50 results about "Signed distance function" patented technology

A method for hole-filling in 3D models includes identifying vertices adjacent to hole boundaries in a mesh of points on a digital image and constructing a signed distance function based on vertices adjacent to hole boundaries. A Radial Basis Function is fit based on the constructed signed distance function and evaluated on a grid, which include the hole. The points on the hole surface are extracted and meshed to fill the hole.

A method for registering two three-dimensional shapes is disclosed whereby the two shapes are represented as zero level set of signed distance functions and the energy between these two functions is minimized. In a first embodiment, two undetailed ear impression models are rigidly registered with each other. In another embodiment, a detailed ear impression is initially aligned with an undetailed ear impression model and, then, the detailed ear impression model is rigidly registered with the undetailed ear impression model as a function of the signed distance functions. In accordance with another embodiment, an undetailed ear impression model is non-rigidly registered with a template ear impression model as a function of the signed distance functions.

A method and system are disclosed for operating a controller of and a RKE system to provide for short distance functions that are actuatable from a key fob at a shorter distance from the vehicle than other long distance functions. This may include receiving a desired type of radio frequency signal; actuating a high gain mode of a receiver of the controller; detecting a message from an acceptable remote keyless entry transmitter; decoding a function code portion of the message; changing the receiver from the high gain mode to a lower gain mode if the function code is not a long distance function; decoding a remaining portion of the message; determining if the remaining portion of the message was decoded properly; and performing the requested function if the remaining portion of the message was decoded properly.

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.

An embodiment of the present invention may be a system or method for simulating the flow of a single-phase fluid flow. Markers represent a moving fluid boundary of the single-phase fluid at a first point in time. The moving fluid boundary separates a simulation space into a fluid space and a non-fluid space. The single-phase fluid inhabits the fluid space. A signed distance function is evaluated at points surrounding the moving fluid boundary based upon markers. The curvature of the moving fluid boundary based on the signed distance function is evaluated near the markers in the non-fluid space. The curvature is not evaluated at the moving fluid boundary. The velocity of the fluid is calculated based upon the curvature of the level set in the non-fluid space. Update the position of the moving fluid boundary at a second point in time based on the velocity of the fluid.

The present invention discloses an object three-dimensional reconstruction method and apparatus. The object three-dimensional reconstruction method includes the following steps that: the initial local truncated signed distance function (TSDF ) value of a voxel in a three-dimensional space is obtained; an optimization problem is solved, the global TSDF value of the voxel is obtained; and an object is reconstructed in a three-dimensional manner based on the global TSDF value. According to the optimization problem, the global TSDF value of the voxel is obtained based on the final local TSDF values of the voxel; the final local TSDF value of the voxel is equal to the initial TSDF value of a voxel which is corresponding to the voxel which has been subjected to rigid transformation; variables are the global TSDF value of the voxel and the parameter of the rigid transformation; and a cost function is related to the sum of squares of the difference of the global TSDF value of the voxel and the initial local TSDF value of the voxel corresponding to the voxel which has been subjected to the rigid transformation.

The invention discloses a human body vein image feature extraction method which comprises the steps of acquiring a human body vein image and establishing the image in a coordinate system, and then extracting the vein direction features through a directional filter. The method is characterized in that vein direction feature extraction through the directional filter is realized by performing convolution operation on the image established in the coordinate system by use of Radon transform to extract the features of the vein image. The whole feature extraction process comprises the following steps: (1) setting a distance function, which is shown in the description; (2) setting a neighborhood consistent with the distance function and dividing the neighborhood into k directions: Lk={(i, j):j=k(i-i0)+j0, i belongs to Zp}, wherein (i, j) belongs to local(i0, j0); and (3) calculating the energy response of the k directions according to a formula in the description. By adopting the human body vein image feature extraction method of the invention, excessive redundant information is removed, the complexity of calculation and the amount of calculation are reduced, more effective information can be contained, and the effective range of the filter neighborhood is determined through construction of the distance function so as to get a better identification effect.

A method for segmenting tubular structures in medical images includes providing at least a start point and an end point in a digital image volume, minimizing an action surface U0(p) which, at each image point p, corresponds to a minimal energy integrated along a path that starts at start point p0 and ends at p, sliding back on the minimal action surface from an end point to the start point to find a minimal path connecting the terminal points, initializing a level set function with points on the minimal path, and evolving the level set function to find a surface of a structure about the minimal path, wherein the level set function is constrained to be close to a signed distance function and wherein the level set function is prevented from growing wider than a predetermined diameter R, wherein the surface about the minimal path defines a tubular structure.

The invention discloses a 3D object reconstruction method and device. The method comprises that an initial local TSDF (Truncated Signed Distance Function) value of a voxel in a 3D space is obtained; an optimization problem is solved to obtain a global TSDF value of the voxel; and 3D reconstruction of an object is realized on the basis of the obtained global TSDF value. In the optimization problem, the global TSDF value of the voxel is obtained on the basis of a final local TSDF value of the voxel, the final local TSDF value of the voxel equals an initial local TSDF value of a corresponding voxel which is obtained by carrying out non-rigid transformation on the original voxel, variables refer to parameters of the global TSDF value and non-rigid transformation of the voxel, and a cost function is related to factors including a quadratic sum of differences between the global TSDF values of specific voxels and initial local TSDF values of voxels obtained by carrying out non-rigid transformation on the specific voxels as well as a sum of offset amounts, caused by the non-rigid transformation, of the specific voxels.