CN116805347B - Volume texture coating interpolation method based on volume data six-boundary surface geometric configuration - Google Patents
Volume texture coating interpolation method based on volume data six-boundary surface geometric configuration Download PDFInfo
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Abstract
The application provides a volume texture coating interpolation method based on a volume data six-boundary surface geometry, which comprises the following steps: judging the geometric configuration type of the volume data according to the longitude, latitude and altitude geographic range of the volume data; uniformly reconstructing the spherical shape of the bilateral interface and the annular shape of the four-sided interface into a new geometric configuration of a virtual six-boundary surface, and constructing a cube texture corresponding to the volume data; constructing a coating film texture according to the constructed cube texture, and replacing the cube texture; coordinate transformation of the volume data and the cube texture is corrected into coordinate transformation of the volume data and the coating body texture; and (3) based on the texture of the coating body and the corrected coordinate transformation, performing light sampling and outputting a rendered two-dimensional image. The application better reduces the problems of boundary surface display blurring and the like in volume rendering through the ring segmentation of the volume data on the digital earth and the effective enhancement processing of the tri-linear interpolation on the boundary surface.
Description
Technical Field
The application relates to the technical field of visualization, in particular to a volume texture coating interpolation method based on a volume data six-boundary surface geometric configuration.
Background
Heterogeneous, multi-source, massive amounts of data are involved in battlefield environments, such as temperature fields, air pressure fields, electromagnetic fields, and the like. Visualization technology is an important way to perspective data and find its trend, where volume rendering is one of the widely applied three-dimensional visualization algorithms. When volume rendering is performed on digital earth, the volume data is generally constructed as an ellipsoidal spatial volumetric data grid that is curved and fits the shape of the ellipsoidal surface, and the grid can be divided into three geometric configurations according to the number of boundary surfaces: double-sided interface spherical, four-sided interface annular, six-boundary surface block type. There is often a phenomenon of display blurring on the boundary surface of volume rendering, and when the geographical range of the volume data is global (bilateral interface sphere type) or annular around the earth (four-sided interface ring type), in order to construct the volume texture (six-boundary surface block type) under cartesian rectangular coordinates, it is necessary to perform destructive segmentation on the volume data and reconstruct the volume data into a six-boundary surface geometry, resulting in failure of the ray sampling tri-linear interpolation operation on the boundary surface at the segmentation point. Therefore, studies on the problems such as the fracture segmentation of the volume data on the digital earth and the three-linear interpolation validation process on the boundary surface have been conducted, and the problem of blurring of the boundary surface display has been made, which is necessary from the viewpoints of perfecting the volume rendering theory and optimizing the engineering application.
Disclosure of Invention
The application provides a volume texture coating interpolation method based on a geometric configuration of a six-boundary surface of volume data, which reduces the problems of fuzzy display of the boundary surface and the like through the destructive segmentation of the volume data on digital earth and the effective treatment of tri-linear interpolation on the boundary surface.
The application also provides a volume texture coating interpolation method based on the geometric configuration of the volume data six-boundary surface, which comprises the following steps:
classifying geometric configuration of the volume data, and judging the geometric configuration type of the volume data according to longitude, latitude and altitude geographic ranges of the volume data, wherein the geometric configuration type comprises a bilateral interface sphere, a four-sided interface sphere and a six-boundary surface sphere;
performing geometric reconstruction of the volume data, and if the geometric configuration type of the volume data is a six-boundary surface geometric type, performing surface coating of the volume texture; if the spherical boundary surface and the ring-shaped boundary surface are double-sided boundary surfaces, selecting a certain longitude data grid point column in a volume data ellipsoid bounding box to break and divide, forming two coincident virtual new boundary surfaces at the dividing position, virtually expanding, uniformly reconstructing the spherical boundary surface and the ring-shaped boundary surface into a new virtual six-boundary surface geometric configuration, and constructing a cube texture corresponding to the volume data according to the virtual six-boundary surface geometric configuration of the volume data;
coating all six surfaces of the cube texture with a layer of new data according to the constructed cube texture, and constructing a coated body texture to replace the original body texture;
coordinate transformation of the volume data and the cube texture is corrected into new coordinate transformation of the volume data and the coating film body texture;
and (3) based on the texture of the coating body and the corrected coordinate transformation, performing light sampling on the RCA, and outputting a rendered two-dimensional image.
Further, the geometric configuration type of the volume data is determined according to the longitude, latitude and altitude geographic range of the volume data, specifically:
when the absolute value of the longitude difference is 2 pi and the absolute value of the latitude difference is pi, judging that the spherical interface is a bilateral interface spherical type;
when the absolute value of the longitude difference is 2 pi and the absolute value of the latitude difference is smaller than pi, judging that the square interface ring type is formed;
when the absolute value of the longitude difference is less than 2 pi and the absolute value of the latitude difference is less than pi, the block type is determined as a six-boundary surface block type.
Further, the coating film on all six surfaces of the cube texture is coated with a layer of new data, which specifically comprises:
when the volume data is a general ellipsoidal grid block, performing copy expansion on each lattice value on the texture surface of the cube, including: (1) The lattice points are arranged in a certain surface and are not arranged on the edge of the surface, and the lattice points are copied and expanded outwards along the outer normal of the boundary surface where the lattice points are arranged; (2) The lattice point is arranged on the intersecting edge of the two surfaces, and is copied and expanded outwards along the intersecting edge of the lattice point, wherein the included angle between the outer direction of the intersecting edge of the lattice point and the outer normal direction of the two adjacent surfaces is an acute angle, and the lattice point is still kept at the new intersecting position of the two expanded edges; (3) The lattice point is arranged on the intersecting edges of the three surfaces, and is copied and expanded outwards along the intersecting edges of the lattice point, wherein the included angle between the outwards of the intersecting edges of the lattice point and the external normal of the three adjacent surfaces is an acute angle, and the lattice point is still kept at the new intersecting positions of the three expanded edges;
when the volume data is a spherical or toroidal grid of ellipsoids, the values of the grid points on the surface of the volume texture cube are duplicated and expanded.
Further, the method further comprises the following steps: boundary stitching is performed on the left and right sides of the boundary surface of the volume data annular division, and on the two opposite boundary surfaces of the corresponding volume texture.
Further, the border stitching specifically includes:
the first class is a non-partitioned actually existing boundary surface, and copy expansion processing is used;
the second type is to break the virtual boundary surface and perform body texture annular coating: firstly, copying two opposite boundary surface lattice point values in the corresponding body textures, expanding outwards along the outer normal of the boundary surface, secondly, replacing left and right, and finally, oppositely exchanging to form the annular coating body textures.
Further, the coordinate transformation of the volume data and the cube texture is specifically:
wherein, the point of the geodetic coordinates (B, L, H) (described based on WGS-84 coordinate system) is in ellipsoidal space, B is latitude, unit: radian, data interval [ -pi/2, pi/2]L is longitude, unit: radian, data interval [ -pi, pi]H is height, unit: meter, (s, t, r) is texture coordinates of a corresponding point in texture space, V is a physical quantity value at (B, L, H), V is a texture value at (s, t, r), and the texture value range [0,1 ]]Vmax and Vmin are the corresponding maximum and minimum values of all grid values in an ellipsoidal grid in the volume data, bmin and Bmax are the latitude minimum and maximum values of the volume data grid or ellipsoidal bounding box, lmin and Lmax are the longitude minimum and maximum values, and Hmin and Hmax are the altitude minimum and maximum values. Volume data grid size isWherein b, l and h are the number of lattice points corresponding to the latitude, longitude and altitude directions, and the corresponding volume texture size is the same as the corresponding volume texture size and is +.>。
The calculation process of the sampling points comprises the following steps: a sample point (B, L, H) within the bounding box of any donor data ellipsoid (containing surface boundaries) is used to calculate the corresponding texture coordinates (s, t, r) using equation (1), then the texture value V at that texture coordinate is queried in texture space by texture querying, and the value V corresponding to the position (B, L, H) is calculated using equation (2).
Further, the coordinate transformation of the volume data and the texture of the coated body is specifically as follows:
establishing a new coordinate transformation relation, wherein the size of the volume data grid is stillThe coordinate transformation between the sampled value of the volume data and the texture query value of the volume texture is kept unchanged, and the size of the texture of the corresponding coating body is increased toCoordinate transformation between the ellipsoid space (B, L, H) and texture space (s, t, r) is corrected, and a new mapping formula is established:
formula (3)
Wherein Bmin and Bmax are latitude minimum and maximum values of the volume data grid or the ellipsoid bounding box, lmin and Lmax are longitude minimum and maximum values, hmin and Hmax are altitude minimum and maximum values; b. l and h are the number of lattice points corresponding to the latitude, longitude and altitude directions, and s, t and r are texture coordinate parameters.
Furthermore, when the light is sampled to the texture of the coating body, a tri-linear interpolation is used for calculating a sampling point value.
Further, the method further comprises the steps of converting the sampling point values into color values based on a transfer function, and accumulating the color values to output a two-dimensional image.
The at least one technical scheme adopted by the application can achieve the following beneficial effects:
(1) The three-linear interpolation failure problem and the processing overall scheme of the volume data boundary surface in the digital earth ray projection algorithm (ERCA) are provided, and the problem of fuzzy display of various boundary surfaces in the ERCA is solved.
(2) The method provides a new concept of block and annular coating body textures, provides a basic realization of coating treatment of the body textures, corrects coordinate transformation between ellipsoidal three-linear interpolation and the coating body textures, solves the problem of three-linear interpolation failure of boundary surfaces in the body textures through a coating treatment technology, and particularly provides a solution of body texture interpolation at boundary positions of bilateral spherical and four-sided interface annular body data in volume drawing existing on digital earth through coating treatment and boundary stitching of microscopic upper body textures by adopting a boundary stitching technology.
(3) The method is characterized in that a new design concept of geometric configuration classification and ring breaking segmentation of the volume data is provided, a uniform virtual six-boundary-surface geometric configuration is reconstructed by ring breaking segmentation technology aiming at various boundary-surface geometric configurations of the volume data, a cube texture corresponding to the volume data is established through the configuration, logic mapping of all boundary surfaces (including two new boundary surfaces with coincident segmentation positions) of the volume data and all boundary surfaces of the volume texture is realized, and a new research thought is provided for boundary surface processing of volume drawing.
Drawings
The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain the application and do not constitute a limitation on the application. In the drawings:
FIG. 1 is a schematic diagram of a volumetric data curved ellipsoidal solid grid;
FIG. 2 is a schematic diagram of a volume texture cube;
FIG. 3 is a diagram of global geographic volume data (inside ellipsoids and outside ellipsoids);
FIG. 4 is a graph of global geographic volume data (single layer data) effects;
FIG. 5 is a schematic diagram of global geographic volume data (single layer data) with circular segmentation along longitude;
FIG. 6 is a schematic diagram of a volumetric data cut of a circular geographic area;
FIG. 7 is a diagram of the ring volume data before cutting (left rectangular point, where there are two new boundary surfaces that overlap) and the volume texture after cutting (right rectangular point, corresponding to two opposite boundary surfaces);
FIG. 8 is a schematic of texture tri-linear interpolation (8 circular neighbors, 7 rectangular interpolation points) in texture space;
FIG. 9 is a schematic diagram of a volume data ellipsoid tri-linear interpolation (8 circular neighbors, 7 rectangular interpolation points) in ellipsoid space;
FIG. 10 is a flow chart of a volume texture coating interpolation algorithm based on a volume data six-boundary surface geometry according to the present application;
FIG. 11 is a schematic diagram of a bulk coating process of the body texture of the present application;
FIG. 12a is a left-right extrapolation of the annular coating process (monolayer) on two opposite boundary surfaces (rectangular lattice points) of the body texture of the present application.
FIG. 12b is a schematic representation of the left and right replacement of the annular coating process (monolayer) on two opposite boundary surfaces (rectangular lattice points) of the body texture of the present application.
FIG. 12c is a schematic illustration of the opposite exchange of annular coating treatments (monolayers) on two opposite boundary surfaces (rectangular lattice points) of a body texture according to the application.
Detailed Description
Examples:
in order to make the objects, technical solutions and advantages of the present application more apparent, the technical solutions of the present application will be clearly and completely described below with reference to specific embodiments of the present application and corresponding drawings. It will be apparent that the described embodiments are only some, but not all, embodiments of the application. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.
The following describes in detail the technical solutions provided by the embodiments of the present application with reference to the accompanying drawings.
The digital earth is mostly described using the WGS-84 coordinate system, which is based on a reference ellipsoid, thus also called an ellipsoid coordinate system, and the positioning uses geodetic coordinates (B, L, H), i.e. latitude, longitude, altitude.
The Ellipsoidal Ray Casting Algorithm (ERCA) is a ray casting algorithm adapted to digital earth, and relates to volume data, volume texture, ellipsoidal tri-linear interpolation, texture query (texture tri-linear interpolation) and the like.
(1) Volumetric data geometry classification
The display data in ERCA, also known as volumetric data, is typically a solid grid data field (described in terms of ellipsoidal coordinates) in curved ellipsoidal space, overlaid on the digital earth, and fitted to the curvature of the digital earth. The volume data can be divided into three types of geometric configurations according to the number of boundary surfaces of the data cube grid: double-sided interface spherical, four-sided interface annular, six-boundary surface block type.
First type (six boundary surface block type): generally, ellipsoidal solid grid data blocks. As shown in fig. 1, the volume data block has six boundary surfaces: an outer surface curved surface ABCD, an inner surface curved surface EFGH, a side surface ABEF, a side surface CDHG, a side surface AEHD, and a side surface BCGF. Similar to a three-dimensional bounding box in a rectangular coordinate system, eight vertexes of ABCDEFGH and related sides (including curved sides) form an 'ellipsoid bounding box' of volume data, and the easiest bounding box form in an ellipsoid space is described by adopting ellipsoid coordinates and is the minimum ellipsoid bounding box of the volume data. The three-dimensional texture or volume texture corresponding to the volume data is then a cube in texture space, and as shown in fig. 2, points within (including surfaces) the volume data ellipsoid bounding box and points within (including surfaces) the volume texture cube can be mapped one-to-one.
Second type (double interface sphere): when the volume data covers the world, the data three-dimensional grid of the volume data only has two spherical boundary surfaces of the inner surface and the outer surface.
Third type (four-sided interface ring): when the volume data is looped around the earth, the data three-dimensional grid of the volume data has an inner and outer looped ellipsoidal surface and two side surfaces, and a total of four boundary surfaces.
(2) Volume data corruption segmentation process
When the volume data is in a bilateral interface sphere or a four-sided interface ring type, because the volume texture is a cube (six-boundary surface block type), the global or annular volume data needs to be subjected to ring breaking and segmentation to construct a unified virtual six-boundary surface geometric configuration so as to be capable of transforming the volume data in the curved ellipsoidal space into the cube in the texture space one by one. The global covered volume data are ellipsoidal on the inside and outside, see fig. 3. For fig. 4, a segmentation is performed along the longitude and a virtual cuboid data grid is generated, see fig. 5. If the global volume data is not the standard division, resampling the original data by adopting tri-linear interpolation according to the grid of the division to construct new volume data. Referring to fig. 6 and 7, the ring-shaped covered volume data is divided, and the ring-shaped covered volume data is broken and divided along a certain column of grid point data (dividing position) in the volume data ellipsoidal data grid, so that two overlapped virtual new boundary surfaces of the volume data are formed at the dividing position, and finally, a virtual cuboid data grid is generated. By the above-described break-up division processing, three types of geometric configurations can be converted into a unified virtual cuboid (six-boundary-surface geometric configuration).
(3) Ellipsoidal tri-linear interpolation in light sampling and GPU-based texture query
The core step of the ray casting algorithm is to perform spatial interpolation sampling along the ray direction. Interpolation sampling mode: (1) NEAREST neighbor sampling (GL_NEAREST). The nearest neighbor point of the sampling point is directly used, the calculation is simple, the speed is the fastest, but when the display value at the boundary is greatly changed, obvious sawtooth or stepped wood grain phenomenon can be generated, and the effect is poor; (2) Linear sampling (GL_LINEAR). The method has the advantages of complex calculation, good antialiasing processing capability and good effect. In most cases, ray casting algorithms mostly use tri-linear interpolation, which is used herein. In texture querying, as shown in fig. 8, because the volume texture is a virtual cube, tri-linear interpolation in a cartesian rectangular coordinate system can be used: according to 8 adjacent points (round dot representation) in texture space, 7 times of one-dimensional linear interpolation (small rectangular representation) is carried out along 3 directions s, t and r, and similarly, as shown in fig. 9, in the ellipsoidal space, according to 8 adjacent points (round dot representation), ellipsoidal three-dimensional linear interpolation (7 times of one-dimensional linear interpolation, small rectangular representation) is carried out along the weft height B, L and the H direction, so that the calculation is very complex due to the curved surface, but the very simple texture query based on GPU hardware can be carried out through the corresponding cube texture, and the coordinate transformation can be carried out to obtain the result, thus the difficulty of directly calculating the ellipsoidal three-linear interpolation with the complex curved surface is avoided.
(4) Three-linear interpolation failure problem on volume data boundary surfaces
a) When the volume data is a general ellipsoidal grid data block, in the process of light sampling, if a sampling point is a point on the surface of the volume data, the sampling point also corresponds to a point on the surface of a cube of the volume texture, because linear interpolation can only be carried out along two directions when texture tri-linear interpolation is carried out on the surface to calculate a texture value, the texture interpolation is incomplete, the problem is called as 'tri-linear interpolation failure', and referring to fig. 2 and 8, the interpolation sampling on a boundary surface of the volume data is insufficient, and the display on the boundary surface is blurred;
b) When the volume data is spherical or ring-shaped ellipsoidal grid data, in the process of light ray sampling, if the sampling points are on two coincident new boundary surfaces at the dividing position of the volume data, the points on two opposite boundary surfaces in the cube of the volume texture are corresponding, the problem of display blurring can occur on the dividing surface due to three-linear interpolation failure, moreover, two coincident new virtual boundary surfaces at the dividing surface of the volume data are corresponding to two separated and opposite boundary surfaces in the volume texture, and the three-linear interpolation of the volume texture on the two opposite boundary surfaces needs to be jointly considered and corrected, so that the specific processing is very complex.
In a comprehensive view, the problem that the three-linear interpolation is invalid and the light sampling and sampling on the boundary surface are insufficient due to the fact that the complete three-linear interpolation cannot be implemented on the boundary surface of the volume data, and the display blurring phenomenon appears on the boundary surface is solved, so that the effective correction processing of the three-linear interpolation on the boundary surface is the basic problem of the display blurring of the boundary surface.
Aiming at the problem of display blurring caused by tri-linear interpolation failure on a volume data boundary surface in ERCA on digital earth, the application provides a volume texture film plating interpolation algorithm based on a volume data six-boundary surface geometric configuration, which mainly comprises the following steps: the basic flow of the method is shown in fig. 10, and the method comprises the steps of geometric configuration classification and geometric reconstruction (break segmentation), surface coating of body textures (boundary stitching), light sampling (coordinate transformation correction based on the textures of the coated bodies) and the like.
Step 1, sorting of geometry of volume data
The volume data in digital geosphere drawing, usually an ellipsoidal volume data grid number field, uses a WGS84 coordinate system to describe the positions of grid points using latitude, longitude and altitude, the position vectors are (B, L, H), and each grid point data value represents a physical quantity at the actual point, such as temperature, pressure, electromagnetic intensity, and the like. Judging the geometric configuration type of the volume data according to the longitude, latitude and altitude geographic range of the volume data: (a) When the absolute value of the longitude difference is 2 pi and the absolute value of the latitude difference is pi, judging that the spherical interface is a bilateral interface spherical type; (b) When the absolute value of the longitude difference is 2 pi and the absolute value of the latitude difference is not pi, judging that the interface is a four-sided interface ring; (c) When the absolute value of the longitude difference is not 2 pi and the absolute value of the latitude difference is not pi, the block type is determined as a six-boundary surface.
Step 2, geometric reconstruction of volume data (break-open segmentation)
(1) If the volume data is of a six-boundary surface geometry type, skipping the step, and executing the step 3;
(2) If the spherical boundary surface and the ring-shaped boundary surface are double-sided interface spherical surfaces and four-sided interface ring-shaped surfaces, a data grid point column of a certain longitude in a volume data ellipsoid bounding box is selected for ring breaking and division, two coincident virtual new boundary surfaces are formed at the division part, virtual expansion is carried out, the double-sided interface spherical surfaces and the ring-shaped boundary surfaces are uniformly reconstructed into a new virtual six-boundary surface geometric configuration, and according to the uniform virtual geometric configuration of the volume data, a cube texture (six-boundary surface geometric configuration) corresponding to the volume data is constructed, so that the logical one-to-one mapping between each boundary surface of the volume data and each boundary surface of the corresponding volume texture is ensured, and a research foundation is laid for the coating of the following volume texture.
Step 3, coating film on the surface of the body texture (boundary stitching)
And (3) aiming at the cube texture constructed in the step (2), completely wrapping up a new layer of data on the six surfaces of the cube texture, and constructing a new body texture called a coated body texture similar to the process of coating a layer of paint on the metal surface to form a protective film layer (see figure 11), and replacing the original body texture with the coated body texture. The processing can ensure that at any point in the original texture, 8 complete adjacent points are arranged in the corresponding coating body texture, and the effective and correct tri-linear interpolation of the texture is ensured.
The whole coating process is described as follows:
a) When the volume data is a general ellipsoidal grid block, copy and expand each lattice value on the surface of the volume texture cube: (1) The lattice points are inside a certain surface and not on the edges of the face. At this time, copying and expanding outwards along the outer normal of the boundary surface where the lattice point is located; (2) the lattice point is on the intersecting edge of the two surfaces. At this time, the lattice point is duplicated and expanded outwards (the included angle between the lattice point and the outer normal of two adjacent surfaces is an acute angle) along the intersection edge where the lattice point is located, and the lattice point still remains at the intersection of the new two edges after expansion; (3) the grid points are on intersecting edges of the three surfaces. At this point, the expansion is replicated outward (at an acute angle to the outer normal of three adjacent surfaces) along the edge where the lattice lies, and the lattice remains at the new three edge intersection after expansion. The copying and expanding process is called as 'block coating of block texture', and the new block texture is called as 'block coating block texture'. In the process of light sampling, if a sampling point is any point in or on the surface of the volume data bounding box, the sampling point corresponds to a point in the texture cube of the film coating body, when the three-linear interpolation calculation is carried out on the point, the point has 8 complete adjacent points, the texture interpolation calculation is effective, and finally, the normal display of the volume data boundary surface can be ensured.
b) When the volume data is spherical or ring-shaped ellipsoidal grid, the values of each grid point on the cube surface of the volume texture are copied and expanded, but special boundary stitching is needed on two opposite boundary surfaces of the corresponding volume texture on the left and right sides of the annular segmentation boundary surface of the volume data.
The first class is a non-partitioned actually existing boundary surface, using the copy extension process in a);
the second type is to break the virtual boundary surface of the division, and the processing is as follows: firstly, two opposite boundary surface lattice point values in the corresponding volume textures are copied and expanded outwards along the outer normal of the boundary surface, namely left-right extrapolation (shown in fig. 12 a), secondly left-right replacement (shown in fig. 12 b), and finally opposite replacement (shown in fig. 12 c), wherein the process is called "volume texture annular coating", and the new volume texture is called "annular coating volume texture", and is shown in fig. 12a, 12b and 12 c. In particular, at the volume data division (where there are two new virtual boundary surfaces that overlap together), two opposite boundary surfaces corresponding thereto (two overlapping boundary surfaces at the corresponding volume data division) in the corresponding volume texture have been logically subjected to a "boundary stitching" process by "opposite exchange". In the whole, the body data is initially subjected to ring breaking and segmentation to construct two new coincident boundary surfaces, the six-boundary-surface geometric configuration of the body data is realized, a cube texture is generated according to the configuration, and finally, in the annular coating body texture, the plating layers of the two opposite boundary surfaces are subjected to data exchange of the opposite boundary surfaces again, and the whole process is called boundary stitching.
Step 4, light sampling (coordinate transformation correction)
And (3) performing light sampling based on the new film-coated body texture created in the step (3) without changing the body data. Calculating ellipsoidal tri-linear interpolation and the like aiming at sampling points, wherein coordinate transformation of volume data and original texture is needed to be corrected into coordinate transformation of volume data and coating body texture:
a) Coordinate transformation before correction
The coordinate conversion formula and the corresponding relation of the values between the volume data and the original volume texture, the ellipsoidal space (B, L, H) and the texture space (s, t, r) are as follows:
formula (1)
Formula (2)
Wherein, the point of the geodetic coordinates (B, L, H) is in the ellipsoidal space, (s, t, r) is the texture coordinate of the corresponding point in the texture space, V is the physical quantity value at (B, L, H), V is the texture value at (s, t, r), the texture value range [0,1]Vmax and Vmin are the corresponding maximum and minimum values of all grid values in the ellipsoidal grid in the volume data. Volume data grid size isThe corresponding volume texture size is the same as that of the corresponding volume texture>。
The calculation process of the sampling points comprises the following steps: the corresponding texture coordinates (s, t, r) are calculated for a sample point (B, L, H) within the bounding box of the donor data ellipsoid (containing the surface boundary) using equation (1), and then the corresponding value V at the position (B, L, H) can be calculated using equation (2) by texture querying, in texture space, the texture value V at the texture coordinates. Computing the values of texture sampling points uses texture queries supported by the hardware GPU.
The corrected coordinate transformation establishes a new coordinate transformation relation for the volume data and the coating body texture. The volume data grid size is stillThe coordinate transformation between the values of the volume data samples and the texture query values of the volume texture remains unchanged, but since the corresponding coated volume texture size has been increased to +.>Therefore, a coordinate transformation between the modified ellipsoid space (B, L, H) and the texture space (s, t, r) is required to build a new mapping formula:
formula (3)
After correction, any point (including inner and outer surfaces and side interfaces) in the volume data ellipsoid bounding box in the ellipsoid space, all points in the corresponding texture space are positioned in the cube of the coating body texture (not including the boundary surface), and complete texture tri-linear interpolation (because the texture query of the point has complete 8 adjacent points at the moment) can be realized, the texture interpolation operation is effective, and finally, the display of the volume data boundary surface can be ensured to be clear.
In summary, the application has the following technical innovations:
(1) The three-linear interpolation failure problem and the processing overall scheme of the volume data boundary surface in the digital earth ray projection algorithm (ERCA) are provided, and the problem of fuzzy display of various boundary surfaces in the ERCA is solved.
(2) The method provides a new concept of block and annular coating body textures, provides a basic realization of coating treatment of the body textures, corrects coordinate transformation between ellipsoidal three-linear interpolation and the coating body textures, solves the problem of three-linear interpolation failure of boundary surfaces in the body textures through a coating treatment technology, and particularly provides a solution of body texture interpolation at boundary positions of bilateral spherical and four-sided interface annular body data in volume drawing existing on digital earth through coating treatment and boundary stitching of microscopic upper body textures by adopting a boundary stitching technology.
(3) The method is characterized in that a new design concept of geometric configuration classification and ring breaking segmentation of the volume data is provided, a uniform virtual six-boundary-surface geometric configuration is reconstructed by ring breaking segmentation technology aiming at various boundary-surface geometric configurations of the volume data, a cube texture corresponding to the volume data is established through the configuration, logic mapping of all boundary surfaces (including two new boundary surfaces with coincident segmentation positions) of the volume data and all boundary surfaces of the volume texture is realized, and a new research thought is provided for boundary surface processing of volume drawing.
The application optimizes the data visualization or data presentation of the large-scale scalar data field data boundary on the digital earth by utilizing the three-dimensional graphics technology in the computer and using the advanced GPU shader programming interface, provides a core foundation visualization technology support for the national important application fields such as weather, electromagnetism, medical treatment, geology and the like, has obvious theoretical value and economic value, and has good application prospect.
The foregoing is merely exemplary of the present application and is not intended to limit the present application. Various modifications and variations of the present application will be apparent to those skilled in the art. Any modification, equivalent replacement, improvement, etc. which come within the spirit and principles of the application are to be included in the scope of the claims of the present application.
Claims (9)
1. The volume texture coating interpolation method based on the geometric configuration of the volume data six-boundary surface is characterized by comprising the following steps:
classifying geometric configuration of the volume data, and judging the geometric configuration type of the volume data according to longitude, latitude and altitude geographic ranges of the volume data, wherein the geometric configuration type comprises a bilateral interface sphere, a four-sided interface sphere and a six-boundary surface sphere;
performing geometric reconstruction of the volume data, and if the geometric configuration type of the volume data is a six-boundary surface geometric type, performing surface coating of the volume texture; if the spherical boundary surface and the ring-shaped boundary surface are double-sided boundary surfaces, selecting a certain longitude data grid point column in a volume data ellipsoid bounding box to break and divide, forming two coincident virtual new boundary surfaces at the dividing position, virtually expanding, uniformly reconstructing the spherical boundary surface and the ring-shaped boundary surface into a new virtual six-boundary surface geometric configuration, and constructing a cube texture corresponding to the volume data according to the virtual six-boundary surface geometric configuration of the volume data;
coating all six surfaces of the cube texture with a layer of new data according to the constructed cube texture, and constructing a coating texture to replace the original cube texture;
coordinate transformation of original volume data and cube texture is corrected into coordinate transformation of the volume data and the current coating body texture;
and (3) based on the texture of the coating body and the corrected coordinate transformation, performing light sampling and outputting a rendered two-dimensional image.
2. The method for interpolating a volume texture coating based on a volume data six-boundary surface geometry according to claim 1, wherein the determining the geometry type of the volume data according to the longitude, latitude and altitude geographic range of the volume data is specifically as follows:
when the absolute value of the longitude difference is 2 pi and the absolute value of the latitude difference is pi, judging that the spherical interface is a bilateral interface spherical type;
when the absolute value of the longitude difference is 2 pi and the absolute value of the latitude difference is smaller than pi, judging that the square interface ring type is formed;
when the absolute value of the longitude difference is less than 2 pi and the absolute value of the latitude difference is less than pi, the block type is determined as a six-boundary surface block type.
3. The volume texture coating interpolation method based on the volume data six-boundary surface geometry according to claim 1, wherein all coating films of six surfaces of the cube texture are coated with a new layer of data, specifically:
when the volume data is a general ellipsoidal grid block, performing copy expansion on each lattice value on the texture surface of the cube, including: (1) The lattice points are arranged in a certain surface and are not arranged on the edge of the surface, and the lattice points are copied and expanded outwards along the outer normal of the boundary surface where the lattice points are arranged; (2) The lattice point is arranged on the intersecting edge of the two surfaces, and is copied and expanded outwards along the intersecting edge of the lattice point, wherein the included angle between the outer direction of the intersecting edge of the lattice point and the outer normal direction of the two adjacent surfaces is an acute angle, and the lattice point is still kept at the new intersecting position of the two expanded edges; (3) The lattice point is arranged on the intersecting edges of the three surfaces, and is copied and expanded outwards along the intersecting edges of the lattice point, wherein the included angle between the outwards of the intersecting edges of the lattice point and the external normal of the three adjacent surfaces is an acute angle, and the lattice point is still kept at the new intersecting positions of the three expanded edges;
when the volume data is a spherical or toroidal grid of ellipsoids, the values of the grid points on the surface of the volume texture cube are duplicated and expanded.
4. A method of volume texture film interpolation based on a volume data six boundary surface geometry according to claim 3, further comprising: boundary stitching is performed on the left and right sides of the boundary surface of the volume data annular division, and on the two opposite boundary surfaces of the corresponding volume texture.
5. The method for interpolating a texture coating based on a six boundary surface geometry of volume data according to claim 4, wherein the boundary stitching is specifically:
the first class is a non-partitioned actually existing boundary surface, and copy expansion processing is used;
the second type is to break the virtual boundary surface and perform body texture annular coating: firstly, copying two opposite boundary surface lattice point values in the corresponding body textures, expanding outwards along the outer normal of the boundary surface, secondly, replacing left and right, and finally, oppositely exchanging to form the annular coating body textures.
6. The method for interpolating a coating film of a volume texture based on a geometry of a six boundary surface of volume data according to claim 1, wherein the coordinate transformation of the volume data and the cube texture is specifically:
the correspondence of the coordinate conversion formula and the values between the ellipsoidal space (B, L, H) and the texture space (s, t, r) is as follows:
formula (1)
Formula (2)
Wherein, the point of the geodetic coordinates (B, L, H) is in the ellipsoidal space, B is the latitude, unit: radian, data interval [ -pi/2, pi/2]L is longitude, unit: radian, data interval [ -pi, pi]H is height, unit: meter, (s, t, r) is texture coordinates of a corresponding point in texture space, V is a physical quantity value at (B, L, H), V is a texture value at (s, t, r), and the texture value range [0,1 ]]Vmax and Vmin are the corresponding maximum and minimum values in all grid values in an ellipsoidal grid in the volume data, bmin and Bmax are the latitude minimum and maximum values of the volume data grid or the ellipsoidal bounding box, lmin and Lmax are the longitude minimum and maximum values, and Hmin and Hmax are the altitude minimum and maximum values; volume data grid size isWherein b, l and h are the number of lattice points corresponding to the latitude, longitude and altitude directions, and the corresponding volume texture size is the same as the corresponding volume texture size and is +.>；
The calculation process of the sampling points comprises the following steps: a sampling point (B, L, H) within the bounding box of the volume data ellipsoid, the corresponding texture coordinates (s, t, r) are calculated using formula (1), then the texture value V at the texture coordinates is queried in texture space by texture query, and the corresponding value V at the position (B, L, H) is calculated using formula (2), wherein the bounding box of the volume data ellipsoid contains the surface boundary.
7. The method for interpolating a coating of a volume texture based on a geometry of a six boundary surface of volume data according to claim 1, wherein the coordinate transformation of the volume data and the coating of the volume texture is specifically:
establishing a new coordinate transformation relation, wherein the size of the volume data grid is stillThe coordinate transformation between the sampled value of the volume data and the texture query value of the volume texture is kept unchanged, and the size of the texture of the corresponding coating body is increased toCoordinate transformation between the ellipsoid space (B, L, H) and texture space (s, t, r) is corrected, and a new mapping formula is established:
formula (3)
Wherein Bmin and Bmax are latitude minimum and maximum values of the volume data grid or the ellipsoid bounding box, lmin and Lmax are longitude minimum and maximum values, hmin and Hmax are altitude minimum and maximum values; b. l and h are the number of lattice points corresponding to the latitude, longitude and altitude directions, and s, t and r are texture coordinate parameters.
8. The method for interpolating a volume texture coating based on a volume data six-boundary surface geometry according to claim 1, wherein a three-linear interpolation is used to calculate a sampling point value when the coating texture is light-sampled.
9. The method of claim 8, further comprising converting the sample point values to color values based on a transfer function, accumulating the color values to output a rendered two-dimensional image.
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102945570A (en) * | 2012-11-23 | 2013-02-27 | 华东师范大学 | Method for constructing full-space three-dimensional digital earth model |
| CN103761761A (en) * | 2014-01-21 | 2014-04-30 | 中国科学院遥感与数字地球研究所 | Marine scalar field volume rendering method based on earth sphere model |
| CN104574263A (en) * | 2015-01-28 | 2015-04-29 | 湖北科技学院 | Quick three-dimensional ultrasonic reconstruction and display method on basis of GPU (graphics processing unit) |
| CN110494895A (en) * | 2016-08-19 | 2019-11-22 | 莫维迪厄斯有限公司 | Use the Rendering operations of sparse volume data |
| CN113298936A (en) * | 2021-06-01 | 2021-08-24 | 浙江大学 | Multi-RGB-D full-face material recovery method based on deep learning |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7586494B2 (en) * | 2006-03-17 | 2009-09-08 | Microsoft Corporation | Surface detail rendering using leap textures |
-
2023
- 2023-08-22 CN CN202311054995.5A patent/CN116805347B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102945570A (en) * | 2012-11-23 | 2013-02-27 | 华东师范大学 | Method for constructing full-space three-dimensional digital earth model |
| CN103761761A (en) * | 2014-01-21 | 2014-04-30 | 中国科学院遥感与数字地球研究所 | Marine scalar field volume rendering method based on earth sphere model |
| CN104574263A (en) * | 2015-01-28 | 2015-04-29 | 湖北科技学院 | Quick three-dimensional ultrasonic reconstruction and display method on basis of GPU (graphics processing unit) |
| CN110494895A (en) * | 2016-08-19 | 2019-11-22 | 莫维迪厄斯有限公司 | Use the Rendering operations of sparse volume data |
| CN113298936A (en) * | 2021-06-01 | 2021-08-24 | 浙江大学 | Multi-RGB-D full-face material recovery method based on deep learning |
Non-Patent Citations (3)
| Title |
|---|
| 三维网格模型的分割及应用技术综述;孙晓鹏, 李华;计算机辅助设计与图形学学报(第08期);全文 * |
| 基于GPU的全球海量数据的快速调度与渲染;万刚;韩阳;曹雪峰;;系统仿真学报(第S1期);全文 * |
| 基于Laplace方程的球面正交曲线格网生成方法;卢付强;宋志尧;雷梦玲;丁凯孟;;地理与地理信息科学(第01期);全文 * |
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