A multi-mode longitudinal displacement monitoring system and method for existing seamless rail tracks

Abstract

This invention provides a multi-mode longitudinal displacement monitoring system and method for existing seamless rail tracks, belonging to the field of railway track engineering monitoring technology. The system includes longitudinal displacement observation piles, an observation base, multi-mode observation equipment, and dedicated barcodes. The observation piles are made from old rails and embedded in the road shoulder. The observation base is fixed to the side of the observation piles. The multi-mode observation equipment is magnetically mounted to the base, and the dedicated barcode is affixed to the web of the seamless rail. The multi-mode observation equipment integrates a coaxially mounted telescope, a red laser indicator light, and an intelligent digital measuring instrument. The dedicated barcodes include optical reading barcodes and electronic reading barcodes. This invention solves the problems of visual errors in manual reading and easy omissions in existing technologies by switching and coordinating three modes: laser positioning coarse measurement, optical fine reading, and electronic automatic measurement, as well as mutual verification of data from the three modes. This achieves high-precision, high-efficiency, and widely adaptable rail displacement monitoring.

Description

Technical Field

[0001] This invention relates to the field of railway track engineering monitoring technology, and in particular to a multi-mode existing seamless rail longitudinal displacement monitoring system and method. Background Technology

[0002] Currently, longitudinal displacement monitoring of existing seamless rail lines mainly relies on laser manual reading devices and purely optical observation equipment. Laser devices project laser light onto the rail gauges, and the values ​​are read manually. Optical equipment calculates displacement by aiming a telescope at the marked points. Both methods are based on the core logic of "equipment projection - manual reading" and are the mainstream monitoring methods in the industry.

[0003] Existing technologies have significant drawbacks: First, they lack precision. Manual laser readings are affected by ambient light and visual errors, while optical observation relies on aiming accuracy, neither of which can meet the high-precision requirements of scenarios such as high-speed rail. Second, they are inefficient, requiring 2-3 people to operate, and each monitoring point is time-consuming, making it impossible to quickly complete long-distance track inspections. Third, their applicability is limited; monitoring reliability drops significantly in complex environments such as strong light and weak light, easily missing displacement anomalies. These problems may lead to safety hazards such as rail bulging and track breakage, while also increasing maintenance labor costs. These deficiencies directly result in the inability to accurately and promptly detect longitudinal displacement anomalies in seamless rails, potentially causing track stress concentration, rail bulging, and track breakage, while inefficient monitoring increases railway maintenance labor costs, prolongs operation time, and enhances the safety risks of existing line construction.

[0004] To address the shortcomings of existing technologies, such as low accuracy, poor efficiency, and narrow applicability, this invention provides a monitoring device that integrates optics, laser, and electronic readings, enabling accuracy adaptation in different environments, improving monitoring efficiency and reliability, and ensuring the safe operation of seamless rail systems. Summary of the Invention

[0005] The main objective of this invention is to provide a multi-mode longitudinal displacement monitoring system and method for existing seamless rails, which solves the problems of visual errors that cannot be identified by manual readings and measurement errors that are easily missed in the prior art. By integrating multiple reading modes and optimizing the monitoring benchmark, it achieves high-precision, high-efficiency and widely adaptable rail displacement monitoring.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is a multi-mode longitudinal displacement monitoring method for existing seamless rail tracks, characterized by comprising the following steps:

[0007] S1. Bury longitudinal displacement observation piles, install observation bases, affix special barcodes to the web of seamless rails, install multi-mode observation equipment on the observation bases and align it with the center of the special barcodes; S2. Turn on the laser emitter. The laser beam is projected onto the optical reading barcode area of ​​the special barcode. The displacement is determined based on the position of the laser spot relative to the scale line. S3. Adjust the telescope of the multi-mode observation equipment so that the crosshairs are aligned with the optical reading barcode area, and read the scale value corresponding to the crosshairs. S4. The intelligent digital measuring instrument of the multi-mode observation equipment acquires the electronic reading barcode image of the special barcode, decodes and identifies the absolute position information, and calculates the displacement value.

[0008] Preferably, step S4 further includes adaptive anti-interference exposure control: The built-in ambient light sensor of the intelligent digital measuring instrument detects the light intensity in real time, and the processor dynamically adjusts the exposure time and gain of the CMOS image sensor according to the light intensity. In strong light environments, shorten the exposure time and activate the built-in polarization filter simulation circuit; In low-light environments, auxiliary lighting LEDs are turned on and a multi-frame cumulative averaging algorithm is used.

[0009] Preferably, in step S4, the displacement value is calculated using the phase correlation method: the processor performs fast Fourier transform on the real-time acquired electronic reading barcode image and the stored reference image respectively, calculates the cross power spectrum of the two images in the frequency domain, performs inverse Fourier transform on the cross power spectrum to obtain the pulse function, detects the peak position of the pulse function to obtain the integer pixel displacement, and then performs subpixel fitting on the neighborhood points around the peak to obtain the subpixel level displacement value.

[0010] Preferably, step S4 further includes multi-mode data fusion: establishing error models for laser positioning mode, optical precision reading mode and electronic automatic measurement mode respectively, calculating the measurement confidence of each mode in the current environment in real time, using a weighted average algorithm to fuse the measurement results of the three modes to obtain the final displacement value, and automatically determining that the mode is invalid and resetting the weight to zero when the confidence of a certain mode is lower than a preset threshold, while prompting to switch to other valid modes.

[0011] Preferably, step S4 further includes self-calibration of the observation pile benchmark: the longitudinal displacement observation pile integrates a dual-axis tilt sensor and a temperature sensor, which transmit the tilt angle change and temperature change to the intelligent digital measuring instrument of the multi-mode observation equipment via wireless communication. The processor performs real-time compensation on the measured displacement value according to the pre-stored calibrated compensation model, eliminating the errors introduced by the thermal expansion and contraction and tilt of the observation pile itself. The compensation model is as follows: the absolute displacement value after compensation is equal to the apparent displacement value directly measured by the multi-mode observation equipment minus the product of the thermal expansion coefficient and the temperature change of the observation pile, and then minus the product of the tilt angle change transmission coefficient to the longitudinal displacement and the tilt angle change, wherein the thermal expansion coefficient and the transmission coefficient are obtained through experimental calibration.

[0012] Preferably, step S4 further includes continuous monitoring and alarm: the intelligent digital measuring instrument continuously collects and records displacement values ​​at set time intervals, and triggers an alarm when the displacement rate exceeds a preset threshold. Track condition diagnosis based on displacement spectrum: the intelligent digital measuring instrument performs a fast Fourier transform on the time series formed by the continuously collected displacement data to decompose it into the spectral characteristics of the displacement. The calculated spectral characteristics are then matched with a preset fault feature library corresponding to different track conditions. When a dangerous frequency component is identified in the displacement spectrum and the amplitude of this component exceeds a preset threshold, an early warning of track instability is issued.

[0013] This invention provides a multi-mode existing seamless rail longitudinal displacement monitoring system, including multi-mode observation equipment, a dedicated barcode, an observation base, and longitudinal displacement observation piles; The multi-mode observation equipment is installed on the observation base via magnetic attachment; A special barcode is affixed to the web of the seamless rail to be monitored; The observation base is fixed to the side of the longitudinal displacement observation pile; Longitudinal displacement monitoring piles are installed on the shoulders of existing lines.

[0014] Preferably, the multi-mode observation equipment integrates a telescope, a red laser indicator, and an intelligent digital measuring instrument; The red laser indicator light emitted by the laser emitter is coaxial with the optical axis of the telescope. The intelligent digital measuring instrument integrates a CMOS image sensor and a high-performance processor, and its measuring optical path is coaxial with the telescope; the multi-mode observation equipment is equipped with a magnetic chuck, which can be magnetically attached to the observation base and can be vertically rotated. The dedicated barcode includes an optical reading barcode area and an electronic reading barcode. The optical reading barcode area is a high-precision scale area, while the electronic reading barcode is a high-density encoding area with encoding rules that match the decoding algorithm of the intelligent digital measuring instrument.

[0015] Beneficial effects: 1. Eliminating visual errors from manual readings and achieving automatic identification and verification of measurement errors: By integrating laser positioning, optical precision reading, and electronic automatic measurement into a single device, with all three modes sharing the same observation center, this invention enables mutual verification of measurement data. When the deviation between the optical and electronic readings exceeds a preset threshold, the device automatically prompts for remeasurement, fundamentally solving the technical problems of unidentifiable visual errors from manual readings and the easy omission of measurement errors in existing technologies, significantly improving the reliability of monitoring data.

[0016] 2. Improved monitoring accuracy: The electronic automatic measurement mode of this invention uses a CMOS image sensor to identify the absolute position code of the encrypted barcode area and combines it with the scale information of the optical reading barcode for error correction, achieving a measurement accuracy of ±0.05mm; the optical precision reading mode uses backlit crosshair aiming, achieving a reading accuracy of ±0.1mm. Compared to the existing laser manual reading devices and purely optical observation equipment with an accuracy of ±0.5mm or more, this invention improves accuracy by more than 90%, meeting the high-precision monitoring requirements of scenarios such as high-speed railways.

[0017] 3. Improved monitoring efficiency: The laser positioning mode of this invention has a single-point positioning time of no more than 3 seconds, suitable for rapid inspection of long-distance tracks; the electronic automatic measurement mode has a single measurement time of no more than 0.5 seconds, supports continuous automatic monitoring, and the data recording interval can be set from 1 second to 1 hour. A single set of equipment can be operated by one person to complete the monitoring task, compared with the existing technology that requires 2-3 people to operate, improving monitoring efficiency by more than 90%, significantly shortening operation time, and reducing the safety risks of construction on existing lines.

[0018] 4. Enhanced environmental adaptability: This invention employs a multi-mode collaborative design, allowing for flexible switching to the appropriate measurement mode in complex environments such as strong light, weak light, and strong electromagnetic interference. The laser mode is suitable for rapid screening, the optical mode is suitable for environments without electronic equipment or with strong electromagnetic interference, and the electronic mode is suitable for high-precision automatic monitoring. The system operates within a temperature range of -40℃ to 80℃, maintaining monitoring reliability even in harsh environments such as rain, fog, and strong light, thus avoiding the limitations of existing technologies in terms of applicable scenarios and the significant decrease in monitoring reliability under complex conditions. Attached Figure Description

[0019] The present invention will be further described below with reference to the accompanying drawings and embodiments: Figure 1 This is a schematic diagram of the overall structure of the system of the present invention; Figure 2 This is a schematic diagram of the left side of the observation equipment structure of the system of the present invention; Figure 3 This is a schematic diagram of the structure of the observation equipment of the system of the present invention on the right side; Figure 4 This is a schematic diagram of the special barcode structure for the system of this invention; Figure 5 This is a schematic diagram of the system base structure of the present invention; Figure 6 This is a diagram showing the positional relationships of the system on the left side of this invention; Figure 7 This is a diagram showing the positional relationships of the system on the right side of this invention; Figure 8 This is a flowchart of the method of the present invention. Detailed Implementation

[0020] Example 1 like Figure 1 As shown, the overall structure of a multi-mode existing seamless rail longitudinal displacement monitoring system includes four core components: a multi-mode observation device 1, a dedicated barcode 2, an observation base 3, and longitudinal displacement observation piles 4. The observation piles 4 are embedded in the shoulder of the existing line, the observation base 3 is fixed to the side of the observation piles 4, the multi-mode observation device 1 is magnetically mounted on the observation base 3, and the dedicated barcode 2 is affixed to the web of the seamless rail 5 to be monitored, serving as a target identifier for displacement monitoring.

[0021] Multi-mode observation equipment 1: such as Figure 2 and Figure 3 As shown, the device adopts an integrated design, combining a telescope, a red laser indicator light, and an intelligent digital measuring instrument. Figure 2 This is a left-side view. Figure 3 The complete structure is shown from the right-hand perspective. Its external structure includes an eyepiece 101, an eyepiece focusing mechanism 102, a measurement key 103, an objective lens focusing mechanism 104, a display screen 105, function keys 106, an objective lens 107, a laser emitter 108, and a magnetic chuck 109. The device is attached to the observation base 103 via the magnetic chuck 109 and precisely positioned using a limiter 104 on the base. It can also rotate vertically to accommodate readings from the left and right rails. The telescope (objective lens 107, eyepiece 101) is equipped with a backlit crosshair and has an adjustable magnification between 10x and 50x for optical precision reading mode. The red laser indicator (laser emitter 108) is coaxial with the telescope's optical axis for quick positioning mode. The intelligent digital measuring instrument integrates a CMOS image sensor and a high-performance processor; its measurement optical path is also coaxial with the telescope for electronic automatic measurement mode.

[0022] Specialized barcode 2: such as Figure 4 As shown, the dedicated barcode 2 is affixed to the web of the seamless rail, its height aligned with the observation center of the multi-mode observation device 1, with a deviation not exceeding ±2cm. This dedicated barcode 2 is divided into two functional areas: an optical reading barcode 202 and an electronic reading barcode 201. The optical reading barcode 202 is a high-precision scale area with a minimum graduation of 0.1mm, used for manual reading in optical mode; the electronic reading barcode 201 is an electronic reading barcode using high-density encoding, its encoding rules matching the decoding algorithm of the intelligent digital measuring instrument, used for absolute position identification in electronic mode. The dedicated barcode is made of weather-resistant PET material, ensuring long-term clear visibility even in harsh environments.

[0023] Observation base 3: such as Figure 5As shown, the observation base 303 is made of 400 series stainless steel and has an inverted L-shaped structure. It includes a base plate 301, an observation pile limiter 302, and an observation equipment limiter 304. During installation, the base plate 301 is fixed to the side of the rail head of the observation pile 304 using stainless steel bolts (torque 35 N·m). The observation pile limiter 302 abuts against the side of the rail head of the observation pile 304 and is finely adjusted using the observation pile limit adjustment screw 303 to ensure the horizontal and vertical alignment of the base installation. The observation equipment limiter 304 is used for guidance and positioning during the installation of the multi-mode observation equipment 301, ensuring that the optical center of the equipment is consistent with the preset monitoring direction after each installation.

[0024] Longitudinal displacement monitoring pile 4: such as Figure 1 , Figure 6 and Figure 7 As shown, Figure 6 This is a left-side view. Figure 7 This is a right-side view. Figure 1 Show the complete structure. Figure 6 and Figure 7 The design also demonstrates the positional relationship in practical applications. Observation pile 4 is constructed from a 2.8-meter-long section of scrap 60kg / m steel rail, buried with the rail head facing upwards. During installation, the pile is buried 1.8 meters underground, with its top surface (the top surface of the rail head) 50 centimeters higher than the existing rail surface. To ensure the long-term stability of the observation pile, the surface is treated for rust removal and corrosion prevention, and the bottom is backfilled with concrete for fixation. Installation holes are pre-drilled on the side of the rail head for fixing the observation base 3. This design utilizes scrap resources, and its metal structure offers better long-term stability compared to concrete piles, providing a reliable benchmark for high-precision monitoring.

[0025] Example 2 like Figure 8 As shown, the system deployment and monitoring method flow in this embodiment is as follows: (1) System deployment phase: S1. Excavate a foundation pit 3.2 meters from the center of the existing track shoulder, and install and calibrate longitudinal displacement observation piles 4 as described above. After 24 hours, install the observation base 3, adjust it to a horizontal state using the observation pile limit adjustment screw 3, and tighten it.

[0026] S2. Clean the web of the seamless rail to be monitored (remove rust with sandpaper and degrease with alcohol), and horizontally affix the special barcode 2 to the web, press for 30 seconds and let it stand for 2 hours.

[0027] S3. Install the multi-mode observation device 1 onto the observation device limiter 304 on the base 3 via the magnetic suction plate 109, turn on the laser indicator light, move the device to align the laser spot with the center of the special barcode 2, and tighten the clamping bolts to fix it, complete the device calibration, and ensure that the optical paths of the three measurement modes are aligned with the same target area.

[0028] (2) Monitoring Implementation Phase: The monitoring method provided in this embodiment includes three switchable working modes to adapt to different monitoring scenarios and accuracy requirements, as detailed below: Laser positioning and coarse measurement mode: In rapid inspection scenarios, the operator activates the laser emitter of the multi-mode observation device 1. The laser beam is projected onto the optical reading barcode 202 of the dedicated barcode 2. By observing the position of the laser spot relative to the scale lines, the operator can quickly and intuitively determine the longitudinal displacement trend and approximate displacement of the rail. This mode has a single-point positioning time of no more than 3 seconds and a coarse measurement accuracy of ±1mm, making it suitable for rapid screening of long-distance rails.

[0029] Optical Precision Reading Mode: In environments with strong electromagnetic interference or when electronic equipment malfunctions, the operator switches to optical mode. By adjusting the eyepiece focus 102 and objective lens focus 104 of the telescope, the backlight crosshairs are clearly aligned with the optical reading barcode 202 of the dedicated barcode 2. The operator reads the scale value corresponding to the crosshair intersection point through the eyepiece 101 and records the displacement data. This mode is unaffected by the electromagnetic environment, with a reading accuracy of ±0.1mm and a single reading time of no more than 10 seconds.

[0030] Electronic Automatic Measurement Mode: When high-precision and high-efficiency monitoring is required, the operator activates the electronic automatic measurement mode. The built-in CMOS image sensor of the intelligent digital measuring instrument acquires the image of the electronic reading barcode 201 of the dedicated barcode 2. The processor analyzes the encrypted image through a built-in decoding algorithm, identifies the absolute position information, and performs error correction by combining the scale information of the optical reading barcode 202, thereby calculating a high-precision displacement value. The measurement result (e.g., "0.08mm") is displayed in real time on the OLED screen 5 and can be transmitted to a mobile terminal via wireless communication modules such as Bluetooth. This mode has a single measurement time of no more than 0.5 seconds, a measurement accuracy of ±0.05mm, and supports continuous automatic monitoring at set intervals (e.g., adjustable from 1 second to 1 hour).

[0031] In this embodiment of the invention, to address the impact of complex lighting conditions at railway sites on electronic measurements, the intelligent digital measuring instrument employs an adaptive anti-interference exposure control strategy. The device's built-in ambient light sensor monitors light intensity in real time. Under strong midday sunlight in summer, the processor automatically shortens the exposure time of the CMOS image sensor from the default 10ms to 0.5ms and reduces the gain. Simultaneously, it activates the built-in polarization filter simulation circuit to effectively filter out specular reflections from the rail surface, ensuring that the acquired electronic reading barcode image is not saturated. At night or in low-light tunnel environments, the processor automatically activates auxiliary lighting LEDs and controls the CMOS sensor to continuously acquire 5-10 frames of images. Through a multi-frame cumulative averaging algorithm, random noise is suppressed to its original level. ,in This significantly improves the decoding success rate in low-light conditions by increasing the number of image frames.

[0032] Based on phase-correlation subpixel displacement calculation, this invention's electronic measurement mode employs a more advanced phase-correlation algorithm, unlike conventional direct decoding methods. The processor performs Fast Fourier Transform (FFT) on both the real-time acquired barcode image and the reference image stored in the device and captured during the system's initial deployment. By calculating the cross-power spectrum of the two images in the frequency domain and then performing an inverse Fourier Transform, a sharp pulse function is obtained. The peak coordinates of this pulse directly correspond to the integer-pixel displacement between the two images. Furthermore, this invention uses a subpixel fitting algorithm to perform quadratic surface fitting on the 3x3 neighborhood points around the peak, thereby improving the positioning accuracy to 0.02 pixels. Combined with high-density barcodes, this ultimately achieves a displacement measurement accuracy better than ±0.02 mm.

[0033] (3) Data collaboration and anomaly handling: This system supports mutual verification of measurement data from three modes. It calculates the measurement confidence level in real time for laser positioning mode, optical precision reading mode, and electronic automatic measurement mode under the current environment, and performs weighted fusion of the measurement results of each mode based on the confidence level, automatically outputting the optimal displacement value. For laser positioning mode, confidence level Mainly affected by ambient light intensity and track surface reflectivity, the processor calculates in real time by analyzing the image contrast and signal-to-noise ratio of the laser spot; For optical precision reading mode, confidence level It depends solely on the sharpness of the backlight crosshairs of the telescope eyepiece, is unaffected by electromagnetic interference, and is evaluated by the processor using an image sharpness evaluation function (such as the Brenner gradient function). For electronic automatic measurement mode, confidence level Taking into account the image transmission error rate, the intensity of the ambient electromagnetic field, and the signal-to-noise ratio of the barcode image, the electromagnetic field intensity is collected in real time by the electromagnetic interference sensor built into the multi-mode observation device.

[0034] Taking a strong electromagnetic interference environment as an example, when an electric locomotive passes by or there is a strong wireless transmission source nearby, the image transmission in the electronic automatic measurement mode will generate stripe noise, leading to an increased decoding failure rate. Once the processor detects that the image signal-to-noise ratio is below a threshold, The real-time adjustment is below 0.1, while the optical fine-reading mode is completely unaffected by electromagnetic interference, and the clarity of its backlight crosshairs remains unchanged. It remains at a high value of 0.95 in laser positioning mode. It is minimally affected by electromagnetic interference and usually remains around 0.85.

[0035] After obtaining the confidence levels of the three modes, the processor executes a weighted fusion algorithm to calculate the final displacement value. As shown in equation (1): (1); in, , and These are the displacement values ​​obtained independently by the three modes at the same time. When the confidence level of a certain mode is lower than a preset threshold (e.g., 0.3), the processor automatically determines that the mode is invalid, resets its weight to zero, meaning that the contribution of this mode is not included in the numerator or denominator of the fusion calculation, thus avoiding erroneous data contaminating the fusion result. The processor sends a prompt message to the operator through the screen display and wireless communication module. In strong electromagnetic interference scenarios, the screen display will show "Electronic mode is interfered with; current results are based on optical and laser modes," and suggest that the operator prioritize using the optical precision reading mode for manual verification. Under normal conditions, the electronic automatic measurement mode has the highest confidence level. The fusion result is mainly contributed by the electronic mode, and the system automatically recommends using the electronic mode for continuous monitoring. The system also features adaptive mode switching. When the processor detects that the confidence level of the currently active single mode remains below 0.2 for more than 10 seconds, the system automatically suggests that the operator switch to the mode with the highest confidence level and provides one-click switching instructions. This dynamic confidence level assessment and weighted fusion mechanism enables the invention to automatically output the most reliable displacement measurement results even in complex environments such as strong light, weak light, rain, snow, strong electromagnetic interference, and vibration. This fundamentally avoids erroneous readings or data omissions caused by the failure of a single measurement mode, effectively solving the technical problems of existing technologies where visual errors in manual readings cannot be identified and measurement errors are easily missed.

[0036] Meanwhile, this invention proposes real-time monitoring and compensation of the observation pile benchmark. Traditional methods assume that the observation pile is absolutely static, but in reality, the road shoulder under the railway track will settle, and the observation pile itself will also expand and contract due to sun exposure. To this end, we integrate a high-precision dual-axis tilt sensor and a temperature sensor inside the observation pile. When the observation pile tilts slightly or the temperature changes, the tilt angle and temperature data are wirelessly transmitted to the multi-mode observation equipment. The processor calculates the compensation model according to the pre-stored calibration, as shown in the following equation (2): (2); in, This is the absolute displacement value after compensation. The apparent displacement values ​​directly measured by multi-mode observation equipment. The change in temperature This represents the change in tilt angle. To observe the thermal expansion coefficient of the pile, The transfer coefficient of longitudinal displacement due to changes in inclination angle enables the system to maintain sub-millimeter-level long-term monitoring accuracy even under harsh conditions such as roadbed deformation and seasonal temperature differences.

[0037] During continuous monitoring, the intelligent digital measuring instrument can automatically record displacement change curves. When the detected displacement rate exceeds a set threshold (e.g., 0.1 mm / h), the equipment triggers an audible and visual alarm. Operators can view the displacement curve through the terminal device and promptly notify the maintenance team to take appropriate measures, such as stress release, thereby effectively preventing safety accidents such as track bulging.

[0038] Example 3 This embodiment provides another monitoring system suitable for scenarios with higher precision requirements, such as high-speed railways. Its core structure and working principle are basically the same as those of Embodiment 1, the difference being that key components have been optimized and upgraded to meet more stringent monitoring requirements.

[0039] Longitudinal displacement monitoring piles: To further improve the long-term stability of the benchmark, the monitoring piles in this embodiment are made of 3.5-meter-long 75kg / m old steel rails, buried at a depth of not less than 2.0 meters underground. The bottom is connected to the concrete foundation of the road shoulder by rebar anchoring (the rebar uses Φ20 threaded steel, with an embedment depth of 30cm). A spirit level is installed on the side of the rail head to ensure that the verticality error of the installation is ≤0.1°.

[0040] Intelligent Digital Measuring Instrument: To achieve higher measurement accuracy and data processing capabilities, the intelligent digital measuring instrument in this embodiment has been upgraded to a 12-megapixel CMOS sensor (model IMX477) and equipped with an NVIDIA Jetson Nano edge computing module. Noise reduction processing has been introduced into the image recognition algorithm, and the data sampling frequency has been increased to 30 frames per second.

[0041] Dedicated Barcode: To match the upgraded measuring instrument, the dedicated barcode size has increased to 15cm × 8cm. Its electronic reading barcode 201 adopts three-dimensional encoding, increasing the encoding density to 2000 dots / cm². In addition, a temperature sensor is integrated into the barcode, which can simultaneously collect rail temperature data for subsequent temperature compensation correction of displacement values.

[0042] The working process of this embodiment is similar to that of Embodiment 1. During the deployment phase, more rigorous benchmark calibration and more precise equipment installation lay the foundation for high-precision measurement. During the monitoring phase, utilizing the upgraded electronic automatic measurement mode, the image recognition algorithm effectively filters out image noise, and the three-dimensional stereo coding provides richer sub-millimeter-level positional information, improving the system's measurement accuracy to ±0.02mm. Simultaneously, by collecting track temperature data in real time through temperature sensors, the system can automatically compensate for temperature variations in displacement data, eliminating the interference of temperature changes on the measurement results. Testing showed that the monitoring system of this embodiment can operate stably on a high-speed rail line with a speed of 350km / h, with a displacement measurement error ≤0.03mm after temperature compensation, fully meeting the stringent accuracy requirements for displacement monitoring on high-speed rail ballastless tracks.

[0043] In summary, this invention utilizes laser, optical, and electronic reading modes of a multi-mode observation device to achieve high-precision, high-efficiency, and high-reliability seamless longitudinal displacement monitoring of rails under various environments. Its observation stake design, which reuses scrap rails, reduces costs; and the mutual verification mechanism of the three modes effectively avoids the technical problems of large visual errors and easy omissions in manual readings found in existing technologies, providing strong protection for railway operation safety.

[0044] The above embodiments are merely preferred technical solutions of the present invention and should not be considered as limitations on the present invention. The scope of protection of the present invention should be limited to the technical solutions described in the claims, including equivalent substitutions of the technical features described in the claims. That is, equivalent substitutions and improvements within this scope are also within the scope of protection of the present invention.

Claims

1. A multi-mode method for monitoring the longitudinal displacement of existing seamless rail tracks, characterized in that, Includes the following steps: S1. Bury longitudinal displacement observation piles (4), install observation base (3), paste special barcode (2) on the web of seamless rail (5), install multi-mode observation equipment (1) on observation base (3) and align it with the center of special barcode (2); S2. Turn on the laser emitter (108), and project the laser beam onto the optical reading barcode area (202) of the special barcode (2). Determine the displacement based on the position of the laser spot relative to the scale line. S3. Adjust the telescope of the multi-mode observation device (1) so that the crosshairs are aligned with the optical reading barcode area (202) and read the scale value corresponding to the crosshairs. S4. The intelligent digital measuring instrument of the multi-mode observation device (1) collects the electronic reading barcode (201) image of the special barcode (2), decodes and identifies the absolute position information, and calculates the displacement value.

2. The method for monitoring longitudinal displacement of existing seamless rails in multiple modes according to claim 1, characterized in that, Step S4 also includes adaptive anti-interference exposure control: The built-in ambient light sensor of the intelligent digital measuring instrument detects the light intensity in real time, and the processor dynamically adjusts the exposure time and gain of the CMOS image sensor according to the light intensity. In strong light environments, shorten the exposure time and activate the built-in polarization filter simulation circuit; In low-light environments, auxiliary lighting LEDs are turned on and a multi-frame cumulative averaging algorithm is used.

3. The method for monitoring longitudinal displacement of existing seamless rails using multiple modes according to claim 1, characterized in that, In step S4, the phase correlation method is used to calculate the displacement value: the processor performs fast Fourier transform on the real-time acquired electronic reading barcode image and the stored reference image respectively, calculates the cross power spectrum of the two images in the frequency domain, performs inverse Fourier transform on the cross power spectrum to obtain the pulse function, detects the peak position of the pulse function to obtain the integer pixel displacement, and then performs subpixel fitting on the neighborhood points around the peak to obtain the subpixel level displacement value.

4. The method for monitoring longitudinal displacement of existing seamless rails in multiple modes according to claim 1, characterized in that, Step S4 also includes multi-mode data fusion: establishing error models for laser positioning mode, optical precision reading mode and electronic automatic measurement mode respectively, calculating the measurement confidence of each mode in the current environment in real time, and using a weighted average algorithm to fuse the measurement results of the three modes to obtain the final displacement value. When the confidence of a certain mode is lower than the preset threshold, the mode is automatically determined to be invalid and the weight is reset to zero, while prompting to switch to other valid modes.

5. The method for monitoring longitudinal displacement of existing seamless rails in multiple modes according to claim 1, characterized in that, Step S4 also includes self-calibration of the observation pile benchmark: the longitudinal displacement observation pile (4) integrates a dual-axis tilt sensor and a temperature sensor, and transmits the tilt change and temperature change to the intelligent digital measuring instrument of the multi-mode observation device (1) via wireless communication. The processor performs real-time compensation on the measured displacement value according to the pre-stored calibrated compensation model, eliminating the error introduced by the thermal expansion and contraction and tilt of the observation pile itself.

6. The method for monitoring longitudinal displacement of existing seamless rails in multiple modes according to claim 5, characterized in that, The compensation model is as follows: the absolute displacement value after compensation is equal to the apparent displacement value directly measured by the multi-mode observation equipment minus the product of the thermal expansion coefficient of the observation pile and the temperature change, and then minus the product of the transfer coefficient of the inclination change to the longitudinal displacement and the inclination change. The thermal expansion coefficient and the transfer coefficient are obtained through experimental calibration.

7. The method for monitoring longitudinal displacement of existing seamless rails using multiple modes according to claim 1, characterized in that, Step S4 also includes continuous monitoring and alarm: the intelligent digital measuring instrument continuously collects and records displacement values ​​at set time intervals, and triggers an alarm when the displacement rate exceeds a preset threshold.

8. The method for monitoring longitudinal displacement of existing seamless rails in multiple modes according to claim 7, characterized in that, It also includes track condition diagnosis based on displacement spectrum: the intelligent digital measuring instrument performs fast Fourier transform on the time series formed by continuously collected displacement data, decomposes it to obtain the spectral characteristics of displacement, and performs pattern matching with the calculated spectral characteristics and the preset fault feature library corresponding to different track conditions. When the displacement spectrum is found to contain dangerous frequency components and the amplitude of the component exceeds the preset threshold, an early warning of track instability trend is issued.

9. A multi-mode longitudinal displacement monitoring system for existing seamless rail tracks, characterized in that, It includes multi-mode observation equipment (1), special barcode (2), observation base (3) and longitudinal displacement observation pile (4); The multi-mode observation device (1) is installed on the observation base (3) by magnetic attraction; A special barcode (2) is affixed to the web of the seamless rail (5) to be monitored; The observation base (3) is fixed to the side of the longitudinal displacement observation pile (4); Longitudinal displacement monitoring piles (4) are buried on the shoulder of the existing line.

10. The multi-mode existing seamless rail longitudinal displacement monitoring system according to claim 9, characterized in that, The multi-mode observation device (1) integrates a telescope, a red laser indicator light, and an intelligent digital measuring instrument; The red laser indicator light emitted by the laser emitter (108) is coaxial with the optical axis of the telescope; The intelligent digital measuring instrument integrates a CMOS image sensor and a high-performance processor, and its measuring optical path is coaxial with the telescope; the multi-mode observation device (1) is equipped with a magnetic plate (109), which is attached to the observation base (3) and can be rotated vertically; The dedicated barcode (2) includes an optical reading barcode area (202) and an electronic reading barcode (201). The optical reading barcode area (202) is a high-precision scale area, and the electronic reading barcode (201) is a high-density encoding area with encoding rules that match the decoding algorithm of the intelligent digital measuring instrument.

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