to 8.55, indicating that as the current disturbance level gradually approaches the normal disturbance reference level, the recovery time required for judgment is shortened accordingly. Overall, it can better reflect the recovery trend and handling timing of abnormal scan disturbances.

[0058] In this implementation scheme, the mirror symmetry deviation characteristics and vibration envelope disturbance separation characteristics can be combined into a unified scanning disturbance intensity index, and the disturbance recovery trend can be dynamically evaluated by combining the continuous scanning time interval. This provides a quantitative basis for determining the recovery waiting time and subsequent handling control, and improves the accuracy, robustness and engineering applicability of online anomaly recovery judgment.

[0059] Specifically, the process of generating the corresponding handling control strategy based on the evaluation results is as follows: When the current scan is determined to be abnormal, the disturbance decay rate and recovery waiting time are calculated to generate the handling control strategy. The determination of the current scan as abnormal is based on the stability judgment result obtained when the aforementioned mirror symmetry deviation value is greater than the deviation threshold, which serves as the triggering premise for generating the handling control strategy. The disturbance decay rate and recovery waiting time are both derived from the calculation results of the aforementioned disturbance recovery trend evaluation step, used to characterize whether the current abnormality is in a recovery state and the expected time required to recover to the normal disturbance level. Based on the current scan abnormality state, the disturbance decay rate, and the recovery waiting time, the control branch for either delaying the rescan or performing abnormality recovery processing is automatically determined. If the disturbance decay rate is greater than zero, it indicates that the current scan disturbance is generally in a decay trend. Therefore, a delay is executed based on the recovery waiting time, and a rescan is performed after the wait ends. Executing a delay based on the recovery waiting time means that the control system pauses the triggering of the next scan task after the current scan ends and maintains a waiting state according to the calculated recovery waiting time, in order to provide a time window for further decay of the abnormal disturbance. Rescanning after the waiting period ends refers to the online control software automatically sending a new scan start command to the spectrometer after the waiting time has elapsed, re-scanning and acquiring data on the current measurement object to verify whether the current disturbance has recovered to an acceptable range. Preferably, before rescanning, the original measurement parameters, scan configuration, and data recording method are kept unchanged to improve the comparability of the two scan results. If the disturbance attenuation rate is less than or equal to zero, it is determined that the abnormality has not attenuated, and the current scan state is not suitable for recovery through simple delay. A recovery strategy is triggered: the scan is stopped, and a control command to restart the Fourier transform infrared spectrometer is generated, along with prompts to check the equipment and environmental status and reacquire the background. Stopping the scan prevents subsequent automatic continuous scanning from continuing to avoid the continuous generation of invalid scan data under abnormal conditions. Generating a control command to restart the Fourier transform infrared spectrometer means that the online control software outputs a control command to the spectrometer control unit to execute the restart operation; when the conditions for automatic restart are not met, the control command can be output to the operation interface in the form of a restart prompt message. The prompts for checking equipment and environmental status are at least used to remind operators to check the current mechanical status of the spectrometer, the status of the light source, the status of the sample chamber, and environmental interference factors; the prompts for re-acquiring the background are used to re-establish valid background reference data after the abnormal status is resolved, so as to reduce the impact of background drift, environmental changes, or previous abnormal status on subsequent scanning results.

[0060] like Figure 4The diagram illustrates a workflow for online self-diagnostic control of Fourier transform infrared (FTIR) spectrometers. First, after starting the online operation of the FTIR spectrometer, it collects online data for each scan in real time, including scan time and interferogram amplitude sequence. The interferogram amplitude sequence undergoes DC removal and normalization processing, and the raw and pre-processed data are stored in the self-diagnostic database. Next, based on the pre-processed interferogram amplitude sequence, the zero optical path difference position is identified, and a centrally symmetric analysis interval is constructed. Within this interval, mirror symmetry features are extracted, and the mirror symmetry deviation value is calculated. This deviation value is then compared with a preset deviation threshold to determine whether the current scan state is stable or abnormal. When stable, the mirror symmetry deviation value and vibration envelope perturbation separation value are recorded and further used in subsequent perturbation intensity calculations. When abnormal, the vibration envelope perturbation separation value is calculated and compared with a separation threshold to distinguish whether the current anomaly originates from mechanical vibration or light source / environmental disturbances. Subsequently, the scan disturbance intensity value is calculated by combining the mirror symmetry deviation characteristics and vibration envelope disturbance separation characteristics, and stored in the self-test database. Then, the disturbance attenuation rate is calculated by combining the previous scan disturbance intensity value and the scan time interval. Simultaneously, a normal disturbance reference value is statistically analyzed based on historical stable data, and the recovery waiting time is derived. Finally, the corresponding handling control strategy is executed according to the disturbance attenuation rate: if the disturbance attenuation rate is greater than zero, a delay waiting period is executed according to the recovery waiting time, and a rescan is performed after the waiting period ends; if the disturbance attenuation rate is less than or equal to zero, the current scan is stopped, an instrument restart control command is generated, and a prompt for equipment and environmental status check and background re-acquisition is simultaneously generated, thereby achieving automatic diagnosis and handling control of online anomalies.

[0061] This implementation plan can adaptively generate delayed rescan or anomaly recovery handling strategies based on the recovery trend of the current scan anomaly. When the disturbance can be attenuated, it reduces ineffective intervention and triggers restart and inspection prompts in a timely manner when the disturbance has not attenuated, thereby improving the pertinence, automation level and engineering application effect of online anomaly handling.

[0062] Reference Figure 2As shown, the second aspect of the present invention provides a Fourier transform infrared spectroscopy online self-test diagnostic control system, applied to the aforementioned Fourier transform infrared spectroscopy online self-test diagnostic control method, comprising: an online data acquisition and processing module, used to acquire the interferogram amplitude sequence of each scan of the spectrometer in real time, preprocess the interferogram amplitude sequence, identify the zero optical path difference position based on the interferogram amplitude sequence, and construct the central symmetry analysis interval of the interferogram; an interferogram quality assessment module, used to analyze the mirror symmetry features using the interferogram amplitude sequence within the central symmetry analysis interval of the interferogram, and assess the current scan stability based on the mirror symmetry features; an anomaly diagnosis and discrimination module, used to extract the envelope amplitude sequence based on the interferogram amplitude sequence, extract the disturbance separation features by combining the envelope amplitude sequence and the interferogram amplitude sequence, and determine the source of the current scan anomaly based on the disturbance separation features; and a recovery control and handling module, used to identify the disturbance intensity by comprehensively considering the mirror symmetry features and the disturbance separation features, assess the current disturbance recovery trend based on the disturbance intensity and the scan time interval, and generate a corresponding handling control strategy based on the assessment results.

[0063] This implementation plan can form a closed-loop self-diagnostic link of "acquisition preprocessing, quality assessment, anomaly identification, and recovery handling" around the interferogram data during the online operation of the spectrometer. It can realize continuous analysis of scanning stability, anomaly sources and recovery trends, and adaptively generate handling strategies based on the assessment results, thereby improving the accuracy of online anomaly identification, the pertinence of recovery control, the automation level of system operation and the engineering application effect.

[0064] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0065] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. As those skilled in the art will understand, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A Fourier transform infrared spectroscopy online self-testing diagnostic control method, characterized in that, Includes the following steps: S1: Real-time acquisition of the interferogram amplitude sequence of each scan by the spectrometer; preprocessing of the interferogram amplitude sequence; identification of the zero optical path difference position based on the interferogram amplitude sequence; and construction of the central symmetric analysis interval of the interferogram. S2, analyze the mirror symmetry features by analyzing the interferogram amplitude sequence within the central symmetry analysis interval of the interferogram, and evaluate the current scan stability based on the mirror symmetry features; The specific process of analyzing mirror symmetry features using the interferogram amplitude sequence within the central symmetry analysis interval of the interferogram is as follows: Read the central symmetry analysis interval of the interferogram, multiply the interferogram amplitudes of the left sampling point and the corresponding right sampling point in the interval pairwise, and sum all the multiplications in the interval to obtain the mirror product value; Calculate and sum the squares of the interferogram amplitudes corresponding to the left sampling points within the central symmetry analysis interval of the interferogram to obtain the left-side sum of squares; calculate and sum the squares of the interferogram amplitudes corresponding to the right sampling points within the central symmetry analysis interval of the interferogram to obtain the right-side sum of squares. Multiply the square roots of the sum of squares on the left and the sum of squares on the right respectively to obtain the normalized product value; Subtract the ratio of the mirror product value to the normalized product value from one to obtain the mirror symmetry deviation value; S3, extract the envelope amplitude sequence based on the interferogram amplitude sequence, combine the envelope amplitude sequence and the interferogram amplitude sequence to extract the perturbation separation feature, and determine the source of the current scanning anomaly based on the perturbation separation feature; The specific process of extracting the envelope amplitude sequence based on the interferogram amplitude sequence and extracting the perturbation separation features by combining the envelope amplitude sequence and the interferogram amplitude sequence is as follows: Read the interferogram amplitude sequence within the central symmetric analysis interval of the interferogram, perform Hilbert transform on the interferogram amplitude sequence to obtain the imaginary part sequence; take the interferogram amplitude sequence as the real part of the complex number and the corresponding imaginary part sequence as the imaginary part of the complex number to construct a complex sequence, and perform modulo operation on each sampling point in the complex sequence to obtain the interferogram envelope amplitude sequence; Perform a second-order difference operation on each interferogram amplitude within the central symmetric analysis interval of the interferogram to obtain the second-order difference value of the interferogram. Square all the second-order difference values ​​of the interferogram within the interval, sum them up, divide by the number of sampling points in the interval minus two, and take the square root of the divisor to obtain the standard value of the second-order difference. Perform a first-order difference operation on each interferogram envelope amplitude within the central symmetric analysis interval of the interferogram to obtain the first-order difference value of the envelope. Square all the first-order difference values ​​of the envelope within the interval, sum them up, divide by the number of sampling points in the interval minus one, and take the square root of the divisor to obtain the standard value of the first-order difference of the envelope. The vibration envelope disturbance separation value is obtained by dividing the second-order difference standard value by the sum of the first-order difference standard value of the envelope and the smallest positive number. S4. The disturbance intensity is identified by combining the mirror symmetry feature and the disturbance separation feature. Based on the disturbance intensity and the scanning time interval, the current disturbance recovery trend is evaluated, and the corresponding handling and control strategy is generated according to the evaluation result. The process of identifying the disturbance intensity using the integrated mirror symmetry feature and the disturbance separation feature, and evaluating the current disturbance recovery trend based on the disturbance intensity and the scanning time interval, is as follows: The scanning disturbance intensity value is obtained by multiplying the mirror symmetry deviation value by the sum of the vibration envelope disturbance separation value and one; the disturbance change amplitude is obtained by subtracting the natural logarithm of the current scanning disturbance intensity value from the natural logarithm of the previous scanning disturbance intensity value; the scanning time interval is obtained by subtracting the previous scanning time from the current scanning end time; and the disturbance decay rate is obtained by dividing the disturbance change amplitude by the scanning time interval. Read the historical scan disturbance intensity value corresponding to the stable scan, take the median and calculate the median absolute deviation, add three times the median absolute deviation to the median to obtain the normal disturbance reference value; subtract the natural logarithm of the normal disturbance reference value from the natural logarithm of the current scan disturbance intensity value, and divide by the disturbance decay rate to obtain the recovery waiting time; The specific process for generating corresponding disposal and control strategies based on the evaluation results is as follows: When an anomaly is detected in the current scan, the disturbance decay rate and recovery waiting time are calculated to generate a handling control strategy: If the disturbance decay rate is greater than zero, a delay wait is performed based on the recovery wait time, and a rescan is performed after the wait is over; If the disturbance decay rate is less than or equal to zero, it is determined that the abnormality has not decayed, and the recovery strategy is triggered: the scan is stopped and a control command to restart the Fourier transform infrared spectrometer is generated, and prompts to check the equipment and environmental status and reacquire the background are generated.

2. The Fourier transform infrared spectroscopy online self-testing diagnostic control method according to claim 1, characterized in that, The specific process for preprocessing the interferogram amplitude sequence obtained from each scan by the real-time acquisition spectrometer is as follows: During the operation of the Fourier transform infrared spectrometer, the online data of the spectrometer for each scan is acquired in real time through the acquisition driver and instrument control interface. The online data of the spectrometer includes: scan start time, scan end time and interferogram amplitude sequence. The interferogram amplitude sequence is processed by deDCing by calculating the average value and subtracting it from the original sequence. The interferogram amplitude sequence is then normalized by dividing the deDCed interferogram amplitude sequence by the maximum absolute interferogram amplitude. An infrared spectroscopy online self-test database is established to store the original and preprocessed spectrometer online data.

3. The Fourier transform infrared spectroscopy online self-testing diagnostic control method according to claim 2, characterized in that, The specific process of identifying the zero optical path difference position based on the interferogram amplitude sequence and constructing the centrally symmetric analysis interval of the interferogram is as follows: In the interferogram amplitude sequence, the sampling point corresponding to the largest absolute value of the interferogram amplitude is selected to obtain the zero optical path difference position. With the zero optical path difference position as the center, the interferogram amplitude is traversed along the left and right sides respectively. The number of sampling points whose interferogram amplitude is continuously greater than or equal to the central peak amplitude ratio threshold is calculated, and the number of the most sampling points on the left and right sides is taken as the length of the central analysis window. With the zero optical path difference position as the center and the length of the central analysis window, the extension range on the left and right sides is determined to construct the central symmetric analysis interval of the interferogram.

4. The Fourier transform infrared spectroscopy online self-test diagnostic control method according to claim 1, characterized in that, The specific process for evaluating the current scan stability based on mirror symmetry features is as follows: The stability is determined by comparing the mirror symmetry deviation value with the deviation threshold. When the deviation value of mirror symmetry is less than or equal to the deviation threshold, the current scan is considered stable; When the deviation value of the mirror symmetry is greater than the deviation threshold, the current scan is determined to be abnormal; The mirror symmetry deviation value and stability judgment result are written into the infrared spectroscopy online self-test database.

5. The Fourier transform infrared spectroscopy online self-testing diagnostic control method according to claim 1, characterized in that, The specific process for determining the source of the current scan anomaly based on the perturbation separation characteristics is as follows: When the current scan is determined to be abnormal, if the vibration envelope disturbance separation value is greater than or equal to the separation determination threshold, the source of the current scan abnormality is determined to be a mechanical vibration type abnormality. If the vibration envelope disturbance separation value is less than the separation judgment threshold, the current scanning anomaly source is determined to be an anomaly of light source and environmental disturbance. When the current scan is determined to be stable, only the vibration envelope disturbance separation value is recorded; The vibration envelope disturbance separation value and anomaly type are written into the infrared spectroscopy online self-test database.

6. A Fourier transform infrared spectroscopy online self-testing diagnostic control system, employing the Fourier transform infrared spectroscopy online self-testing diagnostic control method as described in any one of claims 1-5, characterized in that, include: The online data acquisition and processing module is used to acquire the interferogram amplitude sequence of each scan of the spectrometer in real time, preprocess the interferogram amplitude sequence, identify the zero optical path difference position based on the interferogram amplitude sequence, and construct the central symmetry analysis interval of the interferogram. The interferogram quality assessment module is used to analyze the mirror symmetry features by using the interferogram amplitude sequence within the central symmetry analysis interval of the interferogram, and to assess the stability of the current scan based on the mirror symmetry features. The anomaly diagnosis and discrimination module is used to extract the envelope amplitude sequence based on the interferogram amplitude sequence, extract the perturbation separation features by combining the envelope amplitude sequence and the interferogram amplitude sequence, and determine the source of the current scan anomaly based on the perturbation separation features; The recovery control and handling module is used to identify the disturbance intensity by combining mirror symmetry features and disturbance separation features. Based on the disturbance intensity and the scanning time interval, it evaluates the current disturbance recovery trend and generates corresponding handling and control strategies based on the evaluation results.

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