Multispectral photoelectric sand meter

Abstract

The invention discloses a spectrum photoelectric sand meter which comprises a cylindrical hollow shell, an end cover and a probe, wherein the end cover and the probe are respectively assembled at two ends of the shell in a sealing manner; and the probe realizes the sand content detection of the liquid to be detected under the condition of sediment mixing in a wide dynamic range through multispectral detection. The probe comprises a light source module, a photoelectric detection module and a data processing module; wherein the light source module is used for emitting light of different wave bands to liquid to be detected; the photoelectric detection module is used for detecting reflected light of liquid to be detected and transmitting spectral response data into the data processing module; and the data processing module is used for preliminarily calculating the concentration of the to-be-detected liquid according to the spectral response data to obtain the sand content, and transmitting a result to an upper computer for subsequent optimization. The device is simple in structure, convenient to operate and high in measurement precision and data reliability.

Description

Technical Field

[0001] The invention belongs to the technical field of sediment monitoring, in particular to a spectral photoelectric sand measuring instrument. Background Art

[0002] Multispectral photoelectric sand measurement technology refers to an advanced detection technology that uses the correlation between spectral features in different bands and sediment content to improve the performance and accuracy of feature extraction and data fusion. The modern river environment is becoming more and more complex, and interference factors are increasing. Traditional single sensor systems are often limited by environmental conditions, target characteristics and other factors, resulting in the inability to fully and accurately obtain target information. Traditional detection equipment has gradually been unable to meet the measurement requirements of current waters, and higher requirements have been placed on the detection of waters in complex environments. With the development of remote sensing technology and the improvement of multispectral imaging capabilities, the technology of using multispectral measurement of sediment content in water bodies has emerged.

[0003] Considering that the probe of the traditional photoelectric sediment content tester can only measure a single sand content concentration and has the disadvantage of large error in measuring the suspended matter concentration of the sediment mixture, it is of great significance to study multiple spectral sand measurement structures. On the basis of solving the multi-spectral data processing, it makes up for the shortcomings of the single-band photoelectric sediment content measurement instrument in the current sand measurement model and meets the special needs in the hydraulic model test. Summary of the invention

[0004] The purpose of the present invention is to provide a spectral photoelectric sand measuring instrument to address the problems existing in the above-mentioned prior art, which can detect the sand content of the liquid to be tested in a wide dynamic range under the condition of mud and sand mixing through multi-spectral detection.

[0005] The technical solution for achieving the purpose of the present invention is: a spectral photoelectric sand measuring instrument, which includes a cylindrical hollow shell, end caps and probes respectively sealed and assembled at both ends of the shell; the probe realizes the sand content detection of the liquid to be tested in the case of mud and sand mixing in a wide dynamic range through multi-spectral detection.

[0006] Furthermore, the probe includes a light source module, a photoelectric detection module and a data processing module;

[0007] The light source module is used to emit light of different wavelengths to the liquid to be tested;

[0008] The photoelectric detection module is used to detect the reflected light of the liquid to be tested and transmit the spectral response data to the data processing module;

[0009] The data processing module is used to preliminarily calculate the concentration of the liquid to be tested according to the spectral response data, that is, to obtain the sand content, and transmit the result to the host computer for subsequent optimization.

[0010] Furthermore, the probe includes a disc-shaped probe base sealed and assembled on the inner wall of one end of the shell, the light source module and the photoelectric detection module are installed on the disc-shaped probe base, the data processing module is installed inside the shell, and the light source module and the photoelectric detection module detect the liquid to be tested through the optical window on the disc-shaped probe base.

[0011] Furthermore, the photoelectric detection module includes a plurality of groups of photoelectric detection units, which are respectively used to detect spectral response data of the liquid to be tested corresponding to different wavebands.

[0012] Furthermore, the photoelectric detection module is used to detect spectral signals of the liquid to be tested at scattering angles of 135° and 90°.

[0013] Furthermore, an optical window is provided at the center of the disc-shaped probe base, and N optical windows are evenly distributed along the circumferential direction with the optical window as the center on the disc-shaped probe base, where N is an even number; three optical windows along each diameter direction of the disc-shaped probe base constitute a group of the photoelectric detection units, wherein a photoelectric detector is provided in the optical window located at the center position, and a light source module and a photoelectric detector are respectively provided in the other two optical windows, and the two photoelectric detectors respectively detect spectral signals of the liquid to be tested with scattering angles of 135° and 90°, and the wavelength bands of the output light of the light source modules in different groups of photoelectric detection units are different.

[0014] Furthermore, the data processing module is used to calculate the concentration of the liquid to be tested according to the spectral response data, and the specific implementation process includes:

[0015] Step 1, randomly select two groups of photoelectric detection units;

[0016] Step 2: According to the spectral response data detected by the two sets of photoelectric detection units, the concentration of the liquid to be tested, i.e., the sand content, is solved using the following formula:

[0017]

[0018] Where a1, b1, a2, b2 are the calibration coefficients of the photodetectors in one group of photodetection units, a3, b3, a4, b4 are the calibration coefficients of the photodetectors in another group of photodetection units, and R t 、r t They respectively represent the spectral response data output by the photoelectric detectors of the two groups of photoelectric detection units; C1' and C2' respectively represent the concentration of mud and sand in the liquid to be tested, and C1'+C2' represents the concentration of the liquid to be tested, that is, the sand content; wherein, a1 / a2≠a3 / a4.

[0019] Furthermore, the process of obtaining the calibration coefficient is as follows:

[0020] For a certain group of photoelectric detection units, two photoelectric detectors therein are recorded as a first photoelectric detector and a second photoelectric detector;

[0021] Step 1, using the group of photoelectric detection units to detect a sediment mixture with a known sediment content;

[0022] Step 2: Substitute the spectral response data detected by the two photodetectors into the following formula:

[0023] R1=a1C1+b1

[0024] R2=a2C2+b2

[0025] r1=a3C1+b3

[0026] r2=a4C2+b4

[0027] Wherein, R1 and R2 are the 135° / 90° spectral response data of mud and sand in the mud-sand mixture detected by the first photoelectric detector, r1 and r2 are the 135° / 90° spectral response data of mud and sand in the mud-sand mixture detected by the second photoelectric detector, C1 and C2 are the concentrations of mud and sand in the mud-sand mixture, a1, b1, a2, and b2 are the calibration coefficients corresponding to the first photoelectric detector, and a3, b3, a4, and b4 are the calibration coefficients corresponding to the second photoelectric detector;

[0028] Step 3, for multiple different sediment mixtures with known sediment contents, repeat steps 1 to 2 to obtain multiple sets of data;

[0029] Step 4, fitting the multiple sets of data to calculate the calibration coefficients corresponding to the first photodetector and the second photodetector;

[0030] Repeat the above process to obtain the calibration coefficients of the photodetectors in all photodetection units.

[0031] Furthermore, a step structure is provided at a portion of the disc-shaped probe base that is in contact with the inner wall of one end of the housing.

[0032] Furthermore, the step structure is provided with a groove for installing a waterproof sealing gasket.

[0033] Compared with the prior art, the present invention has the following significant advantages:

[0034] (1) The present invention uses multispectral data fusion technology to study the use of the differential response of the backscatter coefficient of the suspended components at three wavelengths to obtain an accurate estimate of the concentration of the mixture. The method is based on the simultaneous solution of a linear equation that relates the output of the optical backscatter sensor to the concentration of the various components of the suspended sediment. The result is an underwater sand concentration tester that is less affected by particle size and particle color.

[0035] (2) The present invention adopts multi-spectral detection, and the emission signal intensity of each band is known, which ensures the consistency of the ratio standard. In addition, the response spectrum of the photoelectric detector is wide enough to meet the test response of each spectrum band, and can effectively realize the sand content detection in the case of wide dynamic range mud and sand mixing.

[0036] (3) The spectral signals at 90° and 135° are obtained simultaneously as the same set of spectra. The curves obtained from the same set of spectra can be used to distinguish specific concentrations by staggering peaks to improve the measurement range. This can meet a wide range of detection needs from low concentrations to high concentrations, thereby maintaining efficient and stable detection performance in various complex environments.

[0037] (4) When using a receiving path with an axial angle of 135°, different spectra can be switched for measurement, which can improve the test range and measurement accuracy.

[0038] (5) A step structure is added to the probe design to improve the overall installation stability and sealing effect of the sand meter.

[0039] (6) A groove is provided on the step structure of the probe for placing a waterproof sealing gasket, which can effectively prevent the entry of moisture or other external impurities and ensure that the instrument can operate normally for a long time underwater or in a high humidity environment.

[0040] (7) The present invention has a simple structure, is easy to operate, and has high measurement accuracy and data reliability.

[0041] The present invention is further described in detail below in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 Schematic diagram of the structure of a multi-spectral photoelectric sand measuring instrument in one embodiment.

[0043] Figure 2 Schematic diagram of the optical path of a multi-spectral photoelectric sand measuring instrument in one embodiment.

[0044] Figure 3 Schematic diagram of the change of the spectrum peak value of the multi-spectral photoelectric sand measuring instrument in one embodiment, wherein the horizontal axis represents a certain measurement data, and the vertical axis represents the output value of the photoelectric detector. DETAILED DESCRIPTION

[0045] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0046] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0047] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or suggesting their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0048] In one embodiment, in combination Figure 1 , provides a spectral photoelectric sand measuring instrument, which includes a cylindrical hollow shell, end caps and a probe 2 respectively sealed and assembled at both ends of the shell; the probe realizes the sand content detection of the liquid to be tested in the case of mud and sand mixing in a wide dynamic range through multi-spectral detection.

[0049] It should be noted here that the shape structure of the housing and the shape structure of the end cover and the probe are not limited to the above description of circles.

[0050] Further, in one of the embodiments, the probe includes a light source module, a photoelectric detection module and a data processing module;

[0051] The light source module is used to emit light of different wavelengths to the liquid to be tested;

[0052] The photoelectric detection module is used to detect the reflected light of the liquid to be tested and transmit the spectral response data to the data processing module;

[0053] The data processing module is used to preliminarily calculate the concentration of the liquid to be tested according to the spectral response data, that is, to obtain the sand content, and transmit the result to the host computer for subsequent optimization.

[0054] Here, in some embodiments, the probe includes a disc-shaped probe base sealed and assembled on the inner wall of one end of the shell, the light source module and the photoelectric detection module are installed on the disc-shaped probe base, the data processing module is installed inside the shell, and the light source module and the photoelectric detection module realize detection of the liquid to be tested through the optical window on the disc-shaped probe base.

[0055] Here, preferably, a step structure is provided at a portion of the disc-shaped probe base that is in contact with the inner wall of one end of the housing.

[0056] Here, preferably, a groove is provided on the step structure for installing the waterproof sealing gasket 1.

[0057] Here, preferably, the light source module adopts but is not limited to broadband LED irradiation or laser.

[0058] Preferably, the probe is fixed to the housing via a screw hole, which further improves the sealing performance of the device and achieves higher measurement accuracy and stability.

[0059] Furthermore, in some embodiments, the photoelectric detection module includes a plurality of groups of photoelectric detection units, which are respectively used to detect spectral response data of the liquid to be tested corresponding to different wavebands.

[0060] Preferably, in some embodiments, the photoelectric detection module is used to detect spectral signals of the liquid to be tested at scattering angles of 135° and 90°.

[0061] It should be noted here that it is not limited to 135° and 90°.

[0062] Preferably, in some embodiments, an optical window is provided at the center of the disc-shaped probe base, and N optical windows are evenly distributed along the circumferential direction of the disc-shaped probe base with the optical window as the center, where N is an even number; three optical windows along each diameter direction of the disc-shaped probe base (such as Figure 1 3, 4, and 5) constitute a group of photoelectric detection units, wherein a photoelectric detector is arranged in the optical window located at the center position, and a light source module and a photoelectric detector are respectively arranged in the other two optical windows. The two photoelectric detectors respectively detect spectral signals of the liquid to be tested with scattering angles of 135° and 90°, and the wavelength bands of the output lights of the light source modules in different groups of photoelectric detection units are different.

[0063] Here preferably, the N is 6, which is divided into three groups of photoelectric detection units.

[0064] Preferably, the three light source modules of the three groups of photoelectric detection units emit light in the 760nm, 850nm, and 960nm bands, respectively, with 850nm being the main monitoring band. Here, the signal intensities of the three groups of light sources in different bands are known, ensuring the consistency of the ratio standard. The spectral signals of 135° and 90° detected by each group of photoelectric detection units are grouped into the same group, and a total of three groups of spectral signals are obtained. Figure 3 As shown, the curves obtained from the same set of spectra can be used to identify specific concentrations by staggering peaks to increase the measurement range, and can adapt to a wide range of detection needs from low concentrations to high concentrations, thereby maintaining efficient and stable detection performance in various complex environments.

[0065] Here, preferably, the optical window located at the center is used as a common optical window for detecting the spectral response data of 135°.

[0066] Furthermore, in some embodiments, the data processing module is used to calculate the concentration of the liquid to be tested according to the spectral response data, and the specific implementation process includes:

[0067] Step 1, randomly select two groups of photoelectric detection units;

[0068] Step 2: According to the spectral response data detected by the two sets of photoelectric detection units, the concentration of the liquid to be tested, i.e., the sand content, is solved using the following formula:

[0069]

[0070] Where a1, b1, a2, b2 are the calibration coefficients of the photodetectors in one group of photodetection units, a3, b3, a4, b4 are the calibration coefficients of the photodetectors in another group of photodetection units, and R t 、r t They respectively represent the spectral response data output by the photoelectric detectors of the two groups of photoelectric detection units; C1' and C2' respectively represent the concentration of mud and sand in the liquid to be tested, and C1'+C2' represents the concentration of the liquid to be tested, that is, the sand content; wherein, a1 / a2≠a3 / a4.

[0071] Here, order The above equation becomes: Ax=y.

[0072] Specifically, the equation estimates x through A and y as x=A -1 y. The actual A and y have related uncertainties. Assuming A = A0 + ΔA, y = y0 + Δy, A0 and y0 represent true values, ΔA and Δy represent errors, multiple spectral channels are used, and multi-channel data space-time fitting is performed to obtain x and eliminate the influence of color.

[0073] Here, in some embodiments, the process of obtaining the calibration coefficient is:

[0074] For a certain group of photoelectric detection units, two photoelectric detectors therein are recorded as a first photoelectric detector and a second photoelectric detector;

[0075] Step 1, using the group of photoelectric detection units to detect a sediment mixture with a known sediment content;

[0076] Step 2: Substitute the spectral response data detected by the two photodetectors into the following formula:

[0077] R1=a1C1+b1

[0078] R2=a2C2+b2

[0079] r1=a3C1+b3

[0080] r2=a4C2+b4

[0081] Wherein, R1 and R2 are the 135° / 90° spectral response data of mud and sand in the mud-sand mixture detected by the first photoelectric detector, r1 and r2 are the 135° / 90° spectral response data of mud and sand in the mud-sand mixture detected by the second photoelectric detector, C1 and C2 are the concentrations of mud and sand in the mud-sand mixture, a1, b1, a2, and b2 are the calibration coefficients corresponding to the first photoelectric detector, and a3, b3, a4, and b4 are the calibration coefficients corresponding to the second photoelectric detector;

[0082] Step 3, for multiple different sediment mixtures with known sediment contents, repeat steps 1 to 2 to obtain multiple sets of data;

[0083] Step 4, fitting the multiple sets of data to calculate the calibration coefficients corresponding to the first photodetector and the second photodetector;

[0084] Repeat the above process to obtain the calibration coefficients of the photodetectors in all photodetection units.

[0085] Furthermore, in one of the embodiments, the sand measuring instrument also includes a display module for displaying the sediment concentration data of each measuring point in real time.

[0086] Furthermore, in one of the embodiments, the sand measuring instrument also includes a storage module for storing data output by the data processing module in real time.

[0087] Furthermore, in one of the embodiments, the sand measuring instrument also includes a transmission module for sending the data information of the storage module to a host computer.

[0088] The method of using the sand measuring instrument of the present invention is as follows: first turn on the power supply, check the cleanliness of the sand measuring instrument and whether the probe is blocked. After the inspection work is completed, the sand measuring instrument is vertically inserted into the area to be measured and fixed; press the power button and the start button to start the test, the sand measuring instrument starts measuring, and the sediment concentration data of each measuring point is displayed in real time; after the test is completed, press the stop button to stop saving data, and the data can be exported through the data interface, and the export format is csv, which is convenient for processing and viewing on the host computer.

[0089] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A spectral photoelectric sand measuring instrument, characterized in that: The sand measuring instrument comprises a cylindrical hollow shell, end caps and a probe which are respectively sealed and assembled at both ends of the shell; the probe realizes the sand content detection of the liquid to be tested in the case of mud and sand mixing in a wide dynamic range through multi-spectral detection.

2. The spectral photoelectric sand measuring instrument according to claim 1, characterized in that: The probe includes a light source module, a photoelectric detection module and a data processing module; The light source module is used to emit light of different wavelengths to the liquid to be tested; The photoelectric detection module is used to detect the reflected light of the liquid to be tested and transmit the spectral response data to the data processing module; The data processing module is used to preliminarily calculate the concentration of the liquid to be tested according to the spectral response data, that is, to obtain the sand content, and transmit the result to the host computer for subsequent optimization.

3. The spectral photoelectric sand measuring instrument according to claim 2, characterized in that: The probe includes a disc-shaped probe base sealed and assembled on the inner wall of one end of the shell, the light source module and the photoelectric detection module are installed on the disc-shaped probe base, the data processing module is installed inside the shell, and the light source module and the photoelectric detection module detect the liquid to be tested through the optical window on the disc-shaped probe base.

4. The spectral photoelectric sand measuring instrument according to claim 3, characterized in that: The photoelectric detection module includes a plurality of groups of photoelectric detection units, which are respectively used to detect the spectral response data of the liquid to be tested corresponding to different wavebands.

5. The spectral photoelectric sand measuring instrument according to claim 4, characterized in that: The photoelectric detection module is used to detect the spectral signals of the liquid to be tested at scattering angles of 135° and 90°.

6. The spectral photoelectric sand measuring instrument according to claim 5, characterized in that: An optical window is provided at the center of the disc-shaped probe base, and N optical windows are evenly distributed along the circumferential direction with the optical window as the center on the disc-shaped probe base, where N is an even number; three optical windows along each diameter direction of the disc-shaped probe base constitute a group of the photoelectric detection units, wherein a photoelectric detector is provided in the optical window located at the center position, and a light source module and a photoelectric detector are respectively provided in the other two optical windows, and the two photoelectric detectors respectively detect spectral signals of the liquid to be tested with scattering angles of 135° and 90°, and the wavelength bands of the output light of the light source modules in different groups of photoelectric detection units are different.

7. The spectral photoelectric sand measuring instrument according to claim 6, characterized in that: The data processing module is used to calculate the concentration of the liquid to be tested according to the spectral response data. The specific implementation process includes: Step 1, randomly select two groups of photoelectric detection units; Step 2: According to the spectral response data detected by the two groups of photoelectric detection units, the concentration of the liquid to be tested, i.e., the sand content, is solved using the following formula: Where a1, b1, a2, b2 are the calibration coefficients of the photodetectors in one group of photodetection units, a3, b3, a4, b4 are the calibration coefficients of the photodetectors in another group of photodetection units, and R t 、r t They respectively represent the spectral response data output by the photoelectric detectors of the two groups of photoelectric detection units; C1' and C2' respectively represent the concentration of mud and sand in the liquid to be tested, and C1'+C2' represents the concentration of the liquid to be tested, that is, the sand content; wherein, a1 / a2≠a3 / a4.

8. The spectral photoelectric sand measuring instrument according to claim 7, characterized in that: The process of obtaining the calibration coefficient is as follows: For a certain group of photoelectric detection units, two photoelectric detectors therein are recorded as a first photoelectric detector and a second photoelectric detector; Step 1, using the group of photoelectric detection units to detect a sediment mixture with a known sediment content; Step 2: Substitute the spectral response data detected by the two photodetectors into the following formula: R1=a1C1+b1 R2=a2C2+b2 r1=a3C1+b3 r2=a4C2+b4 Wherein, R1 and R2 are the 135° / 90° spectral response data of mud and sand in the mud-sand mixture detected by the first photoelectric detector, r1 and r2 are the 135° / 90° spectral response data of mud and sand in the mud-sand mixture detected by the second photoelectric detector, C1 and C2 are the concentrations of mud and sand in the mud-sand mixture, a1, b1, a2, and b2 are the calibration coefficients corresponding to the first photoelectric detector, and a3, b3, a4, and b4 are the calibration coefficients corresponding to the second photoelectric detector; Step 3, for multiple different sediment mixtures with known sediment contents, repeat steps 1 to 2 to obtain multiple sets of data; Step 4, fitting the multiple sets of data to calculate the calibration coefficients corresponding to the first photodetector and the second photodetector; Repeat the above process to obtain the calibration coefficients of the photodetectors in all photodetection units.

9. The spectral photoelectric sand measuring instrument according to claim 3, characterized in that: A step structure is provided on the disc-shaped probe base at a location in contact with the inner wall of one end of the shell.

10. The spectral photoelectric sand measuring instrument according to claim 9, characterized in that: The step structure is provided with a groove for installing a waterproof sealing gasket.

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