130,562 research outputs found
An Invariant Model of the Significance of Different Body Parts in Recognizing Different Actions
In this paper, we show that different body parts do not play equally
important roles in recognizing a human action in video data. We investigate to
what extent a body part plays a role in recognition of different actions and
hence propose a generic method of assigning weights to different body points.
The approach is inspired by the strong evidence in the applied perception
community that humans perform recognition in a foveated manner, that is they
recognize events or objects by only focusing on visually significant aspects.
An important contribution of our method is that the computation of the weights
assigned to body parts is invariant to viewing directions and camera parameters
in the input data. We have performed extensive experiments to validate the
proposed approach and demonstrate its significance. In particular, results show
that considerable improvement in performance is gained by taking into account
the relative importance of different body parts as defined by our approach.Comment: arXiv admin note: substantial text overlap with arXiv:1705.04641,
arXiv:1705.05741, arXiv:1705.0443
Volumetric Super-Resolution of Multispectral Data
Most multispectral remote sensors (e.g. QuickBird, IKONOS, and Landsat 7
ETM+) provide low-spatial high-spectral resolution multispectral (MS) or
high-spatial low-spectral resolution panchromatic (PAN) images, separately. In
order to reconstruct a high-spatial/high-spectral resolution multispectral
image volume, either the information in MS and PAN images are fused (i.e.
pansharpening) or super-resolution reconstruction (SRR) is used with only MS
images captured on different dates. Existing methods do not utilize temporal
information of MS and high spatial resolution of PAN images together to improve
the resolution. In this paper, we propose a multiframe SRR algorithm using
pansharpened MS images, taking advantage of both temporal and spatial
information available in multispectral imagery, in order to exceed spatial
resolution of given PAN images. We first apply pansharpening to a set of
multispectral images and their corresponding PAN images captured on different
dates. Then, we use the pansharpened multispectral images as input to the
proposed wavelet-based multiframe SRR method to yield full volumetric SRR. The
proposed SRR method is obtained by deriving the subband relations between
multitemporal MS volumes. We demonstrate the results on Landsat 7 ETM+ images
comparing our method to conventional techniques.Comment: arXiv admin note: text overlap with arXiv:1705.0125
An introduction to domain adaptation and transfer learning
In machine learning, if the training data is an unbiased sample of an
underlying distribution, then the learned classification function will make
accurate predictions for new samples. However, if the training data is not an
unbiased sample, then there will be differences between how the training data
is distributed and how the test data is distributed. Standard classifiers
cannot cope with changes in data distributions between training and test
phases, and will not perform well. Domain adaptation and transfer learning are
sub-fields within machine learning that are concerned with accounting for these
types of changes. Here, we present an introduction to these fields, guided by
the question: when and how can a classifier generalize from a source to a
target domain? We will start with a brief introduction into risk minimization,
and how transfer learning and domain adaptation expand upon this framework.
Following that, we discuss three special cases of data set shift, namely prior,
covariate and concept shift. For more complex domain shifts, there are a wide
variety of approaches. These are categorized into: importance-weighting,
subspace mapping, domain-invariant spaces, feature augmentation, minimax
estimators and robust algorithms. A number of points will arise, which we will
discuss in the last section. We conclude with the remark that many open
questions will have to be addressed before transfer learners and
domain-adaptive classifiers become practical.Comment: Technical Report. 41 pages, 5 figure
Predictive biometrics: A review and analysis of predicting personal characteristics from biometric data
Interest in the exploitation of soft biometrics information has continued to develop over the last decade or so. In comparison with traditional biometrics, which focuses principally on person identification, the idea of soft biometrics processing is to study the utilisation of more general information regarding a system user, which is not necessarily unique. There are increasing indications that this type of data will have great value in providing complementary information for user authentication. However, the authors have also seen a growing interest in broadening the predictive capabilities of biometric data, encompassing both easily definable characteristics such as subject age and, most recently, `higher level' characteristics such as emotional or mental states. This study will present a selective review of the predictive capabilities, in the widest sense, of biometric data processing, providing an analysis of the key issues still adequately to be addressed if this concept of predictive biometrics is to be fully exploited in the future
Visual Affordance and Function Understanding: A Survey
Nowadays, robots are dominating the manufacturing, entertainment and
healthcare industries. Robot vision aims to equip robots with the ability to
discover information, understand it and interact with the environment. These
capabilities require an agent to effectively understand object affordances and
functionalities in complex visual domains. In this literature survey, we first
focus on Visual affordances and summarize the state of the art as well as open
problems and research gaps. Specifically, we discuss sub-problems such as
affordance detection, categorization, segmentation and high-level reasoning.
Furthermore, we cover functional scene understanding and the prevalent
functional descriptors used in the literature. The survey also provides
necessary background to the problem, sheds light on its significance and
highlights the existing challenges for affordance and functionality learning.Comment: 26 pages, 22 image
Non-line-of-sight Imaging
Emerging single-photon-sensitive sensors combined with advanced inverse
methods to process picosecond-accurate time-stamped photon counts have given
rise to unprecedented imaging capabilities. Rather than imaging photons that
travel along direct paths from a source to an object and back to the detector,
non-line-of-sight (NLOS) imaging approaches analyse photons {scattered from
multiple surfaces that travel} along indirect light paths to estimate 3D images
of scenes outside the direct line of sight of a camera, hidden by a wall or
other obstacles. Here we review recent advances in the field of NLOS imaging,
discussing how to see around corners and future prospects for the field
Diversity in Machine Learning
Machine learning methods have achieved good performance and been widely
applied in various real-world applications. They can learn the model adaptively
and be better fit for special requirements of different tasks. Generally, a
good machine learning system is composed of plentiful training data, a good
model training process, and an accurate inference. Many factors can affect the
performance of the machine learning process, among which the diversity of the
machine learning process is an important one. The diversity can help each
procedure to guarantee a total good machine learning: diversity of the training
data ensures that the training data can provide more discriminative information
for the model, diversity of the learned model (diversity in parameters of each
model or diversity among different base models) makes each parameter/model
capture unique or complement information and the diversity in inference can
provide multiple choices each of which corresponds to a specific plausible
local optimal result. Even though the diversity plays an important role in
machine learning process, there is no systematical analysis of the
diversification in machine learning system. In this paper, we systematically
summarize the methods to make data diversification, model diversification, and
inference diversification in the machine learning process, respectively. In
addition, the typical applications where the diversity technology improved the
machine learning performance have been surveyed, including the remote sensing
imaging tasks, machine translation, camera relocalization, image segmentation,
object detection, topic modeling, and others. Finally, we discuss some
challenges of the diversity technology in machine learning and point out some
directions in future work.Comment: Accepted by IEEE Acces
A Methodological Review of Visual Road Recognition Procedures for Autonomous Driving Applications
The current research interest in autonomous driving is growing at a rapid
pace, attracting great investments from both the academic and corporate
sectors. In order for vehicles to be fully autonomous, it is imperative that
the driver assistance system is adapt in road and lane keeping. In this paper,
we present a methodological review of techniques with a focus on visual road
detection and recognition. We adopt a pragmatic outlook in presenting this
review, whereby the procedures of road recognition is emphasised with respect
to its practical implementations. The contribution of this review hence covers
the topic in two parts -- the first part describes the methodological approach
to conventional road detection, which covers the algorithms and approaches
involved to classify and segregate roads from non-road regions; and the other
part focuses on recent state-of-the-art machine learning techniques that are
applied to visual road recognition, with an emphasis on methods that
incorporate convolutional neural networks and semantic segmentation. A
subsequent overview of recent implementations in the commercial sector is also
presented, along with some recent research works pertaining to road detections.Comment: 14 pages, 6 Figures, 2 Tables. Permission to reprint granted from
original figure author
Appearance Descriptors for Person Re-identification: a Comprehensive Review
In video-surveillance, person re-identification is the task of recognising
whether an individual has already been observed over a network of cameras.
Typically, this is achieved by exploiting the clothing appearance, as classical
biometric traits like the face are impractical in real-world video surveillance
scenarios. Clothing appearance is represented by means of low-level
\textit{local} and/or \textit{global} features of the image, usually extracted
according to some part-based body model to treat different body parts (e.g.
torso and legs) independently. This paper provides a comprehensive review of
current approaches to build appearance descriptors for person
re-identification. The most relevant techniques are described in detail, and
categorised according to the body models and features used. The aim of this
work is to provide a structured body of knowledge and a starting point for
researchers willing to conduct novel investigations on this challenging topic
A Spatiotemporal Context Definition for Service Adaptation Prediction in a Pervasive Computing Environment
Pervasive systems refers to context-aware systems that can sense their
context, and adapt their behavior accordingly to provide adaptable services.
Proactive adaptation of such systems allows changing the service and the
context based on prediction. However, the definition of the context is still
vague and not suitable to prediction. In this paper we discuss and classify
previous definitions of context. Then, we present a new definition which allows
pervasive systems to understand and predict their contexts. We analyze the
essential lines that fall within the context definition, and propose some
scenarios to make it clear our approach.Comment: Context-aware; Pervasive Computing; Context Definition; 2015.
International Journal of Advanced Studies in Computer Science and Engineering
(IJASCSE) http://www.ijascse.org/publications ;201
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