Co-Planar Stereotaxic Atlas of the Human Brain—3-Dimensional Proportional System: An Approach to Cerebral Imaging, J. Talairach, P. Tournoux. Georg Thieme Verlag, New York (1988), 122 pp., 130 figs. DM 268

Monthly Notices is one of the three largest general primary astronomical research publications. It is an international journal, published by the Royal Astronomical Society. This article 1 describes its publication policy and practice.

Monthly Notices of the Royal Astronomical Society

Initial-value ordinary differential equation solution via variable order Adams method (SIVA/DIVA) package is collection of subroutines for solution of nonstiff ordinary differential equations. There are versions for single-precision and double-precision arithmetic. Requires fewer evaluations of derivatives than other variable-order Adams predictor/ corrector methods. Option for direct integration of second-order equations makes integration of trajectory problems significantly more efficient. Written in FORTRAN 77.

Solving Ordinary Differential Equations

Computational geometry

We present a sketching interface for quickly and easily designing freeform models such as stuffed animals and other rotund objects. The user draws several 2D freeform strokes interactively on the screen and the system automatically constructs plausible 3D polygonal surfaces. Our system supports several modeling operations, including the operation to construct a 3D polygonal surface from a 2D silhouette drawn by the user: it inflates the region surrounded by the silhouette making wide areas fat, and narrow areas thin. Teddy, our prototype system, is implemented as a Java™ program, and the mesh construction is done in real-time on a standard PC. Our informal user study showed that a first-time user typically masters the operations within 10 minutes, and can construct interesting 3D models within minutes.

/pdf/teddy-a-sketching-interface-for-3d-freeform-design-qlbvzvgvwj.pdf

Teddy: a sketching interface for 3D freeform design

This paper presents a new multi-view stereo approach that reconstructs aerial or outdoor scenes in both a planar and a point representation. One of the key features is to integrate two heterogeneous schemes for planar and non-planar reconstruction, given a color segmentation where each segment is classified as either planar or non-planar. In planar reconstruction, an optimal plane for each segment is chosen among possible plane candidates by comparing the remapped reference segment region with multiple target images in parallel on a GPU. In point reconstruction for non-planar objects, remapped pixel descriptors along an epipolar line pair are efficiently matched on a GPU. Our method also detects and discards incorrect segment planes and outliers that have a large 3D discontinuity with the neighboring segment planes. Several aerial and outdoor scene reconstruction results with quantitative analyses are provided.

Gpu-friendly multi-view stereo for outdoor planar scene reconstruction

Author(s): Linsen, Lars; Hamann, Bernd; Joy, Ken | Abstract: For view-dependent visualization, adaptively refined volumetric meshes are used to adapt resolution to given error constraints. A mesh hierarchy based on the '3rd-root-of-2'-subdivision scheme produces structured grids with highest adaptivity. Downsampling filters reduce aliasing effects and lead to higher-quality data representation (in terms of lower approximation error) at coarser levels of resolution. We present a method for applying wavelet-based downsampling filters to adaptively refined meshes. We use a linear B-spline wavelet lifting scheme to derive narrow filter masks. These masks are applicable to adaptively refined meshes without imposing any restrictions on the adaptivity of the meshes, i.\,e., all wavelet filtering operations can be performed without further subdivision steps. We define rules for vertex dependencies in wavelet-based adaptive refinement and resolve them in an unambiguous manner. We use the wavelet filters for view-dependent visualization in order to demonstrate the functionality and the benefits of our approach. When using wavelet filters, less polyhedra need to be traversed by a visualization method and less triangles need to be drawn to satisfy a certain error bound.

/pdf/wavelets-for-adaptively-refined-3rd-root-of-2-subdivision-4lqjumaywp.pdf

Wavelets for adaptively refined '3rd-root-of-2'-subdivision meshes

This paper presents a framework for GPU-accelerated N-view triangulation in multi-view reconstruction that improves processing time and final reprojection error with respect to methods in the literature. The framework uses an algorithm based on optimizing an angular error-based L 1 cost function and it is shown how adaptive gradient descent can be applied for convergence. The triangulation algorithm is mapped onto the GPU and two approaches for parallelization are compared: one thread per track and one thread block per track. The better performing approach depends on the number of tracks and the lengths of the tracks in the dataset. Furthermore, the algorithm uses statistical sampling based on confidence levels to successfully reduce the quantity of feature track positions needed to triangulate an entire track. Sampling aids in load balancing for the GPU's SIMD architecture and for exploiting the GPU's memory hierarchy. When compared to a serial implementation, a typical performance increase of 3–4× can be achieved on a 4-core CPU. On a GPU, large track numbers are favorable and an increase of up to 40× can be achieved. Results on real and synthetic data prove that reprojection errors are similar to the best performing current triangulation methods but costing only a fraction of the computation time, allowing for efficient and accurate triangulation of large scenes.

/pdf/gpu-accelerated-and-efficient-multi-view-triangulation-for-8u1jljgfgz.pdf

GPU-accelerated and efficient multi-view triangulation for scene reconstruction

From 15.07. to 20.07.07, the Dagstuhl Seminar 07291 ``Scientific Visualization'' was held in the International Conference and Research Center (IBFI),Schloss Dagstuhl.
During the seminar, several participants presented their current
research, and ongoing work and open problems were discussed. Abstracts of
the presentations given during the seminar as well as abstracts of
seminar results and ideas are put together in this paper. The first section
describes the seminar topics and goals in general.
Links to extended abstracts or full papers are provided, if available.

https://drops.dagstuhl.de/opus/volltexte/2008/1414/pdf/07291_abstracts_collection.1414.pdf/

07291 Abstracts Collection -- Scientific Visualization

Integration-based flow visualization provides important visual cues about fluid transport. Analyzing the behavior of infinitesimal volumes as opposed to the behavior of rigid particles provides additional details valuable to flow visualization research. Our work concentrates on examining the local velocity gradient tensor along the path of a particle seeded within time-varying flow to produce a visualization highlighting temporal characteristics of particle behaviors, such as deformation. We present a framework for the analysis and visualization of such characteristics, focused on providing concise representations of physically meaningful flow features such as separation regions and vorticity. We apply the derived techniques to two data sets, highlighting the importance of such higher order Lagrangian analysis techniques to time-varying flow analysis.

Kenneth I. Joy

Papers

Gpu-friendly multi-view stereo for outdoor planar scene reconstruction

Wavelets for adaptively refined '3rd-root-of-2'-subdivision meshes

GPU-accelerated and efficient multi-view triangulation for scene reconstruction

07291 Abstracts Collection -- Scientific Visualization

A Framework for the Visualization of Finite-Time Continuum Mechanics Effects in Time-Varying Flow