Optical Sensor System and Method for Multi-Response Measurement for Structural Integrity Assessment of Piping

Abstract

The present invention relates to an optical sensor system and method for measuring multiple responses for evaluating the structural integrity of a pipe, and more specifically, to an optical sensor system and method for measuring multiple responses for evaluating the structural integrity of a pipe that uses optical fiber sensors installed along the longitudinal direction of the pipe to precisely measure multiple responses such as deformation, temperature, and vibration, and processes these signals at high speed to monitor the abnormal condition of the pipe in real time.

Description

Technology Field

[0001] The present invention relates to an optical sensor system and method for measuring multiple responses for evaluating the structural integrity of a pipe, and more specifically, to an optical sensor system and method for measuring multiple responses for evaluating the structural integrity of a pipe that uses optical fiber sensors installed along the longitudinal direction of the pipe to precisely measure multiple responses such as deformation, temperature, and vibration, and processes these signals at high speed to monitor the abnormal condition of the pipe in real time. Background Technology

[0002] In modern industrial society, large-scale infrastructure such as petrochemical plants, power plants, gas supply networks, and water and sewage systems constitutes the core infrastructure that forms the foundation of the national economy and people's lives. These facilities are equipped with vast pipeline networks for the transport of fluids or gases, and maintaining the structural integrity of these pipelines is an essential element not only for the stable operation of the facilities but also for preventing environmental pollution and major disasters. However, most industrial pipelines are often buried underground or installed in harsh environments such as inaccessible high-altitude areas or the seabed, which limits the effectiveness of visual inspections or periodic checks. Furthermore, as facilities age, the risk of pipeline damage due to corrosion, fatigue failure, and ground subsidence increases exponentially; additionally, natural disasters such as the recent frequent earthquakes pose a fatal threat to aging pipelines that lack conventional seismic design. According to statistics, the proportion of piping with seismic design applied currently does not even reach 50% of the total, and consequently, the need for monitoring technology capable of monitoring the condition of piping in real time and detecting abnormal signs early is more critical than ever.

[0003] Conventional pipeline monitoring technology has primarily relied on electric point sensors, such as strain gauges or accelerometers. While these electric sensors have the advantage of precisely measuring deformation or vibration at specific points, they have a critical limitation in that they cannot detect localized damage or leaks occurring in sections where sensors are not installed. Monitoring linear structures extending for several kilometers, such as pipelines, requires the installation of numerous sensors, which leads to increased installation costs and complex wiring issues. Furthermore, electric sensors suffer from poor durability due to susceptibility to corrosion caused by moisture or chemicals; above all, they are sensitive to electromagnetic interference (EMI) and pose a risk of sparking, which limits their application in areas handling flammable materials, such as gas pipelines or petrochemical complexes, where anti-explosion treatment is required.

[0004] To overcome the limitations of such electric sensors, distributed measurement technology using fiber optic sensors has been studied. Fiber optic sensors have the significant advantages of being unaffected by electromagnetic interference, having excellent durability, and being able to measure temperature or strain distribution across an entire section using a single optical fiber line. Representative technologies such as OTDR (Optical Time Domain Reflectometry) and BOTDA (Brillouin Optical Time Domain Analysis) are utilized, but these conventional distributed optical sensor technologies also face several technical challenges.

[0005] First, there are limitations in measurement speed and data processing. Conventional distributed sensing technology has the disadvantage of long measurement times because it undergoes a process of averaging multiple measurement data to increase the signal-to-noise ratio (SNR). While this may be suitable for monitoring gradual corrosion or ground subsidence, it has limitations in capturing dynamic behaviors in real time, such as pipe rupture or sudden vibrations during an earthquake.

[0006] In particular, high-speed signal processing technology is essential for collecting and analyzing vast amounts of light scattering data generated in long-distance pipelines spanning several kilometers in real time, but conventional systems frequently experience bottlenecks in processing such big data.

[0007] Second, there is the problem of separating and measuring multiple physical quantities. The detection signal of a fiber optic sensor, particularly the Brillouin Frequency Shift, has the characteristic of being sensitive to both strain and temperature. Therefore, when strain is detected in a pipe, it is often difficult to clearly distinguish whether it is deformation caused by actual physical external forces or thermal expansion due to simple temperature changes. In conventional technology, attempts have been made to compensate for this by installing separate temperature sensors in parallel or applying complex mathematical models, but it is still difficult to ensure the accuracy and reliability of the measurement.

[0008] Third, there is a lack of sensor packaging and installation technology. For fiber optic sensors to accurately reflect the behavior of the piping, they must be firmly attached to the pipe surface. However, conventional simple adhesive methods cause measurement errors as the adhesive weakens or peels off over time. Furthermore, sensor placement and packaging technologies for detecting changes in the surrounding environment—such as ground subsidence—rather than deformation of the pipe itself, are still inadequate.

[0009] Fourth, there is a lack of an integrated control system that considers user convenience. Existing systems primarily output results based on waveform graphs or numerical data that require expert interpretation, making it difficult for field managers to intuitively grasp the condition of the pipelines and make quick decisions. Since a visualized monitoring interface that takes into account the three-dimensional shape of the pipelines and the burial environment is not provided, there is a problem of delay in immediately identifying the location of anomalies and responding to them.

[0010] Consequently, in order to improve the seismic performance of existing and new piping systems and ensure the safety of large industrial facilities, there is an urgent need to develop an integrated optical sensor system that includes packaging technology and an intuitive 3D visualization monitoring platform capable of maintaining the advantages of distributed sensing while enabling high-speed real-time measurement, precisely separating deformation and temperature, and maintaining a stable installation state for a long period. The problem to be solved

[0011] The present invention has been devised to improve upon the aforementioned problems. The purpose of the present invention is to provide an optical sensor system and method for measuring multiple responses for evaluating the structural integrity of a pipe, which uses optical fiber sensors installed along the longitudinal direction of a pipe to simultaneously and precisely measure multiple responses of deformation, temperature, and vibration, and analyzes them in real time through high-speed parallel processing technology to evaluate the structural integrity of the pipe.

[0012] In addition, according to an embodiment of the present invention, the purpose is to provide a system capable of detecting sudden pipe deformation or vibration in real time by combining precise control of a wavelength-tunable light source and high-speed sweeping technology with an FPGA-based parallel signal processing architecture to collect and process large volumes of distributed sensing data without delay.

[0013] In addition, according to an embodiment of the present invention, the purpose is to provide a method that corrects errors caused by temperature changes and accurately calculates only pure mechanical deformation by mutually fusing and analyzing data from the BOFDA method and the FBGi method, and minimizes false alarms and predicts abnormal signs through a statistical analysis engine including time series and correlation analysis.

[0014] In addition, according to an embodiment of the present invention, the purpose is to provide an integrated solution that ensures long-term durability of the sensor by applying an anchor fixing method or an epoxy / carbon fiber sheet lamination method that considers the material and environmental characteristics of the pipe, and enables a manager to intuitively monitor the condition of the pipe through a visualization platform that links 3D modeling data and measurement data of the pipe. means of solving the problem

[0015] To solve the aforementioned problem, the present invention relates to an optical sensor system for evaluating the structural integrity of a pipe, which measures multiple responses using an optical fiber sensor installed along the longitudinal direction of a pipe to evaluate the structural integrity of the pipe, comprising: a wavelength-tunable light source that generates an optical signal whose wavelength is varied according to a set current control signal; a light output from the wavelength-tunable light source that branches to generate a Single Sideband Modulator (SSBM) signal for detecting Brillouin scattering and an Intensity Modulator (IM) signal for inducing stimulated Brillouin scattering, and combines the generated signals to incident the wavelength-tunable optical signal and the Brillouin-induced optical signal on the optical fiber sensor; and an optical modulation module that is attached along the longitudinal direction to the surface of the pipe via an epoxy sheet or a carbon fiber sheet or fixed via an anchor, and in response to deformation, temperature, and vibration of the pipe, back-scattering light or An optical system module that generates reflected light; a photodetector module that converts the analog backscattered light or reflected light received from the optical system module into a voltage signal, which is an electrical signal, using a high-sensitivity photodiode, and amplifies and outputs the converted voltage signal; an embedded module comprising an analog-to-digital converter that converts the analog voltage signal output from the photodetector module into a digital signal, and a Field Programmable Gate Array (FPGA) that collects the data converted into the digital signal at high speed, performs parallel processing, and generates a control signal for driving the wavelength-tunable light source;The system comprises a signal processing and monitoring server that operates a statistical analysis engine to perform time series analysis, correlation analysis, and regression analysis based on digital data transmitted from the embedded module, calculates strain, temperature change, and vibration occurrence locations at each location of the pipe, and determines an abnormal state of the pipe by comparing the calculated data with preset reference data.

[0016] The present invention relates to a method for monitoring the condition of a pipe using an optical sensor system connected to an optical fiber sensor installed in the pipe, comprising: a light source driving step in which an embedded module controls a wavelength-tunable light source to generate an optical signal in which the wavelength is continuously varied according to a driving signal with a period of 1000 Hz; an optical modulation and incidence step in which an optical modulation module receives the optical signal generated from the wavelength-tunable light source, generates a single-sideband modulation signal and an intensity modulation signal for Brillouin scattering detection, and transmits the signal to an optical fiber sensor installed in the pipe; a light detection step in which an optical detection module receives backscattered light or reflected light returning from the optical fiber sensor and converts the received optical signal into an analog voltage signal using a high-sensitivity photodiode; and a signal acquisition and preprocessing step in which the embedded module converts the analog voltage signal into digital data and collects and performs primary computational processing on the digital data in real time using parallel processing logic of an FPGA. The system comprises a state analysis and event determination step in which a signal processing and monitoring server receives digital data transmitted from the embedded module, performs time series analysis and correlation analysis through a statistical analysis engine to calculate the deformation amount and temperature distribution by location of the pipe, and determines that an event has occurred if the calculated deformation amount and temperature distribution exceed a preset threshold range. Effects of the invention

[0017] According to one embodiment of the present invention, by applying a distributed optical sensor system to industrial facilities using high-pressure piping, such as petrochemical plants, power plants, LNG and hydrogen storage facilities, the blind spots of the existing point sensor method are eliminated and precise monitoring of the entire piping section is possible, thereby strengthening seismic performance and significantly ensuring the safety of the facility.

[0018] In addition, according to one embodiment of the present invention, by applying AIoT-based high-speed parallel signal processing and statistical analysis technology, the real-time deformation and stress status of the piping can be accurately detected, and by providing an immediate early warning through the system in the event of an anomaly, the golden time can be secured and the spread to a major accident can be prevented in advance.

[0019] In addition, according to one embodiment of the present invention, by developing a pipe life prediction model and linking it with a maintenance system, the maintenance cycle can be optimized, unnecessary replacement costs can be reduced, and the efficiency of pipe management can be significantly improved.

[0020] In addition, according to one embodiment of the present invention, through specialized packaging and algorithms capable of monitoring not only displacement detection of underground buried pipes but also changes in the surrounding environment such as ground subsidence, it can be effectively utilized for safety management of city gas pipeline networks or aging pipes, and through 3D modeling-linked visualization technology, it provides a user-friendly control environment in which even non-expert managers can easily identify the condition of the pipes and respond quickly. Brief explanation of the drawing

[0021] FIG. 1 is a schematic diagram showing the overall configuration of a multi-response measurement optical sensor system for evaluating the structural integrity of a pipe according to one embodiment of the present invention. FIG. 2 is a diagram schematically showing an experimental measurement configuration for verifying the driving performance and operation characteristics of a wavelength-tunable light source according to one embodiment of the present invention. FIG. 3 is a timing diagram showing the temporal structure and waveform of a driving pulse signal for controlling a wavelength-tunable light source (VCSEL) according to one embodiment of the present invention. FIG. 4 is a cross-sectional example diagram showing an anchor-based method and a sheet-stacking method, respectively, for installing a fiber optic sensor on a pipe surface according to one embodiment of the present invention. FIG. 5 is a conceptual diagram showing the loop-shaped arrangement and attachment structure of a BOFDA optical fiber sensor for detecting ground subsidence and relative displacement of a pipe according to one embodiment of the present invention. FIG. 6 is a block diagram showing the hardware configuration of an embedded module according to one embodiment of the present invention and the slave FIFO interface structure between an FPGA and a USB controller. FIG. 7 is a diagram illustrating the concept and signal processing process for calculating the location of an event occurrence in a pipe using the time-linked reflected light signal collection principle according to an embodiment of the present invention. FIG. 8 is a diagram showing an OpenMP-based parallel processing architecture and data flow for high-speed processing of large-capacity data according to an embodiment of the present invention. FIG. 9 is a block diagram showing the data processing structure and detailed analysis functions of a statistical analysis engine within a signal processing and monitoring server according to an embodiment of the present invention. FIG. 10 is an example of a user interface screen of a monitoring system that displays the piping condition by linking 3D modeling data and measurement data according to one embodiment of the present invention. FIG. 11 is a conceptual diagram showing the system architecture of a real-time server monitoring and visualization service for platform infrastructure management according to one embodiment of the present invention. Specific details for implementing the invention

[0022] The present invention relates to an optical sensor system and method for measuring multiple responses for evaluating the structural integrity of a pipe, and more specifically, to a system that uses optical fiber sensors installed along the longitudinal direction of a pipe to precisely measure multiple responses such as deformation, temperature, and vibration, and processes these signals at high speed to monitor the abnormal condition of the pipe in real time. The optical sensor system (10) for evaluating the structural integrity of a pipe according to the present invention is largely composed of an optical modulation module (100) that generates and controls an optical signal, an optical system module (200) installed on the pipe (P) to detect physical changes, an optical detection module (300) that converts the optical signal into an electrical signal, an embedded module (400) that performs data collection and calculation, and a signal processing and monitoring server (500) that finally analyzes and visualizes the data.

[0023] The optical modulation module (100) performs the role of generating and modulating the light source of the system. A wavelength-tunable light source (111) is provided inside the optical modulation module (100), and a vertical resonant surface emitting laser (VCSEL) in the 1550 nm band may be used as the wavelength-tunable light source (111). The wavelength-tunable light source (111) operates in synchronization with a light source driving signal of a predetermined frequency, for example, 1000 Hz, applied from the embedded module (400). At this time, the wavelength-tunable light source (111) is controlled to generate a wavelength-tunable optical signal having a line width of 0.03 nm and a scanning range of 10 nm within a current range of at least 4 mA to a maximum of 15 mA.

[0024] The light output from the wavelength-tunable light source (111) is split through a 50:50 coupler and used to generate a single-sideband modulation (SSBM) signal for detecting Brillouin scattering and an intensity modulation (IM) signal for inducing stimulated Brillouin scattering. The frequency-shifted pump pulse through the single-sideband modulation and the probe pulse generated through the intensity modulation are combined again and incident on the optical system module (200). In particular, when driving the wavelength-tunable light source (111), a method is applied in which the total pulse-on time is divided into multiple step times and the current amount is increased stepwise for each step time to vary the wavelength.

[0025] In addition, by securing a separate processing time between the current 64-pulse cycle and the next 64-pulse cycle to generate a driving signal, it is configured to correct wavelength drift caused by heat generation that may occur during continuous driving of the wavelength-tunable light source (111) and to perform stable wavelength-tunable operation.

[0026] That is, the optical sensor system for evaluating pipe structural integrity according to the present invention uses '64 pulses' as a control signal unit for driving a wavelength-tunable light source (VCSEL) (but is not entirely limited thereto).

[0027] In order to increase data processing efficiency, the above system sets a predetermined number of pulses, namely 64 pulses, as a unit and continuously transmits them.

[0028] At this time, a PC processing time is secured between the end of the above 64-pulse cycle and the next 64-pulse cycle. The PC processing time serves as a rest period and performs the function of effectively correcting wavelength drift caused by internal heat generation that may occur during the continuous operation of the wavelength-tunable light source (VCSEL). As a result, the system is capable of ensuring stable wavelength-tunable operation and the reliability of measurement data even during long-term operation.

[0029] The optical system module (200) is installed on the surface of the pipe (P) to detect actual physical changes and includes a fiber optic sensor (210). The fiber optic sensor (210) is attached along the longitudinal direction of the pipe (P) and transmits backscattered light or reflected light generated in response to deformation, temperature, or vibration of the pipe (P) by wavelength-tunable optical signals and Brillouin-induced optical signals incident from the optical modulation module (100) to the optical detection module (300).

[0030] The packaging technology for installing the fiber optic sensor (210) in the pipe (P) is an important factor in determining the accuracy of the measurement. According to one embodiment, a method of fixing the fiber optic sensor (210) to the surface of the pipe (P) using anchors may be applied. In this case, a plurality of anchor members are welded or bolted to the pipe (P), and a clamping member positioned between the plurality of anchor members firmly fixes the fiber optic sensor (210) in a tensioned state.

[0031] According to another embodiment, a method of attaching the optical fiber sensor (210) via an epoxy sheet or a carbon fiber sheet may be applied. Specifically, an epoxy sheet layer is placed between the surface of the pipe (P) and the optical fiber sensor (210) to transmit minute deformations of the pipe (P) to the sensor, and a carbon fiber sheet layer covering the top of the optical fiber sensor (210) combines with the epoxy sheet layer to protect the sensor and maximize deformation transmission efficiency. Additionally, the optical fiber sensor (210) may be installed in a structure placed between the pipe (P) and the ground to detect ground subsidence.

[0032] The light detection module (300) converts an analog optical signal, i.e., backscattered light or reflected light, received from the optical system module (200) into an electrical signal. To this end, the light detection module (300) is equipped with a high-sensitivity photodiode (PD), converts the received minute optical signal into a voltage signal, amplifies it, and outputs it. At this time, the converted signal represents a change in light intensity over time and includes status information for each location of the pipe (P).

[0033] The embedded module (400) converts an analog voltage signal output from the photodetector module (300) into digital data and performs the role of collecting and processing it at high speed. The embedded module (400) collects data converted into a digital signal through an analog-to-digital converter (ADC) and performs parallel processing logic using an embedded FPGA.

[0034] In particular, an OpenMP-based parallel loop structure is applied to process large volumes of continuous photodetection data for the entire section of the pipe (P) in real time. This is a method of distributing the data collection, computation, and storage steps to each of multiple CPU cores. Specifically, when the master task issues a work instruction, the OpenMP parallel loop starts, and multiple cores simultaneously perform a data processing process divided into Stage 1 and Stage 2. Subsequently, the parallel-processed data is aggregated to complete one cycle, thereby minimizing data processing delay.

[0035] In addition, the embedded module (400) includes a slave FIFO interface section and transmits digital data processed in the FPGA at high speed to the signal processing and monitoring server (500) via a USB 3.0 interface or a Gigabit Ethernet interface. The embedded module (400) also performs the function of maintaining synchronization of the entire system by generating a control signal for driving the wavelength-tunable light source (111).

[0036] The signal processing and monitoring server (500) performs a final analysis and judgment based on digital data transmitted from the embedded module (400). The signal processing and monitoring server (500) operates a statistical analysis engine to comprehensively diagnose the condition of the piping (P). The statistical analysis engine performs time series analysis to derive the trend of data change over time, performs correlation analysis to identify the mutual relationship between deformation and temperature, and performs regression analysis to predict future changes.

[0037] For example, by mutually complementarily fusing and analyzing deformation data measured by the BOFDA method and temperature and vibration data measured by the FBGi method, error components caused by temperature changes included in the deformation data can be corrected and the amount of pure mechanical deformation of the pipe (P) can be calculated. The signal processing and monitoring server (500) synthesizes these analysis results to determine abnormal events caused by leakage, damage, or ground subsidence of the pipe (P).

[0038] In addition, the signal processing and monitoring server (500) provides a visualization function so that the user can intuitively understand the condition of the pipe. The signal processing and monitoring server (500) loads 3D modeling data of the pipe (P) and maps the previously calculated deformation amount and temperature distribution data by location to corresponding coordinates on the 3D modeling data and displays them on the screen.

[0039] If the occurrence of an event is determined by the statistical analysis engine, an alarm system is activated to display an alarm icon at the corresponding location on the 3D modeling data and send a warning message to the administrator terminal. In addition, data collected by the agent is stored in a database through a real-time server monitoring service, and an interface is provided that allows monitoring in a web or mobile environment through a visualization server and a real-time processing server.

[0040] The operation process of the optical sensor system (10) for evaluating the structural integrity of a pipe according to the present invention, having such a configuration, is as follows. First, the embedded module (400) controls the wavelength-tunable light source (111) to generate an optical signal in which the wavelength is continuously varied according to a predetermined period. Subsequently, the optical modulation module (100) modulates the generated optical signal and sends it to the optical fiber sensor (210) installed in the pipe (P).

[0041] The backscattered light or reflected light returning from the fiber optic sensor (210) is converted into an electrical signal by the light detection module (300). The embedded module (400) collects the converted signal as digital data and performs high-speed preprocessing through the parallel processing logic of the FPGA. Finally, the signal processing and monitoring server (500) analyzes the received data using a statistical analysis engine to calculate the deformation amount and temperature distribution by location of the pipe (P), and determines whether it exceeds a preset threshold range to alert of an abnormal condition.

[0042] Therefore, the present invention overcomes the limitations of measurement inherent in conventional point sensor methods and enables precise evaluation of structural integrity through distributed measurement of the entire pipeline section. In particular, by applying high-speed parallel signal processing technology and statistical analysis techniques, large volumes of data can be processed in real time and the false alarm rate can be reduced. Furthermore, through 3D visualization technology, managers can intuitively identify maintenance timing, thereby significantly improving safety in industrial sites.

[0043] FIG. 2 illustrates a measurement configuration for verifying the performance and operation characteristics of a wavelength-tunable light source (111) according to an embodiment of the present invention. Referring to the figure, the wavelength-tunable light source (111) operates in synchronization with a light source driving signal having a period of 1000 Hz, and accordingly outputs a light signal in which the wavelength is varied.

[0044] The optical signal output from the wavelength-tunable light source (111) is split equally into two paths through a 50:50 coupler for precise characteristic analysis. Each of the split optical signals passes through an isolator to prevent damage to the light source due to backflow of light, after which one side is input to an Optical Spectrum Analyzer (OSA) to measure changes in wavelength on the spectrum, and the other side is input to an Oscilloscope to monitor the driving waveform in the time domain.

[0045] Looking at the main specifications of the wavelength-tunable light source (111) verified through such a measurement configuration, it can be seen that stable operation control is possible within a driving current range of at least 4 mA to a maximum of 15 mA.

[0046] In addition, the wavelength-tunable light source (111) maintains a high dynamic range of 40 dB and a narrow linewidth of 0.03 nm while securing a wide scanning range of 10 nm, so it can be confirmed that it provides suitable performance as a core light source for a high-precision optical sensing system for evaluating the structural integrity of pipes.

[0047] FIG. 3 illustrates the temporal structure and waveform of a control signal for driving a wavelength-tunable light source (111) according to the present invention, specifically a VCSEL in the 1550 nm band. Referring to the figure, the wavelength-tunable light source (111) is not driven by a constant current during the on-pulse time (2), which is a single pulse interval, but is controlled by dividing it into step times (1) with fine intervals.

[0048] The embedded module (400) applies a control signal that increases the driving current stepwise at each step time (1), thereby inducing the output wavelength of the wavelength-tunable light source (111) to vary linearly.

[0049] These pulse signals are generated repeatedly with a period of 1-pulse time (3), and for the efficiency of data processing, a predetermined number of pulses, for example 64 pulses, are grouped into one unit and continuously transmitted during the total pulse-on time (4). In particular, a PC processing time (5) is allocated between the current 64-pulse cycle and the next 64-pulse cycle. The PC processing time (5) functions as a rest period during which the embedded module (400) processes collected data and prepares for the next operation.

[0050] The total sample time (6) is determined by the sum of the total pulse-on time (4) and the PC processing time (5). This time-division driving method suppresses internal heat generation due to the continuous operation of the wavelength-tunable light source (111), thereby preventing wavelength drift caused by temperature changes, and provides the effect of ensuring stable wavelength tunability characteristics and the reliability of measurement data even during long-term operation.

[0051] FIG. 4 illustrates two different packaging and attachment methods for installing a fiber optic sensor (210), which is a core component of the optical system module (200) according to the present invention, on a pipe (P) that is to be measured. These can be selectively applied depending on the field conditions and the characteristics of the pipe.

[0052] First, configuration (A) connected to the electric filterless wavelength-tunable module and signal processing unit represents a mechanical fixing method using anchors. The method begins with the step of securely installing a plurality of anchor members on the surface of the pipe (P) by welding or bolting them together.

[0053] Referring to the enlarged cross-sectional view, the anchor member moves in an integrated manner with the pipe (P), and the optical fiber sensor (210) is placed between the anchor members and then fixed in a tensioned state using a clamping member or the like. At this time, by filling the space inside or around the anchor with epoxy, the structure prevents movement of the optical fiber sensor (210) and protects against damage caused by external forces.

[0054] Next, configuration (B), connected to the electric filterless wavelength-tunable module and signal processing unit, represents an attachment method using laminated epoxy sheets and carbon fiber sheets.

[0055] The above method is characterized by placing an epoxy sheet layer with excellent adhesion and deformation transmission capabilities between the surface of the pipe (P) and the optical fiber.

[0056] As illustrated in the enlarged cross-sectional view, the optical fiber sensor is positioned beneath the epoxy sheet layer, and a sandwich structure is formed in which a high-strength carbon fiber sheet layer covers the outside of the sensor. This packaging structure transmits minute strains of the piping (P) to the optical fiber or optical fiber sensor without loss, thereby maximizing measurement sensitivity, while simultaneously providing durability to protect the sensor from the external environment.

[0057] FIG. 5 illustrates the arrangement and attachment structure of a fiber optic sensor (210) to which the BOFDA (Brillouin Optical Frequency Domain Analysis) method is applied to precisely detect ground subsidence or relative displacement of a pipe in a pipe structure integrity evaluation system according to the present invention. The figure specifically shows a structure for measuring physical displacement by placing the fiber optic sensor (210) between the pipe (P) and the ground.

[0058] Referring to the enlarged cross-sectional view on the right, the optical fiber sensor (210) is installed so as to be in close contact with the outer surface of the pipe (P), and at this time, an epoxy sheet that performs adhesive and protective functions covers and fixes the optical fiber sensor (210).

[0059] In particular, the path of the fiber optic sensor (210) is configured to extend in a loop shape not only to the upper surface of the pipe (P) but also to the lower ground area supporting the pipe (P).

[0060] This arrangement structure enables simultaneous monitoring of changes in the relative position between the pipe (P) and the ground that occur when the ground supporting the pipe (P) subsides or rises, in addition to deformation caused by the contraction or expansion of the pipe (P) itself.

[0061] Therefore, the above BOFDA system can analyze signals obtained through these optical fiber loops to distinguish between mechanical deformation of the piping and external factors caused by ground instability, and provide complex integrity assessment data.

[0062] FIG. 6 illustrates the actual hardware implementation of an embedded module (400) responsible for the Slave FIFO interface and data transmission, and the logical interface structure thereof.

[0063] The above-described embedded module (400) has a structure in which a Xilinx FPGA EVM capable of high-performance computation and a Cypress FX3 EVM supporting high-speed data transmission are combined to collect and process large volume data generated in the optical sensor system in real time. Referring to the block diagram and VHDL code hierarchy on the left side of the drawing, the FPGA operates as the master of the system to control the data flow, and the FX3 controller operates as a slave to transmit the data received from the FPGA to the USB host.

[0064] Communication between them is performed via a Sync Slave FIFO interface protocol, which enables high-speed data transmission synchronized with a clock signal through a wide-bandwidth parallel data bus. As a result, the embedded module (400) ensures the speed and stability of data processing for real-time pipe health assessment by transmitting the collected optical detection data to the signal processing and monitoring server (500) without bottlenecks through this hardware configuration.

[0065] FIG. 7 conceptually illustrates the time-coupled reflected light signal collection and processing process for acquiring pipe status information using the time of flight of a light pulse in a light sensor system according to the present invention.

[0066] The optical signal generated from the pulsed laser source passes through a circulator and enters the fiber under test (FUT).

[0067] At specific event points (Event 1, 2, 3) where physical changes exist along the length direction of the above FUT, reflected light or backscattered light is generated, which travels in the reverse direction and is transmitted again to the detector, which is the light detection module (300), through the circulator. The detector detects the intensity (I_x) and arrival time (t_x) of the received light signal.

[0068] The signal processing unit of the embedded module (400) then converts the detected analog signal into digital data and performs analysis. In particular, as specified in the graph and formula at the bottom right of the drawing, the signal processing unit calculates the speed of light (c), the refractive index (n) of the optical fiber core, and the measured time (t_x) information to accurately calculate the distance location (x) where each event occurred.

[0069] Based on these Time Domain Reflective Measurement (OTDR) principles, the present invention provides a data processing process capable of identifying and visualizing the location of deformations or abnormal signs occurring throughout the entire pipeline in real time.

[0070] FIG. 8 illustrates an OpenMP (Open Multi-Processing) based parallel processing architecture adopted by the embedded module (400) to process large volumes of light detection data in real time.

[0071] Referring to the left flowchart of Figure 8 above, when the Master task responsible for controlling the entire system issues a data processing command, the work is branched at the 'OpenMP parallel loop start' stage.

[0072] At this time, a plurality of CPU cores (CPU core #1 to CPU core #n) of the processor mounted on the embedded module (400) are activated, and the structure has a structure for simultaneously performing allocated data collection and computation tasks in a distributed manner.

[0073] The specific data processing process is subdivided into Stage 1 and Stage 2 within one cycle. As illustrated in the data flow diagram on the right side of the drawing above, the input data undergoes a primary operation through Stage 1, followed by a secondary operation through Stage 2.

[0074] The aforementioned multiple CPU cores perform these complex stage processes in parallel, thereby eliminating bottlenecks that may occur during single-core processing and maximizing computational efficiency. Once the computation of all cores is completed, the data processed from each core is aggregated in the 'OpenMP Parallel Loop Termination' stage and returned to the master task.

[0075] This parallel processing structure enables the collection and analysis of a vast amount of digital data generated by high-speed sweeping of the wavelength-tunable light source (111) in real time without delay, and consequently provides a technical effect that dramatically improves the monitoring response speed of the entire system.

[0076] FIG. 9 illustrates the data processing structure and functional detailed blocks of a statistical analysis engine installed in a signal processing and monitoring server (500) according to the present invention. The signal processing and monitoring server (500) receives two types of input data to precisely diagnose the health of a pipe (P).

[0077] The first is Fundamental Data, which is measured in advance and stored in a database when the above-mentioned pipe (P) is in a normal state, and

[0078] The second is an event data stream collected in real time through the above-mentioned optical sensor system.

[0079] The above statistical analysis engine integrates the input basic data and event data streams to perform multifaceted analysis.

[0080] Specifically, first, Time Series Analysis tracks the trends of change in collected data over time to distinguish between temporary noise and continuous variations.

[0081] Next, correlation analysis is utilized to identify the interrelationship between deformation data and temperature data, thereby separating and correcting for thermal expansion caused by temperature changes and actual deformation caused by mechanical external forces.

[0082] Finally, regression analysis plays the role of detecting potential risks in advance by predicting trends of future transformations based on past data patterns.

[0083] The above statistical analysis engine integrates these analysis processes to perform a final event determination step, thereby precisely determining whether actual abnormal events, such as leakage, damage, or ground subsidence of the pipe (P), have occurred, thereby minimizing false alarms and ensuring the reliability of the system.

[0084] FIG. 10 illustrates an example of the actual implementation of a 3D modeling-linked monitoring user interface (UI) provided by a signal processing and monitoring server (500) according to the present invention. This embodies visualization technology, wherein the signal processing and monitoring server (500) integrates digitized data and spatial information and provides them to an administrator.

[0085] Referring to Figure 10 above, the left screen displays measurement data collected from multiple fiber optic sensors by channel and location in the form of a real-time numerical table to support precise status verification, and the right screen shows the buried path of the pipe (P) visualized in an overlay form on a satellite map or 3D terrain data.

[0086] The signal processing and monitoring server (500) maps the calculated deformation amount and temperature data by location to corresponding coordinates on the 3D modeling data in real time. If an abnormal sign exceeding a threshold is detected at a specific location as a result of statistical analysis, a visual alarm icon or color change is displayed at the corresponding coordinates on the UI screen and a warning message is generated, thereby enabling the administrator to intuitively and immediately identify the location of the problem and take prompt maintenance measures.

[0087] FIG. 11 illustrates the visualization service structure and data flow of a Real-Time Server Supervisory system built for the stable operation of a signal processing and monitoring server (500) and platform infrastructure management according to the present invention.

[0088] Referring to Figure 11 above, the entire system is broadly divided into a Target Server area for collecting data, a Monitoring Server area for managing integrated data, and an Output area for providing information to users. First, multiple Target Servers distributed at the site are each equipped with an Agent program and operated.

[0089] The above agent performs the function of periodically reading and reporting the system resource status of the target server and collected sensing data, and transmits the data to a central monitoring server via the Internet.

[0090] The signal processing and monitoring server (500) has a structure centered on a database (DB) for permanently preserving received data and managing history, and organically links a visualization server and a real-time processing server. Data stored in the database (DB) is retrieved by the visualization server and converted into various statistical visualization data, such as pie charts, bar graphs, or line graphs, as exemplified on the right side of the drawing.

[0091] This visualization information is transmitted to the administrator's monitoring terminal and displayed in real time via a web browser or a dedicated application. At the same time, the real-time processing server continuously monitors the incoming data stream and immediately generates an alert signal if abnormal signs exceeding a preset threshold or a server failure are detected.

[0092] The generated alarm signal transmits push notifications to the administrator's mobile device, etc., providing a high-availability monitoring environment that enables immediate recognition and response to abnormal system conditions even from physically distant remote locations.

[0094] In the step where a statistical analysis engine performs time series analysis based on the input data to derive trends of change over time, performs correlation analysis to identify the mutual relationship between deformation and temperature, and performs regression analysis to predict future changes;

[0095] Predicting future changes by performing the above regression analysis involves the following steps: the statistical analysis engine verifying data integrity by checking for data packet loss and timestamp errors regarding the input data; grouping the verified data by sensor location and classifying it according to physical properties such as strain, temperature, and vibration; filtering time-series noise by applying a Moving Average or Kalman Filter; extracting trend components representing the long-term direction of change while excluding seasonal fluctuations; calculating the Pearson Correlation Coefficient between deformation data and temperature data for the same time period; separating the pure mechanical deformation component by subtracting the thermal deformation component based on the calculated correlation coefficient and the Coefficient of Thermal Expansion (CTE) of the pipe material; constructing a training dataset for regression analysis by matching the separated pure deformation data with past failure cases; generating a prediction function model by applying linear regression or polynomial regression algorithms; verifying the model parameters through residual analysis; and simulating the deformation state at a future point in time and calculating a risk score using the verified model. Perform sequentially. Explanation of the symbols

[0096] 10: Optical sensor system for evaluating pipe structural integrity 100 : Optical modulation module 111 : Wavelength-tunable light source (VCSEL) 200 : Optical system module 210: Fiber optic sensor 300 : Photodetector module 400 : Embedded module 500: Signal processing and monitoring server P : Piping

Claims

Claim 1 A photometric sensor system (10) for evaluating the structural integrity of a pipe, which measures multiple responses using a fiber optic sensor (210) installed along the longitudinal direction of a pipe (P) to evaluate the structural integrity of the pipe, comprises: a wavelength-tunable light source (111) that generates a light signal whose wavelength is varied according to a set current control signal; a photometric modulation module (100) that branches the light output from the wavelength-tunable light source (111) to generate a Single Sideband Modulator (SSBM) signal for detecting Brillouin scattering and an Intensity Modulator (IM) signal for inducing induced Brillouin scattering, and combines the generated signals to incident the wavelength-tunable light signal and the Brillouin-induced light signal on the fiber optic sensor (210); and a photometric modulation module (100) that is attached along the longitudinal direction to the surface of the pipe (P) via an epoxy sheet or a carbon fiber sheet or fixed through an anchor, thereby preventing strain of the pipe (P). An optical sensor system for evaluating the structural integrity of a pipe, characterized by comprising: an optical system module (200) that generates back-scattering light or reflected light for the incident wavelength-tunable optical signal and Brillouin-induced optical signal in response to temperature and vibration; and a photodetector module (300) that converts the analog form of the back-scattering light or reflected light received from the optical system module (200) into an electrical voltage signal using a high-sensitivity photodiode (PD), and amplifies and outputs the converted voltage signal. Claim 2 In claim 1, the optical modulation module (100) uses a vertical cavity surface emitting laser (VCSEL) of a certain band as the wavelength-tunable light source (111), is synchronized with a light source driving signal of a certain Hz applied from the embedded module (400), generates a wavelength-tunable optical signal having characteristics of a certain linewidth and scanning range within a certain current range, splits the generated wavelength-tunable optical signal through a 50:50 coupler, combines a pump pulse frequency-shifted through the single-sideband modulation (SSBM) with a probe pulse generated through the intensity modulation (IM), and transmits the combined pulse to the optical system module (200), and performs statistical analysis including time series analysis, correlation analysis, and regression analysis based on digital data transmitted from the embedded module (400). An optical sensor system for evaluating the structural integrity of a pipe, further comprising: a signal processing and monitoring server (500) that drives a statistical analysis engine to calculate the strain, temperature change, and vibration occurrence location at each location of the pipe (P), and determines the abnormal condition of the pipe (P) by comparing the calculated data with preset reference data. Claim 3 In claim 1, the optical system module (200) has a packaging structure comprising: an epoxy sheet layer disposed between the surface of the pipe (P) and the optical fiber sensor (210) to transmit minute deformation of the pipe (P) to the optical fiber sensor (210) when attaching the optical fiber sensor (210) to the surface of the pipe (P); and a carbon fiber sheet layer that covers the upper part of the optical fiber sensor (210) and combines with the epoxy sheet layer to protect the optical fiber sensor (210) and increase deformation transmission efficiency; or a plurality of anchor members welded or bolted to the pipe (P); and a clamping member that fixes the optical fiber sensor (210) in a tension state between the plurality of anchor members. Claim 4 In claim 1, the embedded module (400) further comprises an analog-to-digital converter (ADC) that converts an analog voltage signal output from the photodetection module (300) into a digital signal, and a Field Programmable Gate Array (FPGA) that collects the data converted into the digital signal at high speed, performs parallel processing, and generates a control signal for driving the wavelength-tunable light source (111); wherein a parallel loop structure based on OpenMP (Open Multi-Processing) is applied to process large volumes of continuous photodetection data received from the photodetection module (300) in real time, and the collection, computation, and storage steps of the photodetection data are distributed and allocated to each of a plurality of CPU cores (Core #1 to Core #n) to process a plurality of data stages simultaneously within one cycle, thereby minimizing data processing delay, and further comprises a slave FIFO (First-In First-Out) interface unit that transmits the processed digital data at high speed to a signal processing and monitoring server (500) through an interface. Optical sensor system for evaluating pipe structure integrity, characterized by Claim 5 A method for monitoring the condition of a pipe using an optical sensor system (10) connected to a fiber optic sensor (210) installed in a pipe (P), comprising: an embedded module (400) controlling a wavelength-tunable light source (111) to generate an optical signal in which the wavelength is continuously varied according to a driving signal of a certain period (S100); an optical modulation and incidence step (S200) in which an optical modulation module (100) receives the optical signal generated from the wavelength-tunable light source (111), generates a single-sideband modulation (SSBM) signal and an intensity modulation (IM) signal for Brillouin scattering detection, and transmits the single-sideband modulation (SSBM) signal and the intensity modulation (IM) signal to the fiber optic sensor (210) installed in the pipe (P); an optical detection step (S300) in which an optical detection module (300) receives backscattered light or reflected light returning from the fiber optic sensor (210) and converts the received optical signal into an analog voltage signal using a high-sensitivity photodiode; A method for evaluating the structural integrity of a pipe, characterized by comprising: a signal acquisition and preprocessing step (S400) in which an embedded module (400) converts the analog voltage signal into digital data and collects and performs a primary operation on the digital data in real time using the parallel processing logic of an FPGA; and a state analysis and event determination step (S500) in which a signal processing and monitoring server (500) receives the digital data transmitted from the embedded module (400), performs time series analysis and correlation analysis through a statistical analysis engine to calculate the deformation amount and temperature distribution by location of the pipe (P), and determines that an event has occurred if the calculated deformation amount and temperature distribution deviate from a preset threshold range. Claim 6 A method for evaluating the integrity of a pipe structure according to claim 5, wherein the light source driving step (S100) includes a step of dividing the total pulse-on time into a plurality of step times for a constant VCSEL, which is the wavelength-tunable light source (111), and increasing the current amount stepwise for each step time to vary the wavelength. Claim 7 In claim 5, the signal acquisition and preprocessing step (S400) is characterized by performing high-speed signal processing, comprising: a step of starting an OpenMP parallel loop when an FPGA in the embedded module (400) receives a work instruction from a master task; a step of multiple CPU cores sharing the digital data acquisition and computation work to perform the data processing process of Stage 1 and Stage 2 in parallel; and a step of combining the parallel-processed data to complete one cycle and terminate the OpenMP parallel loop. Claim 8 In claim 5, the state analysis and event determination step (S500) comprises: a step in which the signal processing and monitoring server (500) inputs fundamental data measured in the normal state of the pipe (P) and an event data stream collected in real time into the statistical analysis engine; a step in which the statistical analysis engine performs time series analysis based on the input data to derive a trend of change over time, performs correlation analysis to identify the mutual correlation between deformation and temperature, and performs regression analysis to predict future changes; and a step of determining an event of deformation caused by leakage, damage, or ground subsidence of the pipe (P) by synthesizing the derived time series analysis results, identified correlation analysis results, and predicted regression analysis results.Including the step of performing the regression analysis to predict future changes, the statistical analysis engine verifies data consistency by checking for data packet loss and timestamp errors regarding the input data; groups the verified data by sensor location and classifies it according to physical properties of strain, temperature, and vibration; filters time-series noise by applying a Moving Average or a Kalman Filter; extracts a trend component representing the direction of long-term change over a certain period; calculates the Pearson Correlation Coefficient between deformation data and temperature data at the same time interval; separates the pure mechanical deformation component by subtracting the thermal deformation component based on the calculated Pearson Correlation Coefficient and the Coefficient of Thermal Expansion (CTE) of the pipe material; constructs a training dataset for regression analysis by matching the separated pure deformation data with past failure cases; generates a prediction function model by applying a linear regression or polynomial regression algorithm; verifies the model parameters through residual analysis; and simulates the deformation state at a future point in time using the verified model. A method for evaluating the structural integrity of a piping system characterized by sequentially performing a process of calculating a risk score.

Images