79,995 research outputs found
Data-Driven Shape Analysis and Processing
Data-driven methods play an increasingly important role in discovering
geometric, structural, and semantic relationships between 3D shapes in
collections, and applying this analysis to support intelligent modeling,
editing, and visualization of geometric data. In contrast to traditional
approaches, a key feature of data-driven approaches is that they aggregate
information from a collection of shapes to improve the analysis and processing
of individual shapes. In addition, they are able to learn models that reason
about properties and relationships of shapes without relying on hard-coded
rules or explicitly programmed instructions. We provide an overview of the main
concepts and components of these techniques, and discuss their application to
shape classification, segmentation, matching, reconstruction, modeling and
exploration, as well as scene analysis and synthesis, through reviewing the
literature and relating the existing works with both qualitative and numerical
comparisons. We conclude our report with ideas that can inspire future research
in data-driven shape analysis and processing.Comment: 10 pages, 19 figure
Modeling and Correspondence of Topologically Complex 3D Shapes
3D shape creation and modeling remains a challenging task especially for
novice users. Many methods in the field of computer graphics have been proposed
to automate the often repetitive and precise operations needed during the
modeling of detailed shapes. This report surveys different approaches of shape
modeling and correspondence especially for shapes exhibiting topological
complexity. We focus on methods designed to help generate or process shapes
with large number of interconnected components often found in man-made shapes.
We first discuss a variety of modeling techniques, that leverage existing
shapes, in easy to use creative modeling systems. We then discuss possible
correspondence strategies for topologically different shapes as it is a
requirement for such systems. Finally, we look at different shape
representations and tools that facilitate the modification of shape topology
and we focus on those particularly useful in free-form 3D modeling
A Compositional Textual Model for Recognition of Imperfect Word Images
Printed text recognition is an important problem for industrial OCR systems.
Printed text is constructed in a standard procedural fashion in most settings.
We develop a mathematical model for this process that can be applied to the
backward inference problem of text recognition from an image. Through ablation
experiments we show that this model is realistic and that a multi-task
objective setting can help to stabilize estimation of its free parameters,
enabling use of conventional deep learning methods. Furthermore, by directly
modeling the geometric perturbations of text synthesis we show that our model
can help recover missing characters from incomplete text regions, the bane of
multicomponent OCR systems, enabling recognition even when the detection
returns incomplete information
Parametric Surfaces for Augmented Architecture representation
Augmented Reality (AR) represents a growing communication channel, responding to the need to expand reality with additional information, offering easy and engaging access to digital data. AR for architectural representation allows a simple interaction with 3D models, facilitating spatial understanding of complex volumes and topological relationships between parts, overcoming some limitations related to Virtual Reality. In the last decade different developments in the pipeline process have seen a significant advancement in technological and algorithmic aspects, paying less attention to 3D modeling generation. For this, the article explores the construction of basic geometries for 3D model’s generation, highlighting the relationship between geometry and topology, basic for a consistent normal distribution. Moreover, a critical evaluation about corrective paths of existing 3D models is presented, analysing a complex architectural case study, the virtual model of Villa del Verginese, an emblematic example for topological emerged problems. The final aim of the paper is to refocus attention on 3D model construction, suggesting some "good practices" useful for preventing, minimizing or correcting topological problems, extending the accessibility of AR to people engaged in architectural representation
Conic Scan-and-Cover algorithms for nonparametric topic modeling
We propose new algorithms for topic modeling when the number of topics is
unknown. Our approach relies on an analysis of the concentration of mass and
angular geometry of the topic simplex, a convex polytope constructed by taking
the convex hull of vertices representing the latent topics. Our algorithms are
shown in practice to have accuracy comparable to a Gibbs sampler in terms of
topic estimation, which requires the number of topics be given. Moreover, they
are one of the fastest among several state of the art parametric techniques.
Statistical consistency of our estimator is established under some conditions
Mesh2Fab: Reforming Shapes for Material-specific Fabrication
As humans, we regularly associate shape of an object with its built material.
In the context of geometric modeling, however, this interrelation between form
and material is rarely explored. In this work, we propose a novel data-driven
reforming (i.e., reshaping) algorithm that adapts an input multi-component
model for a target fabrication material. The algorithm adapts both the part
geometry and the inter-part topology of the input shape to better align with
material specific fabrication requirements. As output, we produce the reshaped
model along with respective part dimensions and inter-part junction
specifications. We evaluate our algorithm on a range of man-made models and
demonstrate non-trivial model reshaping examples focusing only on metal and
wooden materials. We also appraise the output of our algorithm using a user
study
A Hybrid Channel Model based on WINNER for Vehicle-to-X Application
V2V and V2I channel modeling became recently more of interest. To provide
realistic radio channels either expensive measurements or complex ray tracing
simulations are mostly used. Stochastic channel models are of low complexity
but do not offer that deterministic repeatable realism. Based on the WINNER
channel model and a simple single path model, a hybrid model has been
developed. The concept relies on a layered structure featuring high flexibility
and scalability.Comment: 5 pages, 3 figures, EURO-COST, IC1004, TD(13)0704
Ebb: A DSL for Physical Simulation on CPUs and GPUs
Designing programming environments for physical simulation is challenging
because simulations rely on diverse algorithms and geometric domains. These
challenges are compounded when we try to run efficiently on heterogeneous
parallel architectures. We present Ebb, a domain-specific language (DSL) for
simulation, that runs efficiently on both CPUs and GPUs. Unlike previous DSLs,
Ebb uses a three-layer architecture to separate (1) simulation code, (2)
definition of data structures for geometric domains, and (3) runtimes
supporting parallel architectures. Different geometric domains are implemented
as libraries that use a common, unified, relational data model. By structuring
the simulation framework in this way, programmers implementing simulations can
focus on the physics and algorithms for each simulation without worrying about
their implementation on parallel computers. Because the geometric domain
libraries are all implemented using a common runtime based on relations, new
geometric domains can be added as needed, without specifying the details of
memory management, mapping to different parallel architectures, or having to
expand the runtime's interface.
We evaluate Ebb by comparing it to several widely used simulations,
demonstrating comparable performance to hand-written GPU code where available,
and surpassing existing CPU performance optimizations by up to 9 when
no GPU code exists
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