Special Sessions
Special Sessions Chair Prof. Maciej Niedzwiecki, Gdañsk University of Technology
E-mail: maciekn@eti.pg.gda.pl
Multidimensional Signal Processing and Systems
Organizers:
Krzysztof Ga³kowski, University of Wuppertal, Germany
Anton Kummert, University of Wuppertal, Germany
- Automotive applications:
- New algorithms based on the use of three-dimensional filters taking not only spatial but also temporal information into account, for automotive applications, as detecting an approaching vehicle or a crossing pedestrian.
- A tracking algorithm for estimating and filtering two-dimensional trajectories of vehicles and various other obstacles that may occur in a traffic scenario.
- Hybrid segmentation methods for cytological images.
- Block based methods of simulation of multi-dimensional (spatio-temporal) systems related to the 2D wave equation for arbitrary geometries.
- Adapting the so-called Iterative Learning Control (ILC), methods for the filtering problems.
Implementations of MIMO Wireless Communication Systems
Organizer:
Andreas Burg, Integrated Systems Laboratory, ETH Zurich, Switzerland
Multiple-input multiple-output (MIMO) technology has started to appear in numerous
standards for wireless communication. For example, MIMO is part of IEEE 802.16e and
will be part of IEEE 802.11n. It is also considered for 3GPP Release 7 and for
3GPP LTE. However, to ensure the commercial success of MIMO technology, some
critical implementation aspects remain to be solved. In the past, Moore's Law has
certainly helped silicon technology to keep up with the more complex algorithms
employed for wireless communication systems. Nevertheless, it has also become clear
that the tremendous growth in computational complexity associated with MIMO requires
considerable research efforts towards developing low-complexity algorithms and
corresponding optimized hardware architectures.
A particularly challenging area of research is the real-time implementation of multiantenna
systems on reconfigurable hardware architectures such as FPGAs or softwaredefined
radio (SDR) platforms. However, on the one hand, such experimental systems
have been recognized as an essential tool for the evaluation and verification of systemlevel
performance and implementation aspects, especially for the exploration of new
concepts such as multi-user MIMO systems. On the other hand, software-defined radio
platforms are the next step in technology, taking reconfigurable architectures from a tool
for prototyping to a technology that can be deployed in a product.
For this session proposal, we have collected five excellent contributions from leading
research groups discussing real-time implementations of MIMO communication systems
on reconfigurable hardware platforms. The invited papers report on algorithms optimized
for hardware implementation, on corresponding efficient system and hardware
architectures, and on measurement results for emerging multi-antenna wireless
communication systems, including experiments with multiuser MIMO concepts. The
contributions highlight the performance of real-world systems and the impact of
implementation trade-offs and constraints.
Since experience shows that efficient implementations of next generation wireless
communication systems require joint consideration of algorithm and VLSI
implementation aspects, we believe that such an interdisciplinary session dealing with
actual implementations of MIMO systems would constitute a most valuable contribution
to EUSIPCO 2007.
The Semantic Gap in Visual Information Retrieval
Organizers:
Ebroul Izquierdo, Queen Mary University of London, United Kingdom
In order to get closer to the vision of useful multimedia-based search and
retrieval, the annotation and search technologies need to be efficient and use semantic
concepts that are natural to the user. Finding a specific image of the last holidays stored
some where in the hard disk of the personal computer can become a time consuming task,
searching for a specific picture in a large digital archive is even more difficult, and
looking for an image on the web can be extremely difficult if not impossible. If images
have been manually labelled with an identifying string, e.g. "My holidays in Africa, wild
life", then the problem may appear to have been finessed. However, the adequacy of such
a solution depends on human interaction, which is expensive, time consuming and
therefore infeasible for many applications. Even the annotation of few hundreds of
personal images captured during the last years is a tedious task that nobody wants to do.
Furthermore, such semantic based annotation is completely subjective and depends on
semantic accuracy in describing the images. While one person could label an image as
"wild life" someone else might prefer "Elephant and trees". This last mentioned problem
could be alleviated by constraining the annotation to words extracted from a pre-defined
dictionary, taxonomy or advanced ontology. Nevertheless, the challenge of automatic
annotation and retrieval using semantic structures natural to humans remains critical.
To develop the technology able to produce accurate levels of abstraction in order to
annotate and retrieve content using queries that are natural to humans is the breakthrough
needed to bridge the semantic gap. To bridge this gap is a challenge that has captured the
attention of researchers in computer vision, pattern recognition, image processing and
other related fields, evidencing the difficulty and importance of such technology and the
fact that the problem is unsolved. The underlying technology offers the possibility of
adding the audiovisual dimension to well-established text databases enabling multimedia
based information retrieval. In this session selected talks on advanced research aimed at
bridging the semantic gap in visual information retrieval will be presented.
Bayesian Localization and Data Fusion Methods for Distributed Systems
Organizer:
Joaquin Miguez, Universidad Carlos III de Madrid, Spain
Distributed systems consisting of a potentially large number of wireless nodes with communication and sensing capabilities will soon become ubiquitous because of their suitability for a broad range of emerging applications, such as environmental monitoring, surveillance and security, vehicle navigation, tracking, logistics, etc... Virtually all of these applications involve the detection, classification and tracking of signals, with the outstanding
peculiarity that large amounts of possibly multimodal data must be handled and integrated in order to perform the prescribed tasks.
Due to this perspective, there has been a surge of interest in the development of new signal processing techniques suitable for the distributed scenario. Two important features are common to most of the applications of wireless distributed systems and have, therefore, become particularly hot topics:
- Localization: The need for accurate localization of both the network nodes and any objects of interest is apparent in the (many) applications involving target tracking or vehicle navigation . However, practically all applications of distributed systems rely, to some extent, on the availability of positioning information.
- Data fusion: Some of the most promising applications of sensor networks, and distributed systems in general, involve the integration of heterogeneous types of data in order to detect, estimate or track signals.
The aim of the proposed special session is to bring together researchers working
in the topics of data fusion and localization (including positioning, navigation
and tracking) for wireless distributed systems, in order to provide an up-to-date
picture of this rapidly advancing field of research. Emphasis is put on powerful
Bayesian techniques, including sequential Monte Carlo methods and recent extensions
of the Kalman filtering methodology, which have become state-of-the-art tools because
of their flexibility and accuracy.
Advanced Digital Signal Processing for Future Wireless System
Organizers:
Krzysztof Weso³owski, Poznañ University of Technology, Poland
Hanna Bogucka, Poznañ University of Technology, Poland
Future wireless systems are envisaged to embody diversified radio access technologies
related to various standards and coverage areas, user mobility patterns and service classes.
In order to ensure the required data rates, network coverage, reliability and Quality of
Service requirements several special means have to be undertaken in different layers of
the future wireless systems and networks. Among them, advanced signal processing
algorithms applied in several tasks of physical and higher layers of wireless
networks are of primary importance.
This two-part special session is focused on several topics associated with them. The first part is devoted to:
- the novel idea of ensuring transmission security taking advantage of physical attributes of wireless channels among the receiver node and transmitter nodes
- results of investigations on power backoff reduction for Generalized Multicarrier (GMC) waveforms proposed in the FP6 WINNER project for uplink transmission in a future 4G wireless system,
- channel prediction algorithms for frequency adaptive multiuser scheduling in OFDMA FDD uplinks investigated in the FP6 WINNER project as well,
- new robust pilot-assisted equalization algorithm for partially loaded UMTS downlink TDD system.
The second part of this special session is devoted to the challenging topics
that concern research of the efficient user-centric access to the future systems.
They are related to the development of flexible terminal platforms that will be
able to roam seamlessly among different wireless systems, to their situational
awareness, learning capabilities, management and control of their adaptation means
including the study of effective radio resource allocation schemes, arranging
communication traffic over the heterogeneous wireless network.
An important direction of research on flexible radio platform design encompasses new
approaches to digital signal waveform description such as Generalized Multi-Carrier
(GMC) and efficient time-frequency description of wireless channels applied in flexible radios.
In the future wireless communications cognitive radio concept will play an important
role. This concept defines the sensing-learning-decision circle for the radio terminals
(radio nodes) allowing for an efficient and 'cognitive' access to a network, spectrum
acquisition and reliable communication without causing interference to the licensed
users. To do that, the cognitive radio nodes will include specialized sensors, learning
algorithms and a large number of adaptation and reconfiguration features in order to
learn and react to changing environmental conditions, to acquire required radio resources.
The second part of this special session will tackle the above mentioned problems and challenges.
Multiple Description Coding (MDC)
Organizers:
Peter Schelkens, Vrije Universiteit Brussel, Belgium
Adrian Munteanu, Vrije Universiteit Brussel, Belgium
Multicast applications require several representations of the same content to be
sent to a variety of end users with different bandwidth provisions and playback
capabilities. In conjunction to that, the data delivered through best-effort
packet-switched networks may be corrupted or incomplete. Furthermore, participants
to multicast sessions cannot not rely on retransmission mechanisms as a large number
of requests and the consequent reiterated packet transmissions would burden the network,
thus increasing the risk of congestion. In such application scenarios, it is essential
to develop scalable multimedia coding techniques that are capable of adapting the
transmitted bitstream to the available channel capacity and user demands and,
at the same, time provide a controllable degree of resiliency against erasures.
In an error-free transmission setting, scalable coding technologies enable the
media providers to generate a single compressed bitstream from which appropriate
subsets can be extracted to meet the preferences and the bit-rate requirements
of a broad range of clients. From a complementary perspective, multiple description
coding (MDC) has been introduced to efficiently overcome the channel impairments over
diversity-based systems allowing the decoders to extract meaningful information
from an incompletely received bitstream. MDC systems are able to generate more
than one description of the source such that (1) each description independently
describes the source with certain fidelity, and (2) when more descriptions are
available at the decoder, they can be combined to enhance the quality of the
decoded signal.
This special session addresses researchers active in the area of multiple
description coding and encourages submission of contributions ranging from
theoretical analysis to practical instantiations of novel MDC systems for
images, videos and multimedia data. Additionally, in light of the increasing
popularity of scalable video coding (SVC), contributions are solicited on the
implementation of the MDC concept into SVC-AVC-compliant codecs as well as
other SVC architectures.
Biometrics Recognition
Organizer:
Paulo Lobato Correia, Instituto Superior Tecnico, Portugal
Reliable and secure access control systems are required for many applications,
such as access to restricted areas, border control, etc. Traditionally, passwords
or ID cards have been used for restricting user access. However, these types of
security control methods present serious disadvantages: passwords can be easily
stolen or lost and ID cards can also be forged. The increased demand for secure
access control systems has been accompanied by a growing research interest in
biometric technologies. Biometric recognition systems refer to the automatic
recognition, or verification, of a person’s identity based on human physical,
physiological or behavioural characteristics. Biometric features are typically
based on characteristics such as fingerprints, face, hand geometry, palmprints,
iris, voice, signature,
etc. Also the usage of multiple biometrics in the same system is often considered
to increase the reliability of th recognition results. The major advantage over
traditional methods is that biometric features cannot be lost or easily stolen,
while being unique for each person. This Special Session addresses biometrics
research topics, targeting reliable and practical solutions for reliable recognition of people.
Quality Evaluation in Image and Video Processing
Organizer:
Paulo Lobato Correia, Instituto Superior Tecnico, Portugal
Nowadays there are numerous alternative published algorithms for performing a
given image or video processing task, such as image and video coding or segmentation.
In order to determine the adequacy of a given solution for an envisaged application,
or to select one among a set of candidates, an evaluation of the proposed processing
algorithms is required. Often the assessment of algorithms for a given image or
video processing task is done
using subjective evaluation methodologies, requiring the participation of human
evaluators under a very well controlled evaluation environment - this is an expensive
procedure and subjective by nature. Many efforts have been made to automate the
evaluation procedures, and if a consensual objective metric is available, it is
often preferred, even if it presents some limitations (as the case of PSNR for
image and video quality evaluation). Lately, there have been many developments
in this area, both concerning objective evaluation methodologies that compare
the results against a reference (taken as the ground truth) - full reference or
relative evaluation - as well as evaluation without a reference - no reference
or standalone evaluation. Also the operation environment (application, screen
size, network limitations) needs to be taken into account when evaluating the
quality perceived by the user. This session addresses novel methods to automatically
estimate the quality of images and video processing tasks.
New Methods for the Analysis of Deformation Signals of Natural and Artificial Structures
Organizer:
Andreas Eichhorn, Institute for Geodesy and Geophysics, Vienna University of Technology, Austria
Monitoring and analysis of short- and long-term deformation signals of buildings
(e.g. dams, bridges) and natural structures (e.g. local and regional geodynamic
processes, slopes, etc.) is a central task for geodetic applications in environmental
monitoring. It is an essential precondition for the development of reliable alert
systems and the prevention of human and material damage.
- High sensitive sensor networks enable the installation of area-wide monitoring networks. The data is used as input for real-time operating alert systems (e.g. in tunneling).
- The pure geometrical analysis dealing with kinematic displacement fields has changed to so called "causative" approaches which also quantify monitored trigger events like traffic loads, temperature, wind etc. One challenge is now to find non-or parametric deformation transfer functions for complex structures which combine the influence quantities with the deformation signals and to separate the (often considerable) disturbances. In this context also AI-methods (e.g. neural networks) are trained and used.
- Development of new methods for modelling of sensor errors. The classical stochastic view is extended to fuzzified approaches quantifying uncertainties in the error distribution. The fuzzyfication enables new concepts for error propagation and statistical tests .
The proposed session will give an overview over the current state of the art
and newest developments in geodetic deformation analysis.
Optimization of Wireless Multiuser MIMO Communication Systems
Organizer:
Christoph Mecklenbräuker, Vienna University of Technology, Austria
The goal of this special session is to highlight optimization techniques for
multi-user MIMO communications both in cellular networks and in ad-hoc mode.
This session will highlight recent advances in multi-user MIMO techniques on
the physical-, medium access-, and radio link control layers. Currently, little
is published about how to optimally leverage the new degrees of freedom resulting
from MIMO terminals in a multi-user context.
The wireless industry has started to integrate single-user MIMO techniques into
existing multi-user cellular standards and to define new cellular standards based
on MIMO. Wireless networks should not be regarded as a set of concurrent
point-to-point links. More appropriate models are many-to-one links where many
users transmit to a single base station and one-to-many links where a single
base station transmits to many users.
Sparse Modelling Approaches to Audio and Music Signal Processing
Organizer:
Simon Godsill, Cambridge University, United Kingdom
Recent advances in methodology for modelling of signals using sparse
representations selected from overcomplete dictionaries of elementary atoms,
such as wavelets or Gabor atoms, are having strong impact in signal processing
applications for audio. When combined with state-of-the-art analysis and inference
methods, these techniques are providing powerful developments in topics such as
source separation, restoration, coding and enhancement, to list but a few.
Methodologies are being successfully developed from several points of view,
ranging from fully Bayesian mnodels to nonparametric classical approaches,
with crossover between disciplines in many cases.
LTE Signal Processing
Organizer:
Thomas Kaiser, Leibniz University of Hannover, Germany
"Long Term Evolution" (LTE) is the next release of UMTS (more precisely E-UTRA)
and was initiated to ensure the competitiveness of 3G technology during the next
10 years and beyond. LTE will be a completely packet-optimized radio-access
technology with a new air interface. Similiar to other wireless standards "MIMO"
meanwhile outgrows its research childhood and becomes a mandatory wireless
technology - also for LTE. Moreover, OFDMA is applied for the downlink in order
to achieve data rates of up to 100 Mbps and with SC-FDMA in the uplink the power
efficiency of a mobile device remains high. The aim of this special session on
"LTE Signal Processing" is to discuss the impact of the mentioned modulation
schemes for LTE and to point out further special features from algorithms to architectures.
Signal Processing in Wireless Testbeds and Prototyping
Organizer:
Markus Rupp, Vienna University of Technology, Austria
While the research of modern communication systems in particular in connection
with multiple antenna techniques has blossomed over the past decade, measurements
and experimental work is seriously lagging behind. The general belief in this
field of research is that simple channel models like iid Rayleigh are sufficient
to describe wireless scenarios.
The complexity of systems is estimated by the order of Multiply-Add instructions
in the required algorithms. Matlab floating point simulations solely build the
base for wireless system design. However, once a system is build with real hardware
components, the true challenges show up that were not addressed in the simulation.
Conducting experiments with real-time measurement equipment as it is common
in wireless testbeds allows to asses the influence of physical wireless channels
and RF components like antennas, mixers and low-noise amplifiers.
On the other hand prototyping allows for building first samples of real-time
hardware typically running in fixed rather than in floating point. Here precision
of AD and DA converters, cost of hardware, and energy consumption become visible
and may have an equal impact of a future wireless product.
This session allows experimental researchers in this field to share experience
in wireless testbeds and prototyping and informs theoretical researchers in
this field about unexpected hurdles when converting algorithmic ideas into working products.
Multimodal Biometrics and Smart Cards
Organizer:
Andrzej Drygaj³o, Swiss Federal Institute of Technology at Lausanne (EPFL), Switzerland
With an increase in identity fraud and the emphasis on security, there is a growing
and urgent need to efficiently identify humans both locally and remotely on a
routine basis. This special session addresses the issues of the global
breakthrough by biometrics in identity verification technology that is
imminent in terms of its use in identity documents and corresponding applications.
Biometric person identity verification (biometric authentication) is a multimodal
signal processing technology in its own right, with many potential applications.
The major technological aspect in this area is that there is a critical need to
understand and exploit a variety of biometric modalities with respect to modelling
biometric signals, creating templates of these models and scaling them to the
needs and limits of smart cards. Acquiring biometric signals of sufficient
quality and suitability and using them for reliable decision making is of
critical importance for automatic multimodal biometric authentication systems.
The quality of biometric data, fusion of modalities and performance of the
recognition systems for each modality are of pivotal importance for large-scale applications.
Nonstationary Process Analysis, Estimation, and Applications
Organizer:
Antonio Napolitano, Parthenope University of Naples, Italy
Nonstationary signal analysis has been considered from several different points
of view. Among them there are Time-frequency and time-scale analysis, Wavelets
analysis, Fractional Fourier transform analysis, Cyclostationary signal analysis,
Self-similar signal analysis, Evolutionary spectral analysis, Adaptive system and
signal analysis. These approaches, although different, have similarities and overlaps.
The aim of this special session is to allow comparisons of different points of
view for nonstationary signal analysis. Overviews, theoretical results, and
applications contributions are welcome.
Coding and Processing of Multi-View Video
Organizer:
André Kaup, University of Erlangen, Germany
Next generation video systems will offer the sensual experience of immersive
video, a new concept for future television entertainment. Immersive media can
be regarded as extension of the successful stereoscopic widescreen presentation
of panoramic views known from IMAX technology. Using image-based rendering
techniques of multi-view recorded real-world scenes the user gets the impression
of being actively present at a remote event. This principle, which is similar to
lightfield recording and rendering, will give the user the possibility to navigate
through the event with the projected scene changing according to his actual position.
At the same time no model generation of the scene is required as it would be
the case for the classical model-based scene rendering. A variety of challenges
are associated with multi-view video, among these are efficient coding of the
multiple camera data streams, rendering of intermediate views from given camera
positions, estimation of depth information, camera rectification and calibration
as well as 3D scene analysis and reconstruction. This special session will
address these issues in selected talks.
Hypercomplex Digital Signal Processing: Fundamentals and Applications
Organizer:
Heinz Göckler, Ruhr University Bochum, Germany
Hypercomplex representation and processing of signals is a gradually emerging
extension of commonly used real and complex DSP. Hence, hypercomplex DSP is an
active field of fundamental research encompassing current applications in signal
and (colour) image processing and coding, computer graphics, signal and system
representation and analysis, digital filter banks, biomedical signal processing,
seismology, etc. Moreover, in physics, hypercomplex algebras have found widespread
application, for instance, in special relativity, quantum mechanics, gauge
theory, motion analysis. Hence, new vistas and novel applications in multimedia
and general DSP are encouraged. This Special Session serves as a forum for
related discussion and exchange of peer experience.
Since hypercomplex algebras (e.g. Quaternions, Octonions, Grassmann-Clifford
algebra, etc.) and processing of hypercomplex signals are not really familiar
to great parts of the DSP community, this Special Session starts with a tutorial
contribution presenting a survey of hypercomplex algebras in conjunction with
some beneficial applications in DSP. Potential advantages and drawbacks of
hypercomplex DSP are discussed. Subsequently, the utility of these concepts
in DSP is shown by contributions discussing applications in fields such as
digital filtering based on hyperbolic number system and multirate filter banks.
Content and Network Aware Video Streaming
Organizers:
Béatrice Pesquet-Popescu, École Nationale Supérieure des Télécommunications (ENST), France
Markus Rupp, Vienna University of Technology, Austria
Multimedia applications have experienced explosive growth in the last decade
and have become a pervasive application over the Internet. Despite the growth in
availability of broadband technology, and progress in video compression, the
quality of video streaming systems is still not on par with SDTV and even further
from HDTV. This is due to the best-effort nature of the network which does not
offer any guaranteed quality of service (QoS) and where bandwidth, delay and
losses may vary unexpectedly. The advent of wireless last hops, and the emergence
of multi-hop ad-hoc networks bring as additional challenges interference,
shadowing and mobility. It is a daunting task to achieve high and constant quality
video, and low startup delays and end-to-end latencies, in such environments.
The aim of this special session is to focus on advances related to error-resilience,
congestion control and multi-path video delivery.