1,719 research outputs found
A Neural Algorithm of Artistic Style
In fine art, especially painting, humans have mastered the skill to create
unique visual experiences through composing a complex interplay between the
content and style of an image. Thus far the algorithmic basis of this process
is unknown and there exists no artificial system with similar capabilities.
However, in other key areas of visual perception such as object and face
recognition near-human performance was recently demonstrated by a class of
biologically inspired vision models called Deep Neural Networks. Here we
introduce an artificial system based on a Deep Neural Network that creates
artistic images of high perceptual quality. The system uses neural
representations to separate and recombine content and style of arbitrary
images, providing a neural algorithm for the creation of artistic images.
Moreover, in light of the striking similarities between performance-optimised
artificial neural networks and biological vision, our work offers a path
forward to an algorithmic understanding of how humans create and perceive
artistic imagery
The planning of a South African airborne synthetic aperture radar measuring campaign
Bibliography: leaves 153-163.This thesis sets out the results of work done in preparation for a South African Airborne Synthetic Aperture Radar (SAR) measuring campaign envisaged for 1994/5. At present both airborne and spaceborne SARs have found a niche in remote sensing with applications in subsurface mapping, surface moisture mapping, vegetation mapping, rock type discrimination and Digital Elevation Modelling. Since these applications have considerable scientific and economic benefits, the Radar Remote Sensing Group at the University of Cape Town committed themselves to an airborne SAR campaign. The prime objective of the campaign is to provide the South African users with airborne SAR data and enable the Radar Remote Sensing Group to evaluate the usefulness of SAR as a remote sensing tool in South Africa
A robust numerical method to study oscillatory instability of gap solitary waves
The spectral problem associated with the linearization about solitary waves
of spinor systems or optical coupled mode equations supporting gap solitons is
formulated in terms of the Evans function, a complex analytic function whose
zeros correspond to eigenvalues. These problems may exhibit oscillatory
instabilities where eigenvalues detach from the edges of the continuous
spectrum, so called edge bifurcations. A numerical framework, based on a fast
robust shooting algorithm using exterior algebra is described. The complete
algorithm is robust in the sense that it does not produce spurious unstable
eigenvalues. The algorithm allows to locate exactly where the unstable discrete
eigenvalues detach from the continuous spectrum. Moreover, the algorithm allows
for stable shooting along multi-dimensional stable and unstable manifolds. The
method is illustrated by computing the stability and instability of gap
solitary waves of a coupled mode model.Comment: key words: gap solitary wave, numerical Evans function, edge
bifurcation, exterior algebra, oscillatory instability, massive Thirring
model. accepted for publication in SIAD
Onion gene expression in response to ethylene and 1-MCP
Onion is regarded as a non-climacteric vegetable. In onions, however,
ethylene can suppress sprouting while the ethylene binding inhibitor, 1-MCP (1-
methylcyclopropene) can also suppress sprout growth yet, it is unknown how ethylene
and 1-MCP elicit the same response. In this study, onions were treated with 10 μL L-1
ethylene or 1 μL L-1 1-MCP individually or in combination for 24 h at 20°C before or
after curing (six weeks) at 20 or 28°C then stored at 1°C. Following curing, a subset
of these same onions was stored separately under continuous air or ethylene (10 μL L-
1) at 1°C
Onions treated with ethylene and 1-MCP in combination after curing for 24 h
had reduced sprout growth as compared with the control 25 weeks after harvest.
Sprout growth following storage beyond 25 weeks was only reduced through
continuous ethylene treatment. This observation was supported by a higher proportion
of down-regulated genes characterised as being involved in photosynthesis measured
using a newly developed onion microarray. Physiological and biochemical data
suggested that ethylene was being perceived in the presence of 1-MCP since sprout
growth was reduced in onions treated with 1-MCP and ethylene applied in
combination but not when applied individually. A cluster of probes representing
transcripts up-regulated by 1-MCP alone but down-regulated by ethylene alone or in
the presence of 1-MCP support this suggestion. Ethylene and 1-MCP both down52
regulated a probe tentatively annotated as an ethylene receptor as well as EIN3,
suggesting that both treatments down-regulate the perception and signalling events of
ethylene
Controlling Perceptual Factors in Neural Style Transfer
Neural Style Transfer has shown very exciting results enabling new forms of
image manipulation. Here we extend the existing method to introduce control
over spatial location, colour information and across spatial scale. We
demonstrate how this enhances the method by allowing high-resolution controlled
stylisation and helps to alleviate common failure cases such as applying ground
textures to sky regions. Furthermore, by decomposing style into these
perceptual factors we enable the combination of style information from multiple
sources to generate new, perceptually appealing styles from existing ones. We
also describe how these methods can be used to more efficiently produce large
size, high-quality stylisation. Finally we show how the introduced control
measures can be applied in recent methods for Fast Neural Style Transfer.Comment: Accepted at CVPR201
Rotation of Coulomb crystals in a magnetized inductively coupled complex plasma
Under suitable conditions, micron-sized dust particles introduced into inductively coupled argon plasma form a stable microscopic crystal lattice, known as a Coulomb (or plasma) crystal. In the experiment described, an external axial magnetic field was applied to various configurations of Coulomb crystal, including small crystal lattices consisting of one to several particles, and large crystal lattices with many hundreds of particles. The crystals were observed to rotate collectively under the influence of the magnetic field. This paper describes the experimental procedures and the preliminary results of this investigation
Texture Modelling Using Convolutional Neural Networks
We introduce a new model of natural textures based on the feature spaces of convolutional neural networks optimised for object recognition. Samples from the model are of high perceptual quality demonstrating the generative power of neural networks trained in a purely discriminative fashion. Within the model, textures are represented by the correlations between feature maps in several layers of the network. We show that across layers the texture representations increasingly capture the statistical properties of natural images while making object information more and more explicit. Extending this framework to texture transfer, we introduce A Neural Algorithm of Artistic Style that can separate and recombine the image content and style of natural images. The algorithm allows us to produce new artistic imagery that combines the content of an arbitrary photograph with the appearance of numerous well-known artworks, thus offering a path towards an algorithmic understanding of how humans create and perceive artistic imagery
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