In 2D-3D Medical Image Registration (MIR), preoperative 3D CT images are registered with intraoperative 2D X-rays images obtained by fluoroscopy or Electronic Portal Imaging Devices (EPID). 2D-3D MIR is established by computing Digitally Reconstructed Radiograph (DRR) images rendered from the volumetric data and is useful in many medical procedures where surgical planning is undertaken using vo...

A volume sculpting system is presented. The system provides tools for interactive editing of a voxel raster that is stored in an octree data structure. Two different modes of sculpting are supported: Sculpting by adding and subtracting solids, and sculpting with tools that are based on a spray can metaphor. The possibility of extending the method to support multiresolution sculpting is discusse...

The quality of images produced by Discrete Ray-Tracing voxel spaces is highly dependent on 3d grid resolution. The huge amount of memory needed to store such grids often discards discrete Ray-Tracing as a practical visualization algorithm. The use of an octree can drastically change this when most of space is empty, as such is the case in most scenes. Although the memory problem can be bypassed...

Octrees are used in many 3-D representation problems because they provide a compact data structure, allow rapid access to occupancy information, and implement many geometric manipulation algorithms efficiently. The initial acquisition of the 3-D information, however, is a common problem. This paper describes an algorithm to construct the octree representation of a 3-D object from silhouette ima...

We introduce a tiled 3D MIP map representation of global illumination data. The representation is an adaptive, sparse octree with a “brick” at each octree node; each brick consists of 83 voxels with sparse irradiance values. The representation is designed to enable efficient caching. Combined with photon tracing and recent advances in distribution ray tracing of very complex scenes, the result ...

This paper discusses a numerical technique that approximates an implicit surface with a polygonal representation. The implicit function is adaptively sampled as it is surrounded by a spatial partitioning. The partitioning is represented by an octree, which may either converge to the surface or track it. A piecewise polygonal representation is derived from the octree. The technique is insensitiv...

We present an algorithm for fast continuous collision detection between points and signed distance fields. Such robust queries are often needed in computer animation, haptics and virtual reality applications, but have so far only been investigated for polygon (triangular) geometry representations. We demonstrate how to use an octree subdivision of the distance field for fast traversal of distan...

Techniques are presented to progressively approximate and compress in a lossless manner two-colored (i.e. binary) 3D objects (as well as objects of arbitrary dimensionality). The objects are represented by a region octree implemented using a pointerless representation based on locational codes. Approximation is achieved through the use of a forest. This method labels the internal nodes of the o...