Particle backscattering coefficient acquisition method and device, storage medium and terminal

Abstract

The invention provides a particle back scattering coefficient acquisition method and device, a storage medium and a terminal, and the method comprises the steps: obtaining wide-angle VSF data of a target sea area, and obtaining back full-angle volume scattering function data corresponding to the wide-angle VSF data through employing an interpolation algorithm; acquiring a corresponding back scattering distribution curve based on the back all-angle volume scattering function data; a plurality of corresponding angle values are extracted from the first interval, the second interval, the third interval and the fourth interval at preset intervals, and all the angle values are permutated and combined to obtain a plurality of different preset angle combinations; performing polynomial fitting based on each preset angle combination to obtain an estimated backscattering coefficient fitting model corresponding to the backscattering distribution curve; and inputting the backward all-angle volume scattering function data into the estimated backward scattering coefficient fitting model for calculation so as to obtain a particle backward scattering coefficient result. According to the invention, the precision of obtaining the particle backscattering coefficient can be improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of marine optics, and relates to a method for obtaining the particulate backscattering coefficient, in particular to a method and device for obtaining the particulate backscattering coefficient, a storage medium, and a terminal. Background Art

[0002] The particulate backscattering coefficient is a core parameter for studying marine ecology and biogeochemistry in marine optics.

[0003] In the prior art, the measurement methods for the particulate backscattering coefficient mainly rely on the single-angle method based on the conversion factor or the in-situ measurement of the three-angle volume scattering function (VSF). However, the defect of the prior art is that the single-angle method based on the conversion factor (χ p ) assumes that χ p is a fixed value that is not affected by regional and wavelength changes. However, χ p is very sensitive to changes in the shape of the scattering phase function. Different particle size distributions and refractive indices will cause significant changes in the scattering phase function and χ p at the backscattering angle. Commercial in-situ backscattering coefficient measurement devices using the single-angle method, such as BB3, BB9, HydroScat-6, etc., all use the volume scattering function at a single angle for measurement and multiply it by a fixed χ p to estimate the particulate backscattering coefficient, resulting in an error of nearly 15% in estimating the particulate backscattering coefficient by the single-angle method. At the same time, the three-angle method has currently been used in the in-situ backscattering coefficient measurement modules of devices such as ECO-VSF and BGC-Argo to measure the VSF before 150 degrees. This three-angle method still has an error of more than 10% in estimating the backscattering coefficient. Summary of the Invention

[0004] The purpose of the present invention is to provide a method and device for obtaining the particulate backscattering coefficient, a storage medium, and a terminal, which are used to solve the technical problem of insufficient accuracy in obtaining the particulate backscattering coefficient in the prior art.

[0005] In a first aspect, the present invention provides a method for obtaining the particulate backscattering coefficient, including:

[0006] Obtaining wide-angle VSF data of a target sea area, and using an interpolation algorithm to obtain the backscattering full-angle volume scattering function data corresponding to the wide-angle VSF data;

[0007] Obtaining a corresponding backscattering distribution curve based on the backscattering full-angle volume scattering function data;

[0008] Extract a plurality of corresponding angular values from the first interval, the second interval, the third interval, and the fourth interval at preset intervals, and perform permutations and combinations on all the angular values to obtain a plurality of different preset angular combinations;

[0009] Perform polynomial fitting based on each of the preset angular combinations to obtain an estimated backscattering coefficient fitting model corresponding to the backscattering distribution curve;

[0010] Input the backscattering full-angle volume scattering function data into the estimated backscattering coefficient fitting model for calculation to obtain the particle backscattering coefficient result;

[0011] Among them, each preset angular combination includes a first angle, a second angle, a third angle, and a fourth angle. The first angle is any angular value extracted from the first interval, the second angle is any angular value extracted from the second interval, the third angle is any angular value extracted from the third interval, and the fourth angle is any angular value extracted from the fourth interval. The angular values of the first interval, the second interval, the third interval, and the fourth interval increase in sequence, and the fourth interval is from 150 degrees to 170 degrees.

[0012] In an embodiment of the present invention, performing polynomial fitting based on each of the preset angular combinations to obtain an estimated backscattering coefficient fitting model corresponding to the backscattering distribution curve includes:

[0013] Obtain a polynomial coefficient matrix corresponding to each preset angular combination to obtain a plurality of polynomial coefficient matrices;

[0014] Obtain the polynomial coefficient matrix with the smallest error from the backscattering distribution curve as the target polynomial coefficient matrix, and collect the target polynomial coefficient matrix and the corresponding preset angular combination as the estimated backscattering coefficient fitting model.

[0015] In an embodiment of the present invention, obtaining the polynomial coefficient matrix corresponding to the preset angular combination includes:

[0016]

[0017] Among them, a represents the polynomial coefficient matrix, and θ n represents the nth angle, represents the backscattering distribution curve value.

[0018] In an embodiment of the present invention, it further includes:

[0019] Obtain the corresponding theoretical value of the particle backscattering coefficient based on the integration of the backscattering full-angle volume scattering function data in the back hemisphere;

[0020] Obtain the absolute difference between the obtained particulate backscattering coefficient result and the theoretical value of the particulate backscattering coefficient. If the absolute difference is greater than a preset threshold, then after reducing the preset interval, re-obtain the particulate backscattering coefficient result; otherwise, output the particulate backscattering coefficient result as the final result.

[0021] In an embodiment of the present invention,

[0022] The first interval is from 90 degrees to 110 degrees, the second interval is from 110 degrees to 130 degrees, and the third interval is from 130 degrees to 150 degrees.

[0023] In an embodiment of the present invention,

[0024] In the wide-angle VSF data, the method for obtaining the VSF data with an angular value greater than 150 degrees includes:

[0025] Direct the direct light through the sample cell and the neutral density filter in sequence and then towards the exit prism to obtain the corresponding reflected light;

[0026] Direct the reflected light through the neutral density filter and the sample cell in sequence and then towards the focusing window to obtain the light to be measured with an angle greater than 150 degrees;

[0027] Use a PMT to measure the light to be measured to obtain the VSF data with an angular value greater than 150 degrees;

[0028] Wherein, the neutral density filter and the exit prism are bonded with Canada balsam.

[0029] In an embodiment of the present invention,

[0030] The preset angle combination further includes a fifth angle, and the fifth angle is any angular value extracted from 170 degrees to 180 degrees.

[0031] In a second aspect, the present invention further provides a device for obtaining a particulate backscattering coefficient, which is characterized by including:

[0032] A data acquisition module, configured to acquire wide-angle VSF data of a target sea area and use an interpolation algorithm to acquire the corresponding backscattering full-angle volume scattering function data of the wide-angle VSF data;

[0033] A curve generation module, configured to acquire a corresponding backscattering distribution curve based on the backscattering full-angle volume scattering function data;

[0034] An angle combination module, configured to extract multiple corresponding angular values from the first interval, the second interval, the third interval, and the fourth interval at preset intervals, and arrange and combine all the angular values to obtain multiple different preset angle combinations;

[0035] A model screening module, configured to perform polynomial fitting based on each of the preset angle combinations to obtain an estimated backscattering coefficient fitting model corresponding to the backscattering distribution curve;

[0036] A backward estimation module, configured to input the backward full-angle volume scattering function data into the estimated backscattering coefficient fitting model for calculation to obtain the particle backscattering coefficient result;

[0037] Wherein, the preset angle combination includes a first angle, a second angle, a third angle, and a fourth angle. The first angle is any angle value extracted from a first interval, the second angle belongs to any angle value extracted from a second interval, the third angle belongs to any angle value extracted from a third interval, and the fourth angle belongs to any angle value extracted from a fourth interval. The angle values of the first interval, the second interval, the third interval, and the fourth interval increase in sequence, and the fourth interval is from 150 degrees to 170 degrees.

[0038] In a third aspect, the present invention further provides a storage medium, on which a computer program is stored, and when the program is executed by a processor, the method for obtaining the particle backscattering coefficient as described above is implemented.

[0039] In a fourth aspect, the present invention further provides a terminal, including a processor and a memory, and the memory is communicatively connected to the processor;

[0040] The memory is configured to store a computer program, and the processor is configured to execute the computer program stored in the memory so that the terminal executes the method for obtaining the particle backscattering coefficient as described above.

[0041] As described above, the method and device for obtaining the particle backscattering coefficient, the storage medium, and the terminal of the present invention have the following beneficial effects:

[0042] The present invention constructs a preset angle combination based on four different angles, obtains an estimated particle backscattering coefficient fitting model through polynomial fitting, and uses the fitting model to obtain the particle backscattering coefficient result. The present invention can capture the scattering characteristics of particulate matter from multiple angles, improve the estimation accuracy of the particle backscattering coefficient to more than four times that of the prior art, and the error can reach as low as 3%, thus significantly improving the estimation accuracy of the particle backscattering coefficient. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 Shows the wide-angle VSF data of multiple sea areas and the corresponding χ p Distribution schematic diagram.

[0044] Figure 2 Shows χ for different particle types pSchematic diagram of the distribution in the range of 90° - 180°.

[0045] Figure 3 Schematic flowchart showing the method for obtaining the particle backscattering coefficient according to an embodiment of the present invention.

[0046] Figure 4 Schematic diagram showing the way of obtaining the VSF data with the angle value greater than 150 degrees in the method for obtaining the particle backscattering coefficient according to an embodiment of the present invention.

[0047] Figure 5 Schematic diagram showing the accuracy of applying the method for obtaining the particle backscattering coefficient according to an embodiment of the present invention to obtain the backscattering coefficient in different global sea areas.

[0048] Figure 6 Schematic diagram showing the error bars of estimating the particle backscattering coefficient in different sea areas using the single - angle method.

[0049] Figure 7 Schematic diagram showing the comparison of the error bars between the method for obtaining the particle backscattering coefficient according to an embodiment of the present invention and the three - angle method.

[0050] Figure 8 Schematic diagram showing the structure of the device for obtaining the particle backscattering coefficient according to an embodiment of the present invention.

[0051] Figure 9 Schematic diagram showing the structure of the terminal according to an embodiment of the present invention. Detailed implementation manners

[0052] The following uses specific specific examples to illustrate the implementation manners of the present invention. Those skilled in the art can easily understand the other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific implementation manners. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, without conflict, the following embodiments and the features in the embodiments can be combined with each other.

[0053] The following will elaborate in detail on the principles and implementation manners of the method and device for obtaining the particle backscattering coefficient, the storage medium, and the terminal in this embodiment, so that those skilled in the art can understand the method, device, storage medium, and terminal for obtaining the particle backscattering coefficient in this embodiment without creative labor.

[0054] In the methods for obtaining the particle backscattering coefficient in the prior art, whether it is the single - angle method or the three - angle method, there are relatively high errors. To solve the above - mentioned technical problems, the present invention has investigated and analyzed a large amount of data to find improvement strategies.

[0055] Figure 1 Shows the wide-angle VSF data of multiple sea areas and the corresponding χ p Distribution schematic diagram, refer to Figure 1 As shown Figure 1 In the two figures in the first row, they are based on the wide-angle VSF data of the East China Sea in China; the two figures in the second row are based on the wide-angle VSF data of the South China Sea in China; the two figures in the third row are based on the wide-angle VSF data of other sea areas in the world. In the above three rows, the left figures (a, c, e) show the changes of the wide-angle VSF data at different angles. It can be seen that at the same angle, the VSF can have a change of nearly three orders of magnitude at most, indicating that the above three types of VSF data are sufficient to cover various different water optical types in the world. The right figures (b, d, f) are the χ calculated according to the VSF data corresponding to the left figures p Distribution in the backward direction (90° - 180°). Based on b and d, it can be seen that the South China Sea and the East China Sea belong to different optical type waters, and there are significant differences in the particle size and shape. By comparing the scattering phase functions of two different types of particles and the shapes of the conversion factors, it can be found that after 150°, the difference in the backward scattering distribution will increase significantly; and based on what is shown in (f), the χ p Mean value has the smallest change at 120°, but its variance is still large. For 140°, both its mean value and variance change greatly. Therefore, the above reasons lead to an increase in the estimation error of the single-angle backward scattering coefficient.

[0056] The present invention further analyzes the χ p Distribution of different particle types Figure 2 Shows the schematic diagram of the distribution of χ p For different particle types in the range of 90° - 180°, refer to Figure 2 As shown, the χ of two different types of particles p Differences gradually increase after 150°, and can exceed 40% at most.

[0057] By analyzing the full-angle volume scattering function, the present invention discovers the differences after 150°, and thus adopts a unique four-angle method, that is, adding an angle after 150° to construct a preset angle combination.

[0058] To solve the above technical problems existing in the prior art, an embodiment of the present invention provides a method for obtaining the particle backward scattering coefficient.

[0059] Figure 3 Shows the schematic flow diagram of the method for obtaining the particle backward scattering coefficient described in the embodiment of the present invention, refer to Figure 3 As shown, the method for obtaining the particle backward scattering coefficient in the embodiment of the present invention mainly includes steps S100 - S500.

[0060] Step S100: Obtain the wide-angle VSF data of the target sea area, and use the interpolation algorithm to obtain the backscattering volume scattering function data corresponding to the wide-angle VSF data.

[0061] The wide-angle VSF (Volume Scattering Function) data refers to the volume scattering function values at different angles, representing the distribution of the scattering intensity of light by particles in a unit volume of water with the change of the scattering angle. Specifically, in step S100, a wide-angle volume scattering function measuring instrument is used to obtain the wide-angle VSF data of the target sea area, which is the sea area where the particle backscattering coefficient is to be obtained. Based on the wide-angle VSF data, the interpolation algorithm is used to obtain the complete data of the backscattering volume scattering function at the full backscattering angle (i.e., 90° to 180°). Optionally, the implementation method of the interpolation algorithm is the interp1 function in Matlab. The implementation process is to call the interp1 function, and based on the measured data from 175° to 178.5° in the wide-angle VSF data, perform linear interpolation to obtain the volume scattering function data at 180°. Combine the wide-angle VSF data and the volume scattering function data at 180° as the backscattering volume scattering function data.

[0062] In the prior art, the measurement of the volume scattering function after 150° will be interfered by the reflected light signal, resulting in a relatively obvious increase in the measurement signal and low accuracy. Therefore, it is difficult to ensure the estimation accuracy when including the fourth angle and the accurate calculation of the particle backscattering coefficient. Optionally, Figure 4 The schematic diagram of the acquisition method of the VSF data with an angle value greater than 150 degrees in the particle backscattering coefficient acquisition method described in the embodiment of the present invention is shown. Figure 4 The upper half part is the front view of the acquisition process, and the lower half part is the corresponding top view. Refer to Figure 4 As shown, in the wide-angle VSF data, the acquisition method of the VSF data with an angle value greater than 150 degrees includes the following steps:

[0063] Step S101: Direct the direct light through the sample cell and the neutral density filter to the exit prism in sequence to obtain the corresponding reflected light.

[0064] In this embodiment, the neutral density filter and the exit prism are bonded with Canada balsam. The sample cell is filled with the suspended particle sample of the target sea area to ensure that the direct light passes through the substance to be measured to measure the optical properties of the sample cell; the exit prism is used to change the light propagation direction to generate the corresponding reflected light; the neutral density filter is used to adjust the light intensity.

[0065] Step S102: Direct the reflected light through the neutral density filter and the sample cell to the focusing window in sequence to obtain the light to be measured with an angle greater than 150 degrees.

[0066] Step S102 passes the light through the sample cell again to strengthen the interaction with the sample cell. Through multiple adjustments of the reflected light and sample interaction, optical information in the high-angle scattering region of the light (i.e., the range greater than 150 degrees) is focused. The focusing window is used to focus the reflected light to extract the light with an angle greater than 150 degrees as the light to be measured.

[0067] Step S103: Use a PMT to measure the light to be measured to obtain VSF data with an angle value greater than 150 degrees.

[0068] The PMT, that is, the photomultiplier tube (PMT, Photomultiplier Tube), is used to measure the light to be measured to obtain VSF data with an angle value greater than 150 degrees.

[0069] In summary, in steps S101 - S103, after the direct light is incident on the P2 prism, it is reflected above the prism through the neutral density filter. Part of the reflected light will still return to the sample cell through the prism. The reflected light passes through the neutral density filter for the second time, and the energy is about 10 -6 , which can be ignored. The backward scattered light after 150° is focused by the prism through the window and then measured by the PMT. The influence of the reflected light is greatly reduced, effectively reducing the problem of overestimation of backward scattering and improving the acquisition quality of VSF data greater than 150 degrees, which is beneficial to improving the estimation accuracy of the particle backward scattering coefficient.

[0070] Step S200: Obtain the corresponding backward scattering distribution curve based on the backward full-angle volume scattering function data.

[0071] The backward scattering distribution curve is a graphical description used to show the distribution of scattering intensity in the backward angle range. The backward scattering distribution curve reflects the trend of the backward scattering intensity changing with the scattering angle, and its height and change range are related to particle size, density, optical properties, etc. Specifically, those skilled in the art can sample and plot based on the backward full-angle volume scattering function data to obtain the corresponding backward scattering distribution curve. In the embodiments of the present invention, the backward scattering distribution curve is the basis for subsequently obtaining the fitting model of the estimated backward scattering coefficient.

[0072] Step S300: Extract multiple corresponding angle values from the first interval, the second interval, the third interval, and the fourth interval at preset intervals, and arrange and combine all the angle values to obtain multiple different preset angle combinations.

[0073] In this embodiment, the preset angle combination includes a first angle, a second angle, a third angle, and a fourth angle. The first angle is any angle value extracted from the first interval, the second angle is any angle value extracted from the second interval, the third angle is any angle value extracted from the third interval, and the fourth angle is any angle value extracted from the fourth interval. The fourth interval is from 150 degrees to 170 degrees, and the angle values of the first interval, the second interval, the third interval, and the fourth interval increase in sequence (the first interval < the second interval < the third interval < the fourth interval). That is, multiple corresponding angle values are extracted from the first interval at a preset interval, multiple corresponding angle values are extracted from the second interval at a preset interval, multiple corresponding angle values are extracted from the third interval at a preset interval, and multiple corresponding angle values are extracted from the fourth interval at a preset interval. Taking the first interval as [50, 100] and the preset interval as 5 as an example, the multiple corresponding angle values after extraction are {50, 55, 60, 65, ……, 95, 100}, and each of them is a first angle. Similarly, the angle values corresponding to the second interval, the third interval, and the fourth interval can be obtained. The set of all the obtained angle values is arranged and combined according to the composition rule of the preset angle combination. Since there are 4 angle values in the preset angle values, namely the first angle, the second angle, the third angle, and the fourth angle, different preset angle combinations can be obtained through permutation and combination based on all the angle values. For example, if there are 10 angle values corresponding to the first interval, 5 angle values corresponding to the second interval, 5 angle values corresponding to the third interval, and 5 angle values corresponding to the fourth interval, then 10 * 5 * 5 * 5, that is, 1250 different preset angle combinations can be obtained based on all the angle values.

[0074] Optionally, the first interval is from 90 degrees to 110 degrees, the second interval is from 110 degrees to 130 degrees, and the third interval is from 130 degrees to 150 degrees. The interval setting of this embodiment can more accurately capture the distribution characteristics of the backscattering, ensure that the sampling covers all key angle regions, and avoid missing important data. According to the actual situation, those skilled in the art can select other appropriate angle values to construct the first interval to the third interval.

[0075] Optionally, the preset angle combination further includes a fifth angle, and the fifth angle is any angle value extracted from 170 degrees to 180 degrees. On the basis of the original preset angle combination, an angle value extracted from the fifth interval is added. The introduction of the fifth angle can provide more preset angle combinations for polynomial fitting, achieve sampling coverage of a larger backward angle range, and improve the expression ability of the fitting model for the backward scattering distribution curve. Therefore, the fitting error can be reduced. The improvement of the present invention does not lie in simply increasing more angles, but in increasing the fourth angle above 150 degrees to significantly improve the accuracy. Those skilled in the art can adopt more angles. The five-angle is the best solution for accuracy. However, compared with the four angles, the estimation accuracy of the backward scattering coefficient only increases by less than 1%. Moreover, as the accuracy increases, its calculation cost and measurement cost increase more significantly. Therefore, the four-angle is the best solution for comprehensive accuracy and calculation efficiency.

[0076] Step S400: Perform polynomial fitting based on each preset angle combination to obtain an estimated backward scattering coefficient fitting model corresponding to the backward scattering distribution curve.

[0077] Specifically, perform polynomial fitting on each preset angle combination to obtain the corresponding fitting result. Screen out the fitting result with the smallest error from all the fitting results, and combine this fitting result and the corresponding preset angle combination as the estimated backward scattering coefficient fitting model. The backward scattering distribution curve describes the scattering intensity at different scattering angles and is an important basic data for the fitting model. In step S400, polynomial fitting is performed on the preset angle combinations composed of different four angles, and these angle values are extracted from four intervals to ensure that the key features of the distribution curve can be covered, and an estimated backward scattering coefficient fitting model corresponding to the backward scattering distribution curve is obtained.

[0078] Optionally, performing polynomial fitting based on each preset angle combination to obtain an estimated backward scattering coefficient fitting model corresponding to the backward scattering distribution curve includes: obtaining the polynomial coefficient matrix corresponding to each preset angle combination to obtain a plurality of polynomial coefficient matrices; obtaining the polynomial coefficient matrix with the smallest error from the backward scattering distribution curve as the target polynomial coefficient matrix, and combining the target polynomial coefficient matrix and the corresponding preset angle combination as the estimated backward scattering coefficient fitting model.

[0079] Optionally, obtaining the polynomial coefficient matrix corresponding to the preset angle combination includes:

[0080]

[0081] where a represents the polynomial coefficient matrix, and θ n represents the nth angle, Represents the backscattering distribution curve value. Specifically, in matrix A, θ n is the angle value, and θ n m represents the m-th power of this angle. The number of rows of matrix A is the number of angle values n, corresponding to the number of angle values in the preset angle combination. The number of columns of matrix A is the order m of the fitting polynomial, which determines the complexity of the fitting. That is, the fitting polynomial is:

[0082]

[0083] Among them, represents the polynomial, and the corresponding polynomial coefficient matrix a is:

[0084] a = [a 0 , a 1 , …, a m T

[0085] In the embodiment of the present invention, the estimated backscattering coefficient fitting model corresponding to the backscattering distribution curve is obtained by fitting the polynomial coefficient matrix a. A T represents the transpose of matrix A, and (A T A) -1 represents the inverse matrix of A T A, which is used to eliminate redundant constraint conditions; is used to map the scattering value vector φ p to the polynomial fitting space. The polynomial coefficient matrix in the above manner is beneficial to accelerating the fitting speed. At the same time, the angle interval and fitting order in the matrix can meet the fitting requirements of different data distributions, and can achieve a high-precision approximation of the complex backscattering distribution curve.

[0086] Step S500: Input the backscattering full-angle volume scattering function data into the estimated backscattering coefficient fitting model for calculation to obtain the particle backscattering coefficient result.

[0087] Taking the backscattering full-angle volume scattering function data obtained in step S100 as the input and substituting it into the estimated backscattering coefficient fitting model, and taking the result calculated by this model as the particle backscattering coefficient result ensures a high degree of matching between the particle backscattering coefficient result and the true scattering characteristics, and reduces the errors caused by insufficient angle sampling and uneven distribution.

[0088] Optionally, the embodiment of the present invention further includes the verification and optimization of the particle backscattering coefficient result, specifically as steps S600 - S700:

[0089] Step S600: Obtain the corresponding theoretical value of the particle backscattering coefficient based on the integration of the backscattering full-angle volume scattering function data in the back hemisphere. ​

[0090] Specifically, the method for obtaining the theoretical value of the particle backscattering coefficient is as follows:

[0091]

[0092] where β p (θ; λ) is the data of the backscattering volume scattering function over all angles (i.e., the measured value of the volume scattering function), and β p (θ; λ)sinθ is the value of the backscattering distribution curve, defined as Specifically That is, the value between 90 degrees and 180 degrees in the backscattering distribution curve. Optionally, the trapz function in Matlab is used to obtain the theoretical value of the particle backscattering coefficient. By setting the fitting angle range to 90° - 180°, the theoretical value of the backscattering coefficient can be obtained.

[0093] Step S700: Obtain the absolute difference between the result of the particle backscattering coefficient and the theoretical value of the particle backscattering coefficient. If the absolute difference is greater than the preset threshold, then re - obtain the result of the particle backscattering coefficient after reducing the preset interval; otherwise, output the result of the particle backscattering coefficient as the final result.

[0094] Specifically, the method for obtaining the absolute difference refers to the following formula:

[0095]

[0096] where b b represents the result of the particle backscattering coefficient, b b 理论 represents the theoretical value of the particle backscattering coefficient, and Δb b represents the absolute difference. If the absolute difference is less than the preset threshold, then directly output the result of the particle backscattering coefficient as the final result. If the absolute difference is greater than the preset threshold, then re - obtain the result of the particle backscattering coefficient after reducing the preset interval. Since the preset interval is the interval for extracting corresponding angles in the first interval, the second interval, the third interval, and the fourth interval, reducing the preset interval can increase the number of extracted angles, increase the number of preset angle combinations, make the extraction granularity of the angle value finer, and is conducive to finding a better solution, thereby improving the accuracy of obtaining the result of the particle backscattering coefficient.

[0097] To verify the technical effect of the method for obtaining the particle backscattering coefficient of the present invention, a comparative experiment was carried out based on the same data set (wide - angle VSF data in the East China Sea area of China, wide - angle VSF data in the South China Sea area of China, wide - angle VSF data in other sea areas of the world). The specific results are as follows:

[0098] Figure 5The figure shows a schematic diagram of the accuracy of the method for obtaining the particulate backscattering coefficient according to the embodiments of the present invention when applied to obtain the backscattering coefficients of different sea areas around the world. As Figure 4 shown, the two figures in the first row are the experimental results based on the wide-angle VSF data of the East China Sea in China, the two figures in the second row are the experimental results based on the wide-angle VSF data of the South China Sea in China, and the two figures in the third row are the experimental results based on the wide-angle VSF data of other sea areas around the world. The first column is the corresponding backscattering distribution curve, the second column is the error of obtaining the particulate backscattering coefficient using the three-angle method of the prior art (there are 3 bars in the figure, that is, three angles), and the second column is the error of obtaining the particulate backscattering coefficient using the method of the present invention of the prior art (there are 4 bars in the figure, that is, four angles). Taking 5 degrees as the preset interval as an example, the present invention method conducts experiments on different angle combinations, and finally locates the four-angle combination of 100°, 120°, 140°, and 160°. For each type of data, its error is significantly lower than that of the three-angle method in the second column. Therefore, the method of the present invention greatly improves the accuracy of obtaining the particulate backscattering coefficient.

[0099] Figure 6 The figure shows a schematic diagram of the error bars for estimating the particulate backscattering coefficients of different sea areas using the single-angle method. Refer to Figure 6 shown, the backscattering coefficients were estimated using the 120° and 140° conversion factors most commonly used in the prior art for the single-angle method. The first column is the result corresponding to 120°, and the second column is the result of 140°. The gray dashed line in the figure represents the 1:1 line, and the surrounding red bars represent the 5% error bars. It can be found that the single-angle method will produce an error of nearly 15% (that is, the MAPD index in the figure). Figure 7 The figure shows a schematic diagram of the comparison of the error bars between the method for obtaining the particulate backscattering coefficient according to the embodiments of the present invention and the three-angle method. Experiments were conducted on three different sets of data in the figure. The first column is the result of the three-angle method, and the second column is the result of the four-angle method of the present invention forming a preset angle combination. Refer to Figure 7 shown, the error of the present invention is lower than 5%. Compared with the traditional three-angle method, the improvement in the estimation accuracy of the present invention exceeds 10%. Moreover, the four-angle method of the present invention breaks through the limitations of regions and wavelengths, and has high accuracy for the backscattering estimation of different sea areas and different wavelengths around the world.

[0100] The protection scope of the method for obtaining the particulate backscattering coefficient according to the embodiments of the present invention is not limited to the execution order of the steps listed in this embodiment. Any solution achieved by adding or subtracting steps of the prior art and replacing steps according to the principle of the present invention is included in the protection scope of the present invention.

[0101] The method for obtaining the particulate backscattering coefficient according to the embodiments of the present invention constructs a preset angle combination based on four different angles, and obtains an estimation particulate backscattering coefficient fitting model through polynomial fitting, and uses this fitting model to obtain the particulate backscattering coefficient result, significantly improving the estimation accuracy of the particulate backscattering coefficient. At the same time, by using the method for obtaining the VSF data with an angle value greater than 150 degrees in the present invention, the quality of the VSF data with an angle greater than 150 degrees can be improved, thereby further improving the estimation accuracy of the particulate backscattering coefficient.

[0102] To solve the above technical problems existing in the prior art, the embodiments of the present invention further provide a device for obtaining the particulate backscattering coefficient.

[0103] Figure 8 The structure diagram of the device for obtaining the particulate backscattering coefficient according to the embodiments of the present invention is shown, referring to Figure 8 As shown, the device for obtaining the particulate backscattering coefficient according to the embodiments of the present invention includes:

[0104] A data acquisition module, configured to acquire wide-angle VSF data of a target sea area, and use an interpolation algorithm to acquire the backscattering full-angle volume scattering function data corresponding to the wide-angle VSF data;

[0105] A curve generation module, configured to acquire a corresponding backscattering distribution curve based on the backscattering full-angle volume scattering function data;

[0106] An angle combination module, configured to extract a plurality of corresponding angle values from a first interval, a second interval, a third interval, and a fourth interval respectively at a preset interval, and arrange and combine all the angle values to acquire a plurality of different preset angle combinations;

[0107] A model screening module, configured to perform polynomial fitting based on each preset angle combination to acquire an estimated backscattering coefficient fitting model corresponding to the backscattering distribution curve;

[0108] A backscattering estimation module, configured to input the backscattering full-angle volume scattering function data into the estimated backscattering coefficient fitting model for calculation to acquire the particulate backscattering coefficient result;

[0109] Wherein, the preset angle combination includes a first angle, a second angle, a third angle, and a fourth angle. The first angle is any angle value extracted from the first interval, the second angle is any angle value belonging to the second interval, the third angle is any angle value belonging to the third interval, the fourth angle is any angle value extracted from the fourth interval. The angle values of the first interval, the second interval, the third interval, and the fourth interval increase in sequence, and the fourth interval is from 150 degrees to 170 degrees.

[0110] The device for obtaining the particle backscattering coefficient according to the embodiment of the present invention constructs a preset angle combination based on four different angles, obtains a fitting model for estimating the particle backscattering coefficient through polynomial fitting, and uses this fitting model to obtain the result of the particle backscattering coefficient, significantly improving the estimation accuracy of the particle backscattering coefficient.

[0111] To solve the above technical problems existing in the prior art, the embodiment of the present invention also provides a storage medium, on which a computer program is stored, and is characterized in that when the program is executed by a processor, all steps of the method for obtaining the particle backscattering coefficient in the embodiment are implemented.

[0112] The specific steps of the method for obtaining the particle backscattering coefficient and the beneficial effects obtained by applying the readable storage medium provided by the embodiment of the present invention are the same as those in the above embodiments, and will not be elaborated herein.

[0113] Those of ordinary skill in the art can understand that all or part of the steps in the method of the above embodiments can be completed by instructing a processor through a program, and the program can be stored in a computer-readable storage medium. The storage medium is a non-transitory medium, such as a random access memory, a read-only memory, a flash memory, a hard disk, a solid-state drive, a magnetic tape, a floppy disk, an optical disc, and any combination thereof. The above storage medium can be any available medium that can be accessed by a computer or a data storage device such as a server or a data center integrating one or more available media. The available medium can be a magnetic medium (for example, a floppy disk, a hard disk, a magnetic tape), an optical medium (for example, a digital video disc (DVD)), or a semiconductor medium (for example, a solid-state disk (SSD)).

[0114] To solve the above technical problems existing in the prior art, the embodiment of the present invention also provides a terminal. Figure 9 The structural schematic diagram of the terminal according to the embodiment of the present invention is shown. Refer to Figure 9 As shown, the terminal according to the embodiment of the present invention includes a processor and a memory, and the memory is communicatively connected to the processor; the memory is used to store a computer program, and the processor is used to execute the computer program stored in the memory so that the terminal executes all steps of the method for obtaining the particle backscattering coefficient in the above embodiment.

[0115] The specific steps of the method for obtaining the particle backscattering coefficient and the beneficial effects obtained by applying the terminal provided by the embodiment of the present invention are the same as those in the above embodiments, and will not be elaborated herein.

[0116] It should be noted that the memory may include a Random Access Memory (RAM), and may also include non-volatile memory, such as at least one disk memory. Similarly, the processor may also be a general-purpose processor, including a Central Processing Unit (CPU), a Network Processor (NP), etc.; it may also be a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components.

[0117] Although the embodiments disclosed in the present invention are as described above, the above content is only an embodiment for facilitating the understanding of the present invention, and is not intended to limit the present invention. Any person skilled in the art within the technical field to which the present invention pertains may make any modifications and changes in the form of implementation and details without departing from the spirit and scope disclosed by the present invention. However, the protection scope of the present invention shall still be subject to the scope defined by the appended claims.

Claims

1. A method for obtaining a particle backscattering coefficient, comprising: Acquire wide-angle VSF data of the target sea area, and use an interpolation algorithm to acquire backward full-angle volume scattering function data corresponding to the wide-angle VSF data; Acquiring a corresponding backscattering distribution curve based on the backscattering full-angle volume scattering function data; Extracting a plurality of corresponding angle values ​​from the first interval, the second interval, the third interval, and the fourth interval at preset intervals, respectively, and arranging and combining all the angle values ​​to obtain a plurality of different preset angle combinations; Performing polynomial fitting based on each of the preset angle combinations to obtain an estimated backscatter coefficient fitting model corresponding to the backscatter distribution curve; Inputting the backscattering function data into the estimated backscattering coefficient fitting model for calculation to obtain the particle backscattering coefficient result; Among them, the preset angle combination includes a first angle, a second angle, a third angle and a fourth angle, the first angle is any angle value extracted from the first interval, the second angle belongs to any angle value extracted from the second interval, the third angle belongs to any angle value extracted from the third interval, and the fourth angle belongs to any angle value extracted from the fourth interval. The angle values ​​of the first interval, the second interval, the third interval, and the fourth interval increase successively, and the fourth interval is 150 degrees to 170 degrees.

2. The particle backscattering coefficient acquisition method according to claim 1, characterized in that: Performing polynomial fitting based on each of the preset angle combinations to obtain an estimated backscatter coefficient fitting model corresponding to the backscatter distribution curve includes: Obtain a polynomial coefficient matrix corresponding to each preset angle combination to obtain multiple polynomial coefficient matrices; A polynomial coefficient matrix with the smallest error with the backscatter distribution curve is obtained as a target polynomial coefficient matrix, and the target polynomial coefficient matrix and a corresponding preset angle combination are combined as a fitting model for estimating backscatter coefficients.

3. The particle backscattering coefficient acquisition method according to claim 2, characterized in that: Obtaining the polynomial coefficient matrix corresponding to the preset angle combination includes: Among them, a represents the polynomial coefficient matrix, θ n represents the nth angle, Represents the backscatter distribution curve value.

4. The method for obtaining particle backscattering coefficient according to claim 1, characterized in that: Also includes: Based on the integration of the backscattering function data in the rear hemisphere, the corresponding theoretical value of the particle backscattering coefficient is obtained; The absolute difference between the particle backscattering coefficient result and the particle backscattering coefficient theoretical value is obtained. If the absolute difference is greater than a preset threshold, the particle backscattering coefficient result is obtained again after reducing the preset interval; otherwise, the particle backscattering coefficient result is output as the final result.

5. The method for obtaining particle backscattering coefficient according to claim 1, characterized in that: The first interval is from 90 degrees to 110 degrees, the second interval is from 110 degrees to 130 degrees, and the third interval is from 130 degrees to 150 degrees.

6. The particle backscattering coefficient acquisition method according to claim 1, characterized in that: In the wide-angle VSF data, the method for obtaining the VSF data with an angle value greater than 150 degrees includes: Direct light is directed through the sample cell and the neutral density filter to the exit prism to obtain the corresponding reflected light; The reflected light is sequentially directed to the focusing window through the neutral density filter and the sample cell to obtain light to be measured with an angle greater than 150 degrees; Measuring the light to be measured by using a PMT to obtain VSF data with an angle value greater than 150 degrees; The neutral density filter and the output prism are bonded with Canada gum.

7. The method for obtaining particle backscattering coefficient according to claim 1, characterized in that: The preset angle combination also includes a fifth angle, and the fifth angle is any angle value extracted from 170 degrees to 180 degrees.

8. A device for obtaining particle backscattering coefficient, characterized in that: include: A data acquisition module is used to acquire wide-angle VSF data of the target sea area, and to acquire backward full-angle volume scattering function data corresponding to the wide-angle VSF data by using an interpolation algorithm; A curve generating module, used for acquiring a corresponding backscattering distribution curve based on the backscattering full-angle volume scattering function data; An angle combination module, used to extract a plurality of corresponding angle values ​​from the first interval, the second interval, the third interval and the fourth interval at preset intervals, and arrange and combine all the angle values ​​to obtain a plurality of different preset angle combinations; A model screening module, used for performing polynomial fitting based on each of the preset angle combinations to obtain an estimated backscatter coefficient fitting model corresponding to the backscatter distribution curve; A backscatter estimation module is used to input the backscattering coefficient fitting model into the backscattering coefficient estimation data to obtain the particle backscattering coefficient result; Among them, the preset angle combination includes a first angle, a second angle, a third angle and a fourth angle, the first angle is any angle value extracted from the first interval, the second angle belongs to any angle value extracted from the second interval, the third angle belongs to any angle value extracted from the third interval, and the fourth angle belongs to any angle value extracted from the fourth interval. The angle values ​​of the first interval, the second interval, the third interval, and the fourth interval increase successively, and the fourth interval is 150 degrees to 170 degrees.

9. A storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the particle backscattering coefficient acquisition method according to any one of claims 1 to 7 is implemented.

10. A terminal, characterized in that: It comprises a processor and a memory, wherein the memory is communicatively connected to the processor; the memory is used to store a computer program, and the processor is used to execute the computer program stored in the memory, so that the terminal executes the particle backscattering coefficient acquisition method according to any one of claims 1 to 7.

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