16,627 research outputs found
Color and texture associations in voice-induced synesthesia
Voice-induced synesthesia, a form of synesthesia in which synesthetic perceptions are induced by the sounds of people's voices, appears to be relatively rare and has not been systematically studied. In this study we investigated the synesthetic color and visual texture perceptions experienced in response to different types of “voice quality” (e.g., nasal, whisper, falsetto). Experiences of three different groups—self-reported voice synesthetes, phoneticians, and controls—were compared using both qualitative and quantitative analysis in a study conducted online. Whilst, in the qualitative analysis, synesthetes used more color and texture terms to describe voices than either phoneticians or controls, only weak differences, and many similarities, between groups were found in the quantitative analysis. Notable consistent results between groups were the matching of higher speech fundamental frequencies with lighter and redder colors, the matching of “whispery” voices with smoke-like textures, and the matching of “harsh” and “creaky” voices with textures resembling dry cracked soil. These data are discussed in the light of current thinking about definitions and categorizations of synesthesia, especially in cases where individuals apparently have a range of different synesthetic inducers
Diffuse-interface polycrystal plasticity: Expressing grain boundaries as geometrically necessary dislocations
The standard way of modeling plasticity in polycrystals is by using the
crystal plasticity model for single crystals in each grain, and imposing
suitable traction and slip boundary conditions across grain boundaries. In this
fashion, the system is modeled as a collection of boundary-value problems with
matching boundary conditions. In this paper, we develop a diffuse-interface
crystal plasticity model for polycrystalline materials that results in a single
boundary-value problem with a single crystal as the reference configuration.
Using a multiplicative decomposition of the deformation gradient into lattice
and plastic parts, i.e. F(X,t) = F^L(X,t) F^P(X,t), an initial stress-free
polycrystal is constructed by imposing F^L to be a piecewise constant rotation
field R^0(X), and F^P = R^0(X)^T, thereby having F(X,0) = I, and zero elastic
strain. This model serves as a precursor to higher order crystal plasticity
models with grain boundary energy and evolution.Comment: 18 pages, 7 figure
A Synergistic Approach for Recovering Occlusion-Free Textured 3D Maps of Urban Facades from Heterogeneous Cartographic Data
In this paper we present a practical approach for generating an
occlusion-free textured 3D map of urban facades by the synergistic use of
terrestrial images, 3D point clouds and area-based information. Particularly in
dense urban environments, the high presence of urban objects in front of the
facades causes significant difficulties for several stages in computational
building modeling. Major challenges lie on the one hand in extracting complete
3D facade quadrilateral delimitations and on the other hand in generating
occlusion-free facade textures. For these reasons, we describe a
straightforward approach for completing and recovering facade geometry and
textures by exploiting the data complementarity of terrestrial multi-source
imagery and area-based information
Single-picture reconstruction and rendering of trees for plausible vegetation synthesis
State-of-the-art approaches for tree reconstruction either put limiting constraints on the input side (requiring multiple photographs, a scanned point cloud or intensive user input) or provide a representation only suitable for front views of the tree. In this paper we present a complete pipeline for synthesizing and rendering detailed trees from a single photograph with minimal user effort. Since the overall shape and appearance of each tree is recovered from a single photograph of the tree crown, artists can benefit from georeferenced images to populate landscapes with native tree species. A key element of our approach is a compact representation of dense tree crowns through a radial distance map. Our first contribution is an automatic algorithm for generating such representations from a single exemplar image of a tree. We create a rough estimate of the crown shape by solving a thin-plate energy minimization problem, and then add detail through a simplified shape-from-shading approach. The use of seamless texture synthesis results in an image-based representation that can be rendered from arbitrary view directions at different levels of detail. Distant trees benefit from an output-sensitive algorithm inspired on relief mapping. For close-up trees we use a billboard cloud where leaflets are distributed inside the crown shape through a space colonization algorithm. In both cases our representation ensures efficient preservation of the crown shape. Major benefits of our approach include: it recovers the overall shape from a single tree image, involves no tree modeling knowledge and minimal authoring effort, and the associated image-based representation is easy to compress and thus suitable for network streaming.Peer ReviewedPostprint (author's final draft
Chiral magnetic textures in Ir/Fe/Co/Pt multilayers: Evolution and topological Hall signature
Skyrmions are topologically protected, two-dimensional, localized hedgehogs
and whorls of spin. Originally invented as a concept in field theory for
nuclear interactions, skyrmions are central to a wide range of phenomena in
condensed matter. Their realization at room temperature (RT) in magnetic
multilayers has generated considerable interest, fueled by technological
prospects and the access granted to fundamental questions. The interaction of
skyrmions with charge carriers gives rise to exotic electrodynamics, such as
the topological Hall effect (THE), the Hall response to an emergent magnetic
field, a manifestation of the skyrmion Berry-phase. The proposal that THE can
be used to detect skyrmions needs to be tested quantitatively. For that it is
imperative to develop comprehensive understanding of skyrmions and other chiral
textures, and their electrical fingerprint. Here, using Hall transport and
magnetic imaging, we track the evolution of magnetic textures and their THE
signature in a technologically viable multilayer film as a function of
temperature () and out-of-plane applied magnetic field (). We show that
topological Hall resistivity () scales with the density of
isolated skyrmions () over a wide range of , confirming the
impact of the skyrmion Berry-phase on electronic transport. We find that at
higher skyrmions cluster into worms which carry considerable
topological charge, unlike topologically-trivial spin spirals. While we
establish a qualitative agreement between and areal
density of topological charge , our detailed quantitative
analysis shows a much larger than the prevailing theory
predicts for observed .Comment: Major revision of the original version. The extensive Supplementary
Information is available upon reques
Motion clouds: model-based stimulus synthesis of natural-like random textures for the study of motion perception
Choosing an appropriate set of stimuli is essential to characterize the
response of a sensory system to a particular functional dimension, such as the
eye movement following the motion of a visual scene. Here, we describe a
framework to generate random texture movies with controlled information
content, i.e., Motion Clouds. These stimuli are defined using a generative
model that is based on controlled experimental parametrization. We show that
Motion Clouds correspond to dense mixing of localized moving gratings with
random positions. Their global envelope is similar to natural-like stimulation
with an approximate full-field translation corresponding to a retinal slip. We
describe the construction of these stimuli mathematically and propose an
open-source Python-based implementation. Examples of the use of this framework
are shown. We also propose extensions to other modalities such as color vision,
touch, and audition
Structure Preserving Large Imagery Reconstruction
With the explosive growth of web-based cameras and mobile devices, billions
of photographs are uploaded to the internet. We can trivially collect a huge
number of photo streams for various goals, such as image clustering, 3D scene
reconstruction, and other big data applications. However, such tasks are not
easy due to the fact the retrieved photos can have large variations in their
view perspectives, resolutions, lighting, noises, and distortions.
Fur-thermore, with the occlusion of unexpected objects like people, vehicles,
it is even more challenging to find feature correspondences and reconstruct
re-alistic scenes. In this paper, we propose a structure-based image completion
algorithm for object removal that produces visually plausible content with
consistent structure and scene texture. We use an edge matching technique to
infer the potential structure of the unknown region. Driven by the estimated
structure, texture synthesis is performed automatically along the estimated
curves. We evaluate the proposed method on different types of images: from
highly structured indoor environment to natural scenes. Our experimental
results demonstrate satisfactory performance that can be potentially used for
subsequent big data processing, such as image localization, object retrieval,
and scene reconstruction. Our experiments show that this approach achieves
favorable results that outperform existing state-of-the-art techniques
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