CN118132031B - Earthquake event space influence strengthening method for simulating light propagation process - Google Patents
Earthquake event space influence strengthening method for simulating light propagation process Download PDFInfo
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Abstract
The invention discloses a seismic event space influence strengthening method for simulating a light propagation process, which belongs to the fields of electric digital data processing technology and geophysics, and comprises the steps of preparing original data, establishing a space coordinate system, taking absolute values of deformation areas to represent absolute deformation, setting a threshold value for threshold segmentation, obtaining the deformation areas meeting threshold value conditions, carrying out communication analysis on the deformation areas subjected to threshold value segmentation, searching for deformation areas with closed and continuous contours, obtaining the contours and generating a mask grid; each geographic object in the grid is divided, and calculation is performed by taking an object block as a unit. According to the invention, the continuous process of spreading the influence of the seismic event in the three-dimensional space is embedded into the model, so that the space distribution of the influence of the seismic event can be effectively quantitatively calculated and evaluated.
Description
Technical Field
The invention discloses a method for strengthening the space influence of seismic events in a simulated light propagation process, and belongs to the fields of electric digital data processing technology and geophysics.
Background
Seismic events cause significant damage to the life and property security of people and impact on the many geographic objects associated with the surface space. The quantization method of the prior art method for the spatial influence distribution mainly uses a Gaussian kernel function or a Bi-Square function, simulates a first law of geography through the attenuation property of the function in a two-dimensional space (the spatial correlation of objects close to the space is larger than that of objects far from the space), and is widely applied to geographic weighted regression; however, this quantification method ignores the continuous process of propagation in the surface space between geographic phenomena and terrain-induced anisotropy. The invention regards the terrain as density, simulates the propagation process of light rays in a non-uniform medium, and can better simulate the spatial influence distribution of seismic events.
Disclosure of Invention
The invention aims to provide a method for realizing the effect of earthquake event space influence in the process of simulating light propagation, which aims to solve the problem that the terrain effect caused by surface fluctuation in the process of propagation cannot be quantitatively simulated in the prior art.
A method for strengthening the space influence of a seismic event in a simulated light propagation process comprises the following steps:
S1, preparing original data, including DEM data and InSAR single-view complex image pairs of a topographic event;
S2, establishing a space coordinate system, performing projection transformation on a first image of original data, performing projection transformation on all image data after the first image by using the first image as a reference through a grid space data conversion library, keeping consistent with a projection method of the first image, and performing calculation processing on the first image as a reference The coordinate offset of the first coordinate of the image data relative to the first coordinate of the first image is used for obtaining the image coordinate of any longitude and latitude position in a space coordinate system;
S3, taking an absolute value of the deformation area to represent absolute deformation quantity, setting a threshold value for threshold segmentation, obtaining the deformation area meeting the threshold value condition, carrying out communication analysis on the deformation area subjected to threshold segmentation, searching for a deformation area with each contour closed and continuous, obtaining the contour and generating a mask grid;
taking deformation quantity in the deformation areas as density, and calculating the mass center position of each deformation area as a specific seismic event occurrence point of deformation;
s4, dividing each geographic object in the grid, and calculating by taking an object block as a unit;
s4.1, dividing the area, namely dividing the area by taking a mountain slope as a basic unit, and dividing geographic units with small space scale;
S4.2, calculating space influence coefficient, including valley inversion, diffuse reflection component and transmission and scattering component calculation.
S1, processing the single-view complex image pair by using a radar image processing plug-in unit of remote sensing processing software, obtaining the surface deformation quantity through D-InSAR processing, and deriving the surface deformation quantity into raster data.
S2, sequentially combining the images, starting from the first image, combining the 2 nd image data with the first image to form the 1 st combined image, sequentially processing, and combining the 1 st imageImage data and the first-1 Combining the combined images to form a firstZhang Gebing images;
s2 comprises computing the first image as a reference The coordinate offset of the first coordinate of the image data relative to the first coordinate of the first image includes:
；；
In the method, in the process of the invention, 、Respectively are、Coordinate offset of coordinates [ ]，) Is the firstFirst coordinates of the images，) Is the first coordinate of the first image,Is the upper left corner of the first image in the geographic transformation parameters of the grid space data conversion libraryThe coordinates pixels are geographic coordinates,Is the geographic transformation parameter of the grid space data conversion baseUpper left corner of the imageThe coordinates pixels are geographic coordinates,Is the upper left corner of the first image in the geographic transformation parameters of the grid space data conversion libraryThe coordinates pixels are geographic coordinates,Is the geographic transformation parameter of the grid space data conversion baseUpper left corner of the imageThe coordinates the geographic coordinates,The resolution of the pixels in the horizontal direction of the first image,The resolution of the pixels in the vertical direction of the first image.
S2 comprises, the firstThe left top coordinate and the right bottom coordinate of the combined image are respectively as follows:
；；
；
；
In the method, in the process of the invention, 、Respectively the firstCombining imagesUpper left head coordinatesThe top left-hand first coordinate is set,、Respectively the firstCombining imagesLower right tail coordinatesThe lower right tail coordinate is used for the position of the left,、Respectively the first-1 Combined imageUpper left head coordinatesThe top left-hand first coordinate is set,、Respectively the first-1 Combined imageLower right tail coordinatesThe lower right tail coordinate is used for the position of the left,、Respectively the firstThe number of wide and high pixels of the combined image;
First, the The top left coordinate of the combined image is the firstAnd the coordinate offset of the first coordinate of the image data relative to the first coordinate of the first image.
S2, traversing the image data, creating a new array covering all data as a working space, wherein the length and width of the new array are as follows:
；；
In the method, in the process of the invention, For the length of the new array to be a new one,To be the width of the new array of data,、Respectively areThe minimum and maximum values of the coordinates,、Respectively areMinimum and maximum of coordinates.
S4.1, calculating a slope direction, reclassifying the forward east direction, the forward west direction, the forward south direction and the forward north direction of the slope direction respectively to obtain a slope dividing map, performing binary division by taking a slope of 5 degrees as a threshold value, taking a slope of less than 5 degrees as 0, taking a value of more than 5 degrees as 1, performing median filtering of 5*5 degrees to remove broken spots, and performing multiplication with the slope dividing map to divide a water body and a plain;
and performing super-pixel segmentation to reduce finely divided patches, dividing the DEM into blocks taking slopes and planes as units, traversing the blocks, and calculating Euclidean distance from the mass center to the event point.
S4.2, processing the DEM, subtracting the elevation of the event point from the DEM, taking an absolute value, and reversing all the depressions below the elevation plane relative to the event point into the projections.
S4.2, regarding diffuse reflection components, regarding the surface of the block as an ideal diffuse reflector, and approximately adopting a lambertian model, wherein the intensity of diffuse reflection is related to an incident angle;
calculating azimuth angle of slope block centroid relative to event Calculating the difference value of the slope direction angle and the event direction angle by taking the right orthogonal angle of the slope normal azimuth as the slope direction angle, and carrying out angle attribution to an acute angle twice through 0 DEG to-180 DEG and 0 DEG to-90 DEG to obtain an acute angle included angle between the event-block direction and the slope, and distinguishing the slope back according to the sign of the difference value of the slope direction angle and the event direction angle;
event-slope angle calculation using sine of complementary angle ：
；
In the method, in the process of the invention,The mean value of all pixels in the block is used as the slope normal azimuth angle of the block,The sign is taken in the representation,Representing taking the smaller of the two values;
The diffuse reflection initial illumination is regarded as an independent point light source different from a scattering transmission light source, is not influenced by shielding, scattering and transmission, is only attenuated along with the distance in the space, and has diffuse reflection components The method comprises the following steps:
；
In the method, in the process of the invention, For the initial light intensity to be the same,As a function of the curve variables,Is the attenuation coefficient [ (])、(,) The centroid position and the event point position of the current block respectively,、For spatial resolution of DEMs in both horizontal and vertical directions,Is the maximum value of the Euclidean distance of all block-events, all negative values are the blocks facing away from the event, and all negative values are set to zero.
S4.2, regarding the DEM as a non-uniform medium distributed in a two-dimensional plane, normalizing, scaling the density value of the medium into a section of (0, 1), assuming that an optical path linearly propagates in the medium, calculating the intensity by using a propagation model of light in the medium without considering the deflection of the optical path caused by the non-uniformity of the medium, wherein the propagation model is as follows:
；
In the method, in the process of the invention, In order for the attenuation coefficient to be a factor,For the sum of the scattering and transmission components,Is the first on the light pathThe normalized elevation of the individual picture elements,Distance between adjacent pixels when the light is stepped;
Gradually calculating intensity attenuation caused by scattering in a light path by adopting a path stepping method, firstly, acquiring a single-pixel linear path between an event point starting point and a block centroid end point by using a bresenham algorithm, then carrying out stepping traversal on points in the path, and taking the average density of a current point and a next point as the density of a current light intensity passing area, wherein the incident light intensity of each step is the emergent light intensity of the last step;
Considering transmission attenuation when light passes through an interface in the stepping process, recording event slope angle symbols of the step and the next step when the light is stepped, and calculating an angle component only for an attenuation part when the light passes through when the symbol difference between the next step and the step is larger than 0 and the light passes through a slope interface facing the event direction for multiplying the emergent light intensity of the light in the step by a transmission attenuation component, wherein the transmitted light intensity is related to an incident angle; the sign difference is 0 and the step decay is 0.
S4.2, under the grid discrete form, the calculation formula of the sum of the scattering and transmission components after the step is completed is as follows:
；
In the method, in the process of the invention, Is the firstThe image coordinates of the individual picture elements,To be the transmission attenuation coefficient when penetrating the interface,For the number of picture elements in the path of the light,Representing a squaring operator;
the two components are weighted and summed and inverted to obtain the dynamic threshold coefficient of each block at the position after attenuation, the value ranges of the diffuse reflection and the transmission scattering components are between (0, 1), and the spatial influence coefficient is obtained The value of (1) is also between (0, 1):
；
In the method, in the process of the invention, AndIs the weight ratio of diffuse reflection to transmission scattering.
Compared with the prior art, the invention has the following beneficial effects: the continuous process of spreading the influence of the seismic event in the three-dimensional space is embedded into the model, so that the space distribution of the influence of the seismic event can be effectively quantitatively calculated and evaluated; the data are divided into relatively independent geographic objects by using a blocking method, and the space influence is calculated by taking the objects as units, so that the calculation efficiency is greatly improved compared with pixel-by-pixel calculation; the slope is used as a basic unit for dividing the geographic object, and the watershed effect of the event in the ground surface space propagation process can be simulated through a diffuse reflection gain method.
Drawings
FIG. 1 is a technical flow chart of the present invention;
FIG. 2 is a cross-sectional view of an event space impact profile;
FIG. 3 is a plot of goodness of fit of the invention to a geographically weighted regression weight function;
FIG. 4 is a chart of red-pool information criteria values applied to a geographically weighted regression weight function in accordance with the present invention.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the present invention more apparent, the technical solutions in the present invention will be clearly and completely described below, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
A method for strengthening the space influence of a seismic event in a simulated light propagation process comprises the following steps:
S1, preparing original data, including DEM data and InSAR single-view complex image pairs of a topographic event;
S2, establishing a space coordinate system, performing projection transformation on a first image of original data, performing projection transformation on all image data after the first image by using the first image as a reference through a grid space data conversion library, keeping consistent with a projection method of the first image, and performing calculation processing on the first image as a reference The coordinate offset of the first coordinate of the image data relative to the first coordinate of the first image is used for obtaining the image coordinate of any longitude and latitude position in a space coordinate system;
S3, taking an absolute value of the deformation area to represent absolute deformation quantity, setting a threshold value for threshold segmentation, obtaining the deformation area meeting the threshold value condition, carrying out communication analysis on the deformation area subjected to threshold segmentation, searching for a deformation area with each contour closed and continuous, obtaining the contour and generating a mask grid;
taking deformation quantity in the deformation areas as density, and calculating the mass center position of each deformation area as a specific seismic event occurrence point of deformation;
s4, dividing each geographic object in the grid, and calculating by taking an object block as a unit;
s4.1, dividing the area, namely dividing the area by taking a mountain slope as a basic unit, and dividing geographic units with small space scale;
S4.2, calculating space influence coefficient, including valley inversion, diffuse reflection component and transmission and scattering component calculation.
S1, processing the single-view complex image pair by using a radar image processing plug-in unit of remote sensing processing software, obtaining the surface deformation quantity through D-InSAR processing, and deriving the surface deformation quantity into raster data.
S2, sequentially combining the images, starting from the first image, combining the 2 nd image data with the first image to form the 1 st combined image, sequentially processing, and combining the 1 st imageImage data and the first-1 Combining the combined images to form a firstZhang Gebing images;
s2 comprises computing the first image as a reference The coordinate offset of the first coordinate of the image data relative to the first coordinate of the first image includes:
；；
In the method, in the process of the invention, 、Respectively are、Coordinate offset of coordinates [ ]，) Is the firstFirst coordinates of the images，) Is the first coordinate of the first image,Is the upper left corner of the first image in the geographic transformation parameters of the grid space data conversion libraryThe coordinates pixels are geographic coordinates,Is the geographic transformation parameter of the grid space data conversion baseUpper left corner of the imageThe coordinates pixels are geographic coordinates,Is the upper left corner of the first image in the geographic transformation parameters of the grid space data conversion libraryThe coordinates pixels are geographic coordinates,Is the geographic transformation parameter of the grid space data conversion baseUpper left corner of the imageThe coordinates the geographic coordinates,The resolution of the pixels in the horizontal direction of the first image,The resolution of the pixels in the vertical direction of the first image.
S2 comprises, the firstThe left top coordinate and the right bottom coordinate of the combined image are respectively as follows:
；；
；
；
In the method, in the process of the invention, 、Respectively the firstCombining imagesUpper left head coordinatesThe top left-hand first coordinate is set,、Respectively the firstCombining imagesLower right tail coordinatesThe lower right tail coordinate is used for the position of the left,、Respectively the first-1 Combined imageUpper left head coordinatesThe top left-hand first coordinate is set,、Respectively the first-1 Combined imageLower right tail coordinatesThe lower right tail coordinate is used for the position of the left,、Respectively the firstThe number of wide and high pixels of the combined image;
First, the The top left coordinate of the combined image is the firstAnd the coordinate offset of the first coordinate of the image data relative to the first coordinate of the first image.
S2, traversing the image data, creating a new array covering all data as a working space, wherein the length and width of the new array are as follows:
；；
In the method, in the process of the invention, For the length of the new array to be a new one,To be the width of the new array of data,、Respectively areThe minimum and maximum values of the coordinates,、Respectively areMinimum and maximum of coordinates.
S4.1, calculating a slope direction, reclassifying the forward east direction, the forward west direction, the forward south direction and the forward north direction of the slope direction respectively to obtain a slope dividing map, performing binary division by taking a slope of 5 degrees as a threshold value, taking a slope of less than 5 degrees as 0, taking a value of more than 5 degrees as 1, performing median filtering of 5*5 degrees to remove broken spots, and performing multiplication with the slope dividing map to divide a water body and a plain;
and performing super-pixel segmentation to reduce finely divided patches, dividing the DEM into blocks taking slopes and planes as units, traversing the blocks, and calculating Euclidean distance from the mass center to the event point.
S4.2, processing the DEM, subtracting the elevation of the event point from the DEM, taking an absolute value, and reversing all the depressions below the elevation plane relative to the event point into the projections.
S4.2, regarding diffuse reflection components, regarding the surface of the block as an ideal diffuse reflector, and approximately adopting a lambertian model, wherein the intensity of diffuse reflection is related to an incident angle;
calculating azimuth angle of slope block centroid relative to event Calculating the difference value of the slope direction angle and the event direction angle by taking the right orthogonal angle of the slope normal azimuth as the slope direction angle, and carrying out angle attribution to an acute angle twice through 0 DEG to-180 DEG and 0 DEG to-90 DEG to obtain an acute angle included angle between the event-block direction and the slope, and distinguishing the slope back according to the sign of the difference value of the slope direction angle and the event direction angle;
event-slope angle calculation using sine of complementary angle ：
；
In the method, in the process of the invention,The mean value of all pixels in the block is used as the slope normal azimuth angle of the block,The sign is taken in the representation,Representing taking the smaller of the two values;
The diffuse reflection initial illumination is regarded as an independent point light source different from a scattering transmission light source, is not influenced by shielding, scattering and transmission, is only attenuated along with the distance in the space, and has diffuse reflection components The method comprises the following steps:
；
In the method, in the process of the invention, For the initial light intensity to be the same,As a function of the curve variables,Is the attenuation coefficient [ (])、(,) The centroid position and the event point position of the current block respectively,、For spatial resolution of DEMs in both horizontal and vertical directions,Is the maximum value of the Euclidean distance of all block-events, all negative values are the blocks facing away from the event, and all negative values are set to zero.
S4.2, regarding the DEM as a non-uniform medium distributed in a two-dimensional plane, normalizing, scaling the density value of the medium into a section of (0, 1), assuming that an optical path linearly propagates in the medium, calculating the intensity by using a propagation model of light in the medium without considering the deflection of the optical path caused by the non-uniformity of the medium, wherein the propagation model is as follows:
；
In the method, in the process of the invention, In order for the attenuation coefficient to be a factor,For the sum of the scattering and transmission components,Is the first on the light pathThe normalized elevation of the individual picture elements,Distance between adjacent pixels when the light is stepped;
Gradually calculating intensity attenuation caused by scattering in a light path by adopting a path stepping method, firstly, acquiring a single-pixel linear path between an event point starting point and a block centroid end point by using a bresenham algorithm, then carrying out stepping traversal on points in the path, and taking the average density of a current point and a next point as the density of a current light intensity passing area, wherein the incident light intensity of each step is the emergent light intensity of the last step;
Considering transmission attenuation when light passes through an interface in the stepping process, recording event slope angle symbols of the step and the next step when the light is stepped, and calculating an angle component only for an attenuation part when the light passes through when the symbol difference between the next step and the step is larger than 0 and the light passes through a slope interface facing the event direction for multiplying the emergent light intensity of the light in the step by a transmission attenuation component, wherein the transmitted light intensity is related to an incident angle; the sign difference is 0 and the step decay is 0.
S4.2, under the grid discrete form, the calculation formula of the sum of the scattering and transmission components after the step is completed is as follows:
；
In the method, in the process of the invention, Is the firstThe image coordinates of the individual picture elements,To be the transmission attenuation coefficient when penetrating the interface,For the number of picture elements in the path of the light,Representing a squaring operator;
the two components are weighted and summed and inverted to obtain the dynamic threshold coefficient of each block at the position after attenuation, the value ranges of the diffuse reflection and the transmission scattering components are between (0, 1), and the spatial influence coefficient is obtained The value of (1) is also between (0, 1):
；
In the method, in the process of the invention, AndIs the weight ratio of diffuse reflection to transmission scattering.
The feature indexes comprise color features and texture features of data to be processed in the current block range, the color features are averaged by using each wave band of the data in the block to obtain a gray image, and then the gray average value in the block is calculatedFor texture features, calculating standard deviation of gray images of texture featuresSum information entropyThe initial threshold is determined according to the mode of multiplying the maximum value of each index in the image by the coefficient when setting the initial threshold, and a 95% confidence interval is adopted for the maximum value, and the dynamic threshold of the three indexes in each block、、The calculation formula of (2) is as follows:
；
In the method, in the process of the invention, 、、The confidence interval maximum values are 95% of the mean value, the standard deviation and the information entropy respectively;、、 the initial coefficients of the thresholds respectively determine the value of the merging threshold when the distance is 0, namely the minimum range of the merging threshold; 、、 the magnification coefficients of the thresholds are respectively determined, and the multiplying power of the merging threshold value relative to the initial value at the position with the largest distance, namely the maximum range of the merging threshold value;
when between two blocks 、、When the average threshold value smaller than two blocks is simultaneously established, the blocks are combined;
dividing raster data into a plurality of block objects according to the self property and the event distance, and after block merging, greatly reducing the number, and using geodesic distance to replace Euclidean distance to measure the space importance;
When the geodesic distance between two points is calculated, resampling the DEM in the working space to 256 x 256, then taking the DEM data as a cost matrix, searching the shortest geodesic line for calculating the mass center pixels of the block and the event mass center position by utilizing an eight-neighborhood Dijkstra algorithm, and calculating the geodesic distance; traversing the data, the blocks and different events until all the data, the block and the geodesic distance of the event are acquired, and storing the data number, the block number, the geodesic distance, the profile and the profile in a space distance table subordinate to the event;
for the time distance, calculating the date difference between the time of the block data and the occurrence of the event, wherein the date difference is represented by positive sign before the event and the date difference is represented by negative sign after the event, and storing the data number, the block number, the time distance, the profile and the profile in a time distance table subordinate to the event;
Normalizing the geodesic distance and the time distance of the data in each class list according to the maximum value, carrying out weighting operation according to the weight of the user requirement to obtain a space-time importance table of each data block-each event, storing the space-time importance scores, sorting the importance scores, screening out the data information with the strongest event dependence, and storing the data number, the data type, the block number, the block sorting sequence number, the score, the outline and the sequence in a sorting distance table subordinate to the event.
The invention is oriented to the research in the earthquake field and the disaster prevention and reduction work demands, considers the change process of the space influence in the three-dimensional continuous process, carries out quantitative evaluation and numerical calculation simulation on the space influence, and comprises the following innovation points: simulating a terrain space into a two-dimensional plane of a non-uniform medium by taking a first law of geography as a basic principle, and developing a seismic event space influence and strength method from data preparation, coordinate space establishment, to the process of geographic object blocking, space influence factor calculation and the like; the components of the spatial influence distribution are calculated by using mutually non-influencing multiple light sources, and the watershed effect and the anisotropy caused by the terrain can be simulated by carrying out diffuse reflection gain by taking the slope as a basic unit.
The basic data of the invention requires DEM (digital elevation model) data, inSAR (synthetic aperture radar interferometry) SLC (Single Look Complex, single vision complex image) pair of topographic events;
in the data preparation stage, a SLC image pair is processed by SARscape plug-ins (radar image processing plug-ins) using ENVI (remote sensing processing software), and the data is processed by D-InSAR (synthetic aperture radar differential interferometry, including the steps of generating an interferogram, self-adaptive filtering and coherence calculation, phase unwrapping, track refining and re-flattening, phase inversion deformation, geocoding and the like, wherein the D-InSAR processing flow is the existing mature technology and is not a core step of the invention, and is not repeated herein), so that the surface deformation is obtained and is derived as a TIF format grid file.
And establishing a coordinate space for reading in required data (deformation data and other grid format images) according to scene requirements, and establishing a unified image coordinate frame in the system.
In the deformation event objectification, the tif file of the D-Insar processing result stores the deformation quantity of each pixel on the earth surface in a numerical form, wherein a positive value represents the deformation towards the sensor, a negative value represents the deformation away from the sensor, a region with larger earth surface deformation means that an event for changing the topography occurs, and the data stored in a grid form cannot meet the requirement of space-time importance calculation, so that the data needs to be objectified into a specific event point.
Firstly, taking an absolute value of deformation data to represent absolute deformation quantity, setting a threshold value, and carrying out threshold segmentation on the absolute deformation quantity to obtain a deformation region meeting a threshold value condition; and carrying out communication analysis on the deformation area subjected to threshold segmentation (searching for the deformation area with each contour closed and continuous, acquiring the contour and generating a mask grid). In this process, incoherent and tiny fragments may appear, so that the deformed object needs to be screened by setting the minimum number of pixels allowed by the fragments.
According to the first law of geology, everything on the earth's surface is related to everything, but near is more related than far, which means that in the same kind of elements, data of different space times, different areas of the same data and the degree of attachment of events are all different, and therefore, it is necessary to calculate the space-time distance from the data to the event point. Considering that the calculation amount of the data points of the grid is huge, and the operation of the center point of the whole image is too general, each geographic object in the grid needs to be divided, and the calculation is performed by taking the object block as a unit.
The invention uses the mountain slope as basic unit to divide the geographic unit with smaller space scale. Firstly, calculating the slope direction of the DEM, and respectively reclassifying and assigning the forward east direction (45 degrees to 135 degrees), the forward west direction (135 degrees to 225 degrees), the forward south direction (225 degrees to 315 degrees) and the forward north direction (315 degrees to 360 degrees and 0 degrees to 45 degrees) of the slope direction to obtain a slope segmentation map.
After the block segmentation is completed, the influence distribution in the terrain space needs to be calculated, and the following characteristics are considered in the process: the event point is taken as a focusing center, the block close to the event needs to be influenced more, and the block far from the event needs to be influenced less; the anisotropy of geographic action caused by terrain obstruction needs to be considered, the unobstructed place is greatly influenced, and the obstructed place is less influenced; the characteristics of the watershed caused by the slope of the terrain need to be considered, the influence on the side facing the occurrence of the event is larger, and the influence on the side facing away from the occurrence of the event is smaller. In consideration of the above characteristics, the spatial distribution of the influence of the event points on the space is similar to the physical process of the irradiation and attenuation of light in the space, so the present invention calculates the distribution of the influence of the space by simulating the irradiation by regarding the event points as point light sources.
The invention regards the earth surface event as a point light source, the earth surface as a two-dimensional plane, the topography height fluctuation on the plane as the medium density in the plane, the slope surface block of the earth surface as each semi-permeable interface between the mediums, and the attenuation process of the light path in the space is simplified into three parts: diffuse reflection, transmission, scattering.
When using geodesic distances to evaluate geographic anisotropy caused by terrain obstructions, the geodesic distances are equal when facing a mountain and a valley where the absolute values of the accumulated elevations are equal, so that the two are equivalent to the event dependence, and therefore, the DEM needs to be processed first. The event-slope angle is the complementary angle of the incident angle, but because the lambertian model adopts cosine to calculate the light intensity of the incident angle and cosine is an even function, the slope is unfavorable to distinguish the back of the slope relative to the event, so the sine of the complementary angle is used for replacing the original model. In order to better simulate the blocking effect of terrain, transmission attenuation of light passing through the interface needs to be considered during stepping. The transmitted light intensity is related to the angle of incidence, where the angle component is calculated only for the attenuated portion of the light path when transmitted, in order to cause the light path to be excessively attenuated over multiple passes through the interface.
According to the program, a certain seismic event is processed, the space influence coefficient value along the terrain section of the occurrence point of the certain seismic event is shown as the figure, and the numerical distribution in the space influence coefficient value shows the characteristic of non-stationarity influenced by the terrain effect, so that the method can well simulate the influence distribution condition of the seismic event in the three-dimensional space;
in the data preparation, the Insar-SLC pair is subjected to Dinsar treatment and surface deformation, and a coordinate frame, namely a coordinate space, is established by the DEM digital elevation model and the surface deformation together. In deformation time objectification, threshold segmentation, communication analysis and seismic event point are carried out, gradient segmentation and valley inversion are carried out, event-slope angle calculation is carried out on the gradient segmentation and seismic event point, diffuse reflection component calculation and transmission component calculation are carried out, component weighting calculation is carried out, and finally spatial influence distribution is obtained. The event space influence force distribution profile is shown in fig. 2, the influence force distribution situation obtained by the method can be further used for being combined with a geographic weighted regression method, as shown in the figure, the space influence force distribution result is applied to a vegetation index fitting result influenced by a certain earthquake, the solid line part in the figure is a fitting goodness and red pool information criterion value (the smaller the value is, the larger the information amount is, the better the fitting effect is), and under the optimal bandwidth, the geographic weighted regression method using the space influence force as a weight function has the highest fitting goodness and the lowest red pool information criterion value, so that the method can better simulate the distribution situation of the event influence force. The goodness of fit of the invention applied to the geographic weighted regression weight function is shown in FIG. 3, and the red pool information criterion value of the invention applied to the geographic weighted regression weight function is shown in FIG. 4.
The above embodiments are only for illustrating the technical aspects of the present invention, not for limiting the same, and although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may be modified or some or all of the technical features may be replaced with other technical solutions, which do not depart from the scope of the technical solutions of the embodiments of the present invention.
Claims (10)
1. A method for modeling seismic event spatial impact of a ray propagation process, comprising:
S1, preparing original data, including DEM data and InSAR single-view complex image pairs of a topographic event;
S2, establishing a space coordinate system, performing projection transformation on a first image of original data, performing projection transformation on all image data after the first image by using the first image as a reference through a grid space data conversion library, keeping consistent with a projection method of the first image, and performing calculation processing on the first image as a reference The coordinate offset of the first coordinate of the image data relative to the first coordinate of the first image is used for obtaining the image coordinate of any longitude and latitude position in a space coordinate system;
S3, taking an absolute value of the deformation area to represent absolute deformation quantity, setting a threshold value for threshold segmentation, obtaining the deformation area meeting the threshold value condition, carrying out communication analysis on the deformation area subjected to threshold segmentation, searching for a deformation area with each contour closed and continuous, obtaining the contour and generating a mask grid;
taking deformation quantity in the deformation areas as density, and calculating the mass center position of each deformation area as a specific seismic event occurrence point of deformation;
s4, dividing each geographic object in the grid, and calculating by taking an object block as a unit;
s4.1, dividing the area, namely dividing the area by taking a mountain slope as a basic unit, and dividing geographic units with small space scale;
S4.2, calculating space influence coefficient, including valley inversion, diffuse reflection component and transmission and scattering component calculation.
2. The method for modeling seismic event space influence and power in a light propagation process according to claim 1, wherein S1 comprises processing the single vision complex image pair with a radar image processing plug-in using remote sensing processing software, obtaining a surface deformation amount through D-InSAR processing, and deriving the surface deformation amount as raster data.
3. The method of modeling seismic event space influence energization of a light propagation process of claim 2, wherein S2 comprises:
Sequentially combining the images, starting from the first image, combining the 2 nd image data with the first image to form the 1 st combined image, sequentially processing, and combining the 1 st combined image Image data and the first-1 Combining the combined images to form a firstZhang Gebing images;
s2 comprises computing the first image as a reference The coordinate offset of the first coordinate of the image data relative to the first coordinate of the first image includes:
；；
In the method, in the process of the invention, 、Respectively are、Coordinate offset of coordinates [ ]，) Is the firstFirst coordinates of the images，) Is the first coordinate of the first image,Is the upper left corner of the first image in the geographic transformation parameters of the grid space data conversion libraryThe coordinates pixels are geographic coordinates,Is the geographic transformation parameter of the grid space data conversion baseUpper left corner of the imageThe coordinates pixels are geographic coordinates,Is the upper left corner of the first image in the geographic transformation parameters of the grid space data conversion libraryThe coordinates pixels are geographic coordinates,Is the geographic transformation parameter of the grid space data conversion baseUpper left corner of the imageThe coordinates the geographic coordinates,The resolution of the pixels in the horizontal direction of the first image,The resolution of the pixels in the vertical direction of the first image.
4. A method of modeling seismic event space influence (S-l) as defined in claim 3, wherein S2 comprisesThe left top coordinate and the right bottom coordinate of the combined image are respectively as follows:
；；
；
；
In the method, in the process of the invention, 、Respectively the firstCombining imagesUpper left head coordinatesThe top left-hand first coordinate is set,、Respectively the firstCombining imagesLower right tail coordinatesThe lower right tail coordinate is used for the position of the left,、Respectively the first-1 Combined imageUpper left head coordinatesThe top left-hand first coordinate is set,、Respectively the first-1 Combined imageLower right tail coordinatesThe lower right tail coordinate is used for the position of the left,、Respectively the firstThe number of wide and high pixels of the combined image;
First, the The top left coordinate of the combined image is the firstAnd the coordinate offset of the first coordinate of the image data relative to the first coordinate of the first image.
5. The method of claim 4, wherein S2 comprises traversing the image data to create a new array covering all the data as a working space, and the length and width of the new array are:
；；
In the method, in the process of the invention, For the length of the new array to be a new one,To be the width of the new array of data,、Respectively areThe minimum and maximum values of the coordinates,、Respectively areMinimum and maximum of coordinates.
6. The method for simulating seismic event space influence and strength in a light propagation process according to claim 5, wherein S4.1 comprises calculating slope direction for DEM, reclassifying and assigning positive east direction, positive west direction, positive south direction and positive north direction of slope direction respectively to obtain slope segmentation map, performing binary segmentation with slope 5 ° as threshold value, setting smaller than 5 ° as 0, setting 5 ° as 1, performing median filtering of 5*5 ° to remove broken spots, multiplying the slope segmentation map, and dividing water body and plains;
and performing super-pixel segmentation to reduce finely divided patches, dividing the DEM into blocks taking slopes and planes as units, traversing the blocks, and calculating Euclidean distance from the mass center to the event point.
7. The method of claim 6, wherein S4.2 includes processing the DEM to subtract the elevation of the event point from the DEM and take the absolute value to invert all the depressions below the elevation plane relative to the event point to the projections.
8. The method of modeling seismic event space influence (S) of a light propagation process according to claim 7, wherein S4.2 comprises regarding the surface of the block as an ideal diffuse reflector for the diffuse reflection component, approximately using a lambertian model, the intensity of diffuse reflection being related to the angle of incidence;
calculating azimuth angle of slope block centroid relative to event Calculating the difference value of the slope direction angle and the event direction angle by taking the right orthogonal angle of the slope normal azimuth as the slope direction angle, and carrying out angle attribution to an acute angle twice through 0 DEG to-180 DEG and 0 DEG to-90 DEG to obtain an acute angle included angle between the event-block direction and the slope, and distinguishing the slope back according to the sign of the difference value of the slope direction angle and the event direction angle;
event-slope angle calculation using sine of complementary angle ：
；
In the method, in the process of the invention,The mean value of all pixels in the block is used as the slope normal azimuth angle of the block,The sign is taken in the representation,Representing taking the smaller of the two values;
The diffuse reflection initial illumination is regarded as an independent point light source different from a scattering transmission light source, is not influenced by shielding, scattering and transmission, is only attenuated along with the distance in the space, and has diffuse reflection components The method comprises the following steps:
；
In the method, in the process of the invention, For the initial light intensity to be the same,As a function of the curve variables,Is the attenuation coefficient [ (])、(,) The centroid position and the event point position of the current block respectively,、For spatial resolution of DEMs in both horizontal and vertical directions,Is the maximum value of the Euclidean distance of all block-events, all negative values are the blocks facing away from the event, and all negative values are set to zero.
9. The method of modeling seismic event space influence (sm) as defined in claim 8, wherein S4.2 includes normalizing the DEM as a non-uniform medium distributed in a two-dimensional plane, scaling a density value of the medium to a range of (0, 1), assuming that an optical path propagates straight through the medium, calculating an intensity using a propagation model of light in the medium, regardless of an optical path deflection due to medium non-uniformity, the propagation model being:
；
In the method, in the process of the invention, In order for the attenuation coefficient to be a factor,For the sum of the scattering and transmission components,Is the first on the light pathThe normalized elevation of the individual picture elements,Distance between adjacent pixels when the light is stepped;
Gradually calculating intensity attenuation caused by scattering in a light path by adopting a path stepping method, firstly, acquiring a single-pixel linear path between an event point starting point and a block centroid end point by using a bresenham algorithm, then carrying out stepping traversal on points in the path, and taking the average density of a current point and a next point as the density of a current light intensity passing area, wherein the incident light intensity of each step is the emergent light intensity of the last step;
Considering transmission attenuation when light passes through an interface in the stepping process, recording event slope angle symbols of the step and the next step when the light is stepped, and calculating an angle component only for an attenuation part when the light passes through when the symbol difference between the next step and the step is larger than 0 and the light passes through a slope interface facing the event direction for multiplying the emergent light intensity of the light in the step by a transmission attenuation component, wherein the transmitted light intensity is related to an incident angle; the sign difference is 0 and the step decay is 0.
10. The method of claim 9, wherein S4.2 comprises, in a grid discrete form, performing a calculation of a sum of the scattering and transmission components after stepping according to the formula:
；
In the method, in the process of the invention, Is the firstThe image coordinates of the individual picture elements,To be the transmission attenuation coefficient when penetrating the interface,For the number of picture elements in the path of the light,Representing a squaring operator;
the two components are weighted and summed and inverted to obtain the dynamic threshold coefficient of each block at the position after attenuation, the value ranges of the diffuse reflection and the transmission scattering components are between (0, 1), and the spatial influence coefficient is obtained The value of (1) is also between (0, 1):
；
In the method, in the process of the invention, AndIs the weight ratio of diffuse reflection to transmission scattering.
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