31 results about "Marching cubes" patented technology

A method for the problem of reconstructing a watertight surface defined by an implicit equation from a finite set of oriented points. As in other surface reconstruction approaches disctretizations of this continuous formulation reduce to the solution of sparse least-squares problems. Rather than forcing the implicit function to approximate the indicator function of the volume bounded by the surface, in the present formulation the implicit function is a smooth approximation of the signed distance function to the surface. Then solution thus introduced is a very simple hybrid FE / FD discretization, which together with an octree partitioning of space, and the Dual Marching Cubes algorithm produces accurate and adaptive meshes.

Systems and methods for tracking a wireless device are disclosed. According to one aspect, the wireless device includes a hybrid global positioning system (GPS) and wireless local area network (WLAN) circuit board for seamless indoor and outdoor tracking. In embodiments, GPS and WLAN data are combined to obtain a position estimate of the device. In other embodiments, the circuit board automatically switches between WLAN and GPS data for indoor and outdoor environments. A Location Based Services (LBS) algorithm for determining the position of a wireless device using WLAN and / or GPS signals is also disclosed. The LBS algorithm is implemented by way of method steps including: sensing GPS and / or WLAN signals, measuring and / or converting the sensed signals to obtain distance data, fusing the distance data, and applying one or more approximation algorithms to the distance data to obtain a position estimate of the wireless device. A method for rendering position data using a Marching Cubes algorithm is further disclosed.

The invention relates to a core fracture identification method based on three-dimensional image information processing, belonging to the technical field of image segmentation. The method comprises the following steps of: scanning a core to be processed by using a CT (computerized tomography) machine, storing a scanned core CT sequence image in a computer, reading the well scanned core CT sequence image by using core three-dimensional image fracture identification software, performing three-dimensional image reconstruction on the core CT sequence image by utilizing a marching cubes algorithm, and performing a series of calculation, getting and screening processed by utilizing the differences among pores, random noise and fracture in morphological features in a three-dimensional data field to achieve the purpose of identifying a core fracture. According to the method provided by the invention, the core fracture can be fast and accurately identified; and the problems of causing error and even mistake due to negligence of communication information of the core fracture between layers in the existing isolate analysis of each core CT sequence image can be solved.

The invention relates to a robust real-time three-dimensional (3D) reconstruction method based on a consumer camera, and aims to solve the problems of high calculation cost and inaccurate and incomplete reconstructed model in the existing method. The method comprises the following steps: 1, estimating the camera pose of each video frame under a scene coordinate system on the basis that a current video frame of a camera is used as input in the camera moving process; 2, selecting an optimized key frame in the video frame for depth estimation; 3, estimating the depth information of each video frame by adopting a quick robust depth estimation algorithm to obtain a depth map of each video frame; and 4, converting the depth map of each video frame into an unblind distance field, parallel executing weighted average of TSDF on voxel, incrementally fusing the depth map of each video frame, and constructing a triangular mesh surface by a Marching cubes algorithm. The method is applied to the field of image processing.

The invention relates to a simulated modeling method of the interaction of moving objects and water based on SPH, which pertains to the computer graphics and the virtual reality field. The method of the invention comprises the following steps: 1. the simulation is initialized, and the initialization comprises the initial configuration of particle properties and the establishment of a neighboring particle list of the particles; 2. neighboring particle lists of water particles are updated; 3. the positions and states of movements of the water particles at the next time step are calculated; 4. the positions and states of movements of object particles at the next time step are calculated; 5. whether the particles collide with the obstacles is judged, if the collision happens, the movement rates and directions of the particles are altered, or the sixth step is directly executed; 6. a water surface topological structure is constructed on the basis of marching cubes algorithm; 7. a graph drawing language is adopted to draw and display the water surface and the object; 8. whether the simulation is stopped is judged. The method of the invention can be utilized to simulate the interactions of moving objects and water and obtain comparatively true simulation results.

The invention discloses a method for extracting the centerline of coronary artery blood vessels, comprising the following steps: Step S1: input the data of coronary artery tree and aorta; Step S2: automatically extract the starting point of coronary artery tree and the end of all branch vessels point; step S3: use the Marching Cubes algorithm to generate grid model data from the coronary tree data; step S4: carry out Delaunay triangulation processing to all points on the grid and generate a three-dimensional Voronol diagram; step S5: on the Voronoi diagram Locate the start point and the end points of all branch vessels, and calculate the shortest path between the start point and the end point to obtain several corresponding curves; step S6: perform equidistant filtering on the obtained curves to form a complete centerline data; its advantage is to automatically obtain the start point and end point of the coronary artery, which ensures the accuracy of the centerline and makes full use of the powerful processing power of the computer, eliminating the steps of obtaining the start point and end point by manual interaction, which greatly Improve the efficiency of doctors' diagnosis.

The invention provides a method for designing a three-period minimum curved surface variable-density lattice structure for additive manufacturing. Firstly, based on the elastic structure static balance theory and unit "life and death" technology, the finite element model of the elastic structure is established, and the extraction method of the structural unit bearing capacity is designed; then, the vector data of the structural unit bearing capacity and the unit node data of the structural finite element model are calculated, And give the bearing capacity cloud diagram of the structural unit; then, process the bearing capacity data of the structural unit, including surface interpolation, spline interpolation and normalization, combine the processed bearing capacity data of the structural unit with the TPMS function; then, combine the TPMS The porosity of the porous structure is used as the evaluation index of the variable density lattice structure, and the Marching cubes algorithm is used to realize the modeling of the TPMS variable density surface; finally, the Boolean operation is performed on the TPMS variable density surface model and the original structure model to realize the surface closure. The invention solves the problems of numerical instability and low efficiency of the topological structure existing in the design of the traditional lattice structure.

Disclosed are a three-dimensional reconstruction method, apparatus, and device, and a storage medium. The three-dimensional reconstruction method comprises: determining a relative camera pose of a current depth image key frame with respect to a preset depth image key frame by using a preset fast global optimization algorithm; determining at least one effective space block corresponding to the current depth image key frame by using a sparse sampling method; fusing the at least one effective space block with a first three-dimensional grid model corresponding to a previous depth image key frame on the basis of the relative camera pose, to obtain a second three-dimensional grid model corresponding to the current depth image key frame; and generating an equivalent contour surface of the second three-dimensional grid model by using an accelerated marching cubes algorithm, to obtain a three-dimensional reconstruction model of a target scene.

The invention relates to a micro-CT technology-based reservoir core three-dimensional entity model reconstruction method. The method includes the following steps that: a micro-CT technology is utilized to scan a reservoir core, so that a sectional scanning image of the reservoir core can be obtained, so that a CT image of a real reservoir core can be obtained, and a watershed algorithm is adopted to perform image segmentation on the CT image, so that the three-dimensional data of the image can be obtained; a Marching Cubes algorithm is adopted to generate a three-dimensional surface model of the reservoir core; and with the three-dimensional surface model of the reservoir core adopted as constraints, a constrained Delaunay tetrahedralization algorithm is utilized to generate the three-dimensional entity model of the reservoir core. According to the method of the invention, the three-dimensional entity model of the real reservoir core is established based on the sectional scanning image of the reservoir core, so that the obtained three-dimensional entity model of the reservoir core is more approximate to the structure of a real reservoir core. The method of the invention has the advantages of high accuracy and high efficiency. With the method adopted, defects of poor accuracy and low efficiency in the reconstruction of the three-dimensional entity model of a reservoir core in the prior art can be eliminated, and an effective guarantee can be provided for reservoir core simulation characteristic research.

The invention discloses an adaptive hierarchical chest large data display implementation method, which comprises the following steps: dividing a CT (computed tomography) sectional image into a target layer image sequence and a background layer image sequence; performing interlayer cubic convolution interpolation on the divided target layer image sequence to form volume data of which each axial resolution is appropriate; making a clear surface drawing by a marching cubes algorithm; performing intraformational and interlayer sampling on the data of the background layer sequence to obtain uninteresting region data of which the resolution is reduced; making a rough body drawing for the data by a ray casting algorithm; displaying the drawing results of the clear surface drawing and the rough body drawing at the same time, and performing hybrid three-dimensional visualization. By the method, the local resolution in the interesting region is increased, and the anisotropic resolution of the uninteresting region is reduced, so that a user is facilitated to know the structure information of a local interesting region, the data volume is decreased and drawing can be implemented on an ordinary computer.

The invention presented in this paper is called a block-based surface reconstruction method from point cloud data based on deep learning. The invention discloses a method for reconstructing a surface model from a point cloud based on deep learning. The method utilizes point cloud data in three-dimensional space to generate SDF (Signed Distance Field, directed distance field) in blocks and integrates each block to obtain a complete SDF, and finally use the Marching Cubes algorithm to get the final patch data. The present invention can still perform robustly in the presence of noise in the point cloud data, especially in the case of normal information deviation, greatly reducing the requirement for the direction accuracy of the collected point cloud data; during operation, the present invention can also process in parallel ,efficient. As for the application of the present invention, it mainly focuses on the field of three-dimensional object reconstruction, and has wide application space in three-dimensional modeling in digital entertainment, computer-aided design and the like.