A sediment concentration monitoring device and method for acoustic-optical signal data fusion

Abstract

The present invention discloses a sediment concentration monitoring device and method for acoustic-optic signal data fusion, which relates to the technical field of hydrological monitoring. The device includes a frame and an integrated device of a turbidimeter and a hydrophone. The integrated device of the turbidimeter and the hydrophone is installed in the center of the frame, and its signal is emitted upward and perpendicular to the water surface. The frame is used to adjust the water entry depth of the integrated device of the turbidimeter and the hydrophone. In the present invention, the turbidimeter and the hydrophone are integrated with a cable through a fixed bracket structure and installed at the bottom of the water body. According to the principle of acoustic backscattering, the sediment concentration value is inversely calculated by using the echo signal of the hydrophone. At the same time, the turbidimeter data and the hydrophone data are fused to obtain the fused sediment concentration value. By fusing the signal data of the turbidimeter and the hydrophone, the present invention overcomes the deficiencies of a single sediment concentration measurement principle and method, meets the requirements of high-precision measurement of sediment concentration under different sediment particle size conditions, and realizes high-precision sediment concentration monitoring.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrological monitoring, and particularly to a sediment monitoring device and method for fusing acoustic and optical signal data. Background Art

[0002] Sediment concentration measurement is an important part of hydrological monitoring. By analyzing the data of river sediment concentration, relevant information on climate and environment can be obtained. Sediment concentration monitoring is of great significance for soil and water conservation, river and lake treatment, wetland function restoration, safety of pumped-storage power stations, etc.

[0003] Sediment concentration monitoring methods are mainly divided into two categories, namely traditional methods and modern methods. The traditional method relies on taking water samples on-site, and then filtering, weighing, and calculating the water samples to obtain the sediment concentration value of the water body. Modern methods mainly use sensors such as optical, acoustic, and isotope sensors to indirectly observe the sediment concentration.

[0004] Compared with the traditional method, the modern method greatly reduces the labor cost. However, single sediment concentration monitoring means often have some inherent defects. Conditions such as sediment particle size, water temperature, and sediment concentration will have different effects on sensors with different principles. The method of fusing acoustic and optical signal data can effectively improve the stability and accuracy of sediment concentration monitoring. Summary of the Invention

[0005] The present invention provides a sediment monitoring device and method for fusing acoustic and optical signal data to solve the problems existing in the single sediment concentration monitoring means.

[0006] The specific solutions are as follows:

[0007] A sediment concentration monitoring device for fusing acoustic and optical signal data, characterized in that it includes a frame and an integrated device of a turbidimeter and a hydrophone. The integrated device of the turbidimeter and the hydrophone is installed in the center of the frame, and its signal is emitted upward and perpendicular to the water surface. The frame is used to adjust the water depth of the integrated device of the turbidimeter and the hydrophone.

[0008] Further, the integrated device of the turbidimeter and the hydrophone includes a fixed support structure, a turbidimeter and a hydrophone arranged on the fixed support structure. The turbidimeter and the hydrophone are fixed on the same plane, and both have 5-core pluggable signal interfaces at the rear ends. The two 5-core pluggable signal interfaces are respectively connected with a first cable and a second cable. The first cable and the second cable respectively form a unified external interface through a first cable routing structure and a second cable routing structure. The cable routing structure is used for routing the cables inside.

[0009] Further, an anti-fouling wiper is integrated in front of the turbidimeter, and the working mode of the wiper is that it will be fixedly activated each time it is powered on. The hydrophone is a combined transceiver ultrasonic transducer with a working frequency of 1.5 MHz.

[0010] Further, the integrated device of the turbidimeter and the hydrophone further includes a data remote telemetry terminal, and the data remote telemetry terminal is used to receive the data output by the turbidimeter and the hydrophone, locally store the data, and then send it to the upper computer terminal through a wireless transmission module.

[0011] Further, the frame includes two vertically arranged rods symmetrically arranged on the left and right, and a cross bar horizontally arranged between the two vertical rods. The vertical rods are perpendicular to the ground and are fixed to the ground through fixed foot rods. Sliding rail grooves for the up and down adjustment of the cross bar are provided on the opposite sides of the two vertical rods, and the end of the cross bar is fixed in the sliding rail groove through a cross bar rotary fixator.

[0012] A method for monitoring sediment concentration by fusing acoustic and optical signal data, characterized by comprising the following steps:

[0013] Step 1): The hydrophone is located at the bottom of the device and vertically emits acoustic wave pulses with a carrier frequency of 1.5 MHz. When the acoustic wave signal encounters sediment particles in the water body, part of the signal forms the backscattered signal at ;

[0014] Step 2): Perform Hilbert transform on the backscattered signal , and take the envelope of the signal , where is the Hilbert transform, is the signal quantity after Hilbert transform, is a constant, is the backscattered signal 's envelope;

[0015] Step 3): Considering that there are many sediment particles in the water body, the scattered signals actually collected by the hydrophone are superimposed by signals with the same frequency but different amplitudes and phases. Therefore, integrate the envelope signal in step 2 over the sampling time to obtain , where is the integral of the envelope signal over the sampling time ;

[0016] Step 4): Perform A / D conversion on to obtain the digital quantity ;

[0017] Step 5): For the digital quantity Multiple samplings are carried out to establish a sample set sampled at a moment ;

[0018] Step 6): Take the average value of the sample set to obtain , and eliminate the instability caused by random variables in the sampling. Among them, is the average value of the sample set ;

[0019] Step 7): Square to obtain the hydrophone sediment concentration value of the acoustic backscattering signal intensity under the condition of . Among them, ;

[0020] Step 8): Establish the relationship between the hydrophone sediment concentration value and the acoustic backscattering intensity: , where is an exponential relationship variable, which is calibrated according to the in-situ ratio measurement information of the water body;

[0021] Step 9): Establish a double-constrained linear regression model , where represents the weighting value, represents the sediment concentration value of the hydrophone, represents the sediment concentration value of the turbidity meter, represents the fused sediment concentration value, represents the system error, which follows a Gaussian distribution with a mean of 0 and a variance of ;

[0022] Step 10): The model obeys the double-constrained condition , where represents the linear constraint, represents the minimum variance distortionless of the system error. In the formula, represents the error covariance matrix. The optimal weight value is solved according to the least squares principle as . Since the error covariance matrix cannot be directly solved, the signal covariance matrix is used instead, and the optimal weight value is ;

[0023] Step 11): The fused sediment concentration value is expressed as .

[0024] The beneficial effects of the present invention are:

[0025] Due to the short wavelength of optical signals, light waves cannot penetrate water bodies with a relatively high particle concentration. Generally, the monitoring range of sediment concentration by optical methods is small. However, sound waves have a better penetration effect in water bodies. The present invention can effectively make up for the deficiencies of light waves through hydrophones. At the same time, the method of fusing acoustic and optical signal data used in the present invention can solve the problem that acoustic and optical signals have different response sensitivities to particles of different particle sizes, and achieve more stable and accurate sediment concentration monitoring. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the overall structure of the device of the present invention

[0027] Figure 2 It is a schematic diagram of the structure of the integrated device of the turbidimeter and the hydrophone in the device of the present invention

[0028] Figure 3 It is a flow chart of the method of the present invention

[0029] LIST OF REFERENCE NUMERALS:

[0030] 1 - vertical rod, 2 - crossbar rotation fixer, 3 - fixed foot rod, 4 - integrated device of turbidimeter and hydrophone, 5 - crossbar, 6 - turbidimeter, 7 - hydrophone, 8 - fixed support structure, 9 - first cable routing structure, 10 - second cable routing structure, 11 - unified interface DETAILED DESCRIPTION OF THE EMBODIMENTS

[0031] The following further clarifies the present invention in conjunction with the drawings and specific embodiments. It should be understood that the following specific embodiments are only used to illustrate the present invention and not to limit the scope of the present invention.

[0032] As Figure 1 shown, the present invention provides a sediment concentration monitoring device that fuses acoustic and optical signal data, including a frame and an integrated device 4 of a turbidimeter and a hydrophone. The integrated device of the turbidimeter and the hydrophone is installed in the center of the frame, and its signal is emitted upward and perpendicular to the water surface. The frame is used to adjust the water depth of the integrated device of the turbidimeter and the hydrophone.

[0033] Among them, the frame includes two vertically arranged vertical rods 1 that are symmetrically arranged left and right, and a crossbar 5 that is horizontally arranged between the two vertical rods. The vertical rods are perpendicular to the ground and are fixed to the ground through fixed foot rods 3. Slide rail grooves for the up and down adjustment of the crossbar are provided on the opposite sides of the two vertical rods, and the ends of the crossbar are fixed in the slide rail grooves through crossbar rotation fixers 2

[0034] As Figure 2As shown in the figure, the integrated turbidity meter and hydrophone device 4 includes a fixed bracket structure 8, a turbidity meter 6 and a hydrophone 7 provided on the fixed bracket structure. The turbidity meter and the hydrophone are fixed on the same plane, and both have 5-core pluggable signal interfaces at the rear end. The two 5-core pluggable signal interfaces are respectively connected with a first cable and a second cable. The first cable and the second cable respectively form a unified external interface 11 through a first cable routing structure 9 and a second cable routing structure 10. The cable routing structure is used for routing the cables inside.

[0035] In this embodiment, an anti-fouling wiper is integrated in front of the turbidity meter, and the working mode of the wiper is to be fixedly activated every time it is powered on. The hydrophone is a combined transmitting and receiving ultrasonic transducer with a working frequency of 1.5 MHz.

[0036] In addition, the integrated turbidity meter and hydrophone device further includes a data remote telemetry terminal, and the data remote telemetry terminal is used to receive the data output by the turbidity meter and the hydrophone, locally store the data and then send it to the host computer terminal through a wireless transmission module.

[0037] As Figure 3 shown, the present invention also provides a method for monitoring sediment concentration by fusing acoustic and optical signal data, including the following steps:

[0038] Step 1): The hydrophone is located at the bottom of the device and vertically emits an acoustic wave pulse with a carrier frequency of 1.5 MHz. When the acoustic wave signal encounters sediment particles in the water body, part of the signal is backscattered to form the backscattered signal at ;

[0039] Step 2): Perform a Hilbert transform on the backscattered signal , and take the envelope of this signal , where is the Hilbert transform, is the signal quantity after the Hilbert transform, is a constant, [[ID='D34']] is the backscattered signal ;

[0040] Step 3): Considering that there are more sediment particles in the water body, the scattered signals actually collected by the hydrophone are superimposed by signals with the same frequency but different amplitudes and phases. Therefore, integrate the envelope signal in step 2 over the sampling time to obtain , where is the integral of the envelope signal over the sampling time ;

[0041] Step 4): Take Perform A / D conversion to obtain a digital quantity ;

[0042] Step 5): Sample the digital quantity multiple times to establish a sample set sampled at a certain moment ;

[0043] Step 6): Take the average of the sample set to obtain , and eliminate the instability caused by random variables in the sampling. Among them, is the average of the sample set ;

[0044] Step 7): Square to obtain the sediment concentration value of the hydrophone the acoustic backscattering signal intensity under certain conditions , where ;

[0045] Step 8): Establish the relationship between the sediment concentration value of the hydrophone and the acoustic backscattering intensity: , where is an exponential relationship variable, which is calibrated according to the in-situ comparison information of the water body;

[0046] Step 9): Establish a double-constrained linear regression model , where represents the weighting value, represents the sediment concentration value of the hydrophone, represents the sediment concentration value of the turbidimeter, represents the fused sediment concentration value, represents the system error, which follows a Gaussian distribution with a mean of 0 and a variance of ;

[0047] Step 10): The model is subject to double-constrained conditions , where represents the linear constraint, represents the minimum variance distortionless of the system error. In the formula, represents the error covariance matrix. The optimal weight value is solved according to the least squares principle as . Since the error covariance matrix cannot be directly solved, use the signal covariance matrix to replace it, then the optimal weight value is ;

[0048] Step 11): The fused sediment concentration value is expressed as . [[ID=?]]

[0049] The present invention performs data fusion processing on the sediment concentration values of an optical turbidimeter and an acoustic turbidimeter. Compared with the original single - means monitoring method, the present invention can effectively reduce the influence of the particle size of water sediment particles on sediment concentration monitoring and improve the stability and accuracy of monitoring.

[0050] The technical means disclosed in the solution of the present invention are not limited to the technical means disclosed in the above - mentioned embodiments, but also include technical solutions composed of any combination of the above - mentioned technical features. It should be noted that for those of ordinary skill in the art of this technology, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements are also regarded as the protection scope of the present invention.

Claims

1. A method for monitoring sediment concentration by fusing acoustic and optical signal data, characterized in that Based on the sediment concentration monitoring device, it includes the following steps: Step 1): The hydrophone is located at the bottom of the device and vertically emits acoustic wave pulses with a carrier frequency of 1.5 MHz. When the acoustic wave signal encounters sediment particles in the water body, part of the signal forms the backscattered signal at ; Step 2): For the backscattered signal perform Hilbert transform , and take the envelope of the signal , where is the Hilbert transform, is the signal quantity after Hilbert transform, is a constant, is the backscattered signal is the envelope of Step 3): Considering that there are many sediment particles in the water body, the scattered signals actually collected by the hydrophone are superimposed by signals with the same frequency but different amplitudes and phases. Therefore, the envelope signal in Step 2 is integrated over the sampling time to obtain , where is the integral of the envelope signal over the sampling time ; Step 4): Convert through A / D conversion to obtain a digital quantity ; Step 5): For digital quantities sample multiple times to establish a set of samples taken at ; Step 6): Take the average value of the sample set to obtain , and eliminate the instability caused by random variables in the sampling, where is the average value of the sample set ; Step 7): Square to obtain the sediment concentration value of the hydrophone under the condition of the acoustic backscattering signal intensity , where ; Step 8): Establish the relationship between the sediment concentration value of the hydrophone and the acoustic backscattering intensity: , where is an exponential relationship variable, which is calibrated according to the in-situ ratio measurement information of the water body; Step 9): Establish a double-constrained linear regression model , where represents the weighting value, represents the sediment concentration value of the hydrophone, represents the sediment concentration value of the turbidimeter, represents the fused sediment concentration value, represents the systematic error, which follows a Gaussian distribution with a mean of 0 and a variance of ; Step 10): The model is subject to double constraint conditions , where represents the linear constraint represents the minimum variance distortionless of the system error. In the formula represents the error covariance matrix. The optimal weight is solved according to the least squares principle as . Since the error covariance matrix cannot be directly solved, the signal covariance matrix is used to replace it. Then the optimal weight is ; Step 11): The value of the sediment concentration after fusion is expressed as .

2. The sediment concentration monitoring method for acousto-optic signal data fusion according to claim 1, wherein, The sediment concentration monitoring device includes a frame and an integrated turbidity meter and hydrophone device. The integrated turbidity meter and hydrophone device is installed in the center of the frame, its signal is emitted upward and perpendicular to the water surface, and the frame is used to adjust the water depth of the integrated turbidity meter and hydrophone device.

3. The sediment concentration monitoring method for acousto-optic signal data fusion according to claim 2, characterized in that: The integrated turbidity meter and hydrophone device includes a fixed bracket structure, a turbidity meter and a hydrophone arranged on the fixed bracket structure. The turbidity meter and the hydrophone are fixed on the same plane, and both have 5-core pluggable signal interfaces at the rear ends. The two 5-core pluggable signal interfaces are respectively connected with a first cable and a second cable, and the first cable and the second cable respectively form a unified external interface through the first cable routing structure and the second cable routing structure.

4. The sediment concentration monitoring method for acousto-optic signal data fusion according to claim 3, characterized in that, A pollution prevention wiper is integrated in front of the turbidity meter, and the working mode of the wiper is to be fixedly activated each time it is powered on.

5. The sediment concentration monitoring method for acoustic-optical signal data fusion according to claim 3, characterized in that, The hydrophone is a transceiver ultrasonic transducer with a working frequency of 1.5 MHz.

6. The sediment concentration monitoring method for acousto-optic signal data fusion according to claim 3, characterized in that, The integrated turbidity meter and hydrophone device also includes a data remote telemetry terminal, which is used to receive the data output by the turbidity meter and the hydrophone, locally store the data and then send it to the upper computer through a wireless transmission module.

7. The sediment concentration monitoring method for acousto-optic signal data fusion according to claim 2, wherein The frame includes two vertically arranged vertical rods symmetrically arranged on the left and right, and a cross bar horizontally arranged between the two vertical rods. The vertical rods are perpendicular to the ground and are fixed to the ground through fixed foot rods. Sliding rail grooves for the up and down adjustment of the cross bar are provided on the opposite sides of the two vertical rods, and the end of the cross bar is fixed in the sliding rail groove through a cross bar rotary fixator.

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