Sensor and sensing device for measuring scattered light of water body, system for measuring optical parameters of water body and method for measuring scattering function of water body

Abstract

The invention discloses a sensor for measuring scattered light of a water body, a sensing device, a system for measuring optical parameters of the water body and a method for measuring a scattering function of the water body, the sensor is used for sensing the light intensity of light entering the water body along a first straight line at each scattering angle, and the sensor is characterized by comprising a plurality of sections of optical fibers, each section of optical fiber receives an optical signal by using the exposed side surface of the core layer, and each section of optical fiber is located in the same plane perpendicular to the first straight line and is arranged corresponding to the same scattering angle; the sections of optical fibers are arranged at intervals along the first straight line direction and have the same sector angle relative to the first straight line; the sensing device comprises a sensor and a seat body; the system for measuring the optical parameters of the water body comprises a transparent container, a laser transmitting module, a signal processing module and the sensing device, according to the measurement method for the water body scattering function, the system for measuring the optical parameters of the water body is adopted to obtain the water body scattering function, scattered light in a large sector angle range in the same scattering angle can be well received, the obtained numerical value can better represent the optical characteristics of the water body, the measurement precision is high, the cost is low, and the benefit is high.

Description

Technical Field

[0001] The present invention relates to the field of ocean laser detection, and in particular to a sensor for measuring scattered light from a water body, a sensing device, a system for measuring optical parameters of a water body, and a method for measuring a scattering function of a water body. Background Art

[0002] Measuring water optical parameters, particularly the water scattering function, is crucial for analyzing water particle characteristics, underwater light field distribution, predicting underwater visibility, monitoring plankton activity, and tracking pollutants. Obtaining the intensity of scattered light at different scattering angles is crucial for measuring water optical parameters. Existing techniques typically employ either a single rotating detector or multiple fixed or array detectors. The rotating mechanism of a single rotating detector affects measurement accuracy, while the rotating structure also reduces measurement speed. Multiple fixed or array detectors, however, suffer from inconsistent responses to temperature and humidity, impacting measurement accuracy. In summary, existing measurement devices typically receive scattered light signals at different scattering angles through rotational motion, resulting in low measurement accuracy and efficiency. Alternatively, they can only receive scattered light signals from a single point within the same scattering angle, potentially leading to significant deviations in the resulting scattered light signals. This is particularly true for anisotropic water bodies within the same scattering angle. Even with multiple detectors or sensors deployed within the same scattering angle, the differences between the detectors and sensors can still introduce measurement errors. Summary of the Invention

[0003] The purpose of the present invention is to overcome the above-mentioned defects or problems existing in the background technology, and to provide a sensor for measuring scattered light of water, a sensing device, a system for measuring the optical parameters of water, and a method for measuring the scattering function of water. The sensor can better receive scattered light within a larger fan angle range within the same scattering angle, and the obtained numerical value can better characterize the optical properties of water, with high measurement accuracy, low cost and high efficiency.

[0004] To achieve the above objectives, the present invention and its related embodiments adopt the following technical solutions but are not limited to the following solutions:

[0005] The first technical solution and its related embodiments relate to a sensor for measuring scattered light from water, which is used to sense the light intensity of light incident on the water along a first straight line at various scattering angles. The sensor includes several sections of optical fiber, each section of optical fiber receives light signals using the exposed side of the core layer, and each section of optical fiber is in the same plane perpendicular to the first straight line and is set corresponding to the same scattering angle; each section of optical fiber is arranged at intervals along the direction of the first straight line and forms the same fan angle relative to the first straight line.

[0006] The second technical solution and its related embodiments relate to a sensing device for measuring scattered light from water, which includes a sensor for measuring scattered light from water as described in the first technical solution and a base body, wherein the base body is provided with a hemispherical cavity, the cavity is hemispherical with a first straight line as the axis, the inner wall of the cavity is provided with a plurality of sections of optical fiber grooves spaced apart in the direction of the first straight line, each section of the optical fiber groove is located at the intersection of a plane perpendicular to the first straight line and the inner wall of the cavity, and the plurality of optical fibers of the sensor are respectively laid in the corresponding optical fiber grooves.

[0007] The third technical solution and its related embodiments relate to a sensing device for measuring scattered light from water, which includes a sensor for measuring scattered light from water as described in the first technical solution and a base body, wherein the base body is provided with a plane perpendicular to a first straight line, and a plurality of optical fiber grooves are provided on the plane in a direction perpendicular to the first straight line at intervals, each optical fiber groove being a circular groove with the first straight line as an axis, and a plurality of optical fiber sections of the sensor are respectively laid in the plurality of optical fiber grooves.

[0008] The fourth technical solution and its related embodiments relate to a system for measuring the optical parameters of water bodies, which is used to sense the light intensity of light incident on the water body along a first straight line at various scattering angles and obtain the optical parameters of the water body. It includes a sensor for measuring scattered light of water bodies, a laser emission module, and a signal processing module as described in technical solution one, wherein the laser emission module emits a pulsed laser along the first straight line direction, and the laser passes through the water body to form scattered light; the sensor senses the scattered light; and the signal processing module is connected to each section of optical fiber in the sensor to collect, process, and calculate the scattered light signals received by each section of optical fiber to generate the optical parameters of the water body.

[0009] The fifth technical solution is based on the fourth technical solution and is a preferred embodiment of the fourth technical solution, wherein the optical fiber segments of the sensor are connected in series through non-exposed delay optical fibers, and the signal processing module includes an optical module, a detector, an acquisition card and a computer unit connected in sequence. The scattered light signals received by the optical fiber segments are introduced into the optical module for optical processing, and then introduced into the detector after optical processing to convert the optical signals into electrical signals. The acquisition card collects the electrical signals and transmits them to the computer unit, and the computer unit generates optical parameters of the water body based on the acquired electrical signals.

[0010] The sixth technical solution is based on the fourth technical solution and is a preferred embodiment of the fourth technical solution, wherein the optical fiber segments of the sensor are connected in series through non-exposed delay optical fibers, and the signal processing module includes an optical module, a detector, an acquisition card and a computer unit connected in sequence. The scattered light signals received by the optical fiber segments are introduced into the optical module for optical processing, and then introduced into the detector after optical processing to convert the optical signals into electrical signals. The acquisition card collects the electrical signals and transmits them to the computer unit, and the computer unit generates optical parameters of the water body based on the acquired electrical signals.

[0011] The seventh technical solution is based on the fourth technical solution and is a preferred embodiment of the fourth technical solution, wherein it further includes a seat body and a transparent container, the seat body is provided with a hemispherical cavity, the cavity is hemispherical with the first straight line as the axis, the inner wall of the cavity is provided with several sections of optical fiber grooves at intervals in the direction of the first straight line, each section of the optical fiber groove is located at the intersection of a plane perpendicular to the first straight line and the inner wall of the cavity, and several sections of optical fiber of the sensor are respectively laid in the corresponding optical fiber grooves; the transparent container is used to accommodate water, and its bottom wall is adapted to be located on the seat body cavity.

[0012] The eighth technical solution is based on the fourth technical solution and is a preferred embodiment of the fourth technical solution, wherein it further includes a base body and a transparent container, the base body is provided with a plane perpendicular to the first straight line, and a plurality of optical fiber grooves are provided on the plane in a direction perpendicular to the first straight line, each optical fiber groove is a circular groove with the first straight line as the axis, and the plurality of optical fiber sections of the sensor are respectively laid in the plurality of optical fiber grooves; the transparent container is used to accommodate water, and the side thereof facing the optical fiber groove is a plane and is parallel to the optical fiber groove.

[0013] The ninth technical solution is based on any one of the fourth to eighth technical solutions and is a preferred embodiment of any one of the fourth to eighth technical solutions, wherein it further includes a power meter for collecting laser power data of the laser emitted by the laser emission module after it passes through the water body. The power meter is arranged in the first straight line direction and is suitable for receiving the laser emitted by the laser emission module along the first straight line direction after it passes through the water body.

[0014] The tenth technical solution and its related embodiments relate to a method for measuring a water body scattering function, which is based on a system for measuring water body optical parameters of the ninth technical solution, including:

[0015] Calibration system for measuring optical parameters of water bodies;

[0016] Put pure water into a transparent container, adjust the power of the laser emission module to the minimum, turn on the detector and acquisition card, observe the detected scattering signal, adjust the power of the laser emission module so that the detector works in the sensitive area, and collect the scattering signal of pure water;

[0017] Place the water body to be tested into a transparent container, keep the power of the laser emission module consistent with the power when collecting the pure water scattering signal, and collect the scattering signal of the water body to be tested;

[0018] The noise is subtracted from the collected pure water scattering signal, and the number of all photons in each signal peak is summed up as the number of photons of pure water corresponding to each scattering angle;

[0019] The noise is subtracted from the collected sample scattering signal, and the number of all photons in each signal peak is summed up as the number of photons corresponding to each scattering angle of the water body to be tested;

[0020] Subtract the number of photons at the corresponding scattering angle of the water body to be tested from the number of photons at the corresponding scattering angle of pure water to obtain the number of photons at the corresponding scattering angle of the water body to be tested;

[0021] Calculate the attenuation coefficient of the water body to be tested based on the data collected by the power meter;

[0022] Mathematical operations are performed on the final photon number, the calibration coefficient of the system for measuring the optical parameters of the water body, and the attenuation coefficient of the water body to obtain the volume scattering function of the measured water body corresponding to the scattering angle.

[0023] From the above description of the present invention and its specific embodiments, it can be seen that compared with the prior art, the technical solution of the present invention and its related embodiments have the following beneficial effects due to the adoption of the following technical means:

[0024] Through continuous observation, experimentation, and research, the applicant has learned that in existing technical solutions, when using optical fibers to receive light signals, the mindset is to only consider the end face of the fiber for reception. Therefore, the received scattered light signal is usually a single-point signal. Since the single-point scattered light signal is obtained, the measurement value is prone to large errors. Moreover, if more scattered light signals are required to receive scattered light signals at the end face of the fiber, a large number of signal receiving points must be arranged, which increases the difficulty and cost of processing the light signals. The present invention breaks with this inherent mindset and utilizes the exposed side of the optical fiber core layer to receive scattered light signals. This can receive scattered light signals over a continuous interval, better avoid data errors, and the obtained measurement data can better represent the characteristics of the water body.

[0025] In the first technical solution and related embodiments, each section of optical fiber is located in the same plane perpendicular to the first straight line and is set corresponding to the same scattering angle. The sections of optical fiber are spaced apart along the direction of the first straight line and form the same fan angle relative to the first straight line. On the one hand, scattered light of multiple different scattering angles can be measured simultaneously, and the temporal and spatial correspondence of the scattering angle data is good, the measurement efficiency is high, and the cost is low. In addition, the optical fiber as a sensor has good temperature and humidity response consistency, ensuring good signal consistency, and no rotation mechanism is required, thereby improving the measurement accuracy. On the other hand, within the same scattering angle, scattered light of a continuous interval can be received, and scattered light signals within the same fan angle of different scattering angles can be obtained. The obtained measurement data can better characterize the characteristics of the scattered light to avoid deviations that may be caused by individual data. In particular, for anisotropic water bodies within the same scattering angle, the measurement data is relatively more accurate. Each section of optical fiber uses the exposed core layer side to receive light signals, which is the technical prerequisite for obtaining a continuous range of scattered light within the same scattering angle. Using the optical fiber side to receive scattered light breaks the conventional practice of using only the end face of the optical fiber to receive light. It also paves the way for using delayed optical fiber in series connection between different sections of optical fiber, thus laying the technical foundation for simplifying the signal processing module, improving signal processing efficiency and reducing signal processing costs.

[0026] In the second technical solution and related embodiments, the seat body is provided with a hemispherical cavity, which is hemispherical with the first straight line as the axis, and the inner wall of the cavity is provided with a plurality of sections of optical fiber grooves at intervals in the direction of the first straight line, and each section of the optical fiber groove is located at the intersection of a plane perpendicular to the first straight line and the inner wall of the cavity. The simple seat body structure facilitates the installation of sensors, so that the same section of optical fiber corresponds to the same scattering angle, and the fan angle formed by each section of optical fiber is the same; it is convenient to set multiple sections of optical fiber in the range of 0 degrees to 180 degrees, thereby increasing the measurement range of the scattering angle and realizing that the received scattered light information is continuous, comprehensive, and wide-range.

[0027] In the third technical solution and related embodiments, the base body is provided with a plane perpendicular to the first line. A plurality of optical fiber slots are spaced apart on the plane in a direction perpendicular to the first line. Each optical fiber slot is a circular slot centered on the first line. This simple base body structure facilitates sensor installation, ensuring that the same optical fiber segment corresponds to the same scattering angle, and each optical fiber segment forms the same fan angle. This makes it more suitable for applications requiring the reception of scattered light signals within a narrow angular range, particularly when only forward scattering parameters need to be measured.

[0028] In the fourth technical solution and related embodiments, the sensor in the first technical solution is adopted, and the system for measuring the optical parameters of water bodies has the effect of the first technical solution. The laser emission module adopts pulsed laser to avoid mutual interference of lasers in the time domain and has a higher signal-to-noise ratio.

[0029] In the fifth technical solution and related embodiments, the various optical fiber segments of the sensor are connected in series through non-exposed delay optical fibers. The delay optical fibers separate the optical signals between the various optical fiber segments in time. The series connection enables the various optical fiber segments to form a continuous signal, which facilitates subsequent signal processing, avoids signal distortion, improves signal processing efficiency, and reduces signal processing costs.

[0030] In the sixth technical solution and related embodiments, each section of the optical fiber of the sensor is connected in parallel to the optical fiber combiner through a non-exposed delay optical fiber, and the signals of each section of the optical fiber are relatively independent, which makes it convenient to attenuate the strong signal according to the strength of the signal of each section of the optical fiber, narrow the intensity gap between the signals, and make the information detection work in a high-sensitivity area, thereby improving the signal-to-noise ratio and enhancing the measurement accuracy.

[0031] In the seventh and eighth technical solutions and related embodiments, the arrangement of the base and the transparent container facilitates the installation of sensors, the holding of water, and the rapid realization of water measurement.

[0032] In the ninth technical solution and related embodiments, a power meter is used to detect in real time the power attenuation of the laser after passing through the water body, which is beneficial for correcting the power of the laser emission module during data processing and improving measurement accuracy.

[0033] In the tenth technical solution and related embodiments, the method for measuring the water scattering function of the system for measuring the water optical parameters using the ninth technical solution, in addition to having the above-mentioned technical effects, is simple and easy to ensure the accuracy of the measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0035] Figure 1 This is a schematic structural diagram of a system for measuring optical parameters of a water body according to Example 1;

[0036] Figure 2 is a perspective view of the sensing device of Example 1;

[0037] Figure 3 This is a schematic structural diagram of a system for measuring optical parameters of a water body according to Example 2;

[0038] Figure 4 This is a schematic structural diagram of a system for measuring optical parameters of a water body according to Example 3;

[0039] Figure 5 is a perspective view of the sensing device of Example 3;

[0040] Figure 6 This is a schematic structural diagram of a system for measuring optical parameters of a water body according to Example 4;

[0041] Description of main reference numerals:

[0042] 1. Laser emission module; 2. Sensing device; 3. Transparent container; 4. Signal processing module 4; 5. Power meter; 6. Convex lens; 7. Sensor; 8. Base; 9. Through hole; 10. Fiber optic slot; 11. Delay fiber; 12. Optical module; 13. Detector; 14. Acquisition card; 15. Computer unit; 16. Fiber optic combiner; 17. Attenuation flange. DETAILED DESCRIPTION

[0043] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are preferred embodiments of the present invention and should not be regarded as excluding other embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0044] In the claims, description and drawings of the present invention, unless otherwise clearly defined, the use of terms such as "first", "second" or "third" is for the purpose of distinguishing different objects rather than for describing a specific order.

[0045] In the claims, specification and the above-mentioned drawings of the present invention, unless otherwise expressly defined, directional words such as the terms "center", "transverse", "longitudinal", "horizontal", "vertical", "top", "bottom", "inside", "outside", "up", "down", "front", "back", "left", "right", "clockwise", "counterclockwise" and the like indicating directions or positional relationships are based on the directions and positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction or be constructed and operated in a specific direction, and therefore cannot be understood as limiting the specific scope of protection of the present invention.

[0046] In the claims, description and above-mentioned drawings of the present invention, unless otherwise expressly defined, the terms "fixed connection" or "fixed connection" should be understood in a broad sense, that is, any connection method without displacement relationship and relative rotation relationship between the two parties, that is, including non-detachable fixed connection, detachable fixed connection, integral connection and fixed connection through other devices or elements.

[0047] In the claims, specification, and drawings of the present invention, the term "fan angle" refers to the angle formed by the line connecting the two endpoints of a plane arc in the plane in which it is located and the center of the circle. Specifically, in this application, it refers to the angle formed by the line connecting the two endpoints of each segment of optical fiber groove or each segment of optical fiber in a plane perpendicular to the first straight line and the intersection of the first straight line on the plane.

[0048] In the claims, description and drawings of the present invention, if the terms "include", "have" and their variations are used, they are intended to mean "including but not limited to".

[0049] Example 1

[0050] See also Figure 1 , Figure 1 The system for measuring the optical parameters of water bodies of this embodiment is shown, which is used to sense the light intensity of light incident on the water body along a first straight line at various scattering angles and obtain the optical parameters of the water body. It includes a laser emission module 1, a sensor device 2, a transparent container 3, a signal processing module 4, and a power meter 5.

[0051] The laser emitting module 1 generates a pulsed laser of a specific wavelength, the power of which is stable and adjustable, and the spot size and polarization state are adjustable. The laser emitting module 1 of this embodiment emits a laser with a wavelength of 532 nm, and the emitted laser is emitted along a first straight line direction. In this embodiment, the first straight line direction is the horizontal direction.

[0052] Sensor device 2, see Figure 2The sensor 7 includes a sensor 7 and a base 8. The sensor 7 includes several segments of optical fiber. Each segment receives light signals using the exposed side of the core layer. Each segment of optical fiber is located in the same plane perpendicular to the first straight line and is arranged corresponding to the same scattering angle. The segments of optical fiber are spaced apart along the first straight line and form the same fan angle relative to the first straight line. The sensor 7 is mounted on the base 8. In this embodiment, the base 8 is hemispherical and bowl-shaped, with a hemispherical cavity. The cavity is hemispherical with the first straight line as the axis. The inner wall of the cavity is spaced apart along the first straight line and has several fiber optic grooves 10 spaced apart. Each fiber optic groove 10 is located at the intersection of a plane perpendicular to the first straight line and the inner wall of the cavity. The several segments of optical fiber of the sensor 7 are laid in the corresponding fiber optic grooves 10. In this way, the line connecting each point on the same optical fiber segment of sensor 7 with the center of the sphere forms the same angle with the first straight line. The same optical fiber segment receives scattered light at the same angle to the first straight line, that is, the same optical fiber segment receives scattered light within the same scattering angle. Furthermore, the housing cavity is hemispherical, suitable for setting scattering angles within the range of 0-180 degrees in the first straight line direction. Fiber slots 10 are spaced apart on the inner wall of the cavity in the first straight line direction, and each fiber slot 10 has an opening of 180 degrees, that is, a fan angle of 180 degrees. Several optical fiber segments receive scattered light within the same fan angle within several scattering angles. Of course, in other embodiments, the openings of the optical fiber segments of sensor 7 may not be 180 degrees. In this embodiment, the optical fiber segments of sensor 7 are connected in series via non-exposed delay optical fibers 11, forming a single optical fiber. Because the delay optical fibers 11 connecting the segments are not exposed, the optical signals between the segments can be isolated from each other and are not subject to interference from external optical signals. Preferably, the intensity of the scattered light signals received by each section of optical fiber is judged, and the optical fiber with a strong light signal is appropriately connected to an attenuation flange 17 and then connected in series with other sections of optical fiber to attenuate the strong signal, so that the intensity difference between the signals of each section of optical fiber is reduced before entering the signal processing module 4, so that the detector 13 behind it operates in the sensitive area.

[0053] The transparent container 3 can contain water, and its bottom wall is hemispherical and fits in the cavity of the seat 8. Its side wall is provided with a flat lens, and the laser enters from one side wall along the first straight line direction and exits from the other side wall.

[0054] Signal processing module 4 is connected to the optical fiber in sensing device 2. It receives the optical signal transmitted by sensing device 2, collects, processes, and calculates it, and outputs water optical parameters. In this embodiment, signal processing module 4 includes an optical module 12, a detector 13, an acquisition card 14, and a computer unit 15. The water scattered light signal received by sensor 7 of sensing device 2 is input to optical module 12 for optical processing such as filtering. After optical processing, it is input to detector 13. Detector 13 is preferably a single-photon detector capable of detecting weak scattered light signals and converting them into electrical signals. Detector 13 outputs the electrical signal to acquisition card 14, which converts the electrical signal into a digital signal and outputs it to the computer unit. Computer unit 15 generates the water optical parameters based on an algorithm.

[0055] The power meter 5 is used to collect the laser power data of the laser emitted by the laser emitting module 1 after it passes through the water body. It is arranged on the side opposite to the laser emitting module 1 outside the transparent container 3, and receives the laser emitted by the laser emitting module 1 after entering the water body from one side wall and irradiating the water body and then being emitted from the other side wall.

[0056] During measurement, the system for measuring water optical parameters in this embodiment places water in a transparent container 3. Laser emitting module 1 emits pulsed laser light along a first straight line. The pulsed laser light passes through the sidewalls of transparent container 3 and the water, exiting through the other sidewall. This laser light is received by power meter 5, which then acquires laser power data. The laser light interacts with particles and other particles within the water, generating scattered light. This scattered light is received by sensor 7 in the optical sensing device and transmitted to signal processing module 4. The corresponding water optical parameters are then combined with the power data from power meter 5 to produce a water scattering function.

[0057] Example 2

[0058] See also Figure 3 , Figure 3 The system for measuring the optical parameters of water bodies of this embodiment is shown, which is used to sense the light intensity of light incident on the water body along a first straight line at various scattering angles and obtain the optical parameters of the water body, including a laser emission module 1, a sensor device 2, a transparent container 3, a signal processing module 4, and a power meter 5.

[0059] The laser emitting module 1 generates a pulsed laser of a specific wavelength with stable and adjustable power, and adjustable spot size and polarization state. Since the attenuation coefficient of blue-green light in water is relatively small, the laser wavelength emitted by the laser emitting module 1 of this embodiment is 532nm. The emitted laser is emitted along a first straight line direction, which is a horizontal direction in this embodiment.

[0060] Sensing device 2 includes sensor 7 and base 8. Sensor 7 includes several optical fiber segments, each of which receives light signals via the exposed side of its core layer. Each segment lies in the same plane perpendicular to a first straight line and is arranged to correspond to the same scattering angle. Each segment is spaced apart along the first straight line and forms the same fan angle relative to the first straight line. Sensor 7 is mounted on base 8. In this embodiment, the base is hemispherical and bowl-shaped, with a hemispherical cavity centered on the first straight line. The inner wall of the cavity is spaced apart along the first straight line, with several optical fiber grooves 10 spaced apart along the inner wall. Each groove 10 is located at the intersection of a plane perpendicular to the first straight line and the inner wall of the cavity. The optical fiber segments of sensor 7 are laid within the corresponding grooves 10. In this way, the line connecting each point on the same optical fiber segment of sensor 7 with the center of the sphere forms the same angle with the first straight line. Therefore, the same optical fiber segment receives scattered light at the same angle to the first straight line, that is, the same optical fiber segment receives scattered light within the same scattering angle. Furthermore, the housing 8 has a hemispherical shape, suitable for setting scattering angles within a range of 0-180 degrees in the first straight line direction. Fiber slots 10 are spaced apart on the inner wall of the housing along the first straight line direction, and each fiber slot 10 has an opening of 180 degrees, that is, a fan angle of 180 degrees. Multiple optical fiber segments receive scattered light within the same fan angle within multiple scattering angles. Of course, in other embodiments, the openings of the optical fiber segments of sensor 7 may not be 180 degrees.

[0061] The transparent container 3 can contain water, has a hemispherical bottom wall that fits the main body cavity, and has a flat lens on its side wall. The laser enters from one side wall along the first straight line direction and exits from the other side wall.

[0062] Signal processing module 4 is connected to the optical fiber in sensor device 2 and receives the optical signals transmitted by sensor device 2 for collection, processing, and calculation, outputting optical parameters related to the water body. In this embodiment, signal processing module 4 includes a fiber combiner 16, an optical module 12, a detector 13, an acquisition card 14, and a computer unit 15. Each optical fiber segment of sensor device 2 is connected in parallel and output to fiber combiner 16 via a non-exposed delay fiber 11. The module distinguishes the strength of the scattered light signals received by each optical fiber segment. For optical fibers with strong optical signals, an attenuation flange 17 is appropriately connected between the delay fiber 11 and the fiber combiner 16 to attenuate the strong signal. This reduces the difference in signal strength between each optical fiber segment before entering the fiber combiner 16, allowing the detector 13 thereafter to operate within its sensitive range. The fiber combiner 16 combines the optical signals from each optical fiber segment into a single optical fiber, which is then output to the optical module 12. Optical module 12 performs optical processing, such as filtering, on the optical signal, which is then fed into detector 13. Detector 13 is preferably a single-photon detector capable of detecting weak scattered light signals and converting them into electrical signals. Detector 13 outputs the electrical signals to acquisition card 14, which converts them into digital signals and outputs them to a computer unit. Computer unit 15 generates the water body's optical parameters based on an algorithm.

[0063] The power meter 5 is used to collect the power of the laser emitted by the laser emitting module 1 after it passes through the water body. It is arranged on the side opposite to the laser emitting module 1 outside the transparent container 3, and receives the laser emitted by the laser emitting module 1 after entering the water body from one side wall and irradiating the water body and then being emitted from the other side wall.

[0064] Example 3

[0065] See also Figure 4 , Figure 4 The system for measuring the optical parameters of water bodies of this embodiment is shown, which is used to sense the light intensity of light incident on the water body along a first straight line at various scattering angles and obtain the optical parameters of the water body, including a laser emission module 1, a sensor device 2, a transparent container 3, a convex lens 6, a signal processing module 4, and a power meter 5.

[0066] The laser emitting module 1 generates a pulsed laser of a specific wavelength, the power of which is stable and adjustable, and the spot size and polarization state are adjustable. The laser wavelength emitted by the laser emitting module 1 of this embodiment is 532nm. The emitted laser is emitted along a first straight line direction, and in this embodiment, the first straight line direction is the horizontal direction.

[0067] Sensor device 2, see Figure 5, comprising a sensor 7 and a base 8. The sensor 7 comprises several segments of optical fiber, each of which receives light signals via the exposed side of its core layer. Each segment of optical fiber is located in the same plane perpendicular to the first straight line and is arranged corresponding to the same scattering angle. The segments of optical fiber are spaced apart along the first straight line and form the same fan angle relative to the first straight line. The sensor 7 is mounted on the base 8. In this embodiment, the base 8 is disc-shaped, with a through hole 9 extending along the first straight line at its center. The base 8 is provided with a plane perpendicular to the first straight line, on which a plurality of optical fiber grooves 10 are spaced apart in a direction perpendicular to the first straight line. Each optical fiber groove 10 is a circular groove with the first straight line as its axis. The optical fiber segments of the sensor 7 are respectively laid in the plurality of optical fiber grooves 10. In this way, the line connecting each point on the same optical fiber segment of sensor 7 and the same point on the first straight line forms the same angle with the first straight line. The same optical fiber segment receives scattered light at the same angle as the first straight line, that is, the same optical fiber segment receives scattered light within the same scattering angle. Furthermore, the base 8 is disc-shaped and suitable for adjusting the scattering angle within a range of 0-90 degrees. Fiber grooves 10 are spaced apart on the inner wall of the cavity perpendicular to the first straight line, and each fiber groove 10 is a circular groove, i.e., each segment has a 360-degree fan angle. The optical fiber segments receive scattered light within the same fan angle within a certain range of scattering angles. Of course, in other embodiments, the fan angles of the optical fiber segments of sensor 7 may not be 360 ​​degrees. In this embodiment, the optical fiber segments are connected in series via non-exposed delay optical fibers 11, forming the optical fiber segments of sensor 7 into a single optical fiber. Because the delay optical fibers 11 connecting the segments are not exposed, the optical signals between the segments can be isolated from each other and are not subject to interference from external optical signals. Preferably, the intensity of the scattered light signals received by each section of optical fiber is judged, and the optical fiber with a strong light signal is appropriately connected to an attenuation flange 17 and then connected in series with other sections of optical fiber to attenuate the strong signal, so that the intensity difference of the signals of each section of optical fiber is reduced before entering the signal processing module 4, so that the detector 13 behind it operates in the sensitive area.

[0068] The transparent container 3 is a square tank suitable for accommodating water, and its side wall is a plane lens, which is suitable for the laser emitted by the laser emitting module 1 to enter from one side wall along the first straight line direction and be emitted from the other side wall.

[0069] Convex lens 6 is disposed between sensing device 2 and transparent container 3, with its optical center and the center of the circular groove aligned on a first straight line. The base 8 of sensing device 2 is positioned on the focal plane of convex lens 6, and the transparent container 3 is positioned twice the focal length of convex lens 6. In other embodiments, convex lens 6 may not be provided, and sensing device 2 may be positioned directly adjacent to transparent container 3.

[0070] Signal processing module 4 is connected to the optical fiber in sensing device 2. It receives the optical signal transmitted by sensing device 2, collects, processes, and calculates it, and outputs water optical parameters. In this embodiment, signal processing module 4 includes an optical module 12, a detector 13, an acquisition card 14, and a computer unit 15. The water scattered light signal received by sensor 7 of sensing device 2 is input to optical module 12 for optical processing such as filtering. After optical processing, it is input to detector 13. Detector 13 is preferably a single-photon detector capable of detecting weak scattered light signals and converting them into electrical signals. Detector 13 outputs the electrical signal to acquisition card 14, which converts the electrical signal into a digital signal and outputs it to the computer unit. Computer unit 15 generates the water optical parameters based on an algorithm.

[0071] The power meter 5 is used to collect power data of the laser emitted by the laser emitting module 1 after it passes through the water body. It is arranged at a position farther away from the transparent container 3 than the sensing device 2 in the first straight line direction and facing the through hole 9 of the sensing device 2. The laser emitted by the laser emitting module 1 enters from one side wall of the transparent container 3, passes through the water body, is emitted from the other side wall, and then passes through the through hole 9 of the base 8 before entering the power meter 5.

[0072] When measuring water optical parameters in this embodiment, the system places water in a transparent container 3. Laser emitting module 1 emits pulsed laser light along a first straight line. The pulsed laser light passes through the sidewalls of transparent container 3 and the water, exiting from the other sidewall. After passing through through-hole 9, it is received by power meter 5, which obtains laser power data. The laser light interacts with particles and other particles in the water, generating scattered light. This scattered light is emitted through the sidewalls of transparent container 3, received by sensor 7 in the optical sensing device, and transmitted to signal processing module 4. The corresponding water optical parameters are obtained and combined with the power data from power meter 5 to produce a water scattering function.

[0073] Example 4

[0074] See also Figure 6 , Figure 6 The system for measuring the optical parameters of water bodies in this embodiment is used to sense the light intensity of light incident on the water body along a first straight line at various scattering angles and obtain the optical parameters of the water body, including a laser emission module 1, a sensor device 2, a transparent container 3, a signal processing module 4, and a power meter 5.

[0075] The laser emitting module 1 generates a pulsed laser of a specific wavelength, the power of which is stable and adjustable, and the spot size and polarization state are adjustable. The laser wavelength emitted by the laser emitting module 1 of this embodiment is 532nm. The emitted laser is emitted along a first straight line direction, and in this embodiment, the first straight line direction is the horizontal direction.

[0076] Sensing device 2 includes sensor 7 and base 8. Sensor 7 includes several segments of optical fiber, each of which receives light signals via the exposed side of its core layer. Each segment of optical fiber is located in the same plane perpendicular to a first straight line and is arranged to correspond to the same scattering angle. Each segment of optical fiber is spaced apart along the first straight line and forms the same fan angle relative to the first straight line. Sensor 7 is mounted on base 8. In this embodiment, base 8 is disc-shaped, with a through hole 9 extending along the first straight line at its center. Base 8 is provided with a plane perpendicular to the first straight line, on which a plurality of optical fiber slots 10 are spaced apart perpendicular to the first straight line. Each optical fiber slot 10 is a circular slot centered on the first straight line. The optical fiber segments of sensor 7 are respectively laid within these slots 10. In this manner, the line connecting each point on the same optical fiber segment of sensor 7 and the same point on the first straight line forms the same angle with the first straight line. The same optical fiber segment receives scattered light at the same angle as the first straight line, i.e., the same optical fiber segment receives scattered light within the same scattering angle. Furthermore, the base 8 is disc-shaped and suitable for setting the scattering angle within a range of 0-90 degrees. Optical fiber grooves 10 are spaced apart on the inner wall of the cavity in a direction perpendicular to the first straight line, and each segment of the optical fiber grooves 10 is a circular groove, i.e., each segment of the optical fiber grooves 10 has a 360-degree fan angle. Multiple optical fiber segments receive scattered light within the same fan angle within a plurality of scattering angles. Of course, in other embodiments, the fan angles of the optical fiber segments of sensor 7 may not be set to 360 degrees.

[0077] The transparent container 3 is a square tank suitable for accommodating water, and its side wall is a flat lens, suitable for the laser emitted by the laser emitting module 1 to enter from one side wall along the first straight line direction and be emitted from the other side wall.

[0078] Convex lens 6 is positioned between sensing device 2 and transparent container 3, with its optical center and the center of the circular groove aligned on a first straight line. The main body of sensing device 2 is positioned on the focal plane of convex lens 6, and transparent container 3 is positioned twice the focal length of convex lens 6. In other embodiments, convex lens 6 may not be provided, and the optical fiber sensing device 2 may be positioned directly adjacent to transparent container 3.

[0079] Signal processing module 4 is connected to the optical fiber in sensor device 2 and receives the optical signals transmitted by sensor device 2, collects, processes, and calculates them, and outputs water optical parameters. In this embodiment, signal processing module 4 includes a fiber combiner 16, an optical module 12, a detector 13, an acquisition card 14, and a computer unit 15. Each optical fiber segment of sensor device 2 is connected in parallel and output to fiber combiner 16 via a non-exposed delay fiber 11. Based on the intensity of the scattered light received by each optical fiber segment, an attenuation flange 17 is appropriately added between the delay fiber 11 and the fiber combiner 16 to attenuate the strong signal. This reduces the intensity difference between the signals of each optical fiber segment before entering the fiber combiner 16, allowing the detector 13 thereafter to operate in its sensitive range. Fiber combiner 16 combines the optical signals of each optical fiber segment into a single optical fiber, which is then output to optical module 12. Optical module 12 performs optical processing, such as filtering, on the optical signal, which is then fed into detector 13. Detector 13 is preferably a single-photon detector capable of detecting weak scattered light signals and converting them into electrical signals. Detector 13 outputs the electrical signals to acquisition card 14, which converts them into digital signals and outputs them to a computer unit. Computer unit 15 generates the water body's optical parameters based on an algorithm.

[0080] The power meter 5 is used to collect power data of the laser emitted by the laser emitting module 1 after it passes through the water body. It is arranged at a position farther away from the transparent container 3 than the sensing device 2 in the first straight line direction, and is directly opposite the through hole 9 of the optical fiber sensing device 2. The laser emitted by the laser emitting module 1 enters from one side wall of the transparent container 3, passes through the water body, is emitted from the other side wall, and then passes through the through hole 9 of the seat body 8 before entering the power meter 5.

[0081] Example 5

[0082] The method for measuring the water body scattering function of this embodiment uses the water body optical parameter measurement system of this application to measure the water body scattering function. The specific steps are as follows:

[0083] 1. Calibration system for measuring optical parameters of water bodies;

[0084] 2. Measure the scattering signal of pure water. Place pure water in the transparent container 3, adjust the power of the laser emission module 1 to the minimum, turn on the detector 13 and the acquisition card 14, observe the detected scattering signal, adjust the power of the laser emission module 1 so that the detector 13 operates in the sensitive area, and collect the scattering signal of the pure water;

[0085] 3. Collecting the scattering signal information of the sample (water body): Put the water body into the transparent container 3, keep the power of the laser emission module 1 consistent with the power when collecting the pure water scattering signal, and collect the scattering signal of the water body.

[0086] 4. Subtract noise from the collected pure water scattering signal and sum all the photon counts at each signal peak to obtain the photon count of pure water at each scattering angle.

[0087] 5. Subtract noise from the collected sample scattering signal and sum all the photon counts of each signal peak as the photon count of the water body corresponding to each scattering angle;

[0088] 6. Subtract the number of photons at the corresponding scattering angle of the water body from the number of photons at the corresponding scattering angle of pure water to obtain the number of photons at the corresponding scattering angle of the water body;

[0089] 7. Calculate the attenuation coefficient of the water body based on the data collected by the power meter 5;

[0090] 8. Perform mathematical calculations on the final photon number, the calibration coefficient of the system for measuring the optical parameters of the water body, and the attenuation coefficient of the water body.

[0091] Obtain the volume scattering function of the water body corresponding to the scattering angle.

[0092] Furthermore, other optical parameters such as scattering phase function, scattering coefficient, forward scattering coefficient and backscattering coefficient can be calculated through the obtained volume scattering function.

[0093] The above description and embodiments are intended to explain the scope of protection of the present invention, but do not constitute a limitation thereto. Modifications, equivalent substitutions, or other improvements to the embodiments of the present invention or portions thereof that can be obtained by a person of ordinary skill in the art through logical analysis, reasoning, or limited experimentation based on the teachings of the present invention or the above embodiments, combined with common knowledge, ordinary technical knowledge in the field, and / or prior art, should all be included within the scope of protection of the present invention.

Claims

1. A sensor for measuring scattered light from a water body, for sensing the light intensity at various scattering angles of light incident on the water body along a first straight line, characterized in that: The optical fiber comprises several sections, each of which receives light signals by using the exposed side of the core layer. Each section of the optical fiber is located in the same plane perpendicular to the first straight line and is arranged corresponding to the same scattering angle. Each section of the optical fiber is arranged at intervals along the direction of the first straight line and forms the same fan angle relative to the first straight line.

2. A sensing device for measuring scattered light from water, comprising a sensor for measuring scattered light from water as claimed in claim 1 and a base, wherein: The seat body is provided with a hemispherical cavity, which is hemispherical with the first straight line as the axis. The inner wall of the cavity is provided with several sections of optical fiber grooves at intervals in the direction of the first straight line. Each section of the optical fiber groove is located at the intersection of a plane perpendicular to the first straight line and the inner wall of the cavity. Several sections of optical fiber of the sensor are laid in the corresponding optical fiber grooves respectively.

3. A sensing device for measuring scattered light from a water body, comprising a sensor for measuring scattered light from a water body as claimed in claim 1 and a base, wherein: The base is provided with a plane perpendicular to the first straight line, and a plurality of optical fiber grooves are provided on the plane in a direction perpendicular to the first straight line. Each optical fiber groove is a circular groove with the first straight line as the axis, and the plurality of optical fiber sections of the sensor are respectively laid in the plurality of optical fiber grooves.

4. A system for measuring optical parameters of a water body, for sensing the light intensity at various scattering angles of light incident on a water body along a first straight line and obtaining the optical parameters of the water body, comprising a sensor for measuring scattered light of a water body, a laser emission module, and a signal processing module as described in claim 1, characterized in that: The laser emission module emits pulsed laser along a first straight line direction, and the laser passes through the water body to form scattered light; the sensor senses the scattered light; the signal processing module is connected to each section of optical fiber in the sensor, collects, processes, and calculates the scattered light signals received by each section of optical fiber to generate optical parameters of the water body.

5. A system for measuring optical parameters of a water body as claimed in claim 4, characterized in that: The optical fiber segments of the sensor are connected in series via non-exposed delay optical fibers. The signal processing module includes an optical module, a detector, an acquisition card, and a computer unit connected in sequence. The scattered light signals received by the optical fiber segments are introduced into the optical module for optical processing. After optical processing, the scattered light signals are introduced into the detector to convert the optical signals into electrical signals. The acquisition card collects the electrical signals and transmits them to the computer unit, which generates the optical parameters of the water body based on the acquired electrical signals.

6. A system for measuring optical parameters of a water body as claimed in claim 4, characterized in that: The signal processing module includes a fiber optic combiner, an optical module, a detector, an acquisition card and a computer unit connected in sequence. The optical fiber segments of the sensor are connected in parallel to the fiber optic combiner through non-exposed delay optical fibers. The fiber optic combiner combines the optical signals introduced in parallel and outputs them to the optical module for optical processing. After optical processing, the optical signals are introduced into the detector to convert them into electrical signals. The acquisition card collects the electrical signals and transmits them to the computer unit. The computer unit generates optical parameters of the water body based on the acquired electrical signals.

7. A system for measuring optical parameters of a water body as claimed in claim 4, characterized in that: It also includes a seat body and a transparent container, the seat body is provided with a hemispherical cavity, the cavity is hemispherical with the first straight line as the axis, the inner wall of the cavity is provided with a plurality of sections of optical fiber grooves at intervals in the direction of the first straight line, each section of the optical fiber groove is located at the intersection of a plane perpendicular to the first straight line and the inner wall of the cavity, and the plurality of sections of optical fiber of the sensor are respectively laid in the corresponding optical fiber grooves; the transparent container is used to accommodate water, and its bottom wall is adapted to be located on the seat body cavity.

8. The system for measuring optical parameters of a water body according to claim 4, wherein: It also includes a base and a transparent container, the base is provided with a plane perpendicular to the first straight line, and a plurality of optical fiber grooves are provided on the plane in a direction perpendicular to the first straight line, each optical fiber groove is a circular groove with the first straight line as the axis, and the plurality of optical fiber sections of the sensor are respectively laid in the plurality of optical fiber grooves; the transparent container is used to accommodate water, and the side facing the optical fiber groove is a plane, which is parallel to the optical fiber groove.

9. A system for measuring optical parameters of a water body according to any one of claims 4 to 8, characterized in that: It also includes a power meter, which is used to collect laser power data of the laser emitted by the laser emitting module after it passes through the water body. It is set in the first straight line direction and is suitable for receiving the laser emitted by the laser emitting module along the first straight line direction after it passes through the water body.

10. A method for measuring the body scattering function of water, based on the system for measuring optical parameters of water according to claim 9, characterized in that: include: Calibration system for measuring optical parameters of water bodies; Place pure water in a transparent container, adjust the power of the laser emission module to the minimum, turn on the detector and acquisition card, observe the detected scattering signal, adjust the power of the laser emission module so that the detector works in the sensitive area, and collect the scattering signal of pure water; place the water body to be tested in a transparent container, keep the power of the laser emission module consistent with the power when collecting the pure water scattering signal, and collect the scattering signal of the water body to be tested; The noise is subtracted from the collected pure water scattering signal, and the number of all photons in each signal peak is summed up as the number of photons of pure water corresponding to each scattering angle; The noise is subtracted from the collected sample scattering signal, and the number of all photons in each signal peak is summed up as the number of photons corresponding to each scattering angle of the water body to be tested; Subtract the number of photons at the corresponding scattering angle of the water body to be tested from the number of photons at the corresponding scattering angle of pure water to obtain the number of photons at the corresponding scattering angle of the water body to be tested; Calculate the attenuation coefficient of the water body to be tested based on the data collected by the power meter; Mathematical operations are performed on the final photon number, the calibration coefficient of the system for measuring the optical parameters of the water body, and the attenuation coefficient of the water body to obtain the volume scattering function of the measured water body corresponding to the scattering angle.

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