A photoacoustic imaging based corrosion detection system for subsea pipelines

Abstract

The utility model discloses a kind of based on photoacoustic imaging's submarine pipe network corrosion detection system, including optical imaging module, acoustic detection module, mechanical scanning platform and data processing unit;The optical imaging module with the acoustic detection module is electrically connected to the data processing unit respectively, and the mechanical scanning platform is signal connected with the data processing unit.By this, the process solves the problem that traditional detection needs to contact pipeline by non-contact photoacoustic signal acquisition, FPGA synchronous control and special chip data processing solve the problem of limited accuracy, mechanical automatic scanning and modular integration solve the problem of dependence diver, the problem of depth limitation by sea condition, the light source of adaptation seawater and waterproof design solve the problem of underwater optical imaging by water turbidity and illumination attenuation, finally realize the accurate detection of submarine pipeline corrosion.

Description

Technical Field

[0001] This utility model relates to the field of submarine pipeline corrosion detection technology, and in particular to a submarine pipeline corrosion detection system based on photoacoustic imaging. Background Technology

[0002] As a vital infrastructure for oil and gas transportation, the integrity of subsea pipelines is crucial for preventing leaks, protecting the marine environment, and ensuring energy security. Currently, external corrosion detection of subsea pipelines mainly relies on methods such as direct detection by divers, DC voltage gradient (DCVG) method, acoustic detection (such as sonar or ultrasonic scanning), and underwater optical imaging. Although photoacoustic imaging technology is widely used in the biomedical field for tumor angiogenesis monitoring, demonstrating high resolution and deep imaging capabilities, its application in non-biological fields such as subsea pipeline corrosion detection is still emerging, and related research is limited.

[0003] Existing detection technologies struggle to achieve high-precision detection of subsea pipeline corrosion while maintaining controllable costs. While DCVG can locate corrosion defects, the equipment is expensive and inefficient, and it relies on on-site operation by divers, severely limited by sea conditions and depth. Sonar or ultrasonic scanning, though capable of large-scale non-destructive testing, is limited by resolution and sound wave propagation characteristics, making it difficult to provide high-precision three-dimensional structural information of corrosion pits. Underwater optical imaging, while capable of acquiring visual information, is easily affected by water turbidity and light attenuation, with images darkening and contrast decreasing beyond a few meters. Photoacoustic imaging, a technology with high-resolution potential, has not yet been applied in this field, failing to meet the detection requirements of balancing cost and accuracy in the complex environment of the deep sea. Utility Model Content

[0004] This utility model aims to at least partially solve one of the technical problems in the related art.

[0005] Therefore, the purpose of this utility model is to propose a photoacoustic imaging-based subsea pipeline corrosion detection system. This system comprises an optical imaging module (FPGA-controlled pulsed light source and low-light CMOS camera), an acoustic detection module (high-frequency ultrasonic probe array), a mechanical scanning platform (stepper motor driven), and a data processing unit (equipped with customized image processing software and dedicated algorithms). Detection is achieved through the collaborative operation of multiple modules. This solution addresses the problems of high cost, limited accuracy, or the need for contact with pipelines in traditional detection methods, and the fact that photoacoustic imaging has not been applied to subsea pipeline corrosion detection. Furthermore, the modular design of the system facilitates integration with autonomous underwater vehicles, meeting the demand for low-cost, high-precision, non-contact detection in complex deep-sea environments.

[0006] To achieve the above objectives, this utility model proposes a corrosion detection system for subsea pipelines based on photoacoustic imaging, comprising a pipeline body, a guide plate, clamping sleeves, a connecting screw, elastic clamping components, a connecting arm, a support base, a detection system, and a limiting component. The tops of two clamping sleeves are slidably engaged with the bottom of the guide plate, and a connecting screw is provided between two adjacent clamping sleeves, connecting them via the connecting screw. Multiple elastic clamping components are mounted in a circumferential array on the clamping sleeves, with the ends of the elastic clamping components abutting against the outer wall of the pipeline body. One end of the connecting arm is rotatably connected to the top of the guide plate, and the top of the support base is rotatably connected to the other end of the connecting arm. A roller is rotatably connected to the bottom of the support base. The limiting component is mounted on the top of the guide plate, with its end abutting against the connecting arm. The detection system is mounted on the side wall of the support base.

[0007] Specifically, the elastic clamping component includes a support sleeve, a support arm, and a ball bearing. One end of the support sleeve is fixedly inserted through the outer wall of the clamping plate, one end of the support arm is elastically slidably inserted through one end of the support sleeve by a support spring, and the ball bearing is rotatably connected to the other end of the support arm.

[0008] Specifically, the limiting assembly includes a fixed arm, a driving device, and a pressing head. One end of the fixed arm is fixedly connected to the top of the guide plate, the driving device is installed at the top of the other end of the fixed arm, and the output end of the driving device passes through the top of the other end of the fixed arm and is fixedly connected to the top of the pressing head. The bottom of the pressing head is snapped onto the connecting arm.

[0009] Specifically, the detection system includes an optical imaging module, an acoustic detection module, a mechanical scanning platform, and a data processing unit. The optical imaging module and the acoustic detection module are electrically connected to the data processing unit, and the mechanical scanning platform is signal-connected to the data processing unit. The optical imaging module includes a field-programmable gate array (FPGA), a pulsed light source, and a low-light CMOS camera. The FPGA is electrically connected to the pulsed light source and the low-light CMOS camera, respectively, and is used to control the laser pulse timing of the pulsed light source and synchronize the image capture action of the low-light CMOS camera. The acoustic detection module includes a high-frequency ultrasonic probe array, which is electrically connected to the data processing unit and is used to capture the photoacoustic signals generated by the pulsed light source in the corrosion area of ​​the subsea pipeline. The mechanical scanning platform includes a stepper motor, which is electrically connected to the data processing unit and is used to drive the platform to scan the subsea pipeline using the optical imaging module and the acoustic detection module. The data processing unit includes a high-performance computing device, which is equipped with customized image processing software for processing optical image data and photoacoustic signal data, and the high-performance computing device is provided with a data storage interface and a data transmission interface.

[0010] This invention relates to a photoacoustic imaging-based subsea pipeline corrosion detection system. The data processing unit sends commands to control the FPGA-synchronized pulse light source of the optical imaging module to emit a laser adapted to the seawater environment, illuminating the subsea pipeline. A low-light CMOS camera captures optical information. The photoacoustic signals generated by the optical absorption differences in the pipeline corrosion area are captured by an ultrasonic probe array with a waterproof sealing shell in the acoustic detection module. Simultaneously, the data processing unit controls the stepper motor of the mechanical scanning platform to drive the optical and acoustic modules through a guide rail slider to achieve full-area scanning of the pipeline. The acquired optical data and photoacoustic signals are processed by a dedicated chip (structure enhancement, noise reduction, super-resolution reconstruction) and customized software in the data processing unit. Modular docking components also enable system integration with external equipment such as AUVs. This process solves the problem of traditional detection requiring contact with the pipeline through non-contact photoacoustic signal acquisition; the FPGA synchronous control and dedicated chip data processing solve the problem of limited accuracy; the automatic mechanical scanning and modular integration solve the problems of reliance on divers and limitations imposed by sea conditions and depth; and the seawater-adapted light source and waterproof design solve the problem of underwater optical imaging being affected by water turbidity and light attenuation. Ultimately, it achieves accurate detection of subsea pipeline corrosion.

[0011] In addition, the submarine pipeline corrosion detection system based on photoacoustic imaging proposed above according to this utility model may also have the following additional technical features:

[0012] Specifically, the pulsed light source is a pulsed laser diode or an Nd:YAG laser; the laser pulse width output by the pulsed light source is in the nanosecond range, the repetition frequency is in the hertz range, and the wavelength of the pulsed light source is selected from the near-infrared band or the visible light band.

[0013] Specifically, the center frequency of the high-frequency ultrasonic probe array is several MHz, and the sampling rate is multiple MHz; the high-frequency ultrasonic probe array is arranged in a ring or linear manner, and the outer periphery of the high-frequency ultrasonic probe array is provided with a waterproof sealing shell, which is adapted to the outer contour of the subsea pipeline to make the probe array fit the water body and surround the pipeline.

[0014] Specifically, the mechanical scanning platform further includes a guide rail and a slider. The guide rail extends axially or circumferentially along the seabed pipe. The slider is slidably mounted on the guide rail and is fixedly connected to the optical imaging module and the acoustic detection module, respectively. The stepper motor is connected to the slider through a gear transmission mechanism and is used to drive the slider to move the optical imaging module and the acoustic detection module along the guide rail.

[0015] Specifically, the high-performance computing device of the data processing unit integrates a dedicated processing chip; the dedicated processing chip includes a structure enhancement operation sub-chip, a noise reduction operation sub-chip, and a super-resolution reconstruction operation sub-chip. The structure enhancement operation sub-chip is configured with hardware circuitry that supports multi-scale filtering and prior edge information processing. The noise reduction operation sub-chip is configured with hardware circuitry that supports a U-Net-based deep learning model. The super-resolution reconstruction operation sub-chip is configured with hardware circuitry that supports the VisionTransformer model.

[0016] Specifically, the system also includes a modular docking assembly, which includes an interface board and a fixed bracket. The interface board is electrically connected to the optical imaging module, the acoustic detection module, the mechanical scanning platform, and the data processing unit, respectively, to realize signal aggregation and power distribution of each module. The fixed bracket is detachably connected to the interface board and each module, and the fixed bracket is provided with mounting holes adapted to autonomous underwater vehicles (AUVs) or offshore platforms to realize docking and fixing of the system with external equipment.

[0017] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0018] The above and / or additional aspects and advantages of this utility model will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, in which:

[0019] Figure 1 This is a schematic diagram of the core control and data interaction of the photoacoustic imaging-based submarine pipeline corrosion detection system of this utility model.

[0020] Figure 2 This is a schematic diagram of the signal acquisition coordination of the photoacoustic imaging-based submarine pipeline corrosion detection system of this utility model;

[0021] Figure 3 This is a schematic diagram of the motion and external integration of the photoacoustic imaging-based submarine pipeline corrosion detection system of this utility model.

[0022] Figure 4 This is a schematic diagram of the guide top plate structure of the submarine pipeline corrosion detection system based on photoacoustic imaging of this utility model;

[0023] Figure 5 This is a schematic diagram of the clamping sleeve structure of the submarine pipeline corrosion detection system based on photoacoustic imaging of this utility model;

[0024] Figure 6 This utility model relates to a photoacoustic imaging-based corrosion detection system for subsea pipelines. Figure 5A magnified structural diagram of part A in the middle. Attached Figure Description

[0026] 1. Pipe body; 2. Guide top plate; 3. Clamping sleeve; 4. Connecting screw; 5. Elastic clamping component; 51. Support sleeve; 52. Support arm; 53. Ball bearing; 6. Connecting arm; 7. Support seat; 8. Detection system; 9. Limiting component; 91. Fixed arm; 92. Drive device; 93. Downward pressure head. Detailed Implementation

[0027] The embodiments of this utility model are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this utility model, and should not be construed as limiting this utility model. Rather, the embodiments of this utility model include all variations, modifications, and equivalents falling within the spirit and scope of the appended claims.

[0028] The following description, in conjunction with the accompanying drawings, describes a photoacoustic imaging-based corrosion detection system for submarine pipelines according to an embodiment of the present invention.

[0029] As shown in Figure 1-2, the photoacoustic imaging-based submarine pipeline corrosion detection system of this utility model includes a pipeline body, a guide top plate, clamping sleeves, a connecting screw, elastic clamping components, a connecting arm, a support base, a detection system, and a limiting component. The tops of two clamping sleeves are slidably engaged with the bottom of the guide top plate. A connecting screw is provided between two adjacent clamping sleeves and they are connected by the connecting screw. Multiple elastic clamping components are installed in a circumferential array on the clamping sleeves, with the ends of the elastic clamping components abutting against the outer wall of the pipeline body. One end of the connecting arm is rotatably connected to the top of the guide top plate, and the top of the support base is rotatably connected to the other end of the connecting arm. A roller is rotatably connected to the bottom of the support base. The limiting component is installed on the top of the guide top plate, with its end abutting against the connecting arm. The detection system is installed on the side wall of the support base.

[0030] It should be noted that the sliding engagement structure between the two clamping sleeves and the guide plate described in this embodiment ensures that the clamping sleeves always move along the preset trajectory of the guide plate when adjusting the spacing, avoiding misalignment that could lead to subsequent alignment deviations with the pipe body. The connecting screw not only connects the two clamping sleeves, but its rotatable adjustment feature also allows for fine adjustment of the clamping sleeve spacing, thus adapting to pipe bodies with different outer diameters. This eliminates the need to design separate clamping structures for pipes of different diameters, improving the system's versatility. The circumferential array installation of the elastic clamping components ensures that the outer wall of the pipe body receives uniform clamping force, preventing damage to the outer wall of the pipe body caused by excessive localized force. Simultaneously, the elastic structure can accommodate slight protrusions or depressions that may exist on the outer wall of the pipe body. To ensure the elastic clamping component remains in close contact with the outer wall of the pipeline body, the system as a whole is connected to the pipeline body with stability, preventing loosening during seabed current impact or system movement. The rotating connection design of the connecting arm, guide plate, and support seat provides multiple degrees of freedom for adjusting the position of the support seat. Together with the rollers at the bottom of the support seat, it can facilitate the axial movement of the system along the pipeline body to achieve full pipeline inspection coverage, and the inspection system can be more accurately aligned with the area to be inspected on the pipeline body by adjusting the position of the support seat. The limiting component fixes the rotation angle of the connecting arm by abutting against it, thereby locking the position of the support seat and the inspection system, avoiding the displacement of the inspection system position due to external interference (such as water flow sloshing) during the inspection process, and ensuring the accuracy of the inspection data.

[0031] Furthermore, the elastic clamping component includes a support sleeve, a support arm, and a ball bearing. One end of the support sleeve is fixedly inserted through the outer wall of the clamping plate, one end of the support arm is elastically slidably inserted through one end of the support sleeve by a support spring, and the ball bearing is rotatably connected to the other end of the support arm.

[0032] It should be noted that the design of the support sleeve fixed through the outer wall of the clamping sleeve described in this embodiment can provide a stable installation benchmark and sliding guide for the support arm, avoiding skewing of the support arm during force or movement, ensuring the precise clamping direction of the elastic clamping member on the pipe body. The support arm, through the elastic sliding cooperation formed by the support spring and the support sleeve, can adaptively extend and retract according to the actual situation of the outer wall of the pipe body. This ensures that the ball can always be in close contact with the outer wall of the pipe body, and reduces the rigid collision between the system and the pipe body through the buffering effect of the support spring, protecting the outer wall of the pipe body from damage. The structure of the ball rotating and connected to the other end of the support arm can convert the sliding friction between the elastic clamping member and the pipe body into rolling friction, greatly reducing the resistance when the system moves along the pipe body, facilitating the smooth completion of the full pipeline inspection. At the same time, the arc-shaped surface of the ball can reduce the contact pressure with the outer wall of the pipe body, further avoiding scratches or indentations on the outer wall of the pipe body.

[0033] Furthermore, the limiting assembly includes a fixed arm, a drive device, and a pressing head. One end of the fixed arm is fixedly connected to the top of the guide plate, the drive device is installed at the top of the other end of the fixed arm, and the output end of the drive device passes through the top of the other end of the fixed arm and is fixedly connected to the top of the pressing head. The bottom of the pressing head is snapped onto the connecting arm.

[0034] It should be noted that the fixed connection structure between the fixed arm and the guide plate described in this embodiment provides a stable installation support for the drive device and the lower pressure head, preventing the limiting component from becoming loose during operation and affecting the limiting effect on the connecting arm. The design of the drive device driving the lower pressure head to move up and down allows for flexible engagement and disengagement of the lower pressure head and the connecting arm. When it is necessary to adjust the angle of the connecting arm to change the position of the detection system, the drive device can drive the lower pressure head to move up and disengage from the connecting arm, releasing the limiting effect. After the position of the detection system is adjusted to the correct position, the drive device drives the lower pressure head to move down and lock the connecting arm, ensuring that the connecting arm maintains a fixed angle. This allows the detection system to be stably aligned with the pipeline body and the area to be detected, preventing the detection system from shifting due to fluctuations in the seabed environment and improving detection accuracy.

[0035] like Figures 1-6 As shown in the figure, the photoacoustic imaging-based subsea pipeline corrosion detection system of this utility model includes an optical imaging module, an acoustic detection module, a mechanical scanning platform, and a data processing unit. The optical imaging module and the acoustic detection module are electrically connected to the data processing unit, and the mechanical scanning platform is signal-connected to the data processing unit. The optical imaging module includes a field-programmable gate array (FPGA), a pulsed light source, and a low-light CMOS camera. The FPGA is electrically connected to the pulsed light source and the low-light CMOS camera to control the timing of the laser pulses of the pulsed light source and to synchronize the image capture action of the low-light CMOS camera. The acoustic detection module includes a high-frequency ultrasonic probe array, which is electrically connected to the data processing unit to capture the photoacoustic signals generated by the pulsed light source in the corrosion area of ​​the subsea pipeline. The mechanical scanning platform includes a stepper motor, which is electrically connected to the data processing unit to drive the platform to scan the subsea pipeline using the optical imaging module and the acoustic detection module. The data processing unit includes a high-performance computing device equipped with customized image processing software for processing optical image data and photoacoustic signal data. The high-performance computing device also has a data storage interface and a data transmission interface.

[0036] It should be noted that the collaborative design of the optical imaging module, acoustic detection module, mechanical scanning platform, and data processing unit described in this embodiment is not a simple module stacking, but rather a closed-loop linkage of "command-acquisition-processing" achieved through electrical and signal connections. The FPGA's synchronous control of the pulse light source and CMOS camera can avoid mismatch between photoacoustic signals and optical images caused by timing deviations. The high-performance computing device of the data processing unit can not only process the data acquired by the two modules in real time, but also retain historical detection data through the data storage interface for comparative analysis. The data transmission interface provides support for subsequent remote monitoring, further improving the reliability and practicality of the system detection.

[0037] Specifically, the working principle of this system is as follows: the data processing unit sends control commands to the optical imaging module, and the FPGA adjusts the pulse light source according to the commands to emit laser pulses to irradiate the subsea pipeline, while simultaneously triggering a low-light CMOS camera to capture optical information; due to the different optical absorption characteristics of the pipeline corrosion area compared to the normal area, it will excite unique photoacoustic signals, which are captured by the high-frequency ultrasonic probe array of the acoustic detection module; the data processing unit then controls the stepper motor of the mechanical scanning platform to drive the optical and acoustic modules to move to cover the entire detection area, and finally the acquired data is processed by customized image processing software; this process solves the problem of traditional detection methods in the background technology requiring contact with the pipeline and having limited accuracy, and achieves accurate identification and location of corrosion conditions through non-contact photoacoustic signal acquisition and multi-module collaboration.

[0038] Furthermore, the pulsed light source is a pulsed laser diode or an Nd:YAG laser; the laser pulse width output by the pulsed light source is in the nanosecond range, the repetition frequency is in the hertz range, and the wavelength of the pulsed light source is selected from the near-infrared band or the visible light band.

[0039] It should be noted that the selection of pulse light source type and wavelength described in this embodiment is determined in combination with the characteristics of the seabed water environment; both pulse laser diodes and Nd:YAG lasers have stable pulse output capabilities, can adapt to the complex pressure and salinity environment of the seabed, and are not prone to failure; while the wavelengths in the near-infrared or visible light bands can effectively reduce the absorption and scattering of the laser by seawater, ensuring that the laser can penetrate a certain depth of water to reach the surface of the pipe, avoiding the situation where the photoacoustic signal is weak and cannot be effectively detected due to excessively rapid laser attenuation, and further ensuring the effectiveness of detection.

[0040] Specifically, the working principle of this pulsed light source is as follows: under the control of FPGA, a pulsed laser diode or Nd:YAG laser is selected to start according to the detection requirements, emitting a laser pulse of a specific wavelength to irradiate the seabed pipeline; after the laser pulse acts on the pipeline, the corrosion area generates photoacoustic signals due to the difference in optical absorption between the corrosion area and the normal area; this design solves the problem of underwater optical imaging being affected by water turbidity and light attenuation in the background technology. By adapting the type and wavelength of the light source to the seawater environment, it ensures that the laser can effectively reach the detection target and excite identifiable photoacoustic signals, laying the foundation for subsequent accurate detection.

[0041] Furthermore, the center frequency of the high-frequency ultrasonic probe array is several MHz, and the sampling rate is multiple MHz; the high-frequency ultrasonic probe array is arranged in a ring or linear manner, and the outer periphery of the high-frequency ultrasonic probe array is equipped with a waterproof sealing shell, which is adapted to the outer contour of the subsea pipeline to make the probe array fit the water body and surround the pipeline.

[0042] It should be noted that the arrangement of the high-frequency ultrasonic probe array and the design of the waterproof sealing shell described in this embodiment fully consider the actual detection scenario of submarine pipelines; the ring arrangement can achieve all-round coverage of the pipeline circumference, while the linear arrangement facilitates scanning along the pipeline axis. The two arrangement methods can be flexibly switched according to the pipeline size and detection requirements to avoid detection blind spots; the waterproof sealing shell can not only isolate seawater and prevent the probe array from being damaged by seawater erosion or high pressure, but its design that adapts to the outer contour of the pipeline can also ensure that the probe array is stably attached to the pipeline in the water, reduce interference during signal transmission, and improve the accuracy of photoacoustic signal capture.

[0043] Specifically, the working principle of this high-frequency ultrasonic probe array is as follows: under the control of the data processing unit, the probe array is stably arranged in the water body around the pipeline through a waterproof sealing shell. When the pulse light source excites the corrosion area of ​​the pipeline to generate photoacoustic signals, the probe array captures the signals in real time and transmits them to the data processing unit. This design solves the problem of limited resolution of sonar or ultrasonic scanning in the background technology and difficulty in accurately locating corrosion defects. Through array-type capture and waterproof anti-interference design, it ensures that the photoacoustic signals can be clearly collected, thereby achieving accurate location of the corrosion area.

[0044] Furthermore, the mechanical scanning platform also includes a guide rail and a slider. The guide rail extends axially or circumferentially along the seabed pipe, and the slider is slidably mounted on the guide rail. The slider is fixedly connected to the optical imaging module and the acoustic detection module, respectively. A stepper motor is connected to the slider through a gear transmission mechanism and is used to drive the slider to move the optical imaging module and the acoustic detection module along the guide rail.

[0045] It should be noted that the design of the guide rail, slider, and gear transmission mechanism of the mechanical scanning platform described in this embodiment focuses on improving the stability and coverage of the scan. The design of the guide rail extending axially or circumferentially along the seabed pipeline can realize scanning of the pipeline in different directions according to the detection requirements, ensuring that the detection range covers the entire pipeline. The fixed connection between the slider and the optical and acoustic modules can prevent the modules from shifting position during movement, while the gear transmission mechanism has the characteristics of high transmission accuracy and stable operation, which can ensure that the stepper motor drives the slider to move at a uniform speed, further ensuring the continuity and accuracy of the collected data, and avoiding missed detections or false detections due to scanning instability.

[0046] Specifically, the working principle of this mechanical scanning platform is that the data processing unit sends a control signal to the stepper motor, and the stepper motor drives the slider to move along the guide rail through the gear transmission mechanism. The slider, along with the optical imaging module and the acoustic detection module, moves synchronously to achieve a full-range scan of the pipeline. This design solves the problems of limited detection range and low efficiency due to reliance on manual operation in traditional detection methods in the background technology. Through automated mechanical scanning, it achieves efficient detection of the entire pipeline area and can complete large-area detection tasks without manual intervention.

[0047] Furthermore, the high-performance computing device of the data processing unit integrates a dedicated processing chip; the dedicated processing chip includes a structure enhancement operation sub-chip, a noise reduction operation sub-chip, and a super-resolution reconstruction operation sub-chip. The structure enhancement operation sub-chip is configured with hardware circuitry that supports multi-scale filtering and prior edge information processing, the noise reduction operation sub-chip is configured with hardware circuitry that supports a U-Net-based deep learning model, and the super-resolution reconstruction operation sub-chip is configured with hardware circuitry that supports the VisionTransformer model.

[0048] It should be noted that the dedicated processing chip and its sub-chips described in this embodiment are custom-developed to address the characteristics of underwater detection data. The hardware circuitry of the structure enhancement computing sub-chip can highlight the pipe structure and corrosion boundaries, the hardware circuitry of the noise reduction computing sub-chip can specifically reduce backscattering noise in the underwater environment, and the hardware circuitry of the super-resolution reconstruction computing sub-chip can restore corrosion details. The three work together to avoid the problems of low efficiency and poor results of a single processing algorithm, significantly improve the data processing speed and the quality of the processed image, and ensure that corrosion defects are clearly visible.

[0049] Specifically, the working principle of this dedicated processing chip is as follows: the high-performance computing device transmits the data collected by the optical imaging module and the acoustic detection module to the dedicated processing chip; the structure enhancement operation sub-chip processes the data to highlight the corrosion boundary; the noise reduction operation sub-chip reduces underwater noise interference; and the super-resolution reconstruction operation sub-chip restores corrosion details, ultimately outputting a clear corrosion detection image. This design solves the problems of existing image processing methods in the background technology, such as high requirements for lighting and water quality conditions and low defect visibility. Through customized hardware processing circuits, it can still effectively process data in complex underwater environments and improve the accuracy of corrosion detection.

[0050] Furthermore, the system also includes a modular docking assembly, which includes an interface board and a fixed bracket. The interface board is electrically connected to the optical imaging module, the acoustic detection module, the mechanical scanning platform, and the data processing unit, respectively, to realize the signal aggregation and power distribution of each module. The fixed bracket is detachably connected to the interface board and each module, and the fixed bracket is provided with mounting holes adapted to autonomous underwater vehicles (AUVs) or offshore platforms to realize the docking and fixation of the system with external equipment.

[0051] It should be noted that the interface board and fixed bracket design of the modular docking component described in this embodiment greatly improves the flexibility and applicability of the system. The interface board summarizes the signals and distributes the power supply to each module, which can avoid signal interference or power instability caused by messy wiring in the underwater environment and ensure that each module operates in coordination. The detachable design of the fixed bracket facilitates the installation, maintenance and replacement of the modules, while the mounting holes that are compatible with AUVs or offshore platforms allow the system to be flexibly deployed on different external devices without relying on on-site operation by divers, thus expanding the detection scenarios.

[0052] Specifically, the working principle of this modular docking assembly is that the interface board aggregates the signals from the optical, acoustic, and mechanical scanning modules and transmits them to the data processing unit, while uniformly distributing power to each module to ensure stable signal and power between modules. The fixing bracket secures each module through detachable connections and uses compatible mounting holes to fix the system on an AUV or offshore platform, achieving automated remote detection. This design solves the problems of traditional detection methods in the background technology, which rely on divers and are severely limited by sea conditions and depth. By achieving system integration with external equipment through modular docking, it eliminates the dependence on manual operation and adapts to the detection needs of different deep-sea environments.

[0053] In summary, the photoacoustic imaging-based submarine pipeline corrosion detection system of this utility model embodiment uses a data processing unit to control the FPGA synchronous pulse light source of the optical imaging module to emit a laser adapted to the seawater environment to irradiate the submarine pipeline, and a low-light CMOS camera to capture optical information. The photoacoustic signal generated by the difference in optical absorption in the pipeline corrosion area is captured by the ultrasonic probe array with a waterproof sealing shell of the acoustic detection module. At the same time, the data processing unit controls the stepper motor of the mechanical scanning platform to drive the optical and acoustic modules to achieve full-area scanning of the pipeline through the guide rail slider. The collected optical data and photoacoustic signals are processed by the dedicated chip (structure enhancement, noise reduction, super-resolution reconstruction) and customized software of the data processing unit. The modular docking components can also realize the integration of the system with external equipment such as AUVs. This process solves the problem of traditional detection requiring contact with the pipeline through non-contact photoacoustic signal acquisition, solves the problem of limited accuracy through FPGA synchronous control and dedicated chip data processing, solves the problem of dependence on divers and limitation by sea conditions and depth through mechanical automatic scanning and modular integration, and solves the problem of underwater optical imaging being affected by water turbidity and light attenuation through the seawater-adapted light source and waterproof design. Ultimately, it achieves accurate detection of submarine pipeline corrosion.

[0054] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A corrosion detection system for subsea pipelines based on photoacoustic imaging, characterized in that, It includes a pipe body (1), a guide top plate (2), a clamping sleeve (3), a connecting screw (4), an elastic clamping component (5), a connecting arm (6), a support base (7), a detection system (8), and a limiting assembly (9), wherein, The tops of the two clamping sleeves (3) are slidably engaged with the bottom of the guide top plate (2), and a connecting screw (4) is provided between the two adjacent clamping sleeves (3) and they are connected by the connecting screw (4); Multiple elastic clamping elements (5) are installed in a circumferential array on the clamping sleeve plate (3), and the ends of the elastic clamping elements (5) abut against the outer wall of the pipe body (1); One end of the connecting arm (6) is rotatably connected to the top of the guide plate (2), the top of the support base (7) is rotatably connected to the other end of the connecting arm (6), the bottom of the support base (7) is rotatably connected to a roller, the limiting component (9) is installed on the top of the guide plate (2), and the end of the limiting component (9) abuts against the connecting arm (6). The detection system (8) is installed on the side wall of the support (7).

2. The photoacoustic imaging-based corrosion detection system for subsea pipelines according to claim 1, characterized in that, The elastic clamping element (5) includes a support sleeve (51), a support arm (52), and a ball (53), wherein, One end of the support sleeve (51) is fixedly inserted through the outer wall of the clamping sleeve (3), and one end of the support arm (52) is elastically slidably inserted through one end of the support sleeve (51) by a support spring. The ball (53) is rotatably connected to the other end of the support arm (52).

3. The photoacoustic imaging-based corrosion detection system for subsea pipelines according to claim 1, characterized in that, The limiting assembly (9) includes a fixed arm (91), a drive device (92), and a pressing head (93), wherein, One end of the fixed arm (91) is fixedly connected to the top of the guide plate (2), and the drive device (92) is installed on the top of the other end of the fixed arm (91). The output end of the drive device (92) passes through the top of the other end of the fixed arm (91) and is fixedly connected to the top of the pressing head (93). The bottom of the pressing head (93) is snapped onto the connecting arm (6).

4. The photoacoustic imaging-based corrosion detection system for subsea pipelines according to claim 1, characterized in that, The detection system (8) includes an optical imaging module, an acoustic detection module, a mechanical scanning platform, and a data processing unit. The optical imaging module and the acoustic detection module are electrically connected to the data processing unit, and the mechanical scanning platform is signal-connected to the data processing unit. The optical imaging module includes a field-programmable gate array (FPGA), a pulsed light source, and a low-light CMOS camera. The FPGA is electrically connected to the pulsed light source and the low-light CMOS camera to control the laser pulse timing of the pulsed light source and synchronize the image capture action of the low-light CMOS camera. The acoustic detection module includes a high-frequency ultrasonic probe array, which is electrically connected to the data processing unit to capture the photoacoustic signal generated by the pulsed light source in the corrosion area of ​​the subsea pipeline. The mechanical scanning platform includes a stepper motor, which is electrically connected to the data processing unit to drive the platform to scan the subsea pipeline using the optical imaging module and the acoustic detection module. The data processing unit includes a high-performance computing device, which is equipped with customized image processing software for processing optical image data and photoacoustic signal data. The high-performance computing device is also equipped with a data storage interface and a data transmission interface.

5. The photoacoustic imaging-based corrosion detection system for subsea pipelines according to claim 3, characterized in that, The pulsed light source is a pulsed laser diode or an Nd:YAG laser; the laser pulse width output by the pulsed light source is in the nanosecond range, the repetition frequency is in the hertz range, and the wavelength of the pulsed light source is selected from the near-infrared band or the visible light band.

6. The subsea pipeline corrosion detection system based on photoacoustic imaging according to claim 3, characterized in that, The center frequency of the high-frequency ultrasonic probe array is several MHz, and the sampling rate is several MHz. The high-frequency ultrasonic probe array is arranged in a ring or linear manner, and the outer periphery of the high-frequency ultrasonic probe array is equipped with a waterproof sealing shell. The waterproof sealing shell is adapted to the outer contour of the subsea pipeline, so that the probe array is arranged in close contact with the water body and surrounds the pipeline.

7. The photoacoustic imaging-based corrosion detection system for subsea pipelines according to claim 3, characterized in that, The mechanical scanning platform also includes a guide rail and a slider. The guide rail extends axially or circumferentially along the seabed pipe, and the slider is slidably mounted on the guide rail. The slider is fixedly connected to the optical imaging module and the acoustic detection module, respectively. The stepper motor is connected to the slider through a gear transmission mechanism and is used to drive the slider to move the optical imaging module and the acoustic detection module along the guide rail.

8. The subsea pipeline corrosion detection system based on photoacoustic imaging according to claim 3, characterized in that, The high-performance computing equipment of the data processing unit integrates a dedicated processing chip; the dedicated processing chip includes a structure enhancement operation sub-chip, a noise reduction operation sub-chip, and a super-resolution reconstruction operation sub-chip. The structure enhancement operation sub-chip is equipped with hardware circuitry that supports multi-scale filtering and prior edge information processing, the noise reduction operation sub-chip is equipped with hardware circuitry that supports a U-Net-based deep learning model, and the super-resolution reconstruction operation sub-chip is equipped with hardware circuitry that supports the VisionTransformer model.

9. The photoacoustic imaging-based corrosion detection system for subsea pipelines according to claim 3, characterized in that, The system also includes a modular docking assembly, which includes an interface board and a mounting bracket. The interface board is electrically connected to the optical imaging module, acoustic detection module, mechanical scanning platform and data processing unit, respectively, to realize signal aggregation and power distribution of each module. The mounting bracket is detachably connected to the interface board and each module, and the mounting bracket is equipped with mounting holes adapted to autonomous underwater vehicles (AUVs) or offshore platforms to realize docking and fixing of the system with external equipment.

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