A method and system for calibrating a fluorescent pressure-sensitive film for underwater pressure measurement

Abstract

The application discloses a fluorescent pressure-sensitive film calibration method and system for underwater pressure measurement, and relates to the field of fluid pressure measurement calibration. The calibration method comprises the following steps: installing the fluorescent pressure-sensitive film to be calibrated in the test section of a closed circulating water tunnel; starting the built-in impeller of the closed circulating water tunnel to drive the fluid in the cavity to form a stable flow field; using an excitation light source to irradiate the fluorescent pressure-sensitive film to excite the fluorescent microspheres to generate a fluorescent signal; using a CCD camera with a filter to collect the luminescence characteristics of the fluorescent pressure-sensitive film; collecting the fluid pressure in the closed circulating water tunnel through a pressure sensor installed at a pressure monitoring port; establishing the corresponding relationship between the luminescence characteristics of the fluorescent pressure-sensitive film and the fluid pressure to obtain a pressure-luminescence characteristic calibration curve; and the fluorescent pressure-sensitive film calibration method and system for underwater pressure measurement significantly improve the accuracy and practicability of the calibration curve through flow field calibration.

Description

Technical Field

[0001] This invention relates to fluid pressure measurement calibration technology, specifically to a fluorescent pressure-sensitive thin film calibration method and system for underwater pressure measurement. Background Technology

[0002] Fluorescent pressure-sensitive films, as a novel pressure measurement element, operate on the principle of utilizing the optical properties (such as luminescence intensity and decay time) of fluorescent microspheres within the film to exhibit a regular response to changes in surrounding fluid pressure. By establishing a pressure-optical property calibration curve, full-field, non-invasive pressure measurement of the measured area can be achieved. Compared to the limitations of traditional pressure sensors that can only achieve single-point measurements, fluorescent pressure-sensitive films offer significant advantages such as full-field measurement, high spatial resolution, and non-invasiveness. Furthermore, compared to pressure-sensitive coatings (PSPs) which are limited to gaseous environments such as air, fluorescent pressure-sensitive films can be applied to liquid fluid environments such as water, showing broad application prospects in fluid dynamics research in fields such as underwater vehicles, hydraulic machinery, and marine engineering structures.

[0003] The accuracy of pressure measurement using fluorescent pressure-sensitive films is highly dependent on the precision of their calibration curves, which in turn depends on whether the calibration environment truly reflects the film's actual operating conditions. Currently, existing methods for calibrating fluorescent pressure-sensitive films have significant drawbacks: most calibration methods are performed in static fluid environments, making calibration in flowing fluids impossible. However, in practical applications, fluorescent pressure-sensitive films are often in flowing liquid environments. The flowing fluid exerts shear forces on the fluorescent elastic microspheres within the film, causing displacement and even rearrangement of the microspheres, directly altering the film's optical response characteristics. If calibration is performed only in static fluids, the obtained calibration curve will deviate significantly from the film's actual optical response under flowing conditions, resulting in calibration results that cannot accurately match actual measurement requirements. Furthermore, turbulence and pressure fluctuations in flowing fluids also affect the stability and acquisition accuracy of the fluorescence signal; these factors cannot be reflected or evaluated in static calibration.

[0004] Taking existing published patents as an example:

[0005] 1) Chinese Patent Publication No. CN219870124U discloses a pressure calibration system that is compatible with traditional electrical signal output type pressure sensors and achieves pressure calibration under temperature compensation conditions, but it can only achieve pressure calibration in a static fluid environment.

[0006] 2) Chinese Patent Announcement No. CN220230799U discloses a liquid pressure calibration system for pressure sensor calibration. Although it uses a liquid calibration medium and has some similarities with the calibration of fluorescent pressure-sensitive films in terms of environmental media, its target is still traditional pressure sensors, and its core working method is still to complete the calibration by applying pressure to the sensor through a static fluid.

[0007] Neither of the two patents can achieve fluid circulation, thus failing to meet the special requirement of calibrating fluorescent pressure-sensitive films in flowing fluids, nor do they consider the influence of flow shear force on the optical response characteristics of fluorescent pressure-sensitive films.

[0008] In summary, the existing technology lacks a method and system for calibrating fluorescent pressure-sensitive films in a stable, flowing liquid environment to accurately simulate the fluid shear forces and flow field environment that the films experience in actual underwater applications, thereby improving the accuracy of calibration curves and the reliability of actual measurements. Summary of the Invention

[0009] The purpose of this invention is to provide a calibration method and system for fluorescent pressure-sensitive films used for underwater pressure measurement, so as to solve the problem that the existing technology cannot calibrate fluorescent pressure-sensitive films in a flowing liquid environment, resulting in a deviation between the calibration curve and the optical response characteristics of the film under actual working conditions.

[0010] To achieve the above objectives, the present invention provides the following technical solution: a method for calibrating a fluorescent pressure-sensitive thin film for underwater pressure measurement, comprising:

[0011] S1: Install the fluorescent pressure-sensitive film to be calibrated in the test section of the closed circulating water tunnel;

[0012] S2: Activate the built-in impeller of the closed circulating water tunnel to drive the fluid in the cavity to form a stable flow field;

[0013] S3: Use an excitation light source to irradiate the fluorescent pressure-sensitive film, thereby exciting the fluorescent microspheres to generate a fluorescence signal;

[0014] S4: Use a CCD camera with a filter to collect the luminescence properties of the fluorescent pressure-sensitive film;

[0015] S5: Collect fluid pressure in the closed circulating water tunnel through a pressure sensor installed at the pressure monitoring port;

[0016] S6: Establish the correspondence between the luminescence characteristics of the fluorescent pressure-sensitive film and the fluid pressure, and obtain the pressure-luminescence characteristic calibration curve;

[0017] S7: By repeatedly changing the pressure of the stable flowing fluid, the pressure on the fluorescent pressure-sensitive film is made to traverse the range of the target calibration pressure, establishing a complete functional relationship, and completing the calibration of the fluorescent pressure-sensitive film.

[0018] Furthermore, the calibration method also includes: acquiring a background noise image using a CCD camera with the excitation light source off;

[0019] During the data processing stage, the background noise image is subtracted from the luminescence characteristic data acquired by the CCD camera to remove background interference.

[0020] Furthermore, the fluid inside the closed-loop circulating water tunnel is a degassed liquid, and the fluid does not contain impurities or bubbles during its flow.

[0021] Furthermore, the fluorescent microspheres within the fluorescent pressure-sensitive film contain coumarin or Nile red fluorescent dye; the wavelength range of the excitation light source is 200–600 nm, and it is matched and selected according to the excitation band of the fluorescent dye used.

[0022] Furthermore, the CCD camera's layout parameters are as follows:

[0023] The angle between the imaging optical axis and the normal to the plane containing the fluorescent pressure-sensitive film is 0–45°.

[0024] The distance between the CCD camera and the fluorescent pressure-sensitive film is 5–4000 cm;

[0025] The exposure time range of the CCD camera is 1μs to 49s.

[0026] Furthermore, the luminescence characteristics include the intensity of the fluorescent emitted light or the time constant and decay curve of the fluorescent emitted light.

[0027] Furthermore, establishing the correspondence between the luminescence properties of the fluorescent pressure-sensitive film and the fluid pressure specifically includes:

[0028] The rotation speed of the built-in impeller was adjusted multiple times to ensure that the pressure on the fluorescent pressure-sensitive film covered the target calibration pressure range.

[0029] At each stable pressure node, pressure data and at least ten fluorescence images are collected simultaneously, and the average value is taken as the pressure value and luminescence characteristic value of that node.

[0030] A fluorescent pressure-sensitive thin-film calibration system for underwater pressure measurement includes:

[0031] The closed circulating water tunnel forms a sealed circulating channel inside, and the circulating channel is equipped with a test section for installing a fluorescent pressure-sensitive film and a pressure monitoring port for collecting pressure.

[0032] The flow field drive module includes a drive motor, a speed controller, and a built-in impeller. The drive motor adjusts the rotational speed of the built-in impeller through the speed controller to control the flow field pressure in the closed circulating water tunnel.

[0033] The optical acquisition module includes an excitation light source, a filter, and a CCD camera. The excitation light source is used to excite the fluorescent pressure-sensitive film, and the CCD camera, in conjunction with the filter, acquires the fluorescence signal.

[0034] The data processing module includes a data acquisition unit and a computer. The data acquisition unit is connected to the pressure sensor at the pressure monitoring port, and the computer is connected to the data acquisition unit and the CCD camera respectively. It is used to process data and fit and generate calibration curves.

[0035] Furthermore, the calibration system also includes a water storage tank and a pressure relief valve. The water storage tank is connected to the inlet of the closed-loop circulating water tunnel and the outlet of the pressure relief valve through pipelines. The pressure relief valve is located on the pipeline of the closed-loop circulating water tunnel and is used to automatically open and discharge fluid into the water storage tank when the system is overpressured.

[0036] Furthermore, the test section of the closed-loop circulating water tunnel is made of a transparent pressure-resistant material, which is selected from tempered glass or acrylic.

[0037] Furthermore, the main body of the circulation pipe of the closed-loop circulating water tunnel is made of pressure-resistant and corrosion-resistant materials, which are selected from carbon steel or stainless steel.

[0038] Furthermore, the excitation source is a UV-LED lamp, and the CCD camera and the excitation source are symmetrically arranged on both sides of the test section.

[0039] Furthermore, the computer has built-in data processing software to denoise, enhance, and normalize the acquired images, and to fit and generate a pressure-luminescence characteristic calibration curve.

[0040] Compared with existing technologies, the present invention provides a method and system for calibrating fluorescent pressure-sensitive films for underwater pressure measurement. This method elevates the calibration environment from traditional static liquid to a controllable, stable flow field, thereby achieving for the first time accurate calibration of fluorescent pressure-sensitive films under real underwater shear conditions. This significantly improves the engineering practicality and measurement accuracy of the calibration curve. Specific technical effects include the following:

[0041] 1. At the calibration principle level, a stable liquid flow field environment is constructed by a closed-loop circulating water tunnel, which accurately simulates the fluid shear force and flow field conditions that the fluorescent pressure-sensitive film is subjected to in actual underwater applications. This overcomes the calibration deviation caused by neglecting the influence of shear force on the arrangement of fluorescent microspheres and optical response characteristics in the film in the existing static calibration method. The obtained pressure-luminescence characteristic calibration curve is more in line with the actual working conditions, which significantly improves the measurement accuracy of the fluorescent pressure-sensitive film from the principle level.

[0042] 2. In terms of calibration operation, the fluorescent pressure-sensitive film to be calibrated is directly installed on the inner wall of the test section of the closed circulating water tunnel, so that the film adheres closely to the wall surface in the flowing fluid and receives uniform pressure transmission. The calibration pressure can be flexibly and continuously controlled by adjusting the speed of the drive motor. It can cover multiple pressure nodes within the target calibration pressure range. The operation is convenient and the pressure control accuracy is high, which can adapt to the calibration needs of different ranges and different types of fluorescent pressure-sensitive films.

[0043] 3. At the system integration level, the system integrates a closed circulating water tunnel, a flow field driving module, an optical acquisition module, a pressure acquisition module, and a data processing module. It has a compact structure, and the control parameters of each component can be adjusted independently. At the same time, through background noise removal and normalization processing, it effectively eliminates ambient stray light and signal differences between different acquisition batches, further ensuring the accuracy and repeatability of the calibration curve. Attached Figure Description

[0044] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0045] Figure 1 This is a flowchart of the calibration method in an embodiment of the present invention;

[0046] Figure 2 This is a schematic diagram of the overall structure of the calibration system in an embodiment of the present invention;

[0047] Figure 3 This is a schematic diagram of the test section structure of the calibration system in an embodiment of the present invention.

[0048] Explanation of reference numerals in the attached figures:

[0049] 1. Closed-loop circulating water tunnel; 2. Fluorescent pressure-sensitive film; 3. Pressure monitoring port; 4. Water storage tank; 5. Pressure relief valve; 6. Built-in impeller; 7. Drive motor; 8. Speed ​​controller; 9. Excitation light source; 10. Filter; 11. CCD camera; 12. Data acquisition instrument; 13. Computer; 14. Exhaust port; 15. Test section. Detailed Implementation

[0050] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0051] As attached Figure 2 To be continued Figure 3 As shown:

[0052] The present invention provides a fluorescent pressure-sensitive thin film calibration system for underwater pressure measurement, comprising a closed circulating water tunnel 1, a flow field driving module, an optical acquisition module, a data processing module, a water storage tank 4, and a pressure relief valve 5.

[0053] In one embodiment of the present invention, the closed-loop circulating water tunnel 1 is a closed-loop circulating pipeline structure, including a main circulating pipeline body and a transparent test section 15. The main circulating pipeline body is equipped with a pressure monitoring port 3, an exhaust port 14, and a pressure relief valve 5. The main circulating pipeline body is made of stainless steel and has a pressure resistance range of 0-1 MPa, forming a closed circulation loop. The test section 15 is made of tempered glass and is the core calibration area, used to install the fluorescent pressure-sensitive film 2 to be calibrated and to provide an optical observation channel. The pressure monitoring port 3 is equipped with a high-precision pressure sensor (measurement accuracy ±0.01 kPa) for real-time sensing of the pressure inside the pipeline. The safety pressure threshold of the pressure relief valve 5 is set to 0.9 MPa, and it automatically opens to relieve pressure when overpressure occurs.

[0054] In one embodiment of the present invention, the water storage tank 4 is made of pressure-resistant and corrosion-resistant material, and has a vent hole at the top to balance the pressure inside the tank. It is connected to the main body of the circulation pipe of the closed circulation water tunnel 1 and the outlet end of the pressure relief valve 5 through pipelines, and is used to replenish degassed clean water into the closed circulation water tunnel 1 and receive the liquid discharged during pressure relief.

[0055] In one embodiment of the present invention, the fluorescent microspheres inside the fluorescent pressure-sensitive film 2 are made of coumarin-6 as a fluorescent dye, and the fluorescent pressure-sensitive film 2 is attached to the pipe wall of the test section 15.

[0056] In one embodiment of the present invention, the flow field driving module includes a drive motor 7, a speed controller 8, and a built-in impeller 6. The built-in impeller 6 is a streamlined aluminum alloy structure and is installed inside the pipe of the closed-loop circulating water tunnel 1. The drive motor 7 is a variable frequency speed control motor (speed range 0-3000 r / min, control accuracy ±1 r / min), and is connected to the built-in impeller 6 via a coupling. The speed controller 8 is electrically connected to the drive motor 7 and is used to control the rotational speed of the built-in impeller 6 by adjusting the speed of the drive motor 7, thereby forming a stable flow field with a target pressure within the closed-loop circulating water tunnel 1.

[0057] In one embodiment of the present invention, the optical acquisition module includes an excitation light source 9, a filter 10, and a CCD camera 11. The excitation light source 9 is a UV-LED lamp with a wavelength of 385nm, used to emit excitation light to the fluorescent pressure-sensitive film 2 within the test section 15. The filter 10 is positioned in front of the lens of the CCD camera 11. The CCD camera 11 has a pixel resolution of 1600×1200 and a frame rate of 30fps. It is symmetrically positioned outside the closed circulating water tunnel 1 with the excitation light source 9. The imaging optical axis of the CCD camera 11 forms a 45° angle with the normal to the plane containing the fluorescent pressure-sensitive film 2. The CCD camera 11 is 72cm away from the fluorescent pressure-sensitive film 2 and is used to acquire the fluorescence image filtered by the filter 10.

[0058] In one embodiment of the present invention, the data processing module includes a data acquisition device 12 and a computer 13. The data acquisition device 12 is electrically connected to the pressure sensor of the pressure monitoring port 3 and is used to acquire pressure data. The computer 13 is connected to both the data acquisition device 12 and the CCD camera 11 for receiving pressure data and fluorescence images, and performs correlation and fitting processing on the pressure data and optical characteristic data extracted from the fluorescence images to generate a pressure-luminescence characteristic calibration curve. The computer 13 has built-in data processing software that supports image preprocessing, data fitting, and calibration curve generation.

[0059] As attached Figure 1 As shown:

[0060] A calibration method for a fluorescent pressure-sensitive thin film used for underwater pressure measurement, employing the above calibration system, includes the following steps:

[0061] Calibration preparation procedure: First, disassemble the test section 15 pipe of the closed-loop circulating water tunnel 1, and attach the fluorescent pressure-sensitive film 2 to be calibrated to the wall of the test section 15 pipe. When attaching, ensure that the film is flat and wrinkle-free, and that there are no air bubbles on the adhesive surface to avoid affecting pressure transmission. Then, reset the test section 15 pipe and seal the pipe joint with a sealing gasket to ensure the pipe is airtight. Open the valve of the water storage tank 4 and inject degassed clean water into the closed-loop circulating water tunnel 1 through the pipeline. Close the pressure relief valve 5 and open the exhaust port 14 to release the gas in the pipe until no more air bubbles overflow. Then close the valve. If insufficient fluid is found during the water injection process, it can be continuously replenished through the water storage tank 4 to ensure that the pipe is full of clean water without air bubbles or impurities.

[0062] System debugging procedure: Start the excitation light source 9 and adjust the irradiation angle to make the light evenly cover the surface of the fluorescent pressure-sensitive film 2; calibrate the pressure sensor of the pressure monitoring port 3 to ensure that the pressure measurement error is ≤0.1%.

[0063] Calibration Procedure: First, with the excitation source 9 off, acquire 5 sets of background noise images using the CCD camera 11, with a 1-second interval between each acquisition. The average value is then used as the background noise matrix. Next, start the drive motor 7 and adjust its speed using the speed controller 8. Adjust the speed in stages: 0, 300, 600, 900, 1200, 1500, 1800, 2100, 2400, 2700, and 3000 r / min. Maintain flow field stability for 2 minutes at each speed node, allowing the fluorescent pressure-sensitive film 2 to traverse multiple pressure conditions within the target calibration pressure range. At each stable pressure node, continuously acquire pressure sensor data from the pressure monitoring port 3 for 30 seconds using the data acquisition instrument 12, and use the average value as the pressure value for that node. Simultaneously, acquire 15 emission light images using the CCD camera 11, and use the average value as the luminescence characteristic value for that node. After all node acquisitions are completed, the speed of drive motor 7 is reduced to zero at a rate of 500 r / min, drive motor 7 is turned off, and pressure relief valve 5 is opened. The fluid in the pipeline is discharged into water storage tank 4 through the pipeline to achieve pressure relief until the pressure in the pipeline drops to normal pressure.

[0064] Data processing steps: Subtract the background noise matrix from the luminescence characteristic data for each working condition to obtain the noise-removed optical characteristic data, then perform normalization processing to obtain the corresponding net light intensity value. Using the pressure value as the x-axis and the corresponding net light intensity value as the y-axis, a pressure-luminescence characteristic calibration curve is generated through curve fitting. The calibration curve and corresponding fitting parameters are stored in computer 13 to generate a calibration report. In actual testing, only the optical signal of the fluorescent pressure-sensitive film 2 needs to be collected and substituted into the corresponding calibration curve to complete the pressure conversion and achieve pressure measurement.

[0065] It should be noted that the scope of protection of this invention is not limited to the specific technical solutions described in the above embodiments. For those skilled in the art, without departing from the principles and spirit of this invention, several improvements and equivalent substitutions can be made to the functional modules, structural components, and operating procedures in the above embodiments. For example, other types of fluorescent dyes can be selected to prepare fluorescent microspheres according to actual needs, the wavelength of the excitation light source 9 can be adjusted to adapt to different fluorescent dyes, the arrangement angle and distance of the CCD camera 11 can be changed to adapt to different test section 15 sizes, or different materials can be used for the main body of the circulation pipe and the transparent test section 15 to meet different pressure resistance and optical observation requirements. These improvements and equivalent substitutions should also be considered within the scope of protection of this invention.

[0066] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A method for calibrating a fluorescent pressure-sensitive thin film for underwater pressure measurement, characterized in that, Includes the following steps: S1: Install the fluorescent pressure-sensitive film (2) to be calibrated in the test section (15) of the closed circulating water tunnel (1); S2: Start the built-in impeller (6) of the closed circulating water tunnel (1) to drive the fluid in the cavity to form a stable flow field; S3: Use the excitation light source (9) to irradiate the fluorescent pressure-sensitive film (2) to excite the fluorescent microspheres to generate a fluorescent signal; S4: The luminescence characteristics of the fluorescent pressure-sensitive film (2) are collected using a CCD camera (11) with a filter (10); S5: The fluid pressure inside the closed circulating water tunnel (1) is collected by a pressure sensor installed at the pressure monitoring port (3); S6: Establish the correspondence between the luminescence characteristics of the fluorescent pressure-sensitive film (2) and the fluid pressure, and obtain the pressure-luminescence characteristic calibration curve; S7: Change the pressure of the stable flowing fluid multiple times so that the pressure on the fluorescent pressure-sensitive film (2) traverses the range of the target calibration pressure, establish the complete correspondence function relationship, and complete the calibration of the fluorescent pressure-sensitive film (2).

2. The method for calibrating a fluorescent pressure-sensitive thin film for underwater pressure measurement according to claim 1, characterized in that, The calibration method further includes: acquiring a background noise image using a CCD camera (11) while the excitation light source (9) is off; During the data processing stage, the background noise image is subtracted from the luminescence characteristic data acquired by the CCD camera (11) to remove background interference.

3. The method for calibrating a fluorescent pressure-sensitive thin film for underwater pressure measurement according to claim 1, characterized in that, The fluid in the closed circulating water tunnel (1) is a degassed liquid, and the fluid does not contain impurities or bubbles during the flow process.

4. The method for calibrating a fluorescent pressure-sensitive thin film for underwater pressure measurement according to claim 1, characterized in that, The fluorescent microspheres in the fluorescent pressure-sensitive film (2) contain coumarin or Nile red fluorescent dye, and the wavelength range of the excitation light source (9) is 200-600 nm.

5. The method for calibrating a fluorescent pressure-sensitive thin film for underwater pressure measurement according to claim 1, characterized in that, The arrangement parameters of the CCD camera (11) are as follows: The angle between the imaging optical axis and the normal to the plane containing the fluorescent pressure-sensitive film (2) is 0 to 45°. The distance between the CCD camera (11) and the fluorescent pressure-sensitive film (2) is 5 to 4000 cm; The exposure time range of the CCD camera (11) is 1μs to 49s.

6. The method for calibrating a fluorescent pressure-sensitive thin film for underwater pressure measurement according to claim 1, characterized in that, The luminescent properties include the intensity of the fluorescent emitted light or the decay curve and time constant of the fluorescent emitted light.

7. The method for calibrating a fluorescent pressure-sensitive thin film for underwater pressure measurement according to claim 1, characterized in that, The establishment of the correspondence between the luminescence properties of the fluorescent pressure-sensitive film (2) and the fluid pressure specifically includes: The rotation speed of the built-in impeller (6) was adjusted multiple times to make the pressure on the fluorescent pressure-sensitive film (2) traverse the target calibration pressure range; At each stable pressure node, pressure data and at least ten fluorescence images are collected simultaneously, and the average value is taken as the pressure value and luminescence characteristic value of that node.

8. A fluorescent pressure-sensitive thin-film calibration system for underwater pressure measurement, characterized in that, For implementing the calibration method according to any one of claims 1-7, the calibration system comprises: A closed circulating water tunnel (1) forms a closed circulating channel inside. The circulating channel is equipped with a test section (15) for installing a fluorescent pressure-sensitive film (2) and a pressure monitoring port (3) for collecting pressure. The flow field driving module includes a drive motor (7), a speed controller (8) and a built-in impeller (6). The drive motor (7) adjusts the rotation speed of the built-in impeller (6) through the speed controller (8) to control the flow field pressure in the closed circulating water tunnel (1). The optical acquisition module includes an excitation light source (9), a filter (10), and a CCD camera (11). The excitation light source (9) is used to excite the fluorescent pressure-sensitive film (2), and the CCD camera (11) works with the filter (10) to acquire the fluorescence signal. The data processing module includes a data acquisition instrument (12) and a computer (13). The data acquisition instrument (12) is connected to the pressure sensor of the pressure monitoring port (3), and the computer (13) is connected to the data acquisition instrument (12) and the CCD camera (11) respectively, for processing data and fitting to generate calibration curves.

9. A fluorescent pressure-sensitive thin-film calibration system for underwater pressure measurement according to claim 8, characterized in that, The calibration system also includes a water storage tank (4) and a pressure relief valve (5). The water storage tank (4) is connected to the inlet of the closed circulating water tunnel (1) and the outlet of the pressure relief valve (5) through pipelines. The pressure relief valve (5) is located on the pipeline of the closed circulating water tunnel (1) and is used to automatically open and discharge fluid into the water storage tank (4) when the system is over-pressured.

10. A fluorescent pressure-sensitive thin-film calibration system for underwater pressure measurement according to claim 8, characterized in that, The test section (15) of the closed circulating water tunnel (1) is made of transparent pressure-resistant material, which is tempered glass or acrylic. The main body of the circulation pipe of the closed circulating water tunnel (1) is made of pressure-resistant and corrosion-resistant material, which is carbon steel or stainless steel; The excitation light source (9) is a UV-LED lamp, and the CCD camera (11) and the excitation light source (9) are symmetrically arranged on both sides of the test section (15).

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