31 results about "Quad-edge" patented technology

Methods and systems for compressing and decompressing 3-D geometry data which includes regularly tiled surface portions. One compression method includes representing a surface portion as a "vertex raster", which comprises specifying an extent value and encoding the vertex parameter values of vertices within the surface portion. The extent of the surface portion specifies the arrangement of vertices within the surface portion, and allows the vertices to be properly assembled into drawing primitives during decompression. The encoded vertex parameter values may be encoded globally (by setting initial values and corresponding delta values), locally (on a per-vertex basis), or using a combination of these techniques. Absolute, delta encoding, or delta-delta encoding may be utilized for these parameter values. Vertex parameters which may be encoded in this manner include position, color, normals, z-displacement values, texture map coordinates, and surface material properties. Additionally, connectivity information may also be encoded using this compression method by specifying quad split bits and half-resolution edges. Quad split bits are used to tessellate a quadrilateral formed by neighboring vertices of a surface portion according to the direction of the strongest color change. Half-resolution edges are utilized to gradually shift from an area of high resolution to an adjacent surface portion represented in lower resolution. For graphical objects which include a plurality of adjacent surface portions, a step command is disclosed which allows data from one surface portion to be advantageously reused. Decompression of a vertex raster representation may comprise decoding the extent value, global parameter values, and a per-vertex stream of local parameter values.

The invention provides a method for reconstructing a micro structure finite element of a multiphase material based on a sequence image, comprising the following steps of: on the basis of collecting, reading and interpolating the sequence image of the material, establishing a finite element topology model forming a mapping relation with the sequence image; using configuration information of the image and a topology structure of the model to determine a node and unit information; and then using a statistical average value of colour information in the image to determine material attributes of each unit of the finite element model. The method disclosed by the invention not only can be used for reconstructing a two-dimensional quadrangular finite element model reflecting a real structure of a material section through a single image, but can also be used for directly reconstructing a three-dimensional hexahedral finite element model reflecting the real structure of the material through the sequence image. By means of the invention, error accumulation in the links of reconstructing, grid dividing and the like in the current geometrical reconfiguration method can be avoided; the reconfiguration time is greatly saved; and the reconfiguration efficiency is improved. The method disclosed by the invention can be widely used in the fields, such as macro-micro cross scale research, optimization design and preparation of the multiphase material.

The invention provides a background grid adaptive segmenting method in a DC resistivity no-unit method. The method comprises the following steps of determining distribution condition of medium, abnormal member, landform, electrode and the like in a two-dimensional ground electric model, establishing a DC resistivity no-unit method calculating domain, and utilizing an irregularly distributed node discrete ground electric model; covering the calculating domain by means of a small number of rough and simple initial quadrangular grids, setting a control value which guides adaptive segmentation, and performing adaptive segmentation by the background grid according to the control value and a node distribution condition; arranging ng Gaussian integration points xg in each background grid, and obtaining a no-unit method equation set of the region; solving the equation set for obtaining a node electric field value, and calculating the vision resistivity parameter of a viewing point. The methodcan be based on any node distribution discrete model. High adaptability for any complicated ground electric model is realized. The background grid adaptive segmenting method improves value stability and computing efficiency in routine DC resistivity no-unit method forward calculation.

The invention discloses a constraint terrain parallel construction method under a single-computer multi-core environment, which comprises the steps of quad-edge structure based CD-TIN data structure and main function design, load balanced based data partition strategy, divide-and-conquer algorithm based subnet parallel construction, subnet parallel merging, grid index construction, constraint point ground object parallel insertion, constraint line ground object parallel insertion, and constraint surface ground object parallel insertion. A requirement for efficient terrain construction of common users is met by bringing parallel computing technologies into to full play, and more powerful experience is brought for the common users. On the basis of the prior art, an appropriate constraint terrain memory description data structure is designed, a database storage model corresponding to the constraint terrain memory description data structure is constructed, and a load balance strategy based discrete point data partition strategy is further provided; a divide-and-conquer algorithm is selected to act as a basic algorithm for terrain construction, a parallel insertion rule for constraint point ground objects, constraint line ground objects and constraint surface ground objects is formulated under the support of a space index technology, and a parallel insertion algorithm is designed.

The present invention relates to a method for rendering a multi-resolution terrain using GPU tessellation.

A method for rendering a terrain using GPU tessellation according to an embodiment of the present invention may include: generating a quad patch to which an inner tessellation factor and an edge tessellation factor are allocated by using a quadtree including a parent node and child nodes; generating a base mesh b using the quad patch; and restoring a terrain by applying a displacement map to the base mesh.

The embodiment of the invention discloses an information processing method and device and a computer readable storage medium, and the method comprises the steps: obtaining a quadrangle in an illumination image, and screening a target quadrangle through rectangular matching; performing parallel clustering based on the target quadrangle to obtain line segment clusters and corresponding clustering lengths; and uniformly adjusting vertex coordinates in illumination mapping of the illumination graph according to the rectangular constraint of the target quadrangle, the clustering length constraint and the angle constraint of the non-target quadrangle. Therefore, a target quadrangle similar to the rectangle in the illumination image is determined; line segment clustering is carried out on the target quadrangle; all line segment clusters and the average length corresponding to each line segment cluster are obtained; and finally, in combination with the rectangular constraint of the target quadrangle, the clustering length constraint of each line segment cluster and the angle constraint that the shape of the non-target quadrangle is not changed, the oblique line in the illumination image isautomatically adjusted into a flat straight line segment or a quadrangle right angle for optimization, and the information processing efficiency is greatly improved.

The invention provides a cubic object recognition method based on a depth image. The method comprises: S1, acquiring the depth image of a target and gradient maps of the target in the X direction andthe Y direction; S2, classifying pixel points in the gradient map according to the gradient map to obtain an edge point map; S3, obtaining segmented images of the upper surface, the left vertical plane and the right vertical plane of the target in the depth image according to the result; S4, performing edge line detection on the edge point graph, and clustering and combining all detected edge lines to obtain a collinear edge line group set; S5, extracting angular points according to the longest edge line of each group in the collinear edge line group set; S6, pairing the extracted corner points to obtain a quadrangle; S7, determining the upper surface and the overall contour of the cubic object; and S8, obtaining left and right vertical planes corresponding to each upper surface quadrangleto realize cubic object positioning. The method is applied to the logistics industry, the problems of volume measurement limitation and time consumption of targets such as cubic object-shaped packages are solved, and the package sorting efficiency is improved.

The invention provides a method for accurately calculating the volume of a cubic object based on a depth image, and the method comprises the steps: obtaining the depth image and a gradient image of the cubic object, carrying out the classification of pixel points in the depth image, and obtaining an edge point image and segmented images of the upper surface, the left vertical plane and the right vertical plane of the cubic object; carrying out edge line detection on the edge point graph, clustering and merging all detected edge lines to obtain a collinear edge line group set, extracting angular points according to the longest edge line of each group, and pairing the angular points; determining the upper surface and the overall contour of the cubic object; obtaining a contour edge line of the upper surface and determining an upper surface quadrangle according to the contour edge line; calculating the length and the width of the cubic object according to the quadrangle on the upper surface, fitting four vertical planes, accurately calculating the length, the width and the height of the cubic object, and calculating the volume of the cubic object. The method is applied to the logistics industry, the problems of volume measurement limitation and time consumption of targets such as cubic object-shaped packages can be solved, and the package sorting efficiency is improved.

A content retargeting method and apparatus are disclosed. An embodiment of the invention provides a content retargeting method that includes: dividing an original content into a grid having M rows×N columns of quads; computing degrees of importance of the divided quads; and scaling the quads based on the computed degrees of importance, the quads axis-aligned by rows or columns.

The invention belongs to the field of structural design topology optimization, and particularly discloses a multivariable cutting level set optimization method for porous structure topology optimization, which comprises the following steps: dividing a design reference domain into M units; describing a microstructure in each unit by using a plurality of basic level set functions and segmentation functions thereof, and performing cutting by using a cutting function to realize shape and topological change of the microstructure; obtaining post-cutting operation, a plurality of virtual microstructures in each unit; combining the components together through Boolean operation; generating actual microstructures; according to the method, a microstructure prototype is mapped from a square grid to aquadrilateral grid; meanwhile, a higher-order cutting function is adopted, the porous structure with a more complex geometric structure can be processed more flexibly, and the problems that in engineering practical application, the macroscopic shape of the porous structure is highly irregular, square grid division cannot be used, a bilinear interpolation function geometric model is not flexible enough, and the porous structure cannot be described well are solved.

The invention discloses a power supply scheme optimization method fusing electric power and traffic information. The method comprises the following steps: establishing a road network topological graph of an area where a power supply scheme is located; wherein the road network topological graph is from a special geographic information data source or a geographic information data source which can be collected publicly, determining the range of an area where the power supply scheme is located, and counting a potential power supply point set in the area; according to the method, different road types and construction conditions are fully considered, the edges of a road network topological graph are transformed, modeling is carried out on an actual road section in a quadrilateral form instead of a road center line, and a novel traffic network model is obtained to consider the influence of the specific road width; according to the unit construction cost of different grades of roads, each edge in the novel traffic network model is weighted, and the weight of each edge is the product of the unit construction cost and the length, namely the total construction cost of the road section; and taking the total construction cost from the power supply point to the position of the powered user as an objective function, and taking a scheme with the minimum objective function value as an optimal power supply scheme.

The invention relates to a DSM data-based rapid indirect positioning method and device for a satellite-borne SAR image, and a computer readable storage medium. The method comprises the steps of acquiring system parameters and image parameters of the satellite-borne SAR image; fitting a satellite orbit curve; determining four angular point coordinates of the SAR image positioned on the ground by anRD model; enabling the four angular point coordinates to form a quadrilateral, and acquiring DSM data in the quadrilateral to construct a three-dimensional grid; and for each ground pixel point in the quadrilateral, determining an orientation position and a distance position corresponding to the ground pixel point by rapidly estimating an orientation moment, thereby realizing indirect positioning. According to the method, the efficiency of determining the orientation moment of a Doppler center by the ground pixel points can be effectively improved, and the determined orientation moment of theDoppler center is the same as the orientation moment of the Doppler center determined by traversing; and the accuracy is high.

The invention belongs to the technical field of satellite communication, and particularly relates to a route selection method based on uncertain link parameters in a low earth orbit satellite network. The method comprises the following steps: acquiring a satellite network topological graph, and selecting a source satellite node and a target satellite node; calculating the shortest path between the source satellite node and the target satellite node and marking the shortest path; whether the source satellite node and the target satellite node are located at the same position on the orbit or not is judged, and if yes, the marked shortest path serves as the optimal path; otherwise, satellite nodes capable of forming a quadrangle are selected around the shortest path; adopting a membership function to describe uncertain parameters of links in the satellite network; according to the uncertain parameters, comprehensive evaluation values of all links in the quadrangle are calculated; selecting the path with the lowest link comprehensive evaluation value as the optimal route; according to the method, a complex satellite network environment is considered, path search is realized by reducing the search space of routing, and the routing efficiency is improved.

The invention discloses a measurement method for reducing an error in an azimuth angle of a tunnel ground control network, which is characterized by comprising the following steps of: constructing thetunnel ground control network, respectively forming a geodetic quadrangle or triangle by control points at an inlet end and an outlet end of a tunnel, carrying out ground precise distance measurementon all short edges, adopting GNSS measurement to obtain all short edges of an inlet end and an outlet end and independent baselines of connecting edges between the inlet end and the outlet end, performing elevation plane modification on a ground precise distance measurement result of a tunnel ground control network to obtain ground distance measurement data of a control point, under a construction coordinate system, performing two-dimensional joint adjustment on GNSS observation values and the ground precise distance measurement data to obtain a two-dimensional joint adjustment result, and obtaining azimuth angles and errors in the azimuth angles of the independent baselines. According to the method, errors in the short-side azimuth angles of the inlet end and the outlet end can be obviously reduced, and larger transverse through errors can be reduced for the long tunnel.

The invention discloses a method and a system for drawing an electronic map grid in a grid data system. The method comprises the following steps of: drawing a primary polygonal grid boundary of each next level in a polygonal grid boundary of a current level of an electronic map based on boundary data of each next level; searching a first target intersection point and a second target intersection point; an edge passing through the first/second target intersection point or an extension line of the edge extends out of the boundary of the current-level polygonal mesh to serve as a first/second edge of a quadrangle to be drawn, and a connecting line between the first edge and the second edge and the end parts located out of the boundary of the current-level polygonal mesh serves as a third edge of the quadrangle; a connecting line between the first edge and the second edge is used as a fourth edge of the quadrangle, and the fourth edge is completely positioned in the polygonal grid of the next level; performing polygon combination on the polygon mesh of the next level and the quadrangle to obtain a large polygon; and cutting off a non-overlapping region of the large polygon and the current-level polygonal mesh, and taking the non-cut partial region in the large polygon as a next-level target polygonal mesh.

A method for generating 3D entity shape data using image recognition which is performed by a computing device, the method includes the steps of: recognizing a grid matching part having four edge vertices of a quadrangle displayed in an image captured by a camera; generating a cube-shaped 3D space grid of a specific distance unit applied to the image by using the grid matching part; and generating shape data for an external object using the 3D space grid.