1,382 research outputs found
PoseTrack: A Benchmark for Human Pose Estimation and Tracking
Human poses and motions are important cues for analysis of videos with people
and there is strong evidence that representations based on body pose are highly
effective for a variety of tasks such as activity recognition, content
retrieval and social signal processing. In this work, we aim to further advance
the state of the art by establishing "PoseTrack", a new large-scale benchmark
for video-based human pose estimation and articulated tracking, and bringing
together the community of researchers working on visual human analysis. The
benchmark encompasses three competition tracks focusing on i) single-frame
multi-person pose estimation, ii) multi-person pose estimation in videos, and
iii) multi-person articulated tracking. To facilitate the benchmark and
challenge we collect, annotate and release a new %large-scale benchmark dataset
that features videos with multiple people labeled with person tracks and
articulated pose. A centralized evaluation server is provided to allow
participants to evaluate on a held-out test set. We envision that the proposed
benchmark will stimulate productive research both by providing a large and
representative training dataset as well as providing a platform to objectively
evaluate and compare the proposed methods. The benchmark is freely accessible
at https://posetrack.net.Comment: www.posetrack.ne
Energy Minimization for Multiple Object Tracking
Multiple target tracking aims at reconstructing trajectories of several
moving targets in a dynamic scene, and is of significant relevance for a
large number of applications. For example, predicting a pedestrian’s
action may be employed to warn an inattentive driver and reduce road
accidents; understanding a dynamic environment will facilitate
autonomous robot navigation; and analyzing crowded scenes can prevent
fatalities in mass panics.
The task of multiple target tracking is challenging for various reasons:
First of all, visual data is often ambiguous. For example, the objects
to be tracked can remain undetected due to low contrast and occlusion.
At the same time, background clutter can cause spurious measurements
that distract the tracking algorithm. A second challenge arises when
multiple measurements appear close to one another. Resolving
correspondence ambiguities leads to a combinatorial problem that quickly
becomes more complex with every time step. Moreover, a realistic model
of multi-target tracking should take physical constraints into account.
This is not only important at the level of individual targets but also
regarding interactions between them, which adds to the complexity of the
problem.
In this work the challenges described above are addressed by means of
energy minimization. Given a set of object detections, an energy
function describing the problem at hand is minimized with the goal of
finding a plausible solution for a batch of consecutive frames. Such
offline tracking-by-detection approaches have substantially advanced the
performance of multi-target tracking. Building on these ideas, this
dissertation introduces three novel techniques for multi-target tracking
that extend the state of the art as follows: The first approach
formulates the energy in discrete space, building on the work of Berclaz
et al. (2009). All possible target locations are reduced to a regular
lattice and tracking is posed as an integer linear program (ILP),
enabling (near) global optimality. Unlike prior work, however, the
proposed formulation includes a dynamic model and additional constraints
that enable performing non-maxima suppression (NMS) at the level of
trajectories. These contributions improve the performance both
qualitatively and quantitatively with respect to annotated ground truth.
The second technical contribution is a continuous energy function for
multiple target tracking that overcomes the limitations imposed by
spatial discretization. The continuous formulation is able to capture
important aspects of the problem, such as target localization or motion
estimation, more accurately. More precisely, the data term as well as
all phenomena including mutual exclusion and occlusion, appearance,
dynamics and target persistence are modeled by continuous differentiable
functions. The resulting non-convex optimization problem is minimized
locally by standard conjugate gradient descent in combination with
custom discontinuous jumps. The more accurate representation of the
problem leads to a powerful and robust multi-target tracking approach,
which shows encouraging results on particularly challenging video
sequences.
Both previous methods concentrate on reconstructing trajectories, while
disregarding the target-to-measurement assignment problem. To unify both
data association and trajectory estimation into a single optimization
framework, a discrete-continuous energy is presented in Part III of this
dissertation. Leveraging recent advances in discrete optimization
(Delong et al., 2012), it is possible to formulate multi-target tracking
as a model-fitting approach, where discrete assignments and continuous
trajectory representations are combined into a single objective
function. To enable efficient optimization, the energy is minimized
locally by alternating between the discrete and the continuous set of
variables.
The final contribution of this dissertation is an extensive discussion
on performance evaluation and comparison of tracking algorithms, which
points out important practical issues that ought not be ignored
Comparison of the scientific performance in hip and knee arthroplasty between the leading continents
Background: Scientific progress in the field of knee and hip arthroplasty has
enabled the preservation of mobility and quality of life in the case of patients
with many primary degenerative and (post-) traumatic joint diseases. This
comparative study aims to investigate differences in scientific performance
between the leading continents in the field of hip and knee arthroplasty.
Methods: Using specific search terms all studies published by the scientific leading
continents Europe, North America, Asia and Oceania listed in the Web of Science
databases were included. All identified publications were analysed and
comparative conclusions were drawn regarding the qualitative and quantitative
scientific merit of each continent.
Results: Europe, followed by North America, Asia, and Oceania, had the highest
overall number of publications in the field of arthroplasty. Since 2000, there has
been a strong increase in knee arthroplasty publication rate, particular pronounced
in Asia. Studies performed and published in North America and those on knee
arthroplasty received the highest number of fundings. Publications regarding hip
arthroplasty achieved the highest average citation rate. In contradistinction to the
others, in North America most funding was provided by private agencies.
Conclusion: Although Europe showed the highest total number of publications,
authors and institutions, arthroplasty research from North America received greater
scientific attention and financial support. Measured by citations, publications on hip
arthroplasty attained higher scientific interest and studies on knee arthroplasty
received higher economic affection
Subgroup analysis of scientific performance in the field of arthroplasty
Introduction: Arthroplasty is the final treatment option for maintaining mobility and
quality of life in many primary degenerative and (post-) traumatic joint diseases.
Identification of research output and potential deficits for specific subspecialties
may be an important measure to achieve long-term improvement of patient care
in this field.
Methods: Using specific search terms and Boolean operators, all studies published
since 1945 to the subgroups of arthroplasty listed in the Web of Science Core
Collection were included. All identified publications were analysed according to
bibliometric standards, and comparative conclusions were drawn regarding the
scientific merit of each subgroup.
Results: Most publications investigated the subgroups of septic surgery and materials
followed by approach, navigation, aseptic loosening, robotic and enhanced recovery
after surgery (ERAS). In the last 5 years, research in the fields of robotic and ERAS
achieved the highest relative increase in publications In contrast, research on
aseptic loosening has continued to lose interest over the last 5 years. Publications
on robotics and materials received the most funding on average while those on
aseptic loosening received the least. Most publications originated from USA,
Germany, and England, except for research on ERAS in which Denmark stood out.
Relatively, publications on aseptic loosening received the most citations, whereas
the absolute scientific interest was highest for the topic infection.
Discussion: In this bibliometric subgroup analysis, the primary scientific outputs
focused on septic complications and materials research in the field of arthroplasty.
With decreasing publication output and the least financial support, intensification
of research on aseptic loosening is urgently recommended
Voice Operated Information System in Slovak
Speech communication interfaces (SCI) are nowadays widely used in several domains. Automated spoken language human-computer interaction can replace human-human interaction if needed. Automatic speech recognition (ASR), a key technology of SCI, has been extensively studied during the past few decades. Most of present systems are based on statistical modeling, both at the acoustic and linguistic levels. Increased attention has been paid to speech recognition in adverse conditions recently, since noise-resistance has become one of the major bottlenecks for practical use of speech recognizers. Although many techniques have been developed, many challenges still have to be overcome before the ultimate goal -- creating machines capable of communicating with humans naturally -- can be achieved. In this paper we describe the research and development of the first Slovak spoken language dialogue system. The dialogue system is based on the DARPA Communicator architecture. The proposed system consists of the Galaxy hub and telephony, automatic speech recognition, text-to-speech, backend, transport and VoiceXML dialogue management modules. The SCI enables multi-user interaction in the Slovak language. Functionality of the SLDS is demonstrated and tested via two pilot applications, ``Weather forecast for Slovakia'' and ``Timetable of Slovak Railways''. The required information is retrieved from Internet resources in multi-user mode through PSTN, ISDN, GSM and/or VoIP network
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