10,855 research outputs found
MVPNet: Multi-View Point Regression Networks for 3D Object Reconstruction from A Single Image
In this paper, we address the problem of reconstructing an object's surface
from a single image using generative networks. First, we represent a 3D surface
with an aggregation of dense point clouds from multiple views. Each point cloud
is embedded in a regular 2D grid aligned on an image plane of a viewpoint,
making the point cloud convolution-favored and ordered so as to fit into deep
network architectures. The point clouds can be easily triangulated by
exploiting connectivities of the 2D grids to form mesh-based surfaces. Second,
we propose an encoder-decoder network that generates such kind of multiple
view-dependent point clouds from a single image by regressing their 3D
coordinates and visibilities. We also introduce a novel geometric loss that is
able to interpret discrepancy over 3D surfaces as opposed to 2D projective
planes, resorting to the surface discretization on the constructed meshes. We
demonstrate that the multi-view point regression network outperforms
state-of-the-art methods with a significant improvement on challenging
datasets.Comment: 8 pages; accepted by AAAI 201
A limiter-based well-balanced discontinuous Galerkin method for shallow-water flows with wetting and drying: Triangular grids
A novel wetting and drying treatment for second-order Runge-Kutta
discontinuous Galerkin (RKDG2) methods solving the non-linear shallow water
equations is proposed. It is developed for general conforming two-dimensional
triangular meshes and utilizes a slope limiting strategy to accurately model
inundation. The method features a non-destructive limiter, which concurrently
meets the requirements for linear stability and wetting and drying. It further
combines existing approaches for positivity preservation and well-balancing
with an innovative velocity-based limiting of the momentum. This limiting
controls spurious velocities in the vicinity of the wet/dry interface. It leads
to a computationally stable and robust scheme -- even on unstructured grids --
and allows for large time steps in combination with explicit time integrators.
The scheme comprises only one free parameter, to which it is not sensitive in
terms of stability. A number of numerical test cases, ranging from analytical
tests to near-realistic laboratory benchmarks, demonstrate the performance of
the method for inundation applications. In particular, super-linear
convergence, mass-conservation, well-balancedness, and stability are verified
Behavior of triangular shell element stiffness matrices associated with polyhedral deflection distributions
Stiffness matrices derived for triangular shell elements associated with polyhedral deflection distribution
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