Volume carving is a well established method for visual hull reconstruction and has been successfully applied in plant phenotyping, especially for 3d reconstruction of small plants and seeds. When imaging larger plants at still relatively high spatial resolution (≤1 mm), well known implementations become slow or have prohibitively large memory needs. Here we present and evaluate a computationall...

We propose a generic point cloud encoder that compresses geometry data including positions and normals of point samples corresponding to 3D objects with arbitrary topology. In this work, the coding process is led by an iterative octree cell subdivision of the object space. At each level of subdivision, positions of point samples are approximated by the geometry centers of all tree-front cells w...

Conservation laws are solved by a local Galerkin nite element procedure with adaptive space-time mesh reenement and explicit time integration. A distributed octree structure representing a spatial decomposition of the domain is used for mesh generation, and later may be used to correct for processor load imbalances introduced at adaptive enrichment steps. A Courant stability condition is used t...

The Parallel Virtual Machine (PVM) tool has been used for a distributed implementation of Greg Ward’s Radiance code. In order to generate exactly the same primary rays with both the sequential and the parallel codes, the quincunx sampling technique used in Radiance for the reduction of the number of primary rays by interpolation, must be left untouched in the parallel implementation. The octree...

A robust and eecient algorithm for discretization of tensor product polynomial surfaces is presented. The advancing front technique operating directly on the surface in the physical space is employed. This avoids diiculties with the anisotropic trian-gulation of parametric space of these surfaces and also guarantees the creation of well shaped triangles even in case of degenerated or badly para...

We introduce a new approach to approximate generalized 3D Voronoi diagrams for different site shapes (points, spheres, segments, lines, polyhedra, etc) and different distance functions (Euclidean metrics, convex distance functions, etc). The approach is based on an octree data structure denoted Voronoi-Octree (VO) that encodes the information required to generate a polyhedral approximation of t...

We present an algorithm to compute an approximation of the generalized Voronoi diagram (GVD) on arbitrary collections of 2D or 3D geometric objects. In particular, we focus on datasets with closely spaced objects; GVD approximation is expensive and sometimes intractable on these datasets using previous algorithms. With our approach, the GVD can be computed using commodity hardware even on datas...

This paper describes an algorithm to extract adaptive and quality quadrilateral/hexahedral meshes directly from volumetric imaging data. First, a bottom-up surface topology preserving octree-based algorithm is applied to select a starting octree level. Then the dual contouring method is used to extract a preliminary uniform quad/hex mesh, which is decomposed into finer quads/hexes adaptively wi...

This paper addresses the problem of constructing plans and schedules for resources that must obey spatial constraints in addition to time and capacity constraints. Spatial constraints are relevant in environments that involve mobile resources whose movements must be coordinated to avoid collisions and near-misses. In air-campaign planning, for example, aircraft are allocated to missions that mu...

An automat ic system for p lanning safe t r a j e c t o r i e s f o r a computer c o n t r o l l e d manipulator among obs tac les i s a key component o f r o b o t assembly operations. This paper describes an a lgor i thm t rans forming C a r t e s i a n o b s t a c l e s i n t o o b s t a c l e s i n t h e space o f t h e f i r s t t h r e e j o i n t s o f a man ipu la to r w i th s i...