Vibration fiber alarm threshold adjusting system and method based on wind speed and direction compensation

Abstract

The present application relates to the technical fields of optical fiber sensing, perimeter security, environmental sensing and computer data processing, in particular to a kind of vibration optical fiber perimeter alarm threshold adaptive adjustment system and method based on wind speed and direction compensation, according to wind speed, wind direction, fence azimuth angle and wind speed and direction sensor installation correction angle, vibration optical fiber perimeter alarm threshold is compensated and adaptively adjusted in real time, it is suitable for fence, border line, oil depot, pipeline, storage area, transformer substation and other outdoor perimeter intrusion monitoring, it can also be used for long distance defense area with obvious wind-induced vibration interference, the present application is aimed at the vibration fiber background vibration fluctuation caused by wind speed and wind direction change in outdoor perimeter, it solves the problem that fixed alarm threshold cannot consider wind-induced false alarm suppression and real intrusion detection, environmental data and vibration data time are inconsistent, the influence degree of wind in different directions on fence is not distinguished, threshold value is suddenly changed with instantaneous data and lack of safety fallback after environmental sensor failure.

Description

Technical Field

[0001] This invention relates to the fields of fiber optic sensing, perimeter security, environmental perception, and computer data processing. Specifically, it relates to a system and method for real-time compensation and adaptive adjustment of vibration fiber optic perimeter alarm thresholds based on wind speed, wind direction, fence azimuth angle, and the installation correction angle of wind speed and direction sensors. This system is suitable for intrusion monitoring of fences, border lines, oil depots, pipelines, storage areas, substations, and other outdoor perimeters, and can also be used in long-distance protection zones with significant wind-induced vibration interference. Background Technology

[0002] Perimeter security systems are used to continuously monitor the boundaries of protected areas. When people climb, knock, cut, pull, or touch the fence, the fence and its fixed sensing media will generate mechanical vibrations. The system detects these vibrations to determine if an intrusion has occurred. Existing perimeter detection methods include vibrating fiber optics, vibrating cables, infrared beams, laser beams, and microwave detection. Vibrating fiber optics have advantages such as no need for power supply at the field sensing end, resistance to electromagnetic interference, long transmission distance, ease of zone delineation, and suitability for complex electromagnetic environments, and are increasingly being used for long-distance fences and perimeters of important facilities.

[0003] A vibration fiber optic perimeter alarm system typically includes a sensing fiber optic cable fixed to the fence, a vibration fiber optic host, and an alarm display terminal. The vibration fiber optic host acquires vibration signals corresponding to fence disturbances. A host computer or main unit analyzes the amplitude, energy, or frequency characteristics of the vibration signals. An alarm is triggered when the analysis results exceed a preset alarm threshold. In existing systems, alarm thresholds are often set once by installers based on field experience, or manually switched between several preset sensitivity levels.

[0004] In outdoor environments, wind acts on fence panels, posts, attached markers, and fiber optic sensors, causing continuous or intermittent background vibrations. The intensity of wind-induced vibration depends not only on wind speed but also on the angle between the wind direction and the fence's extension direction, the fence material, the tightness of the mesh, the installation location, and the local terrain. When the wind direction is close to the fence's normal direction, the fence's wind-exposed area is usually larger; when the wind direction is close to the fence's extension direction, the direct wind impact is usually smaller. Therefore, relying solely on wind speed or using only fixed alarm thresholds is insufficient to accurately reflect changes in background vibration under different wind conditions. The main problems include: (1) The fixed alarm threshold cannot change with the wind field. When the threshold is set according to calm or light wind conditions, strong winds and gusts may cause the background vibration to exceed the threshold and generate false alarms; when the threshold is increased for a long time to suppress false alarms in strong winds, the detection sensitivity of the system may be reduced when the wind force decreases or a real intrusion occurs.

[0005] (2) Existing environmental sensing equipment and vibration fiber optic equipment often work independently. The sampling period, transmission path and time reference of environmental data and vibration data are inconsistent. The system cannot reliably determine the wind speed and wind direction corresponding to a certain vibration analysis window, resulting in mismatch between environmental compensation and vibration signal.

[0006] (3) Some solutions only adjust the threshold linearly according to the wind speed, without considering the fence azimuth and sensor installation direction. When the same wind speed acts on the fence from different directions, using the same compensation amount will result in insufficient or excessive compensation.

[0007] (4) When wind speed and direction data change instantaneously, sensor communication is interrupted, or network packets are lost, if the threshold is changed directly according to the latest data, it is easy to cause sudden changes in the threshold, fluctuating alarm status, or the threshold remaining in an unreasonable state for a long time.

[0008] (5) In traditional systems, vibration alarm, video monitoring, environmental status and alarm records are independent of each other. After an alarm occurs, it is necessary to manually search for the corresponding camera and environmental information, which is not conducive to rapid verification and evidence preservation.

[0009] Therefore, there is a need for a vibration fiber optic perimeter alarm system and method that does not rely on deep learning training data, can calculate alarm thresholds in real time based on interpretable wind speed and direction compensation relationships, and simultaneously has time synchronization, threshold limiting, rate of change constraint, anomaly backoff and alarm linkage functions. Summary of the Invention

[0010] To address the above issues, this invention provides an adaptive adjustment system and method for vibration fiber optic perimeter alarm thresholds based on wind speed and direction compensation. It overcomes the problem that fixed alarm thresholds cannot simultaneously suppress wind-induced false alarms and detect actual intrusions, addressing background vibration fluctuations in outdoor perimeters caused by changes in wind speed and direction. It also resolves issues such as inconsistencies between environmental and vibration data timelines, lack of differentiation in the impact of wind from different directions on the fence, threshold abrupt changes with instantaneous data, and the lack of safety fallback after environmental sensor failure. This invention configures or associates wind speed and direction information with fence azimuth parameters in each vibration fiber optic protection zone. Under a unified time reference, it matches environmental data with the vibration analysis window, calculates the wind field threshold compensation based on the wind speed coefficient and relative wind direction coefficient, and then generates the current dynamic alarm threshold through upper and lower limits, time smoothing, and rate of change constraints. Based on this dynamic alarm threshold, alarm judgment and video linkage are then performed.

[0011] The complete technical solution of this invention includes: An adaptive adjustment system for vibration fiber optic perimeter alarm thresholds based on wind speed and direction compensation includes a vibration fiber optic sensing unit, an environmental sensing unit, an embedded acquisition unit, a data communication and time synchronization unit, a dynamic threshold calculation unit, an alarm judgment unit, a video linkage and storage unit, and a host computer display and interaction unit. These units can be housed in the same device or distributed across a field controller, a vibration fiber optic host, an edge computing device, and a host computer server.

[0012] In the vibration fiber optic sensing unit, vibration fibers are deployed along the perimeter fence and divided into one or more zones according to spatial location. The vibration fiber optic host collects vibration signals from each zone and outputs the original waveform, characteristic values, or pre-alarm analysis data. Each zone corresponds to a unique zone number and stores the fence azimuth angle, basic threshold, and compensation parameters for that zone.

[0013] The environmental sensing unit includes at least wind speed and direction sensors to output the current wind speed and direction. The environmental sensing unit may also include temperature sensors, humidity sensors, door sensors, or other switching sensors for status display, alarm assistance, and operation recording. Temperature, humidity, and door sensors are not necessary inputs for wind speed and direction compensation unless configured as auxiliary compensation values ​​after field calibration.

[0014] The embedded acquisition unit connects to wind speed and direction sensors, temperature and humidity sensors, and door magnets. It performs protocol parsing, range checks, outlier checks, and data packaging on the sensor data, and adds device number, zone number, acquisition timestamp, and check code to the data frame.

[0015] The data communication and time synchronization unit transmits environmental and vibration data via Ethernet, fiber optic data bus, serial bus, or wireless network. Ethernet and TCP protocols are preferred. This unit uses a unified clock or a calibrated local clock as its time reference, writes environmental and vibration data into a buffer queue according to the zone number and timestamp, and matches wind speed and direction data for the corresponding time period with the vibration analysis window as a reference.

[0016] The dynamic threshold calculation unit filters the matched wind speed and direction, calculates the relative wind direction coefficient based on the wind direction, fence azimuth angle and installation correction angle, calculates the normalized wind speed coefficient based on the wind speed, and calculates the wind field threshold compensation amount. After superimposing the compensation amount with the basic alarm threshold, the unit sequentially executes the upper and lower limit constraints of the threshold, time smoothing and single-cycle change rate constraints, and outputs the current dynamic alarm threshold of each defense zone.

[0017] The alarm determination unit extracts at least one feature from the vibration signal, including waveform peak value, peak-to-peak value, root mean square value, and frequency band energy, and compares it with the current dynamic alarm threshold. The alarm determination unit can use continuous threshold counting, multi-window voting, or a state machine with hysteresis to confirm the alarm, in order to reduce false triggering caused by isolated pulses and jitter near the threshold.

[0018] The video linkage and storage unit establishes a correspondence between the zone number and the camera number. When an alarm is confirmed, the corresponding camera is used to capture an image or to save a video of a preset duration before and after the alarm, and the alarm time, zone number, vibration characteristics, dynamic threshold, wind speed, wind direction, and equipment status are recorded.

[0019] The host computer display and interaction unit includes functional modules such as network connection, device status, vibration waveform, environmental parameters, dynamic threshold, manual / automatic mode, video monitoring, alarm prompts, and alarm logs. In automatic mode, the threshold is generated by the dynamic threshold calculation unit; during maintenance or debugging, it can be switched to manual mode, where the manually entered threshold is still subject to the allowable range.

[0020] The dynamic threshold calculation unit uses the following methods for wind speed and direction compensation and dynamic threshold calculation: For ease of explanation, the defense zone number is as follows: The current calculation time is Each defense zone is pre-configured with a basic threshold. Threshold lower limit Threshold upper limit Fence azimuth angle Wind speed and direction sensor installation correction angle Compensation for initial wind speed , set upper limit wind speed Wind speed index Maximum compensation coefficient directional residual coefficient Smoothing coefficient Threshold rise rate limit and threshold descent rate limit The above parameters can use the device's default values ​​and be corrected during the on-site installation and commissioning phase based on non-intrusive background data.

[0021] 1) Data preprocessing and time matching. Median filtering, moving average, or low-pass filtering are applied to the wind speed data to obtain the filtered wind speed. ( For wind direction data, use circular or vector averages to avoid... and Numerically, it was mistakenly considered as a difference. For each vibration analysis window Based on the center or end time, select data from the environmental cache queue whose time difference is not greater than the preset matching tolerance; when there are multiple valid environmental data, calculate the average wind speed and average wind direction within the window.

[0022] (2) Calculation of relative wind direction coefficient. The wind direction angle output by the wind direction sensor and the azimuth angle of the defense zone fence use the same angular reference. The installation correction angle is used to compensate for the deviation between the zero direction of the sensor and the system angular reference. The relative wind direction coefficient is calculated according to formula (1): (1) in, Let be the relative wind direction coefficient of the j-th defense zone, with a value ranging from 0 to 1; The current wind direction angle; For the first The azimuth angle corresponding to the direction of the extension of the defense zone fence; This is the installation correction angle for the wind speed and direction sensor.

[0023] Because the absolute value of a sine wave is used, when the wind direction is parallel to the direction of the fence... Approaching 0, when the wind direction is perpendicular to the direction of the fence. It is close to 1, and the wind coming from both sides of the fence can be treated consistently.

[0024] (3) Calculation of wind speed coefficient. The filtered wind speed is normalized according to the compensation starting wind speed and the calibration upper limit wind speed, and then calculated using an exponential function. The nonlinear effect of adjusting wind speed on the compensation amount is calculated according to formula (2): (2) in, This is the normalized wind speed coefficient; This means that the value inside the parentheses is limited to between 0 and 1; The wind speed at which wind field compensation begins; To determine the upper limit wind speed, Greater than ; A wind speed index greater than 0. When the wind speed is lower than... hour, =0; when the wind speed reaches or exceeds hour, The value is 1.

[0025] (4) Calculation of wind field threshold compensation. The threshold compensation is calculated based on the wind speed coefficient and relative wind direction coefficient. The wind field threshold compensation amount for the defense zone is preferably calculated according to formula (3): (3) in, This is the wind field threshold compensation amount; For the first The maximum compensation range of the defense zone under the specified upper limit wind speed; This is the directional residual coefficient, ranging from 0 to 1, used to characterize the residual wind-induced vibrations that may still be caused by turbulence, fence appurtenances, or local topography even when the wind direction is close to the fence direction. When the site structure is simple and the effect of parallel winds is negligible... It can be set to 0.

[0026] (5) Calculation of the original dynamic threshold. The original dynamic threshold is obtained by adding the basic threshold and the wind field threshold compensation amount, and then calculated according to formula (4): (4) in, For the first The current original dynamic threshold of the defense zone, The baseline threshold is determined under calm or light wind conditions.

[0027] (6) Threshold upper and lower limits constraint. To avoid excessive compensation leading to missed alarms, and to avoid incorrect parameter settings resulting in excessively low thresholds, the original dynamic threshold is limited according to formula (5): (5) in, This is the threshold after limiting. Upper threshold. The threshold margin for target events such as climbing, knocking, shearing, or touching should be determined through field intrusion testing, ensuring that such events remain within acceptable threshold margins even under the most unfavorable wind conditions.

[0028] (7) Time smoothing and rate of change constraints. To avoid sudden changes in the threshold due to gusts, wind direction jumps, or single abnormal data, the final dynamic alarm threshold is generated according to formula (6): (6) in, This represents the current output threshold for the j-th defense zone. The smoothing coefficient is between 0 and 1; and These represent the maximum allowable increase and decrease in the threshold within a single calculation cycle. To ensure the system quickly recovers detection sensitivity when wind speed decreases, the threshold decrease rate can be limited. Set to a rate of increase not less than the threshold At the same time, appropriate smoothness is maintained to prevent frequent switching of alarm states.

[0029] (8) Vibration characteristics and alarm determination. Preferably within a time window. The maximum absolute amplitude of the vibration waveform relative to the window mean is calculated using formula (7):

[0030] in, For the first Current vibration characteristic values ​​of the protected area These are vibration sample values. The mean value is the window value. The system can also use peak-to-peak value, root-mean-square value, or band energy as characteristic values. When continuous More than 10 windows Or recently At least one window More than 10 windows When a vibration alarm is detected, a hysteresis threshold lower than the alarm threshold is used to clear the alarm, in order to avoid repeated alarm activation and deactivation caused by fluctuations in the characteristic value around the threshold.

[0031] (9) Environmental Data Anomaly Rollback. When wind speed and direction data verification fails, exceeds the effective range, timestamp expires, or communication is interrupted, the system does not use the abnormal data to calculate a new threshold. During short-term anomalies, the most recent effective threshold is maintained; after the anomaly persists for more than a preset time, the system switches to a preset safety threshold and outputs the environmental sensor fault status. The safety threshold is not higher than the upper limit of the threshold and is determined by on-site acceptance testing. After the environmental data is restored, the system gradually restores the automatic threshold through smoothing and rate of change constraints.

[0032] Parameter calibration method: This invention does not require the use of deep learning or neural networks. System parameters can be determined through non-intrusive background data during the installation and debugging phase, manual intrusion testing, and an interpretable parameter calibration process. Specifically, this includes: Step A: Set the azimuth angle of the fence for each defense zone and the installation correction angle for the wind speed and direction sensors, and confirm that all angles use the same reference direction.

[0033] Step B: When there is no intrusion and the wind speed is lower than the compensation start wind speed. Under these conditions, characteristic values ​​from multiple vibration analysis windows are collected, and preset quantiles are used. And increase safety margin The basic threshold is obtained, and it is preferably calculated according to formula (8): (8) in, This represents quantile operations. The probability of false triggering in the background can be set according to the allowed settings; This indicates no intrusion and wind speed is lower than the compensation start wind speed. The first time the data was collected Set of background vibration characteristic values ​​for the defense zone; For safety margin, if long-term data collection cannot be completed on-site temporarily, the equipment's empirical value can be used as a basic threshold and updated in subsequent maintenance.

[0034] Step C: Record the upper bound of background vibration at different wind speeds and directions under non-intrusion conditions. Determine the maximum compensation coefficient based on the increase of the upper bound of background vibration relative to the base threshold. Wind speed index and directional residual coefficient The parameters can be determined manually by segmentation, least squares fitting, or table lookup interpolation, without needing to divide the data into training and test sets.

[0035] Step D: Conduct simulated intrusion tests such as climbing, knocking, cutting, and touching to determine the upper limit of the threshold. The upper limit of the threshold should simultaneously meet the requirements of suppressing strong wind background vibration and preserving the detection margin of target intrusion signals.

[0036] Step E: Based on the rate of wind speed change and the system's allowable alarm response time, set the smoothing coefficient, threshold rise / fall rate limit, vibration analysis window length, and number of alarm confirmation windows.

[0037] In another implementation, the wind speed range and the relative wind direction coefficient range can be divided into a two-dimensional grid, and the threshold compensation amount obtained from the field calibration can be stored in a two-dimensional compensation table. During runtime, nearest neighbor lookup or bilinear interpolation is performed based on the current wind speed and relative wind direction coefficient. The compensation amount output by the two-dimensional compensation table also needs to be subject to threshold upper and lower limits, time smoothing, rate of change constraints, and anomaly backoff.

[0038] 5) Working steps of the method of the present invention Step S1: System initialization. Read the basic threshold, upper and lower limits of the threshold, fence azimuth angle, installation correction angle, wind speed parameters, compensation parameters, smoothing parameters and alarm confirmation parameters of each defense zone, and establish the association between the defense zone and the camera.

[0039] Step S2: The vibration fiber optic sensing unit, wind speed and direction sensor, auxiliary environmental sensor and camera start working; the embedded acquisition unit parses, verifies and timestamps the environmental data, and sends it to the host computer or server via the network.

[0040] Step S3: The data communication and time synchronization unit receives environmental data and vibration data, writes them into the cache according to the protection zone number, and matches the same vibration analysis window with the corresponding environmental data in time.

[0041] Step S4: The dynamic threshold calculation unit filters the wind speed and wind direction, calculates the relative wind direction coefficient, wind speed coefficient and wind field threshold compensation amount, and generates the original dynamic threshold.

[0042] Step S5: Apply upper and lower limit constraints, time smoothing and change rate constraints to the original dynamic threshold to obtain the current dynamic alarm threshold of the protection zone; when the environmental data is abnormal, perform threshold rollback and output the fault status.

[0043] Step S6: The alarm determination unit extracts vibration features from the vibration data, compares the vibration features with the current dynamic alarm threshold, and confirms the alarm through continuous over-threshold counting, multi-window voting, or a state machine with hysteresis.

[0044] Step S7: After alarm confirmation, the host computer displays the alarm zone and alarm information, outputs audible and visual alarms or network alarms, calls the corresponding camera to capture or save video, and writes the wind speed, wind direction, dynamic threshold and vibration characteristics at the time of the alarm into the alarm log.

[0045] Step S8: After the alarm is cleared, the system continues to collect and calculate data. When the user switches to manual mode, the automatic compensation output is paused and the threshold is manually set, but environmental data and vibration data continue to be recorded for subsequent debugging.

[0046] Compared with the prior art, the beneficial effects of the present invention are as follows: 1) This invention considers the relationship between wind speed and wind direction relative to the direction of the fence, so that the same wind speed produces different compensation amounts under different wind directions. Compared with adjusting only according to wind speed or fixing the threshold, it is more in line with the actual wind conditions of the fence.

[0047] (2) An interpretable threshold calculation link is formed by the basic threshold, wind field compensation amount, upper and lower limits of the threshold and change rate constraints. It does not rely on a large number of labeled samples and neural network training, which facilitates on-site deployment, parameter checking and fault location.

[0048] (3) The environmental data and vibration analysis window are matched according to the zone number and timestamp, which can reduce the error compensation caused by the mismatch between environmental information and vibration signal.

[0049] (4) The upper limit of the threshold is used to limit the threshold from rising too much under strong wind conditions. The threshold decrease rate can be set to recover faster, thereby reducing wind-induced false alarms and avoiding the system from being in a low-sensitivity state for a long time.

[0050] (5) Time smoothing, rate of change constraint, hysteresis alarm and multi-window confirmation jointly suppress instantaneous wind speed jumps, isolated pulses and jitter near the threshold, and improve the stability of alarm output.

[0051] (6) When the environmental sensor is abnormal, the most recent effective threshold or safety threshold is used, and the fault status is output synchronously to avoid abnormal environmental data directly causing threshold loss of control.

[0052] (7) Alarm events are associated with wind speed, wind direction, dynamic threshold, vibration waveform and video capture and stored, which is beneficial for alarm review, parameter traceability and subsequent operation and maintenance. Attached Figure Description

[0053] Figure 1 This is a schematic diagram of the overall system structure of the present invention.

[0054] Figure 2 This is a flowchart illustrating the time synchronization process between environmental data and vibration data in this invention.

[0055] Figure 3 This is a flowchart of the wind speed and direction compensation and dynamic alarm threshold calculation of the present invention.

[0056] Figure 4 This is a flowchart of the vibration alarm confirmation and video linkage process of the present invention. Detailed Implementation

[0057] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments. The embodiments are used to illustrate possible implementations of the present invention, and are not intended to limit the scope of protection. Communication protocols, sampling frequencies, time windows, threshold parameters, and device models not specifically described can be adjusted according to the scale of the site and the performance of the equipment.

[0058] (I) System composition and connection relationship like Figure 1 As shown, this embodiment installs a vibration fiber optic sensing unit on the perimeter fence and divides the perimeter into multiple defense zones. Each defense zone is assigned a zone number. Save the azimuth angle of the fence in this defense zone. And threshold parameters. Wind speed and direction sensors are installed at locations that can represent the wind field of the corresponding defense zone. When a sensor covers multiple adjacent defense zones, each defense zone shares the same wind speed and direction data, but uses its own fence azimuth, basic threshold, and compensation parameters for calculation. When the perimeter span is large or the terrain differences are significant, multiple wind speed and direction sensors are set up along the perimeter, and a mapping relationship between sensor number and defense zone number is established.

[0059] In this embodiment, the wind speed and direction sensor can be an XM8189 or a sensor with equivalent output functionality; the vibration fiber optic device can be a TZ02 or other device capable of outputting vibration waveforms, peak values, or characteristic data of the protected area; the embedded acquisition unit can be an STM32 series microcontroller; and the host computer can be developed using Qt. The above-mentioned models and software framework are merely implementation examples and do not constitute a necessary limitation of the present invention.

[0060] The wind speed and direction sensors are connected to the embedded acquisition unit via an RS485 interface. The embedded acquisition unit can also connect to a door sensor via a digital input interface, and to a temperature and humidity sensor via I²C, a single bus, or a serial interface. The vibration fiber optic host and the embedded acquisition unit are connected to a network switch, and the camera connects to the same data network via a wired or wireless network. The host computer acts as a TCP server or client to receive data from each device; the specific connection role is determined by the on-site network structure.

[0061] The dynamic threshold calculation unit and alarm determination unit are preferably located in a host computer or edge server to simultaneously obtain vibration waveforms, wind speed and direction, and zone configuration parameters. In another embodiment, the dynamic threshold calculation unit can be located in an embedded controller or vibration fiber optic host, and the calculation results are directly used for local alarm determination, while the current threshold and alarm results are uploaded to the host computer.

[0062] (ii) Environmental data acquisition, communication and time synchronization The embedded data acquisition unit periodically reads wind speed and direction. Each environmental data frame includes at least a frame header, protocol version, device number, associated zone number or zone group number, acquisition timestamp, wind speed value, wind direction value, data validity flag, device status, and checksum; optional data may include temperature, humidity, and door / magnet status. The data validity flag indicates whether the sensor is out of range, whether communication is normal, and whether the current data is a hold value.

[0063] Vibration fiber optic data frames must include at least the device number, zone number, sampling start and end times, number of sampling points, and vibration waveform or characteristic value. After receiving the data, the host computer first checks the frame length and checksum, then checks the validity of wind speed, wind direction, and vibration values ​​based on the device's measurement range. Valid data is written to a circular buffer or queue according to the zone number.

[0064] like Figure 2 As shown, the system uses the vibration analysis window as the time matching reference. For example, the vibration waveform can be analyzed using a 400ms sliding window, and the window length can also be set to other values ​​based on the sampling rate and the duration of the target event. For the window... The system searches the environment cache for timestamps that are within the window or closest to the center of the window and do not exceed the matching tolerance. The data is processed as follows: If there are multiple wind speed data points in the window, the average, median, or maximum value is calculated; if there are multiple wind direction data points, each wind direction is first converted into a unit vector, then the vector components are averaged and the circumferential average wind direction is obtained through the arctangent function.

[0065] To ensure a unified time base for different devices, the host computer can periodically send time synchronization commands to the embedded acquisition unit and the vibration fiber optic host, or each device can obtain its time through a network time protocol. If the devices cannot synchronize their time directly, the host computer records the data arrival time and the device's sequential number, estimating and correcting for fixed transmission delays.

[0066] (III) Initialization of zone parameters After system startup, it reads the zone configuration file or database. Each zone must be configured with at least the following parameters: zone number, fence azimuth. Basic threshold Threshold lower limit Threshold upper limit Compensation for initial wind speed , set upper limit wind speed Maximum compensation coefficient Wind speed index directional residual coefficient Installation correction angle Smoothing coefficient Threshold rise / fall rate limit, number of alarm confirmation windows, alarm clearance hysteresis, and associated camera number.

[0067] The fence azimuth is the angle of the fence's extension direction relative to a unified reference direction. For defense zones with zigzag or arc-shaped sections, the zone can be further divided into multiple sub-zones, or the fence azimuth can be set as the equivalent azimuth of the main wind-receiving section. The wind speed and direction sensor installation correction angle is measured during installation and is used to convert the sensor's zero-position direction to a unified reference direction.

[0068] In automatic mode, the above parameters are used for dynamic threshold calculation. In manual mode, the user inputs a manual threshold, and the system checks whether the threshold is within the range specified in the manual threshold calculation. and The setting will be set within the allowed range if the setting exceeds the specified range or if it is restricted to the allowed range. Manual mode is only used during commissioning, maintenance, or special operations; the system will continue to record wind speed, direction, and vibration data.

[0069] (iv) Wind speed and direction compensation and dynamic threshold calculation like Figure 3 As shown, the dynamic threshold calculation unit first checks the valid flags and timestamps of the current environmental data. After filtering, the valid data is used to calculate the relative wind direction coefficient according to formula (1). This coefficient uses the difference between the wind direction, the fence azimuth angle, and the installation correction angle, and can handle winds coming from both sides of the fence simultaneously. When the fence direction is nearly parallel to the wind direction, the direction coefficient is small; when the two are nearly perpendicular, the direction coefficient is large.

[0070] Then, the wind speed coefficient is calculated according to formula (2). When the wind speed is lower than the initial wind speed of compensation, the system keeps the threshold near the basic threshold and does not frequently change the threshold due to small wind speed fluctuations; when the wind speed is between the initial wind speed of compensation and the upper limit wind speed of calibration, the wind speed coefficient increases continuously with the wind speed; when the wind speed is higher than the upper limit wind speed of calibration, the wind speed coefficient remains at 1 to avoid infinitely increasing compensation after exceeding the calibration range.

[0071] The dynamic threshold calculation unit calculates the wind field threshold compensation amount according to formula (3), and then superimposes it with the basic threshold according to formula (4). Directional residual coefficient This describes vibrations that may still be generated by parallel winds and turbulence. The size can be appropriately increased when there are signs, slack mesh, or cable accessories on the site fence. When the fence structure is regular and the impact of parallel winds is minimal, the size can be reduced. .

[0072] After the original dynamic threshold is constrained by the upper and lower limits of formula (5), time smoothing and rate of change constraints are then applied according to formula (6). When the threshold rises, the following applies: Limitations are implemented to prevent a single gust of wind from immediately causing a significant increase in the threshold; when the threshold decreases, measures are taken to prevent this. Restrictions, and can make Greater than This allows the system to quickly regain sensitivity after the wind force decreases.

[0073] In an optional implementation, the system further calculates the gust coefficient, which is the difference between the maximum wind speed in the current short window and the average wind speed in the long window, and adds a limited gust compensation amount when the difference exceeds a preset condition. The gust compensation amount is also limited by a threshold upper limit and the rate of change. This optional compensation is used in scenarios where wind speed changes rapidly and does not affect the technical solution based on the wind speed coefficient and relative wind direction coefficient.

[0074] (v) Vibration alarm judgment and video linkage After data validity checks and baseline removal, the waveform output by the vibration fiber optic host is used to calculate the maximum absolute amplitude within the analysis window. In another embodiment, peak-to-peak value, root mean square value, or energy of a specific frequency band can be calculated, and one of these features can be compared with a dynamic threshold, or thresholds can be set for multiple features separately.

[0075] like Figure 4 As shown, when Exceeding the current dynamic threshold When the system continuously exceeds the threshold, the count is incremented; when If the threshold is not exceeded, the count is decremented or reset to zero. Ideally, an alarm should be confirmed when the threshold is exceeded for q consecutive windows, or when at least q of the most recent m windows exceed the threshold. For example, multiple analysis windows spanning from 100 ms to several seconds can be used for voting, with the specific number of windows set based on the system sampling rate and the duration of the target behavior.

[0076] Upon alarm confirmation, the host computer sets the corresponding zone to alarm status, the interface indicator light changes to the alarm color, and an audible alert is emitted. Simultaneously, the corresponding camera is accessed via the zone-camera mapping table. The camera module saves the image at the moment of the alarm, or saves cached video before the alarm and a video of a preset duration after the alarm. The alarm log records at least the alarm number, time, zone, vibration characteristics, dynamic threshold, basic threshold, wind speed, wind direction, directional coefficient, device online status, and the path to the captured image file.

[0077] Alarm clearing employs a hysteresis mechanism. A clearing threshold is set below the current alarm threshold; the alarm is only cleared when the vibration characteristics remain below the clearing threshold for multiple consecutive windows, thus preventing the alarm state from repeatedly switching around the threshold. Door magnetic alarms are treated as an independent alarm type, and their on / off determination rules are not altered by wind speed and direction compensation. However, door magnetic alarms can utilize the same video linkage and log storage processes.

[0078] (vi) Handling environmental sensor and network anomalies When an environmental data frame verification error occurs, wind speed or direction exceeds the measurement range, data timestamp exceeds the valid time, or the device goes offline, the dynamic threshold calculation unit marks the data as invalid. During short-term anomalies, the most recent valid threshold is retained, and new wind field compensation is frozen; if the anomaly persists for more than a preset time, it switches to a preset safety threshold, and simultaneously outputs environmental sensor fault in the interface and logs.

[0079] When vibration fiber optic data is interrupted, the system sets the corresponding protection zone to a device fault state and does not use the missing data for alarm judgment. When the camera is offline, the vibration alarm remains valid, and the log records a video linkage failure. After the network is restored, each cache queue discards expired data according to the timestamp, re-establishes synchronization relationships, and the dynamic threshold is restored through a smoothing process to avoid threshold jumps during network recovery.

[0080] (vii) Parameter calibration and acceptance process After the system is installed, first verify the direction of the wind speed and direction sensors and the azimuth of the fences in each defense zone. Then, collect background vibrations under calm or light wind conditions without personnel intrusion, and determine the basic threshold according to formula (8). If all wind speed conditions cannot be completed on site at once, preset parameters can be used for initial operation, and calibration records can be gradually supplemented when different wind conditions occur.

[0081] Under different wind speeds and directions, the upper bound of the non-intrusive background vibration and the corresponding wind speed, wind direction, and directional coefficients were recorded. These were determined through manual adjustment or least-squares fitting. , and This process ensures that the calculated dynamic threshold is slightly higher than most wind-induced background vibrations, while not exceeding the upper limit of the threshold determined by intrusion testing. This process is parameter calibration and does not require training a neural network model.

[0082] After completing the background calibration, simulated events such as climbing, knocking, shearing, and touching were implemented to check the alarm status under various wind conditions. If the target event characteristics are close to the upper limit of the threshold under high wind speed conditions, the maximum compensation coefficient or the upper limit of the threshold should be reduced; if false background alarms still occur frequently in a specific wind direction, the fence azimuth angle, installation correction angle, or direction residual coefficient should be corrected.

[0083] Acceptance records should include the basic thresholds, compensation parameters, threshold limits, test event types, and wind speed and direction during each protection zone. During subsequent system maintenance, these parameters can be manually updated based on the wind speed, wind direction, dynamic thresholds, and vibration characteristics stored in the alarm logs.

[0084] (viii) Implementation of host computer software The host computer software includes a network connection module, an environmental data module, a vibration waveform display module, a dynamic threshold and parameter setting module, an automatic / manual mode switching module, a camera display module, a security door status module, an alarm prompt module, and an alarm recording module.

[0085] The software preferably adopts a multi-threaded or asynchronous event mechanism: the network receiving thread is responsible for environmental data, vibration data and video status; the parsing thread is responsible for data verification and protocol conversion; the synchronization thread is responsible for matching data according to the protection zone and timestamp; the threshold thread periodically calculates the dynamic threshold of each protection zone; the alarm thread performs feature comparison, counting and state machine; the interface thread is only responsible for display, to avoid waveform drawing or video decoding blocking alarm calculation.

[0086] When parameters are modified, the host computer first checks the parameter range and logical relationships, for example, if required... Greater than , Not less than The smoothing coefficient is between 0 and 1. After verification, the parameters are written to the configuration file or database, and the modification time and operator are recorded. During system operation, the basic threshold, wind field compensation amount, and final dynamic threshold are simultaneously displayed on the interface for easy monitoring of the compensation process.

[0087] The wind speed and direction sensor in this invention can be an integrated sensor or a combination of independent wind speed and direction sensors; the communication method can be RS485, CAN, Ethernet or wireless communication; the dynamic threshold calculation can be set in the host computer, edge device or vibration fiber optic host.

[0088] Without altering the fundamental principles of wind speed and direction compensation, the wind speed coefficient can be calculated using a piecewise linear function, a power function, or interpolation via a lookup table; the relative wind direction coefficient can be calculated using the absolute value of a sine wave, a power function of the absolute value of a sine wave, or a direction weight table calibrated on-site. All replacement methods must retain at least one safety constraint among fence direction correction, threshold upper and lower limits, time smoothing, and anomaly backoff.

[0089] The above embodiments illustrate the main technical concept of the present invention. For those skilled in the art, equivalent substitutions made to the module deployment location, communication protocol, filtering method, feature extraction method, and parameter form without departing from the core idea of ​​the present invention—generating a dynamic alarm threshold for vibration fiber optic based on wind speed and direction compensation—can all be considered as embodiments of the present invention.

Claims

1. An adaptive adjustment system for vibration fiber optic perimeter alarm threshold based on wind speed and direction compensation, characterized in that: It includes a vibration fiber optic sensing unit, an environmental sensing unit, an embedded acquisition unit, a data communication and time synchronization unit, a dynamic threshold calculation unit, an alarm judgment unit, a video linkage and storage unit, and a host computer display and interaction unit. In the vibration fiber optic sensing unit, vibration fibers are deployed along the perimeter fence and divided into one or more zones according to spatial location. The vibration fiber optic host collects vibration signals from each zone and outputs the original waveform, characteristic values, or pre-alarm analysis data. Each zone corresponds to a unique zone number and stores the fence azimuth angle, basic threshold, and compensation parameters for that zone. The environmental sensing unit includes at least wind speed and direction sensors to output the current wind speed and direction; The embedded acquisition unit connects to the wind speed and direction sensor, temperature and humidity sensor and door magnet, performs protocol parsing, range checking, outlier checking and data packaging on the sensor data, and adds device number, zone number, acquisition timestamp and check code to the data frame. The data communication and time synchronization unit transmits environmental and vibration data via Ethernet, fiber optic data bus, serial bus, or wireless network. The dynamic threshold calculation unit filters the matched wind speed and wind direction, calculates the relative wind direction coefficient based on the wind direction, fence azimuth angle and installation correction angle, calculates the normalized wind speed coefficient based on the wind speed, and calculates the wind field threshold compensation amount; after superimposing the compensation amount with the basic alarm threshold, the upper and lower limit constraints of the threshold, time smoothing and single-cycle change rate constraints are executed in sequence, and the current dynamic alarm threshold of each defense zone is output. The alarm determination unit extracts at least one feature from the vibration signal, including waveform peak value, peak-to-peak value, root mean square value, and frequency band energy, compares it with the current dynamic alarm threshold, and confirms whether to trigger an alarm. The video linkage and storage unit establishes a correspondence between the zone number and the camera number. When an alarm is confirmed, the corresponding camera is called to capture an image or to save a video of a preset duration before and after the alarm.

2. The adaptive adjustment system for vibration fiber optic perimeter alarm threshold based on wind speed and direction compensation according to claim 1, characterized in that, The vibration fiber optic sensing unit, environmental sensing unit, embedded acquisition unit, data communication and time synchronization unit, dynamic threshold calculation unit, alarm judgment unit, video linkage and storage unit, and host computer display and interaction unit are set in the same device, or distributed in the field controller, vibration fiber optic host, edge computing device and host computer server.

3. The vibration fiber optic perimeter alarm threshold adaptive adjustment system based on wind speed and direction compensation according to claim 2, characterized in that, The environmental sensing unit may also include temperature sensors, humidity sensors, door magnetic sensors or other switching sensors for status display, alarm assistance judgment and operation recording.

4. The vibration fiber optic perimeter alarm threshold adaptive adjustment system based on wind speed and direction compensation according to claim 3, characterized in that, The data communication and time synchronization unit uses a unified clock or a calibrated local clock as the time reference, writes environmental data and vibration data into the buffer queue according to the zone number and timestamp, and matches the wind speed and direction data within the corresponding time period based on the vibration analysis window.

5. The vibration fiber optic perimeter alarm threshold adaptive adjustment system based on wind speed and direction compensation according to claim 4, characterized in that, The alarm determination unit uses continuous over-threshold counting, multi-window voting, or a state machine with hysteresis to confirm the alarm, and records the alarm time, zone number, vibration characteristics, dynamic threshold, wind speed, wind direction, and equipment status.

6. The vibration fiber optic perimeter alarm threshold adaptive adjustment system based on wind speed and direction compensation according to claim 5, characterized in that, The host computer display and interaction unit includes modules for network connection, device status, vibration waveform, environmental parameters, dynamic thresholds, manual / automatic mode, video monitoring, alarm prompts, and alarm logs. In automatic mode, the threshold is generated by the dynamic threshold calculation unit; during maintenance or debugging, it can be switched to manual mode, where manually entered thresholds are still subject to allowable range constraints.

7. The adaptive adjustment system for vibration fiber optic perimeter alarm threshold based on wind speed and direction compensation according to claim 6, characterized in that, The parameter calibration of the dynamic threshold calculation unit is determined through non-intrusive background data during the installation and commissioning phase, manual intrusion testing, and an interpretable parameter calibration process.

8. The vibration fiber optic perimeter alarm threshold adaptive adjustment system based on wind speed and direction compensation according to claim 7, characterized in that, The parameter calibration process specifically includes: Step A: Set the azimuth angle of the fence for each defense zone and the installation correction angle of the wind speed and direction sensors, and confirm that all angles use the same reference direction; Step B: When there is no intrusion and the wind speed is lower than the compensation start wind speed. Under these conditions, characteristic values ​​from multiple vibration analysis windows are collected, and preset quantiles are used. And increase safety margin The basic threshold is obtained; Step C: Record the upper bound of background vibration at different wind speeds and directions under non-intrusion conditions. Determine the maximum compensation coefficient based on the increase of the upper bound of background vibration relative to the base threshold. Wind speed index and directional residual coefficient ; Step D: Simulate intrusion tests to determine the upper limit of the threshold. The upper threshold simultaneously meets the requirements of suppressing strong wind background vibration and preserving the detection margin of target intrusion signals; Step E: Based on the rate of wind speed change and the system's allowable alarm response time, set the smoothing coefficient, threshold rise / fall rate limit, vibration analysis window length, and number of alarm confirmation windows.

9. The vibration fiber optic perimeter alarm threshold adaptive adjustment system based on wind speed and direction compensation according to claim 7, characterized in that, The wind speed range and the relative wind direction coefficient range are divided into two-dimensional grids, and the threshold compensation amount obtained from the field calibration is stored in the two-dimensional compensation table. During operation, the nearest neighbor search or bilinear interpolation is performed based on the current wind speed and relative wind direction coefficient. The compensation amount output by the two-dimensional compensation table is also subject to threshold upper and lower limits, time smoothing, change rate constraints and abnormal rollback.

10. A method for adaptively adjusting the vibration fiber optic perimeter alarm threshold based on wind speed and direction compensation using the system of any one of claims 1-9, characterized in that, Includes the following steps: Step S1: System initialization, read the basic threshold, upper and lower threshold, fence azimuth angle, installation correction angle, wind speed parameters, compensation parameters, smoothing parameters and alarm confirmation parameters of each defense zone, and establish the association between the defense zone and the camera; Step S2: The vibration fiber optic sensing unit, wind speed and direction sensor, auxiliary environmental sensor and camera start working; the embedded acquisition unit parses, verifies and timestamps the environmental data, and sends it to the host computer or server via the network; Step S3: The data communication and time synchronization unit receives environmental data and vibration data, writes them into the cache according to the protection zone number, and matches the same vibration analysis window with the environmental data corresponding in time. Step S4: The dynamic threshold calculation unit filters the wind speed and wind direction, calculates the relative wind direction coefficient, wind speed coefficient and wind field threshold compensation amount, and generates the original dynamic threshold. Step S5: Apply upper and lower limit constraints, time smoothing, and change rate constraints to the original dynamic threshold to obtain the current dynamic alarm threshold of the protection zone; when the environmental data is abnormal, perform threshold rollback and output the fault status; Step S6: The alarm determination unit extracts vibration features from the vibration data, compares the vibration features with the current dynamic alarm threshold, and confirms the alarm by counting consecutive over-thresholds, multi-window voting, or a state machine with hysteresis. Step S7: After alarm confirmation, the host computer displays the alarm zone and alarm information, outputs audible and visual alarms or network alarms, calls the corresponding camera to capture or save video, and writes the wind speed, wind direction, dynamic threshold and vibration characteristics at the time of the alarm into the alarm log. Step S8: After the alarm is cleared, the system continues to collect and calculate data. When the user switches to manual mode, the automatic compensation output is paused and the threshold is manually set, but environmental data and vibration data continue to be recorded for subsequent debugging.

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