Pedestrian crossing signal control method and system based on distributed optical fiber sensing

Abstract

The invention relates to the technical field of road traffic signal control, and provides a pedestrian crossing signal control method and system based on distributed optical fiber sensing, and the method comprises the steps: laying distributed optical fibers on a road surface in an array, dividing an optical fiber laying region into three functional regions: an incoming line segment, an occupation segment, and a shore segment, each functional section comprises a plurality of virtual channels, and coordinates of each virtual channel are determined; carrying out band-pass filtering and energy statistics on the original vibration sequence collected by the virtual channel, and constructing a channel-level event probability; based on the channel-level event probability, respectively constructing the occupancy probability and the incoming line intensity, outputting a pedestrian phase request, recording the latest effective incoming line moment, taking occupancy protection as a constraint, taking incoming line gap termination as a dominant, and combining emptying confirmation, residual clearance time estimation, entrance locking and queue request mechanisms to obtain a pedestrian phase request; and outputting the lighting, keeping and extinguishing control results of the pedestrian release lamp. And the comprehensive level of crossing safety and passing efficiency is improved.

Description

Technical Field

[0001] This invention belongs to the field of road traffic signal control technology, and in particular relates to a pedestrian crossing signal control method and system based on distributed optical fiber sensing. Background Technology

[0002] The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.

[0003] With the continuous growth of urban road traffic flow, vulnerable road users such as pedestrians face a higher risk of traffic conflicts at non-signaled intersections or areas with high pedestrian crossing demand. Especially at school gates, bus stops, and community entrances, pedestrian arrivals exhibit both randomness and clustering characteristics, potentially resulting in prolonged periods without pedestrians crossing, or periods of continuous arrival and intermittent crossing. Using fixed-time pedestrian phases or manual intervention often leads to problems such as unnecessary delays for vehicles due to empty lanes, or an inability to respond promptly to sudden surges in demand, resulting in pedestrians rushing across the street, making it difficult to balance pedestrian safety and traffic efficiency.

[0004] To address the issue of triggering pedestrian crossing requests, existing technologies typically employ methods such as button-based pedestrian requests, video detection, millimeter-wave radar, and geomagnetic and pressure sensing to generate pedestrian phase requests and control pedestrian signal display. Among these, button-based solutions rely on active pedestrian operation, which is prone to missed or accidental presses, or difficulties for children and the elderly to operate; video detection is susceptible to factors such as insufficient lighting at night, rain, fog, backlight, obstruction, and privacy compliance, limiting its stability and usability; radar-based solutions have limited ability to finely identify target categories and occupancy boundaries, and are prone to false triggers in dense crowds and multi-target interference situations; and buried sensors have high construction and maintenance costs and limited coverage. More importantly, many existing solutions only achieve coarse-grained control of "detection triggers" or "fixed extensions," making it difficult to reliably determine the real-time occupancy and clearance status of zebra crossings. This can lead to problems such as continuously extending pedestrian phases in continuous arrival scenarios, causing long-term obstruction of vehicles, or premature termination in intermittent walking scenarios, resulting in pedestrian congestion.

[0005] Distributed fiber optic sensing technology boasts advantages such as distributed continuous measurement, resistance to electromagnetic interference, strong environmental tolerance, and long-distance coverage, and has been applied in areas such as infrastructure safety monitoring in recent years. However, existing fiber optic sensing applications mostly focus on objects such as structural deformation, temperature, or perimeter vibration. Research on the identification of the "entry, occupancy, gap, and clearing" status of pedestrian crossings on urban roads and its closed-loop linkage with signal control strategies is relatively insufficient. It is still difficult to simultaneously meet the requirements of controllable batch service under continuous arrival conditions, safe termination under occupancy protection conditions, and stable identification under complex background vibration interference. Summary of the Invention

[0006] To address the technical problems mentioned above, this invention provides a pedestrian crossing signal control method and system based on distributed optical fiber sensing. This system provides end-to-end control of pedestrian crossing needs, continuously sensing the entry segment, occupancy segment, and arrival segment via distributed optical fiber. The vibration signal of the crossing is preprocessed with bandpass, and short-time energy statistics and standardized to map into event probabilities. Based on this, the entry strength and occupancy probability are generated. This system ensures that signals are not left unused when no one is present and are triggered promptly when someone is present, thereby improving the overall level of pedestrian safety and traffic efficiency.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: The first aspect of the present invention provides a pedestrian crossing signal control method based on distributed optical fiber sensing, comprising: Distributed optical fibers are laid in an array on the road surface, and the fiber laying area is divided into three functional sections: the entry section, the occupied section, and the destination section. Each functional section contains several virtual channels, and the coordinates of each virtual channel are determined. Bandpass filtering and energy statistics are performed on the raw vibration sequences acquired by the virtual channel to construct channel-level event probabilities; Based on channel-level event probabilities, occupancy probabilities and line entry strengths are constructed respectively. Pedestrian phase requests are output, and the most recent valid line entry time is recorded. With occupancy protection as a constraint and line entry gap termination as the main factor, combined with clearing confirmation, remaining clearing time estimation, entrance locking and queue request mechanisms, the results of pedestrian release light illumination, maintenance and extinguishing control are output.

[0008] Furthermore, the probability of the channel-level event is: ; in, Indicates channel The probability of the event, Indicates the slope coefficient. Represents the bias coefficient, standardized energy statistic. Virtual Channel At any moment short-term energy , Indicates the length of the sliding window. This represents the filtered vibration sequence. Indicates the discrete sampling sequence number within the sliding window. Indicates the background mean. This represents the background standard deviation.

[0009] Furthermore, the occupancy protection is represented as: ;in, Indicates that the output is in use for protection. The threshold for determining occupancy; occupancy probability. , For virtual channels The probability of channel-level events. This is an occupied segment.

[0010] Furthermore, the wire gap For the current moment Compared with the most recent valid entry time The difference.

[0011] Furthermore, the remaining clearance time is: Among them, the location occupying the centroid position , Indicates channel The probability of the event, For occupied segment, The coordinates of the virtual channel. Indicates protection against division by zero; Indicates the safety margin time; estimates the propulsion speed. , Indicates the calculation interval. This indicates the minimum safe speed limit; This indicates the effective length of the zebra crossing.

[0012] Furthermore, the clear confirmation is expressed as follows: ; in, This indicates that the confirmation quantity has been cleared. Indicates the time to clear the hold period. For the probability of occupancy, This is the threshold for determining occupancy. Let t be the indicator function, and t be the current time.

[0013] Furthermore, the entry locking and queue request mechanism is expressed as follows: ; when ; ; in, Indicates a pending service request flag. This indicates that the entrance is locked. Indicates the duration of the current pedestrian phase. Indicates the entry lock trigger time, when The latest valid online entry time will no longer be updated. , Pedestrian phase request.

[0014] Furthermore, the output of the pedestrian traffic light's illumination, holding, and extinguishing control results includes: ; ,when And it meets the controller's release conditions; ,when or ; ; ,when or ; ; in, Indicates the status of the pedestrian crossing light. Indicates the valid pedestrian phase indicator. This indicates that output will be terminated. This indicates that the output should be extended. Indicates a pedestrian phase request. Indicates that the output is in use for protection. For the gap between the incoming lines, This indicates that the confirmation quantity has been cleared. Indicates the threshold of the incoming line gap. Indicates the minimum extension threshold. Indicates the duration of the current pedestrian phase. This indicates the maximum release time.

[0015] Furthermore, it also includes: updating the background mean and background standard deviation based on the channel-level event probability, wherein the background mean and background variance are used for energy statistics; and updating the occupancy threshold based on the quantile statistics of the occupancy probability, wherein the occupancy threshold is used for occupancy protection.

[0016] A second aspect of the present invention provides a pedestrian crossing signal control system based on distributed optical fiber sensing, comprising: The fiber optic sensor deployment and section construction module is configured to: lay distributed optical fibers in an array on the road surface, divide the fiber optic laying area into three functional sections: the entry section, the occupied section, and the arrival section. Each functional section contains several virtual channels, and the coordinates of each virtual channel are determined. The signal preprocessing and event probability extraction module is configured to perform bandpass filtering and energy statistics on the raw vibration sequences acquired by the virtual channel to construct channel-level event probabilities. The adaptive signal control and lamp status output module is configured to: construct occupancy probability and line entry strength based on channel-level event probability, output pedestrian phase request, and record the most recent valid line entry time. With occupancy protection as a constraint and line entry gap termination as the main factor, combined with clearing confirmation, remaining clearing time estimation, entrance locking and queue request mechanism, output the lighting, holding and extinguishing control results of pedestrian release lights.

[0017] Compared with the prior art, the beneficial effects of the present invention are: This invention addresses the end-to-end control of pedestrian crossing needs by using distributed optical fibers to continuously sense the entry section, occupied section, and arrival section. The vibration signal of the crossing is preprocessed with bandpass, and short-time energy statistics and standardized mapping are used to map it into event probabilities. Based on this, the entry strength and occupancy probability are formed, which can prevent the crossing from being left unattended when no one is there and trigger it in a timely manner when someone is there, thereby improving the overall level of pedestrian crossing safety and traffic efficiency.

[0018] This invention establishes a safety constraint chain with occupancy protection and clearance confirmation. When occupancy exists, passage is allowed. After the entry gap is satisfied, the occupancy must be verified to be continuously below the threshold within the holding window before termination is allowed. This avoids intermittent stops and instantaneous disturbances that may cause accidental clearance or premature light extinguishing, thereby reducing the risk of pedestrian congestion and conflicts.

[0019] This invention addresses the pain point of continuous pedestrian arrivals leading to infinite phase continuation by introducing an entrance locking, queue request, and maximum release time mechanism. Once locked, the most recent entry time is no longer refreshed, and new arrivals are transferred to the next release, realizing batch service and controllable yielding on the vehicle side, improving the predictability and fairness of intersection operation during high-traffic periods.

[0020] This invention adaptively adjusts the extension amount by estimating the remaining clearance time. It uses spatial statistics of the event probability of the occupied segment to estimate the centroid of the occupied segment and the advance speed to obtain the remaining clearance time, which is used to extend or terminate the clearance more reasonably. Compared with fixed extension, it is closer to the actual situation of slow-moving groups and group crossings, and reduces unnecessary delays.

[0021] This invention dynamically suppresses false alarms and missed alarms caused by environmental vibration, road surface condition changes and sensor drift through background baseline recursion and threshold adaptive update, and forms a closed-loop linkage with the signal light output. It has long-term stable operation and engineering feasibility, and is suitable for densely populated pedestrian scenarios such as schools and hospitals. Attached Figure Description

[0022] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0023] Figure 1This is a flowchart of a pedestrian crossing signal control method based on distributed optical fiber sensing, according to Embodiment 1 of the present invention. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0025] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0026] Terminology Explanation: Distributed fiber optic sensing: Distributed fiber optic sensing refers to using optical fiber as a continuous sensing medium, demodulating the changes in scattered light along the fiber caused by external disturbances, and obtaining vibration response information distributed along the fiber space, thereby realizing distributed monitoring and location of micro-vibration events such as walking and stepping in pedestrian crossing areas.

[0027] Virtual channel: A virtual channel is a discrete spatial sampling unit obtained by dividing the optical fiber along the line according to the equivalent spatial resolution of the distributed optical fiber. Each virtual channel corresponds to a fixed position interval on the road surface and is used to calculate the vibration sequence, short-time energy and event probability of the interval, and serves as the basic spatial statistical unit for the entry segment, the occupied segment and the landing segment.

[0028] Event probability: Event probability refers to the probabilistic judgment quantity obtained by transforming the standardized statistics of the channel-level vibration signal through a probability mapping function after band-limited preprocessing, short-time energy statistics and standardization. It is used to characterize the possibility of a valid target event occurring in the corresponding channel at a given time, and serves as the basic input for incoming line strength, occupancy probability and arrival confirmation.

[0029] Clear confirmation: Clear confirmation refers to the consistency verification mechanism in the termination determination stage for the state where the occupancy probability of the occupied segment is continuously lower than the occupancy threshold within a continuous time window. It is used to avoid false clearing caused by instantaneous disturbances or intermittent stops, so as to output the pedestrian phase termination and light extinguishing command on the premise of ensuring that the zebra crossing occupancy disappears.

[0030] Entry Lock: Entry lock refers to the control state triggered when the duration of the pedestrian phase reaches the preset locking condition. In this state, the system no longer refreshes the most recent entry time with new entry events, thereby blocking the continuous arrival of the current phase and causing the current phase to enter the entry gap termination and clearing confirmation process, while ensuring that the service on the motor vehicle side is controllable.

[0031] Example 1 This embodiment provides a pedestrian crossing signal control method based on distributed optical fiber sensing.

[0032] This embodiment provides a pedestrian crossing signal control method based on distributed optical fiber sensing, which is applied to pedestrian crossing scenarios such as pedestrian crossings and intersections on urban roads. It is particularly suitable for pedestrian entry and occupancy status recognition and adaptive control of pedestrian release signals in densely populated areas such as schools and hospitals.

[0033] This embodiment provides a pedestrian crossing signal control method based on distributed optical fiber sensing, such as... Figure 1 As shown, it includes the following steps: Step 1: Fiber Optic Sensor Deployment and Segment Construction: Select a flat and dry sidewalk base, clean it, and lay distributed optical fibers in an array on the road surface to ensure stable coupling between the sensor and the road surface and effectively capture vibration signals; divide the optical fiber laying area into three functional segments: entry segment A, occupation segment B, and arrival segment C, and establish channel mapping to provide a spatial reference for subsequent event judgment, extraction, and control decisions.

[0034] Step 1.1: Calculate the number of channels, determined by the length of each segment and the spatial resolution: ; ; ; in, Indicates the length of the incoming line segment. Indicates the effective length of the zebra crossing. Indicates the length of the section to the shore. This represents the equivalent spatial resolution of distributed optical fibers. These represent the number of virtual channels for the incoming segment, the occupied segment, and the destination segment, respectively.

[0035] Step 1.2: Channel coordinate calculation, used for subsequent centroid and space statistics: ; in, Indicates the first Distance coordinates of the center of each virtual channel Indicates the starting coordinates of the segment. Indicates the channel number. The meaning is the same as in step 1.1.

[0036] Step 1.3: Define the channel set to limit the statistical range of inbound segments, occupied segments, and arrival segments: ; ; ; in, These represent the sets of channels for the incoming segment, the occupied segment, and the arrival segment, respectively. The calculation method is described in step 1.1.

[0037] Step 2, Signal Preprocessing and Event Probability Extraction: Fiber optic signal acquisition, band-limited reconstruction and energy statistics are performed on the original vibration sequences acquired by each virtual channel to construct channel-level event probabilities, providing a basis for the unified quantification of incoming line strength and occupancy probability.

[0038] Step 2.1: Obtain the bandpass filtered signal to suppress background disturbances and preserve the pedestrian event frequency band. ; in, Indicates the first The original vibration sampling sequence of each virtual channel, This represents the filtered vibration sequence. This represents the bandpass filter operator. Indicates the lower cutoff frequency. Indicates the upper cutoff frequency. Indicates the virtual channel number.

[0039] Step 2.2: Energy statistics and standardization calculations, used to construct dimensionless determination quantities: ; ; in, Indicates virtual channel At any moment Short-term energy, Indicates the length of the sliding window. Indicates the first The vibration sequence after filtering by virtual channels is in discrete sampling sequence number The amplitude at that point, Indicates the discrete sampling sequence number within the sliding window. Represents the standardized energy statistics. Indicates the background mean. Indicates the background standard deviation. and The update method is described in step 5.1.

[0040] Step 2.3: Event probability calculation, used to map statistics to probabilistic decision variables: ; in, Indicates virtual channel The probability of the event, Indicates the slope coefficient. This represents the bias coefficient. The calculation method is described in step 2.2.

[0041] Step 3, Inbound Occupancy and Landing Quantization: Construct occupancy probability and inbound strength respectively, output pedestrian phase request, and record the most recent inbound time to provide a basis for gap termination.

[0042] Step 3.1: Occupancy probability calculation, used to determine whether the zebra crossing is occupied: ; ; in, This indicates that segment B is occupied at time [time]. The probability of occupancy. Indicates the amount of the indicator in use. See step 1.3. The calculation method is described in step 2.3. This indicates the threshold for determining occupancy. This is an indicator function.

[0043] Step 3.2: Incoming line strength calculation, used to quantify the spatial convergence intensity of incoming line events: ; ; in, Indicates the strength of the incoming line. This indicates the strength of the input line after smoothing. See step 1.3. Indicate the weight of the incoming channel and satisfy the following conditions: , The calculation method is described in step 2.3. This represents the smoothing coefficient.

[0044] Step 3.3: Arrival strength calculation, used to confirm that pedestrians have reached the opposite bank and to suppress false triggering of lingering in place: ; ; in, Indicates the intensity upon arrival at shore. The calculation method is described in step 1.3. Indicate the weight of the onshore channel and satisfy the following conditions: , This indicates that the data has been confirmed upon arrival at the shore. This represents the threshold for arrival at shore.

[0045] Step 3.4: Phase request output and most recent incoming line time update are used to trigger control and support gap calculation: ; when ; when ; in, This indicates a pedestrian phase request output. Indicates the trigger threshold. The calculation method is described in step 3.2. Indicates the most recent valid entry time. This indicates the most recent confirmed arrival time. This indicates that the data has been confirmed upon arrival at the shore.

[0046] Step 4, Adaptive control and lamp status output for clearing the gap occupied by the incoming line: With occupancy protection as the constraint and the termination of the gap occupied as the main factor, combined with clearing confirmation, clearing estimation and maximum protection mechanism, the output results of pedestrian release light lighting, holding and turning off control are given.

[0047] Step 4.1: Occupancy protection determination, used to ensure that the light does not turn off prematurely when occupancy exists: ; in, Indicates that the output is in use for protection. The calculation method is described in step 3.1. The meaning is the same as in step 3.1.

[0048] Step 4.2: Calculate the incoming line gap to determine whether to proceed to the termination determination stage. ; in, Indicates the duration of the gap between incoming lines. The update method is described in step 3.4.

[0049] Step 4.3: Estimate the remaining clearing time, used to generate an adaptive extension and improve control granularity: ; ; ; in, Indicates the location occupied by the centroid. See step 1.3. The calculation method is described in step 1.2. The calculation method is described in step 2.3. This indicates that the quantity is divided by zero. Indicates the calculation interval. Indicates the estimated propulsion speed. This indicates the minimum safe speed limit. Indicates the remaining clearance time. Indicates the safety margin time. The meaning is the same as in step 1.1.

[0050] Step 4.4: Clear the confirmation calculation, used to confirm that the occupancy has disappeared after the gap is satisfied before turning off the light: ; in, This indicates that the confirmation quantity has been cleared. Indicates the time to clear the hold period. The calculation method is described in step 3.1. The meaning is the same as in step 3.1. This is an indicator function.

[0051] Step 4.5: Entry point locking determination, used to prevent indefinite extension and form batched services in continuous arrival scenarios: ; when ; in, This indicates that the entrance is locked. Indicates the duration of the current pedestrian phase. Indicates the entry lock trigger time, when The latest online time will no longer be updated. Enter the gap termination and clearing process.

[0052] Step 4.6: Queue request generation, used to transfer new arrivals during the locking period to the next release: ; ; in, This indicates a pending service request; if a new request is generated during the lock period, it will remain active. This is used to trigger the next release, preventing the current phase from being extended indefinitely due to new incoming lines.

[0053] Step 4.7: Light status output and termination output, used to form the final control output result of this invention, and to specify when the pedestrian traffic light is lit, when it is kept lit, and when it is turned off to drive the traffic signal to execute: ; ,when And it meets the controller's release conditions; ,when or ; ; ,when or ; ; in, Indicates the status of the pedestrian crossing light. The signal light indicates that the vehicle is on. The traffic lights are off to indicate that the vehicle is ready to proceed. Indicates the valid pedestrian phase indicator. This indicates that output will be terminated. This indicates that the output should be extended. The calculation method is described in step 3.4. The calculation method is described in step 4.1. The calculation method is described in step 4.2. The calculation method is described in step 4.4. Indicates the threshold of the incoming line gap. Indicates the minimum extension threshold. The calculation method is described in step 4.3. This indicates the maximum allowable time, used to force batch service in high-traffic scenarios.

[0054] Step 4.8: Queue triggering after the phase ends, used to release the next batch: ; ; in, This indicates the current non-pedestrian phase. If there is a pending service request, the pedestrian phase will be triggered to enter the next time the controller allows it, and the queue flag will be cleared after entering.

[0055] Step 5, Self-calibration and threshold update: Dynamic baseline correction and adaptive threshold update eliminate drift and environmental interference, ensuring long-term stability of event probability, occupancy determination and control output.

[0056] Step 5.1: Recursively update background statistics to update the baseline parameters required for standardization: ; ; ; in, This indicates that the background update gate value is being used. Indicates the background gating threshold. Indicates the forgetting factor, The calculation method is described in step 2.2. Indicates the background mean. Indicates background variance. The background standard deviation, and For the standardized calculations in step 2.2, The calculation method is described in step 2.3.

[0057] Step 5.2: Adaptive update of occupancy threshold to improve the robustness of occupancy determination under different noise levels: ; in, This represents the adaptive value of the occupancy threshold, i.e. , Represents the quantile operator. For quantile parameters, The calculation method is shown in step 3.1.

[0058] Taking a pedestrian crossing at the entrance of a school in a certain city as an example, the crossing length is... , lane width Length of the waiting area on the import side Export side buffer length Vibration signals are acquired using a distributed fiber optic sensing and demodulation host, with a sampling frequency of [missing information]. Equivalent spatial resolution .

[0059] Fiber optic sensor deployment involves cleaning the waiting area and zebra crossing surfaces, creating shallow trenches, and backfilling with a protective layer. Fiber optic cables are then pre-buried in an array to cover the waiting area, crosswalk, and arrival area, forming entry segments. Occupied section and the shore section The number of channels is This is used to establish a stable sensing foundation and to define the three functional areas of entry line, occupation, and arrival. Signal preprocessing, for vibration sequences of each channel Bandpass filtering is performed to obtain Take the frequency band of the vibration. , It is used to suppress low-frequency background noise and high-frequency noise from vehicles and improve the separability of pedestrian events; Short-time energy calculation, with window length Calculate short-time energy The corresponding statistical window is 0.5s, which is used to convert the original vibration waveform into comparable energy statistics; Standardization and event probability, using background statistics Will Standardization Then mapped to event probability Suppose at some point a channel enters the line segment. ,Pick , ,but This indicates that there are significant incoming events in the channel, which are then used for subsequent incoming and occupancy quantification. Incoming line and occupancy quantification: Constructing the incoming line strength based on the highest event probability of the incoming line segment. occupancy probability is constructed using the average value of the occupied segments. Assuming the incoming line strength at the trigger time Simultaneous Occupancy Probability These are used to determine whether someone has reached the entrance and whether someone is still occupying the zebra crossing; Phase request and time recording, setting incoming threshold ,when Output phase request And record the most recent online time. This is used to trigger pedestrian access and provide a time reference for subsequent gap clearing decisions; Gap clearing determination, setting the incoming line gap threshold. Clear hold time Clear threshold ;when And the probability of occupancy continuous Less than Then clear and confirm. This indicates that the zebra crossing has been cleared and the decision to terminate the passage can be made. The minimum and maximum clearance times are calculated based on the safe walking speed of vulnerable pedestrians. Configuration, take startup loss Traffic signs Then the minimum release time Take margin Maximum release time This is used to simultaneously ensure the safe crossing of the street for vulnerable pedestrians and limit the indefinite extension of green lights; Lamp output, when And the vehicle phase meets the minimum release window. Start pedestrian access and set the pedestrian green light. The pedestrian green light lasts for at least When the condition is satisfied And clear confirmation Stop allowing pedestrians to pass and set the pedestrian red light. When the green light continues to reach Regardless of whether the light is cleared or not, the process is forcibly terminated to avoid continuous arrivals that could lead to indefinite extension. This step is the final output step of the invention, which clarifies when the light turns on, how long it stays on, and when it turns off. Entry locking and batch service: Set the entry locking trigger time to after the start of access control. Once locked, new arrivals are only registered as queue requests and transferred to the next round of passage to avoid continuous arrivals causing the pedestrian green light to be continuously extended in this round, and to ensure the periodic passage window on the motor vehicle side; Self-calibration and threshold update: Gated recursive update is used. and A background baseline is established, and the occupancy threshold is updated according to the quantile rule, so that the system can adapt to changes in rainfall, road conditions and traffic vibrations, reduce false triggers and missed triggers and ensure long-term operational stability.

[0060] This embodiment provides a pedestrian crossing signal control method based on distributed optical fiber sensing, which addresses the entire process of pedestrian crossing needs. It continuously senses the entry segment, occupancy segment, and arrival segment through distributed optical fiber. The vibration signal of the passage is preprocessed by bandpass, and short-time energy statistics and standardized mapping are mapped into event probabilities. Based on this, the entry strength and occupancy probability are formed. It can prevent the signal from being left unattended when no one is there and trigger it in time when someone is there, thereby improving the overall level of pedestrian crossing safety and traffic efficiency.

[0061] This embodiment provides a pedestrian crossing signal control method based on distributed optical fiber sensing. It establishes a safety constraint chain with occupancy protection and clearance confirmation. When occupancy exists, passage is allowed. After the entry gap is satisfied, the occupancy must be verified to be continuously below the threshold within the holding window before termination is allowed. This avoids intermittent stopping and walking, instantaneous disturbances that may cause accidental clearance or premature light extinguishing, and reduces the risk of pedestrian congestion and conflict.

[0062] This embodiment provides a pedestrian crossing signal control method based on distributed optical fiber sensing. Addressing the pain point of continuous pedestrian arrivals leading to infinite phase continuity, it introduces an entrance locking, queue request, and maximum release time mechanism. After locking, the most recent entry time is no longer refreshed, and new arrivals are transferred to the next release, realizing batch service and controllable yielding on the vehicle side, improving the predictability and fairness of intersection operation during high-traffic periods.

[0063] This embodiment provides a pedestrian crossing signal control method based on distributed optical fiber sensing. It adaptively adjusts the extension amount by estimating the remaining clearance time, and uses spatial statistics of the event probability of the occupied segment to estimate the occupancy centroid and the advance speed to obtain the remaining clearance time. This is used to extend or terminate the signal more reasonably. Compared with fixed extension, this method is closer to the actual situation of slow-moving groups and group crossings, and reduces unnecessary delays.

[0064] This embodiment provides a pedestrian crossing signal control method based on distributed optical fiber sensing. By recursively pushing the background baseline and adaptively updating the threshold, it dynamically suppresses false alarms and missed alarms caused by environmental vibration, changes in road surface conditions, and sensor drift. It also forms a closed-loop linkage with the signal light output, which has the characteristics of long-term stable operation and engineering feasibility. It is suitable for densely populated pedestrian scenarios such as schools and hospitals.

[0065] Example 2 This embodiment provides a pedestrian crossing signal control system based on distributed optical fiber sensing, including: The fiber optic sensor deployment and section construction module is configured to: stably couple distributed optical fibers to the road surface in an array, divide the laying area into entry section, occupied section and shore section, establish spatial channel mapping, and provide a unified spatial benchmark for subsequent statistical extraction and control determination.

[0066] The signal preprocessing and event probability extraction module is configured to: perform band-limited filtering and short-time energy statistics on the channel-level vibration sequence, combine background statistics with recursive updates to achieve dimensionless standardization, and map the standardized statistics to channel-level event probabilities, providing a basis for the unified quantification of line strength and occupancy probability.

[0067] The entry and occupancy quantification module is configured to: construct occupancy probability and entry intensity respectively, generate pedestrian phase request output, and record the most recent valid entry time and arrival confirmation information, providing a basis for entry gap determination, clearance estimation and termination decision.

[0068] The adaptive signal control and light status output module is configured to: use occupancy protection as a safety constraint, use the entry gap termination as the main exit mechanism, and combine clearing confirmation, remaining clearing time estimation and maximum release duration constraints to give clear outputs on, maintain, extend and turn off the pedestrian release light; at the same time, it introduces an entrance locking and queue request mechanism so that new arrivals during the locking period are transferred to the next release, avoiding continuous arrivals that cause the current pedestrian phase to be extended indefinitely, and realizing controllable batch service.

[0069] The self-calibration and threshold update module is configured to suppress the influence of environmental vibration and sensor drift on event probability and occupancy determination through background baseline recursion and threshold adaptive update, thereby ensuring the long-term stability and robustness of the control output.

[0070] It should be noted that each module in this embodiment corresponds one-to-one with each step in Embodiment 1, and their specific implementation processes are the same, so they will not be repeated here.

[0071] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A pedestrian crossing signal control method based on distributed optical fiber sensing, characterized in that, include: Distributed optical fibers are laid in an array on the road surface, and the fiber laying area is divided into three functional sections: the entry section, the occupied section, and the destination section. Each functional section contains several virtual channels, and the coordinates of each virtual channel are determined. Bandpass filtering and energy statistics are performed on the raw vibration sequences acquired by the virtual channel to construct channel-level event probabilities; Based on channel-level event probabilities, occupancy probabilities and line entry strengths are constructed respectively. Pedestrian phase requests are output, and the most recent valid line entry time is recorded. With occupancy protection as a constraint and line entry gap termination as the main factor, combined with clearing confirmation, remaining clearing time estimation, entrance locking and queue request mechanisms, the results of pedestrian release light illumination, maintenance and extinguishing control are output.

2. The pedestrian crossing signal control method based on distributed optical fiber sensing as described in claim 1, characterized in that, The probability of the channel-level event is: ； in, Indicates channel The probability of the event, Indicates the slope coefficient. Represents the bias coefficient, standardized energy statistic. Virtual Channel At any moment short-term energy , Indicates the length of the sliding window. This represents the filtered vibration sequence. Indicates the discrete sampling sequence number within the sliding window. Indicates the background mean. This represents the background standard deviation.

3. The pedestrian crossing signal control method based on distributed optical fiber sensing as described in claim 1, characterized in that, The occupancy protection is represented as follows: ;in, Indicates that the output is in use for protection. The threshold for determining occupancy; occupancy probability. , For virtual channels Channel-level event probability, This is an occupied segment.

4. The pedestrian crossing signal control method based on distributed optical fiber sensing as described in claim 1, characterized in that, The gap between the wires For the current moment Compared with the most recent valid entry time The difference.

5. The pedestrian crossing signal control method based on distributed optical fiber sensing as described in claim 1, characterized in that, The remaining time for clearing out is: Among them, the location occupying the centroid position , Indicates channel The probability of the event, For occupied segment, The coordinates of the virtual channel. Indicates protection against division by zero; Indicates the safety margin time; estimates the propulsion speed. , Indicates the calculation interval. This indicates the minimum safe speed limit; This indicates the effective length of the zebra crossing.

6. The pedestrian crossing signal control method based on distributed optical fiber sensing as described in claim 1, characterized in that, The clear confirmation is indicated as follows: ； in, This indicates that the confirmation quantity has been cleared. Indicates the time to clear the hold period. For the probability of occupancy, This is the threshold for determining occupancy. Let t be the indicator function, and t be the current time.

7. The pedestrian crossing signal control method based on distributed optical fiber sensing as described in claim 1, characterized in that, The entry locking and queue request mechanism is represented as follows: ； when ; ； in, Indicates a pending service request flag. This indicates that the entrance is locked. Indicates the duration of the current pedestrian phase. Indicates the entry lock trigger time, when The latest valid online entry time will no longer be updated. , Pedestrian phase request.

8. The pedestrian crossing signal control method based on distributed optical fiber sensing as described in claim 1, characterized in that, The output of the pedestrian traffic light's on / off control results includes: ； ,when And it meets the controller's release conditions; ,when or ; ； ,when or ; ； in, Indicates the status of the pedestrian crossing light. Indicates the valid pedestrian phase indicator. This indicates that the output will be terminated. This indicates that the output should be extended. Indicates a pedestrian phase request. Indicates that the output is in use for protection. For the gap between the incoming lines, This indicates that the confirmation quantity has been cleared. Indicates the threshold of the incoming line gap. Indicates the minimum extension threshold. Indicates the duration of the current pedestrian phase. This indicates the maximum release time.

9. The pedestrian crossing signal control method based on distributed optical fiber sensing as described in claim 1, characterized in that, Also includes: Based on the channel-level event probability, the background mean and background standard deviation are updated, and the background mean and background standard deviation are used for energy statistics; Based on the quantile statistics of the occupancy probability, the occupancy threshold is updated, and the occupancy threshold is used for occupancy protection.

10. A pedestrian crossing signal control system based on distributed optical fiber sensing, characterized in that, include: The fiber optic sensor deployment and section construction module is configured to: lay distributed optical fibers in an array on the road surface, divide the fiber optic laying area into three functional sections: the entry section, the occupied section, and the arrival section. Each functional section contains several virtual channels, and the coordinates of each virtual channel are determined. The signal preprocessing and event probability extraction module is configured to perform bandpass filtering and energy statistics on the raw vibration sequences acquired by the virtual channel to construct channel-level event probabilities. The adaptive signal control and lamp status output module is configured to: construct occupancy probability and line entry strength based on channel-level event probability, output pedestrian phase request, and record the most recent valid line entry time. With occupancy protection as a constraint and line entry gap termination as the main factor, combined with clearing confirmation, remaining clearing time estimation, entrance locking and queue request mechanism, output the lighting, holding and extinguishing control results of pedestrian release lights.

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