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Lehrstuhl für Allgemeine Elektrotechnik und Theoretische Nachrichtentechnik


Prof. Dr.- Ing. Anton Kummert

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Dr.-Ing. Jörg Velten

 

Kontakt

Raum:FE 1.06
Telefon:+49 (0)202 439 1811
E-Mail: velten{at}uni-wuppertal.de

 

Publikationen

Referenzen
54.
Sam Schauland; Jörg Velten; Anton Kummert
A new anti-aliasing approach for improved motion-based object detection using linear filters
of the IEEE Intelligent Vehicles Symposium (IV'10) , Seite 915 - 920.
San Diego, California, USA
Juni 2010

Schlüsselwörter: antialiasing, antialiasing approach, blind spot warning systems, camera signal, cameras, computational power, driver assistance systems, driver information systems, improved motion based object detection, linear filter, linear shift invariant, low temporal resolution, object detection

Zusammenfassung: In this paper a new anti-aliasing approach for motion-based object detection using linear shift invariant (LSI) filters is presented. Mainly originating from the field of signal processing, LSI-filter-based motion detection has been topic of research for a long time, though due to low computational power of contemporary computers the developed systems have been unfeasible for application in mass products like driver assistance systems. However, recent progress in hardware in conjunction with decreasing costs makes using linear filters a very interesting alternative of increasing performance of common approaches. One of the most important factors falsifying object detection results obtained using linear shift invariant (LSI) is aliasing. This is mostly caused by the low temporal resolution of the camera signal which leads to the fact that the sampling theorem does not hold for objects moving at high speed in the image plane. In general, aliasing errors cannot be removed after sampling. Under certain conditions, however, their impact on the filter result can be successfully decreased using the approach presented in this paper. The applicability of the new approach is demonstrated using scenes recorded by a camera installed in a blind spot warning system.

53.
Jörg Velten; Sam Schauland; Anton Kummert; Krzysztof Galkowski
Application specific stability of 2-D Roesser model realizations
of 2010 IEEE International Symposium on Circuits and Systems (ISCAS'10) , Seite 1001 -1004.
Paris, France
Juni 2010

Schlüsselwörter: 1D state space description, 1D system matrix, 2D Roesser model realizations, application specific stability, block Toeplitz matrix, discrete 2D system realizations, discrete systems, kD system stability, multidimensional signal processing, multidimensional system stability, n-D systems, Stability, stability test, state-space methods, Toeplitz matrices

Zusammenfassung: Stability of multidimensional (k-D) systems is still a challenging field of work. Well known and established stability measures may lead to complex mathematical problems, while simple tests are restricted to special cases of n-D systems. A new stability test for certain discrete 2-D system realizations given in a Roesser model description is proposed. This test is suitable for signals bounded with respect to both coordinate directions, like images. The 2-D system is observed in real operation, i.e. considering a sequence of processing, which leads to a 1-D state space description. The resulting 1-D system matrix is some kind of a block Toeplitz matrix that allows definition of the test.

52.
Sam Schauland; Jörg Velten; Anton Kummert
Realization of a new anti-aliasing method for linear filter based object detection in video scenes
of the IEEE International Conference on Acoustics Speech and Signal Processing (ICASSP'10) , Seite 1170 - 1173.
Dallas, Texas, USA
März 2010

Schlüsselwörter: antialiasing method, cheap sensors, costing, demand low production costs, driver assistance systems, image sequences, linear filter, object detection, Shannon sampling theorem, traffic engineering computing, video scenes, video signal processing

Zusammenfassung: This paper presents a new hardware-efficient method of eliminating aliasing artifacts in time direction occurring in filter results of velocity or directional filters applied to image sequences recorded by a camera. Aim is to deliver reliable input data for object detection in a driver assistance system, for example. Applications designed for mass products like these demand low production costs and therefore cheap sensors and hardware. Thus, resolution as well as frame rate of the captured image sequences are often limited and therefore Shannon's sampling theorem is not always satisfied. For the case that aliasing only occurs in the pass band, a method to remove unwanted aliasing components from the filter result without any additional filter hardware is proposed and demonstrated by means of examples.

51.
Jörg Velten; Anton Kummert
Active-Safety-Car aus Wuppertal
Bergische Universität Wuppertal, Nr3 Sommersemester 2010:6-11
2010
50.
Sam Schauland; Jörg Velten; Anton Kummert
Realization of a recursive 3-D cone filter for video processing applications
of the 52nd IEEE International Midwest Symposium on Circuits and Systems (MWSCAS'09) , Seite 632 - 635.
Cancun, Mexico
August 2009

Schlüsselwörter: cone-shaped frequency response, field programmable gate arrays, filter design method, hardware implementation, image sequences, multidimensional wave digital filters, recursive 3D cone filter, recursive estimation, shift operators, signal size, video processing applications, video sequence, video signal processingFPGA

Zusammenfassung: In this paper a realization of a recursive 3-D cone filter applicable for low cost hardware like FPGAs, for instance, is presented. Based on the filter design method proposed by Bolle, multidimensional wave digital filters are used to approximate a cone-shaped frequency response. Focus is not set on filter design but on filter implementation and problems arising in that context. In detail, the impact of signal size, chosen processing scheme and shift operators on hardware implementation is illuminated and a suitable solution is proposed. For verification, an example of a filtered video sequence showing moving objects is given.

Bemerkung: CD

49.
Hongwei Li; Sam Schauland; Jörg Velten; Anton Kummert
3D wave digital filter implementation on a virtex2 FPGA board with external SDRAM
of the International Workshop on Multidimensional (nD) Systems (nDS'09)
Thessaloniki, Greece
Juli 2009

Schlüsselwörter: DRAM chips, external SDRAM, field programmable gate arrays, hardware architecture, LCD monitor, n-D signal processing application, synchronous dynamic random access memory, virtex2 FPGA board, wave digital filters3D spatio-temporal wave digital filter

Zusammenfassung: Many n-D signal processing applications require realization in real time. We propose the realization of a 3-D spatio-temporal wave digital filter (WDF) in an FPGA. Optimization of the implemented hardware architecture includes evaluation of two different kinds of overflow handling, namely by saturation and a ldquomodulo 2rdquo type operation. The FPGA board is processing DVI signals that can be provided by usual PC hardware. The processing output is observed in real time on an LCD monitor.

Bemerkung: CD

48.
Sam Schauland; Jörg Velten; Anton Kummert; Krzysztof Galkowski
Insufficiencies of the practical BIBO stability concept with regard to signal processing systems
of the International Workshop on Multidimensional (nD) Systems (nDS'09)
Thessaloniki, Greece
Juli 2009

Schlüsselwörter: discrete systems, Fourier transform, frequency response, impulse response, signal processing, signal processing systems, spatio-temporal signal, Stability, transfer function, transfer functionsBIBO stability

Zusammenfassung: In this paper the practical BIBO stability concept introduced by Agathoklis and Bruton is analyzed with respect to its applicability in the field of signal processing applications. In the field of n-D signal processing signals are often bounded to all but one dimension like be the time-direction of a spatio-temporal signal, for instance. This property makes the use of systems which meet the conditions of practical BIBO stability, mainly known from the field of control theory, appear to be feasible. However, it can be shown hat practical stability in its original form is not sufficient in signal processing if not further conditions are supposed. This is done by comparing the 2D Fourier transform of the actually measured impulse response of exemplary systems to the frequency response expected on basis of the transfer function. Additionally, an application example is given to verify the presented observations.

Bemerkung: CD

47.
Jörg Velten; Sam Schauland; Anton Kummert
A realization framework based on a natural state space description of discrete k-D signal processing systems
of the International Workshop on Multidimensional (nD) Systems (nDS'09)
Thessaloniki, Greece
Juli 2009

Schlüsselwörter: discrete k-D signal processing systems, natural state space description, signal processingdiscrete domain linear k-D systems, system description

Zusammenfassung: The paper presents a realization framework based on a natural state space description of n-D systems with a focus on design and analysis of discrete domain linear k-D systems. While widely used models satisfy control theoretic needs, the presented description addresses design, analysis, and realization of k-D signal processing systems. It provides a system description that offers better compliance with possible hardware realizations than existing models and thus allows evaluation and consideration of many realization specific effects. Non-causal systems that may be of interest in k-D signal processing can be described as well as shift operations / delays with respect to more than one coordinate direction.

Bemerkung: CD

46.
Sam Schauland; Jörg Velten; Anton Kummert; Krzysztof Galkowski
On the usability of practical stable n-D systems for signal processing applications
of the IEEE International Symposium on Circuits and Systems (ISCAS'09) , Seite 317 - 320.
Mai 2009

Schlüsselwörter: Fourier transforms, frequency response, impulse response, line-scan camera, signal processing, spatio-temporal signal, stable n-D systems, transfer function, transfer functions, transient response2D Fourier transform

Zusammenfassung: In practice, n-D signal processing problems often show the property that underlying signals are unbounded with respect to only one direction, like the spatio-temporal signal of a line-scan camera, for example. Thus, the use of systems which meet the conditions of practical BIBO stability, mainly known from the field of control theory, seems to be feasible. In this paper the practical BIBO stability concept introduced by Agathoklis and Bruton [1] is analyzed with respect to its applicability in the field of signal processing applications. It is shown that practical stability in its original form is not sufficient in signal processing if not further conditions are supposed. This is done by comparing the 2D Fourier transform of the actually measured impulse response of exemplary systems to the frequency response expected on basis of the transfer function.

45.
Jörg Velten; Sam Schauland; Anton Kummert
Multidimensional velocity filters for visual scene analysis in automotive driver assistance systems
Multidimensional Systems and Signal Processing, 19(3-4):401 - 410
Dezember 2008

Zusammenfassung: Automotive scenery often contains objects that can be classified by object speed andmovement direction. These features can be extracted from video data by linear n-D filters, which have already been analyzed in the past. While soundness of results was convincing, interest in those systems declined due to the reduced computational abilities of contemporary computers. Modern hardware allows realization of velocity filters, if the n-D system is carefully adapted to the analysis problem. The present paper analyzes the premises for application of velocity filters in the domain of automotive driver assistance systems, i.e. with respect to detectability of objects and implementability in a cost effective way. Especially the influence of the frame rate and the temporal violation of the sampling theorem are analyzed. Transfer functions for n-D filters working in a vision-based blind spot collision avoidance system are presented and discussed, and promising approaches for future application fields are proposed.

44.
Sam Schauland; Jörg Velten; Anton Kummert
Implementation of hardware-optimized 3D wave digital filters for motion-based object detection in video scenes
of the 16th European Signal Processing (EUSIPCO'08)
Lausanne, Swiss
August 2008

Bemerkung: CD

43.
Sam Schauland; Jörg Velten; Anton Kummert
Motion-based object detection using 3D wave digital filters
of the IEEE 8th International Conference on Computer and Information Technology (CIT'08) , Seite 857 - 861.
Sidney, Australia
Juli 2008

Bemerkung: CD

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