87,497 research outputs found
GRASS: Generative Recursive Autoencoders for Shape Structures
We introduce a novel neural network architecture for encoding and synthesis
of 3D shapes, particularly their structures. Our key insight is that 3D shapes
are effectively characterized by their hierarchical organization of parts,
which reflects fundamental intra-shape relationships such as adjacency and
symmetry. We develop a recursive neural net (RvNN) based autoencoder to map a
flat, unlabeled, arbitrary part layout to a compact code. The code effectively
captures hierarchical structures of man-made 3D objects of varying structural
complexities despite being fixed-dimensional: an associated decoder maps a code
back to a full hierarchy. The learned bidirectional mapping is further tuned
using an adversarial setup to yield a generative model of plausible structures,
from which novel structures can be sampled. Finally, our structure synthesis
framework is augmented by a second trained module that produces fine-grained
part geometry, conditioned on global and local structural context, leading to a
full generative pipeline for 3D shapes. We demonstrate that without
supervision, our network learns meaningful structural hierarchies adhering to
perceptual grouping principles, produces compact codes which enable
applications such as shape classification and partial matching, and supports
shape synthesis and interpolation with significant variations in topology and
geometry.Comment: Corresponding author: Kai Xu ([email protected]
Procedural Modeling and Physically Based Rendering for Synthetic Data Generation in Automotive Applications
We present an overview and evaluation of a new, systematic approach for
generation of highly realistic, annotated synthetic data for training of deep
neural networks in computer vision tasks. The main contribution is a procedural
world modeling approach enabling high variability coupled with physically
accurate image synthesis, and is a departure from the hand-modeled virtual
worlds and approximate image synthesis methods used in real-time applications.
The benefits of our approach include flexible, physically accurate and scalable
image synthesis, implicit wide coverage of classes and features, and complete
data introspection for annotations, which all contribute to quality and cost
efficiency. To evaluate our approach and the efficacy of the resulting data, we
use semantic segmentation for autonomous vehicles and robotic navigation as the
main application, and we train multiple deep learning architectures using
synthetic data with and without fine tuning on organic (i.e. real-world) data.
The evaluation shows that our approach improves the neural network's
performance and that even modest implementation efforts produce
state-of-the-art results.Comment: The project web page at
http://vcl.itn.liu.se/publications/2017/TKWU17/ contains a version of the
paper with high-resolution images as well as additional materia
A Gravitational Theory of the Quantum
The synthesis of quantum and gravitational physics is sought through a
finite, realistic, locally causal theory where gravity plays a vital role not
only during decoherent measurement but also during non-decoherent unitary
evolution. Invariant set theory is built on geometric properties of a compact
fractal-like subset of cosmological state space on which the universe is
assumed to evolve and from which the laws of physics are assumed to derive.
Consistent with the primacy of , a non-Euclidean (and hence non-classical)
state-space metric is defined, related to the -adic metric of number
theory where is a large but finite Pythagorean prime. Uncertain states on
are described using complex Hilbert states, but only if their squared
amplitudes are rational and corresponding complex phase angles are rational
multiples of . Such Hilbert states are necessarily -distant from
states with either irrational squared amplitudes or irrational phase angles.
The gappy fractal nature of accounts for quantum complementarity and is
characterised numerically by a generic number-theoretic incommensurateness
between rational angles and rational cosines of angles. The Bell inequality,
whose violation would be inconsistent with local realism, is shown to be
-distant from all forms of the inequality that are violated in any
finite-precision experiment. The delayed-choice paradox is resolved through the
computational irreducibility of . The Schr\"odinger and Dirac equations
describe evolution on in the singular limit at . By contrast,
an extension of the Einstein field equations on is proposed which reduces
smoothly to general relativity as . Novel proposals for
the dark universe and the elimination of classical space-time singularities are
given and experimental implications outlined
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