Abstract: A method and system for shading large volumetric data sets using partial derivatives computed in screen-space. The method and system provide a fast and efficient shading a large datasets. Screen space derivatives are computed efficiently by evaluating neighboring pixel information together. The method can be efficiently implemented using GPUs (graphics processing units) that provides some access to information about neighboring pixels using ddx and ddy fragment processing functions.

Abstract: A hidden-line removal method is provided which is executed in an image processing apparatus. The method includes the steps of extracting portions of the polygons contained in each of the divided areas on a two-dimensional plane using the projected three-dimensional model and calculating memory consumption for each of the areas using the extracted polygons. The method includes the steps of determining the optimized division style based on the calculated memory consumption and executing the hidden-line removal based on the optimized division style.

Abstract: A three dimensional image is displayed by providing initial data corresponding to the three dimensional image, generating a plurality of sets of data from the initial data, each set of data corresponding to an intersection of the three dimensional image with a surface, and displaying the three dimensional image using a three dimensional display based on the sets of data. A data processor is used to operate on the sets of data to re-center the three dimensional image.

Abstract: A map display apparatus includes a view transformation matrix generation unit which generates a view transformation matrix, including four rows and four columns, for transforming a global coordinate of a three-dimensional object into a view coordinate system; a view transformation matrix change unit which (i) changes, to 0, (a) the value of the first row in the second column and (b) the value of the third row in the second column in the view transformation matrix, in the case where the coordinate transformation is executed by multiplying a coordinate with the view transformation matrix from the left side of the coordinate, and (ii) changes, to 0, (a) the value of the second row in the first column and (b) the value of the second row in the third column in the view transformation matrix, in the case where the coordinate transformation is executed by multiplying the coordinate with the view transformation matrix from the right side of the coordinate; and a view transformation unit which transforms the global co

Abstract: Method for producing an interactive virtual movie, which simulates walking of a user within a real site, comprising: (a) Defining first minimal conditions: (b) Defining second minimal conditions; (c) Moving a scanning apparatus along routes within the site, measuring the x,y, displacement, and angular orientation of the scanning apparatus at any given time, and creating a new node at least whenever such first minimal conditions are met; (d) Obtaining an image data at each node location reflecting a camera unit field of view, and associating the image data and its orientation with the x,y. coordinates of the present node; (e) Finding and registering neighborhood links between pairs of nodes, each link satisfies at least said second minimal conditions; and (f) Further associating with each created link an exit angular orientation and entry angular orientation to nodes of each pair.

Abstract: The invention describes a method and system for use in occlusion culling of polygons in an interactive environment, such as a game. The invention employs a boundary box to simplify the testing of occludee polygons. Occluders and occludees are also transformed into non-interpenetrating, non-overlapping polygons. Winged-edges are employed to minimize a per occludee computational cost due to precision problems that may arise at non-overlapping edges. The invention then proceeds through an active edge list to identify edge discontinuities (e.g., where an edge is added or removed from the active edge list). Depth analysis is employed to determine whether an occluder occludes an occludee at the edge discontinuity. Moreover, the invention only performs depth analysis for those locations of a screen display where an occludee is determined to reside, thereby minimizing unnecessary computations.

Abstract: The size of a tool displayed in a user interface can be dynamically adjusted based on the current needs of the tool. When the user chooses a new function to perform using the tool, the tool's size and appearance is adjusted to an interface tailored for the selected function. To minimize confusion to the user, these dynamic adjustments can be performed using animation effects.

Abstract: A method of creating an animation with a sequence of images which includes the steps of optimising requests for obtaining images from a remote terminal depending on at least one criterion, and creating a file comprising the optimised requests. For example, two computers may be employed wherein a first computer is used to submit requests which are received by the second computer. The second computer optimises the received requests in the form of animations, creates a file, and sends the corresponding data back to the first computer in digital form.

Abstract: An information processing apparatus for generating a three-dimensional image obtained by projecting a three-dimensional space onto a plane and determining a depth of a vertex of a polygon from a viewpoint in the three-dimensional space, the polygon forming a surface of a solid object from which the three-dimensional image is generated, and moving the position of the vertices by the amount of movement determined in accordance with the determined depth.

Abstract: A method is disclosed for culling an object database in a graphics processing system. In one embodiment, the method comprises encoding per-object parameters and culling parameters. The per-object parameters are encoded in texture format thereby creating at least one per-object texture containing the encoded per-object parameters. Next, a fragment program used in a fragment processor of the GPU is optionally updated. The updated fragment program embodies a culling operation. A polygon is then rendered, wherein the rendering step includes per-fragment operations. During the per-fragment operations, the updated fragment program is executed. The culling operation embodied therein (i) accesses the culling parameter, (ii) samples the per-object textures, and (iii) produces cull results for a set of database objects. In this fashion, the fragment processor in the GPU is leveraged to perform computationally intensive culling operations.

Abstract: A fragment program may configure a fragment processor to compute several output positions and associated data for a fragment, effectively scattering the fragment. Each output position may be independent of a position computed for the fragment during rasterization of a primitive. Each output position may be computed based on a point light source position to compute a shadow map corresponding to the point light source. A raster operation unit writes processed fragment data to each output position. Furthermore, the fragment program may configure the fragment processor to compute per-output position parameters for the fragment such as stencil and alpha values.

Abstract: In a visualization system a three-dimensional scene (43) is projected onto a camera's view projection plane (42) from a camera's defined viewpoint (41) and mapped onto a two-dimensional display. For positioning a pointer (45) in the three-dimensional scene (43), the view of the three-dimensional scene is animated automatically to provide to a user the view of the three-dimensional scene with a kinetic depth effect. The view of the three-dimensional scene is animated by applying a spatial transformation to the three-dimensional scene (43) or the camera. The transformation is applied to the three-dimensional (43) scene or the camera such that the projected view of the pointer (45) remains essentially static. The pointer (45) is positioned based on signals received from the user, while the view is animated.

Abstract: A path between specified start and end voxels along a biological object with a lumen, such as a vessel, within a patient image three-dimensional volume data set comprising an array of voxels of varying value is identified using an algorithm that works outwards from the start voxel to identify paths of low cost via intermediate voxels. The intermediate voxels are queued for further expansion of the path using a priority function comprising the sum of the cost of the path already found from the start voxel to the intermediate voxel and the Euclidean distance from the intermediate voxel to the end voxel. A cost function that depends on the voxel density is used to bias the algorithm towards paths inside the object. The number of iterations of the voxel required to find a path from the start to the end voxel, and hence the time taken, can be significantly reduced by scaling the Euclidean distance by a constant. Usefully, the constant is greater than 1, such as between 1.5 and 2.

Abstract: A system and methods are disclosed for automatically approximating an editable surface from a 3D data set or a 3D point set, which may be imaged in the form of a NURBS surface.

Abstract: A method and apparatus for representing a deformable volume of interest in four dimensions is described, where the four dimensions are three spatial dimensions and one temporal dimension including discrete points in time, and where the deformable volume of interest can be represented at intermediate points in time by interpolation.

Abstract: A method of registering a digital image with a polygonal mesh comprising the steps of providing a digital image, providing a polygonal mesh comprising a plurality of vertices that approximates an object in the digital image, propagating a ray from a vertex of the polygonal mesh into the digital image and calculating a line integral of opacity values wherein each opacity value corresponds to the intensity of a pixel of the image through which said ray passes, terminating the ray at a point in the image when an opacity threshold is reached, and adding the termination point to a set of closest points. A registration is computed between the vertices of the polygonal mesh and the set of closest points, and the registration is applied to the polygonal mesh to obtain a new set of vertices.

Abstract: A computer automated process is presented for accelerating the rendering of sparse volume data on Graphics Processing Units (GPUs). GPUs are typically SIMD processors, and thus well suited to processing continuous data and not sparse data. The invention allows GPUs to process sparse data efficiently through the use of scatter-gather textures. The invention can be used to accelerate the rendering of sparse volume data in medical imaging or other fields.

Abstract: A first adding circuit sums an input image signal of a target pixel and a value that is derived by multiplying respective display errors of three pixels, which are before the target pixel by one line, by weighting factors. A gradation candidate converter converts the gradation of the summed image signal to a plurality of available gradation candidates that are convertible when an error of the immediate left pixel is added. A delaying circuit delays the summed image signal. A second adding circuit sums the delayed image signal and a value that is derived by multiplying the error generated in the immediate left pixel by a weighting factor. A gradation selector selects a gradation closest to the gradation of the image signal to which the error is added from a plurality of gradation candidates, and outputs it as an image signal of the target pixel. A differencing circuit determines a display error of the target pixel.

Abstract: A system and method for performing a virtual endoscopy is provided. The method comprises the steps of: calculating a distance map using three-dimensional (3D) data of a lumen; calculating a multiplanar reconstruction (MPR) of the lumen, wherein the MPR is calculated orthogonal to the lumen at an endoscope position; performing a first region growing on the MPR of the lumen at the endoscope position, wherein data associated with the first region is marked; calculating a minimum distance and a maximum distance from the marked data of the first region growing using corresponding distances from the distance map; performing a second region growing on the MPR of the lumen for data outside the first region growing, wherein data associated with the second region is marked; and performing a 3D rendering of the marked data associated with the first region growing and the second region growing.

Abstract: Different rendering techniques are selected for portions of a scene based on statistical estimates of the portions' rendering costs. A scene is partitioned into a bounding volume hierarchy. Each bounding volume includes a statistical model of the spatial distribution of geometric primitives within the bounding volume. An image to be rendered is partitioned into screen regions and each screen region is associated with one or more bounding volumes and their statistical models. The associated statistical models of a screen region are evaluated to estimate the rendering cost, such as the probable number of geometric primitives per pixel, for the screen region. Based on the rendering cost, the screen region is assigned to a dense geometry renderer, such as a ray tracing renderer, or a sparse geometry renderer, such as a rasterization renderer. Rendered screen regions are combined to form a rendered image.