843 results about "Computer graphics" patented technology

Methods, systems, devices and computer program products operable in a computer graphics system include constructing a hierarchical ray tracing acceleration data structure comprising a tree structure, the modes of which are generated utilizing a bounding interval hierarchy based on defining an axis-aligned scene bounding box and two parallel planes to partition a set of objects in a sense into left objects and right objects, and matching split planes to object bounding boxes. The two planes are perpendicular to a selected one of x, y, or z-axes. Given a splitting plane, each object in an image is classified either left or right based on a left/right selection criterion, and two splitting plane values of the child modes are determined by the maximum and minimum coordinate of the left and right objects, respectively.

Methods for defining smooth and continuous coordinate systems in a volume comprised of a lattice structure of guide columns derived from arbitrarily modeled surface topologies involving polygons, nurbs, linear segments, and subdivision surfaces. Applications of these techniques in computer graphics and computer animation include: (1) the definition of pseudo-coordinate systems for use in creating geometry which must grow from said surface (2) the creation of a highly stable coordinate system involving guide columns in which Cartesian physical simulations may be carried out and rendered as well as deformed and rerendered if desired.

The present invention provides methods, systems and computer program code (software) products for terminating spatial partition hierarchies and other hierarchies by a priori bounding, thereby to provide, among other aspects, more efficient ray tracing in computer graphics systems.

Systems and methods are provided for controlling texture sampling in connection with computer graphics in a computer system. In various embodiments, improved mechanisms for controlling texture sampling are provided that enable 3-D accelerator hardware to greatly increase the level of realism in rendering, including improved mechanisms for (1) motion blur; (2) generating anisotropic surface reflections (3) generating surface self-shadowing (4) ray-cast volumetric sampling (4) self-shadowed volumetric rendering and (5) self-shadowed volumetric ray-casting. In supplementing existing texture sampling techniques, parameters for texture sampling may be replaced and/or modified.

A digital elevation database is compressed to create a compressed digital map database which is used by a digital computer system for displaying three-dimensional terrain data in the form of polygons. The compressed digital map database is produced from a database of elevation points by selecting every mth row and every nth column, thereby resulting in a reduction of database storage requirements. During program run-time the intersection of rows and columns forms cells with four corners. The elevation value of a center elevation point for each cell is formed by various methods, thereby creating a cell made up of four three-dimensional triangles. One method for creating the elevation of the center elevation point uses the elevations of the four corners of the cell. Another method uses extrapolated elevation values from the cell's extended diagonals. The three-dimensional triangles formed from the center elevation point are then transformed and projected using standard computer graphics methods on a digital computer to produce a three-dimensional projected display.

The invention relates to a scattered point cloud Delaunay triangulation curved surface reconstruction method based on a mapping method and belongs to the field of a computer graphics and virtual reality technology. The method specifically includes the first step of obtaining original point cloud data of a target, the second step of obtaining K-level neighborhoods and unit normal vectors of all points in the original point cloud data, the third step of fragmenting the point cloud data, the fourth step of parameterizing fragmented point clouds to a two-dimensional plane, the fifth step of conducting Delaunay triangulation on the point clouds in the two-dimensional plane and mapping the point clouds back to corresponding three-dimensional space, and the sixth step of optimizing an initial triangle mesh model. Compared with the prior art, the scattered point cloud Delaunay triangulation curved surface reconstruction method based on the mapping method has the advantages that the quality of a triangle mesh can be ensured and triangle meshing on the scattered point clouds can be quickly realized when mesh modeling is carried out on large-scale point cloud data, and the method has a better effect on large-scale point clouds.

A computer graphics system may comprise a graphics processor, a sample buffer, and a sample-to-pixel calculation unit. The graphics processor renders samples into the sample buffer in response to received graphics data. The sample-to-pixel calculation unit generates a plurality of output pixels by filtering the rendered samples based on a filter function. The pixels may be computed by generating a weighted sum of sample values (e.g. red sample values) for samples falling within the filter support. The coefficients used in the weighted sum may be added to form a normalization factor. One weighted sum of sample values may be computed per pixel attribute such as red, green, blue and alpha. The normalization factor may be computed in parallel with one or more of the weighted sums. Normalized pixel values may be obtained by dividing the weighted-sums by the normalization factor.

The invention discloses an expression cloning method and device capable of realizing real-time interaction with a virtual character and belongs to the fields such as computer graphics and virtual reality. The method includes the following steps that: 1, modeling and skeleton binding are performed on the virtual character; 2, the basic expression base of the virtual character is established; 3, expression input training is carried out: the maximum displacement of facial feature points under each basic expression is recorded; 4, expression tracking is carried out: the facial expression change of a real person is recorded through motion capture equipment, and the weights of the basic expressions are obtained through calculation; 5, expression mapping is carried out: the obtained weights of the basic expressions are transferred to the virtual character in real time, and rotation interpolation is performed on corresponding skeletons; and the real-time rendering output of the expression of the virtual character is carried out. With the method adopted, the expression of the virtual character can be synthesized rapidly, stably and vividly, so that the virtual character can perform expression interaction with the real person stably in real time.

The invention provides a method for measuring and reconstructing a tree based on single three-dimensional laser scanning, and relates to the technologies of computer graphs and computer vision. The method comprises steps of data preprocessing, axial estimation, three-dimensional framework computation and three-dimensional model generation. The method only utilizes single scanning data of a laser scanner to obtain branch shape and radius information faithful to the primary tree, carries out main operations in a two-dimensional image space, has simple and effective algorithm and accurate reconstruction result, and has important application values in the computer graphics application fields such as virtual reality, computer game, natural scene simulation, urban landscape design and the like and in the fields such as agriculture and forestry investigation, tree measurement, etc.

The invention discloses a method for fast constructing a high-accuracy personalized face model on the basis of facial images, which belongs to the cross field of computer vision and computer graphics, and aims at achieving the purposes of fast reconstructing a personalized 3D geometrical facial model and a high-accuracy 2D facial texture mapping on the basis of real facial images. The method comprises the following steps: firstly, shooting five facial images from multiple angles; secondly, marking positions and corresponding relationships of forty-one characteristic points on the facial images and a neutral facial model; thirdly, aligning the projection of the neutral facial model on a virtual camera focal plane with the facial images; fourthly, carrying out hierarchical geometrical deformation on the neutral facial model to obtain the personalized geometrical facial model; and finally, synthesizing the high-accuracy facial texture mapping according to the five facial images. The face modeling method has the advantages of convenience for data acquisition, high modeling speed and modeling accuracy, and the like, and achieves higher practical values in the fields of video communication, electronic games, man-machine interaction, and the like.

The invention relates to a caption rendering technology in a field of producing television programs, in particular to a caption rendering method based on a curve-profiled closed loop domain and a pixel mask code matrix. The method is that: after a Bezier curve vector profile of a caption object is discretized into a polygon vector, according to the direction and embordering type of a polygon, the polygon vector used for embordering is further created, thus systematically combining the computer graphics with the digital image processing, converting the vector information of the caption object into the pixel mask code matrix based on a contour line and applying the pixel mask code matrix throughout all links of the caption rendering; therefore, the effect of the caption rendering is improved, the ever-increasing demands of the caption quality and the caption effect from the television programs producing and broadcasting organizations are sufficed, the important social property of serving the mass people by television media is reflected even more directly, and better social benefits are obtained.

The invention relates to non-photorealistic rendering in computer graphics, in particular to digital simulation and synthesis with artistic style of Yunnan heavy-color painting, and belongs to the technical field of non-photorealistic graphic rendering. The digital simulation and synthesis are characterized in that: the digital simulation and synthesis comprise an establishment and management module of a Yunnan heavy-color painting basic graphic element library, a graphic element library-based Yunnan heavy-color painting traditional delineation drawing rendering module, and a Yunnan heavy-color painting traditional delineation drawing-based coloring and rendering module. The basic graphic element library is used for providing graphic elements needed by foreground traditional delineation drawings, such as hair, facial forms, trunks and the like. The Yunnan heavy-color painting traditional delineation drawing rendering module can select appropriate graphic elements from the graphic element library to combine the graphic elements by layers so as to generate the Yunnan heavy-color painting traditional delineation drawings. In order to harmoniously collocate all the graphic elements, a system provides multiple kinds of operation for the graphic elements, such as translation, selection, scaling and the like and can modify the shapes of the graphic elements at the same time. The Yunnan heavy-color painting traditional delineation drawing-based coloring and rendering module is in charge of coloring the traditional delineation drawings, and the effects of coloring can reflect texture characteristics and color characteristics in an original drawing of the heavy-color painting, and special characteristic simulation of the Yunnan heavy-color painting, such as character edge hollow sense, background fusion and the like is realized.

The present invention belongs to the computer graphics field, and concretely relates to a RGB-D and SLAM scene reconfiguration method based on the FAST and FREAK feature matching algorithm. The method comprises: performing calibration of the Kinect; performing FAST feature point extraction of a color image, employing the FREAK feature descriptors to perform image matching, employing the RANSAC algorithm of the feature points to reject the exterior points, and retaining the internal points. The RGB-D and SLAM scene reconfiguration method based on the FAST and FREAK feature matching algorithm screens the key frames and performs cloud point jointing of the key frames so as to greatly reduce the joint number of times of the cloud points. The RGB-D and SLAM scene reconfiguration method based on the FAST and FREAK feature matching algorithm employs the loop detection algorithm based on the graph optimization to construct a posture graph and perform global optimization so as to greatly reduce the error accumulation.

This invention discloses a kind of digitized measure and reconstruction method and equipment that can capture the three-dimensional space object image, which based on computer stereo vision, computer graphics and optical imaging theory. By at least two image sensors that with the set distance and known parameters, it images the same space object and gets at least two opposite pictures, which are transferred to the computer. Then it confirms the three-dimensional coordinates at any target point based on the optical imaging theory. According to the three-dimensional coordinates of multiple target points, it determines the geometric parameter of space object by the geometrical relationship and finishes the measurement of space object. According to the geometric parameter of measured space object, it can draw interactively with the existing drawing software, or build the three-dimensional digital model directly.