677,070 research outputs found
Ambient Sound Helps: Audiovisual Crowd Counting in Extreme Conditions
Visual crowd counting has been recently studied as a way to enable people
counting in crowd scenes from images. Albeit successful, vision-based crowd
counting approaches could fail to capture informative features in extreme
conditions, e.g., imaging at night and occlusion. In this work, we introduce a
novel task of audiovisual crowd counting, in which visual and auditory
information are integrated for counting purposes. We collect a large-scale
benchmark, named auDiovISual Crowd cOunting (DISCO) dataset, consisting of
1,935 images and the corresponding audio clips, and 170,270 annotated
instances. In order to fuse the two modalities, we make use of a linear
feature-wise fusion module that carries out an affine transformation on visual
and auditory features. Finally, we conduct extensive experiments using the
proposed dataset and approach. Experimental results show that introducing
auditory information can benefit crowd counting under different illumination,
noise, and occlusion conditions. The dataset and code will be released. Code
and data have been made availabl
PDANet: Pyramid Density-aware Attention Net for Accurate Crowd Counting
Crowd counting, i.e., estimating the number of people in a crowded area, has
attracted much interest in the research community. Although many attempts have
been reported, crowd counting remains an open real-world problem due to the
vast scale variations in crowd density within the interested area, and severe
occlusion among the crowd. In this paper, we propose a novel Pyramid
Density-Aware Attention-based network, abbreviated as PDANet, that leverages
the attention, pyramid scale feature and two branch decoder modules for
density-aware crowd counting. The PDANet utilizes these modules to extract
different scale features, focus on the relevant information, and suppress the
misleading ones. We also address the variation of crowdedness levels among
different images with an exclusive Density-Aware Decoder (DAD). For this
purpose, a classifier evaluates the density level of the input features and
then passes them to the corresponding high and low crowded DAD modules.
Finally, we generate an overall density map by considering the summation of low
and high crowded density maps as spatial attention. Meanwhile, we employ two
losses to create a precise density map for the input scene. Extensive
evaluations conducted on the challenging benchmark datasets well demonstrate
the superior performance of the proposed PDANet in terms of the accuracy of
counting and generated density maps over the well-known state of the arts
TasselNet: Counting maize tassels in the wild via local counts regression network
Accurately counting maize tassels is important for monitoring the growth
status of maize plants. This tedious task, however, is still mainly done by
manual efforts. In the context of modern plant phenotyping, automating this
task is required to meet the need of large-scale analysis of genotype and
phenotype. In recent years, computer vision technologies have experienced a
significant breakthrough due to the emergence of large-scale datasets and
increased computational resources. Naturally image-based approaches have also
received much attention in plant-related studies. Yet a fact is that most
image-based systems for plant phenotyping are deployed under controlled
laboratory environment. When transferring the application scenario to
unconstrained in-field conditions, intrinsic and extrinsic variations in the
wild pose great challenges for accurate counting of maize tassels, which goes
beyond the ability of conventional image processing techniques. This calls for
further robust computer vision approaches to address in-field variations. This
paper studies the in-field counting problem of maize tassels. To our knowledge,
this is the first time that a plant-related counting problem is considered
using computer vision technologies under unconstrained field-based environment.Comment: 14 page
Deconstructing triplet nucleon-nucleon scattering
Nucleon-nucleon scattering in spin-triplet channels is analysed within an
effective field theory where one-pion exchange is treated nonperturbatively.
Justifying this requires the identification of an additional low-energy scale
in the strength of that potential. Short-range interactions are organised
according to the resulting power counting, in which the leading term is
promoted to significantly lower order than in the usual perturbative counting.
In each channel there is a critical momentum above which the waves probe the
singular core of the tensor potential and the new counting is necessary. When
the effects of one- and two-pion exchange have been removed using a
distorted-wave Born approximation, the residual scattering in waves with L<=2
is well described by the first three terms in the new counting. In contrast,
the scattering in waves with L>=3 is consistent with the perturbative counting,
at least for energies up to 300 MeV. This pattern is in agreement with
estimates of the critical momenta in these channels.Comment: 13 pages, RevTeX, 8 figures, minor clarifications adde
Baryon self energies in the chiral loop expansion
We compute the self energies of the baryon octet and decuplet states at the
one-loop level applying the manifestly covariant chiral Lagrangian. It is
demonstrated that expressions consistent with the expectation of power counting
rules arise if the self energies are decomposed according to the
Passarino-Veltman scheme supplemented by a minimal subtraction. This defines a
partial summation of the chiral expansion. A finite renormalization required to
install chiral power counting rules leads to the presence of an infrared
renormalization scale. Good convergence properties for the chiral loop
expansion of the baryon octet and decuplet masses are obtained for natural
values of the infrared scale. A prediction for the strange-quark matrix element
of the nucleon is made.Comment: 36 pages, 4 figures, 8 tables. The revised manuscript contains a
proof that given any one-loop integral that arises when computing one-baryon
processes it is sufficient to renormalize the scalar master-loop functions of
the Passarino-Veltman reduction in a manner that the latter are compatible
with the expectation of chiral counting rule
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