Debris flow channel source volume acquisition method

Abstract

The invention provides a debris flow channel source volume acquisition method, and relates to the technical field of debris flow prevention and control engineering design application, and the method comprises the steps: obtaining end points at two sides of a channel source on a section line and section line point sets at the outer sides of the end points based on debris flow channel source data; carrying out centralization and data decomposition on the end point outer side section line point set to obtain intersection points of point set fitting straight lines; fitting an intersection point of straight lines based on end points on two sides of a channel object source on a section line and a section line point set outside the end points, and obtaining an inner center coordinate through calculation; obtaining a plurality of B-spline curves based on the end points on the two sides of the channel object source and the inner center coordinates; performing curved surface fitting on the B spline curve through an interpolation method to obtain the original terrain of the debris flow channel; the debris flow channel source volume is obtained by performing difference calculation on the original terrain and the actual terrain of the debris flow channel and performing accumulation, and the debris flow channel source volume is obtained. The problem that the debris flow channel material source volume is difficult to accurately calculate is solved.

Description

Technical Field

[0001] This specification relates to the field of debris flow prevention and control engineering design and application technology, and in particular to a method for obtaining the source volume of debris flow channels. Background Art

[0002] Debris flow sources are primarily categorized as landslide sources, slope sources, and channel sources. Traditionally, identification of channel source volume often relies on manual estimation. Zhou Bifan et al. used the cross-section and longitudinal cone methods to estimate channel source volume. Hungr et al. calculated channel source volume by estimating the effective volume of scour material in the river channel. Qiao Jianping et al., based on their research on debris flow source initiation patterns, used geometric analysis to develop a debris flow reserve calculation model. However, these methods primarily rely on manual field surveys to assess debris flow source volume, resulting in high computational complexity and limited accuracy. Furthermore, in areas with complex geological conditions, such as dense vegetation and high mountains and steep slopes, manual identification and calculation of debris flow channel sources is even more difficult to perform to meet the needs of control projects.

[0003] Calculating the volume of debris flow sources is crucial for disaster risk assessment and the formulation of emergency response measures. Traditional volume measurement methods usually rely on ground surveys or simple remote sensing analysis, which are often time-consuming and have limited accuracy and cannot meet the needs of rapid response. Summary of the Invention

[0004] In view of the above-mentioned deficiencies in the prior art, the present invention provides a method for obtaining the debris flow channel source volume, which solves the problem that the debris flow channel source volume is difficult to calculate accurately.

[0005] In order to achieve the above-mentioned object of the invention, the technical solution adopted by the present invention is: a method for obtaining the source volume of debris flow channel, comprising: S1: Based on the debris flow channel source data, multiple profile lines are analyzed to obtain the end points on both sides of the channel source on the profile line and the profile line point set outside the end points; S2: performing centralization and data decomposition on the cross-section point set outside the endpoint to obtain the intersection of the fitting straight line of the point set; S3: Based on the intersection of the endpoints on both sides of the channel material source on the profile line and the fitting straight line of the profile point set outside the endpoint, the inward coordinates are obtained by calculation; based on the endpoints on both sides of the channel material source and the inward coordinates, multiple B-spline curves are obtained; S4: performing surface fitting on the B-spline curve by an interpolation method to obtain the original topography of the debris flow channel; S5: The debris flow channel source volume is obtained by performing differential calculation on the original topography and the actual topography of the debris flow channel and accumulating the difference, thereby completing the acquisition of the debris flow channel source volume.

[0006] Furthermore, the S2 includes: Centralizing the cross-section point set outside the endpoint to obtain a centralized point set and a centroid of the point set; Performing singular value decomposition on the central point set, decomposing the matrix into three matrices, and obtaining the principal component directions; Based on the centroid of the point set and the direction of the principal component, a fitting line is constructed to obtain an intersection point of the fitting line of the point set.

[0007] Furthermore, the expression of the principal component direction is: ; in, represents the centralized point set matrix, represents the left singular vector matrix of the point set, represents a diagonal matrix, Represents the right singular vector matrix of the point set; where, The first line The direction of the principal component.

[0008] Furthermore, the expression of the B-spline curve is: ; in, represents the parametric equation of the B-spline curve, represents the B-spline curve control parameters, Indicates that the B-spline curve is The coordinate value of the direction, Indicates that the B-spline curve is The coordinate value of the direction, Indicates that the B-spline curve is The coordinate value of the direction.

[0009] Furthermore, the weighting method of the B-spline curve is determined by a quadratic B-spline basis function, and the expression of the quadratic B-spline basis function is: ; ; in, represents a B-spline curve, Indicates that the B-spline curve is The coordinate value of the direction, Indicates that the B-spline curve is The coordinate value of the direction, Indicates that the B-spline curve is The coordinate value of the direction, represents the quadratic B-spline basis function of the first control point, Indicates that the first control point is The coordinate value of the direction, represents the quadratic B-spline basis function of the second control point, Indicates that the second control point is The coordinate value of the direction, represents the quadratic B-spline basis function of the third control point, Indicates that the third control point is The coordinate value of the direction, Indicates that the first control point is The coordinate value of the direction, Indicates that the second control point is The coordinate value of the direction, Indicates that the third control point is The coordinate value of the direction, Indicates that the first control point is The coordinate value of the direction, Indicates that the second control point is The coordinate value of the direction, Indicates that the third control point is The coordinate value of the direction, represents the node vector of the first control point in parameter space, represents the node vector of the second control point in parameter space, The knot vector representing the third control point in parameter space.

[0010] Furthermore, the original terrain of the debris flow channel includes the elevation value of each target point, wherein the elevation value of the target point is expressed as: ; ; in, Indicates the elevation value of the target point. 、 and Both represent the elevation parameters of the target point. Indicates that the B-spline curve is The coordinate value of the direction, Indicates that the B-spline curve is The coordinate value of the direction, Indicates that the first control point is The coordinate value of the direction, Indicates that the second control point is The coordinate value of the direction, Indicates that the third control point is The coordinate value of the direction, Indicates that the first control point is The coordinate value of the direction, Indicates that the second control point is The coordinate value of the direction, Indicates that the third control point is The coordinate value of the direction, Indicates that the first control point is The coordinate value of the direction, Indicates that the second control point is The coordinate value of the direction, Indicates that the third control point is The coordinate value of the direction.

[0011] The beneficial effects of the present invention are as follows: a method for obtaining debris flow channel material source volume is provided. By centralizing and decomposing the data of the point set outside the endpoints on multiple debris flow channel material source profiles, the intersection of the fitted lines is obtained. The incenter is calculated using the intersection of the fitted lines and the endpoints on both sides of the profile line. A B-spline curve is then calculated using the endpoints on the profile line and the incenter to obtain the debris flow channel material source volume. This method can greatly improve the efficiency and accuracy of debris flow volume assessment and is applicable to debris flow channels of different scales and shapes. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] This specification will be further described in the form of exemplary embodiments, which will be described in detail with reference to the accompanying drawings. These embodiments are not limiting, and in these embodiments, like numbers represent like structures, wherein: Figure 1 This is an exemplary flow chart of a method for obtaining debris flow channel source volume according to some embodiments of this specification. DETAILED DESCRIPTION

[0013] The specific embodiments of the present invention are described below to facilitate understanding of the present invention by those skilled in the art. However, it should be clear that the present invention is not limited to the scope of the specific embodiments. For those skilled in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the appended claims, these changes are obvious, and all inventions and creations utilizing the concepts of the present invention are protected.

[0014] Example Figure 1 This is an exemplary flow chart of a method for obtaining debris flow channel source volume according to some embodiments of this specification. Figure 1 As shown, the process includes the following steps. In some embodiments, the process can be executed by a processor.

[0015] S1: Based on the debris flow channel material source data, by analyzing multiple profile lines, we can obtain the end points on both sides of the channel material source on the profile line and the profile line point sets outside the end points.

[0016] Debris flow channel provenance data is data reflecting the boundaries of debris flow channels and debris flow topographic profiles.

[0017] In some embodiments, the processor may use a laser radar to identify debris flow channel material sources, and obtain debris flow channel boundaries and debris flow terrain profile lines as debris flow channel material source data.

[0018] The two end points of the channel provenance are the two end points of the debris flow channel boundary on the profile line.

[0019] The endpoint outer profile line point set is a set of points on the endpoint outer profile lines on both sides of the debris flow channel boundary on the profile line.

[0020] In some embodiments, the processor can obtain the coordinates of the profile line points within the channel boundary, and use the convex hull algorithm to find the two outermost points of the inner profile line segment as the two end points of the debris flow channel boundary on the profile line, thereby obtaining the end points X1 and X2 on both sides of the channel source and the point set on the profile line on the left side of X1 and the right side of X2.

[0021] S2: performing centralization and data decomposition on the profile point set outside the endpoint to obtain the intersection points of the point set fitting straight lines.

[0022] The intersection of the fitted straight lines is the theoretical intersection point of the terrain on both sides after being extended downward.

[0023] In some embodiments, the processor can center the profile line point set outside the endpoint to obtain the centralized point set and the centroid of the point set; perform singular value decomposition on the centralized point set to decompose the matrix into three matrices to obtain the principal component directions; construct a fitting straight line based on the centroid of the point set and the principal component directions to obtain the intersection X0 of the fitting straight line of the point set.

[0024] The centralized point set is the result of the centralized processing of the hatch point set outside the endpoint.

[0025] The centroid of a point set is the centroid location of the centered point set.

[0026] The direction of the principal component reflects the changing trend of the centralized point set.

[0027] In some embodiments, the processor can use the principal component analysis method to centralize the point set data outside the channel source endpoint, obtain the centralized point set and calculate the center of mass of the point set, and make the center of mass the origin by translating all points; perform singular value decomposition on the centralized point set to obtain the principal component direction.

[0028] In some embodiments, the expression of the principal component direction may be: ; in, represents the centralized point set matrix, represents the left singular vector matrix of the point set, represents a diagonal matrix, Represents the right singular vector matrix of the point set; where, The first line The direction of the principal component.

[0029] S3: Based on the intersection of the endpoints on both sides of the channel material source on the profile line and the fitting straight line of the profile line point set outside the endpoints, the inward center coordinates are obtained by calculation; based on the endpoints on both sides of the channel material source and the inward center coordinates, multiple B-spline curves are obtained.

[0030] The B-spline curve is a smooth curve that reflects the bottom scour surface, that is, the original topography of the debris flow channel on a single profile line.

[0031] In some embodiments, the processor may calculate the three vertices of △X0X1X2, and then make the angle bisectors of the three angles intersect at one point to obtain the incenter X3 of the triangle; and use the three points X1, X2, and X3 for fitting to obtain a B-spline curve.

[0032] In some embodiments, the expression of the B-spline curve may be: ; in, represents the parametric equation of the B-spline curve, represents the B-spline curve control parameters, Indicates that the B-spline curve is The coordinate value of the direction, Indicates that the B-spline curve is The coordinate value of the direction, Indicates that the B-spline curve is The coordinate value of the direction.

[0033] In some embodiments, the weighting method of the B-spline curve is determined by a quadratic B-spline basis function, and the expression of the quadratic B-spline basis function can be: ; ; in, represents a B-spline curve, Indicates that the B-spline curve is The coordinate value of the direction, Indicates that the B-spline curve is The coordinate value of the direction, Indicates that the B-spline curve is The coordinate value of the direction, represents the quadratic B-spline basis function of the first control point, Indicates that the first control point is The coordinate value of the direction, represents the quadratic B-spline basis function of the second control point, Indicates that the second control point is The coordinate value of the direction, represents the quadratic B-spline basis function of the third control point, Indicates that the third control point is The coordinate value of the direction, Indicates that the first control point is The coordinate value of the direction, Indicates that the second control point is The coordinate value of the direction, Indicates that the third control point is The coordinate value of the direction, Indicates that the first control point is The coordinate value of the direction, Indicates that the second control point is The coordinate value of the direction, Indicates that the third control point is The coordinate value of the direction, represents the node vector of the first control point in parameter space, represents the node vector of the second control point in parameter space, The knot vector representing the third control point in parameter space.

[0034] S4: performing surface fitting on the B-spline curve by an interpolation method to obtain the original topography of the debris flow channel.

[0035] The original terrain of the debris flow channel is obtained by interpolating and fitting the debris flow boundary range. For example, the original terrain of the debris flow channel may include the elevation values ​​of each target point.

[0036] In some embodiments, the expression for the elevation value of the target point may be: ; ; in, Indicates the elevation value of the target point. 、 and Both represent the elevation parameters of the target point. Indicates that the B-spline curve is The coordinate value of the direction, Indicates that the B-spline curve is The coordinate value of the direction, Indicates that the first control point is The coordinate value of the direction, Indicates that the second control point is The coordinate value of the direction, Indicates that the third control point is The coordinate value of the direction, Indicates that the first control point is The coordinate value of the direction, Indicates that the second control point is The coordinate value of the direction, Indicates that the third control point is The coordinate value of the direction, Indicates that the first control point is The coordinate value of the direction, Indicates that the second control point is The coordinate value of the direction, Indicates that the third control point is The coordinate value of the direction.

[0037] S5: The debris flow channel source volume is obtained by performing differential calculation on the original topography and the actual topography of the debris flow channel and accumulating the difference, thereby completing the acquisition of the debris flow channel source volume.

[0038] The debris flow channel source volume is a parameter that reflects the size of the debris flow channel source volume. For example, the debris flow channel source volume calculation results can be shown in Table 1.

[0039] Table 1 Calculation results of debris flow channel source volume

[0040] In some embodiments, the processor can resample the original terrain surface of the debris flow channel so that it has the same pixel size as the actual terrain; perform differential calculation on the original terrain surface of the debris flow channel and the actual terrain, and calculate the elevation difference between the original terrain surface and the actual terrain surface for each pixel point; and use the elevation difference of the pixel and the pixel area to calculate the volume difference between individual pixels; finally, accumulate the volume differences of all pixel points to obtain the total volume difference, and obtain the source volume of the debris flow channel.

[0041] In some embodiments, the expression for debris flow channel source volume may be: ; in, represents the debris flow channel source volume, Ω represents the three-dimensional spatial domain of the debris flow source area, Represents a volume element.

[0042] In some embodiments, the expression for the debris flow channel source volume obtained by discrete calculation can be: ; in, Represents the elevation value of the real terrain at the pixel location (i, j), Represents the elevation value of the original terrain at the pixel location (i, j), It represents the surface area corresponding to pixel (i, j), m and n represent the number of DEM grid rows and columns respectively.

[0043] In some embodiments of this specification, a method for determining the source volume of debris flow channels is proposed. This method centers and decomposes the data of the outer point sets of endpoints on multiple debris flow channel source profiles to obtain the intersection points of fitted lines. The intersection points of the fitted lines are then used to calculate the incenter using the endpoints on both sides of the profile line. A B-spline curve is then calculated using the endpoints on the profile line and the incenter to obtain the source volume. This B-spline curve is then used for fitting and differential calculation to determine the source volume. This method significantly improves the efficiency and accuracy of debris flow volume assessment and is applicable to debris flow channels of varying scales and shapes.

Claims

1. A method for obtaining debris flow channel source volume, characterized in that: include: S1: Based on the debris flow channel source data, multiple profile lines are analyzed to obtain the end points on both sides of the channel source on the profile line and the profile line point set outside the end points; S2: performing centralization and data decomposition on the cross-section point set outside the endpoint to obtain the intersection of the fitting straight line of the point set; S3: Based on the intersection of the endpoints on both sides of the channel material source on the profile line and the fitting straight line of the profile point set outside the endpoint, the inward coordinates are obtained by calculation; based on the endpoints on both sides of the channel material source and the inward coordinates, multiple B-spline curves are obtained; S4: performing surface fitting on the B-spline curve by an interpolation method to obtain the original topography of the debris flow channel; S5: The debris flow channel source volume is obtained by performing differential calculation on the original topography and the actual topography of the debris flow channel and accumulating the difference, thereby completing the acquisition of the debris flow channel source volume.

2. The method for obtaining debris flow channel source volume according to claim 1, characterized in that: The S2 includes: Centralizing the cross-section point set outside the endpoint to obtain a centralized point set and a centroid of the point set; Performing singular value decomposition on the central point set, decomposing the matrix into three matrices, and obtaining the principal component directions; Based on the centroid of the point set and the direction of the principal component, a fitting line is constructed to obtain an intersection point of the fitting line of the point set.

3. The method for obtaining debris flow channel source volume according to claim 2, characterized in that: The expression of the principal component direction is: ； in, represents the centralized point set matrix, represents the left singular vector matrix of the point set, represents a diagonal matrix, Represents the right singular vector matrix of the point set; where, The first line The direction of the principal component.

4. The method for obtaining debris flow channel source volume according to claim 1, characterized in that: The expression of the B-spline curve is: ； in, represents the parametric equation of the B-spline curve, represents the B-spline curve control parameters, Indicates that the B-spline curve is The coordinate value of the direction, Indicates that the B-spline curve is The coordinate value of the direction, Indicates that the B-spline curve is The coordinate value of the direction.

5. The method for obtaining debris flow channel source volume according to claim 4, characterized in that: The weighting method of the B-spline curve is determined by the quadratic B-spline basis function, and the expression of the quadratic B-spline basis function is: ； ； in, represents a B-spline curve, Indicates that the B-spline curve is The coordinate value of the direction, Indicates that the B-spline curve is The coordinate value of the direction, Indicates that the B-spline curve is The coordinate value of the direction, represents the quadratic B-spline basis function of the first control point, Indicates that the first control point is The coordinate value of the direction, represents the quadratic B-spline basis function of the second control point, Indicates that the second control point is The coordinate value of the direction, represents the quadratic B-spline basis function of the third control point, Indicates that the third control point is The coordinate value of the direction, Indicates that the first control point is The coordinate value of the direction, Indicates that the second control point is The coordinate value of the direction, Indicates that the third control point is The coordinate value of the direction, Indicates that the first control point is The coordinate value of the direction, Indicates that the second control point is The coordinate value of the direction, Indicates that the third control point is The coordinate value of the direction, represents the node vector of the first control point in parameter space, represents the node vector of the second control point in parameter space, The knot vector representing the third control point in parameter space.

6. The method for obtaining debris flow channel source volume according to claim 1, characterized in that: The original terrain of the debris flow channel includes the elevation value of each target point, wherein the elevation value of the target point is expressed as: ； ； in, Indicates the elevation value of the target point. 、 and Both represent the elevation parameters of the target point. Indicates that the B-spline curve is The coordinate value of the direction, Indicates that the B-spline curve is The coordinate value of the direction, Indicates that the first control point is The coordinate value of the direction, Indicates that the second control point is The coordinate value of the direction, Indicates that the third control point is The coordinate value of the direction, Indicates that the first control point is The coordinate value of the direction, Indicates that the second control point is The coordinate value of the direction, Indicates that the third control point is The coordinate value of the direction, Indicates that the first control point is The coordinate value of the direction, Indicates that the second control point is The coordinate value of the direction, Indicates that the third control point is The coordinate value of the direction.

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