Prof. Rik Van de Walle Profile

Prof. Rik Van de Walle

Professor at Univ Gent

SPIE Involvement:

Author

Publications (38)

Proceedings Article | 15 October 2012 Paper

Refining WZ rate estimation in DVC with feedback channel constraints

Jürgen Slowack, Peter Lambert, Rik Van de Walle

Proceedings Volume 8499, 84990L (2012) https://doi.org/10.1117/12.929536

KEYWORDS: Computer programming, Error analysis, Motion estimation, Video compression, Video coding, Statistical analysis, Video surveillance, Video, Binary data, Visualization

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Proceedings Article | 2 September 2009 Paper

Motion estimation for H.264/AVC on multiple GPUs using NVIDIA CUDA

Bart Pieters, Charles Hollemeersch, Peter Lambert, Rik Van de Walle

Proceedings Volume 7443, 74430X (2009) https://doi.org/10.1117/12.825995

KEYWORDS: Computer programming, Motion estimation, Video, Video acceleration, Visualization, Computing systems, Video processing, Video coding, Standards development, Computer architecture

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SPIE Journal Paper | 1 October 2008

Robust spatio-temporal multimodal background subtraction for video surveillance

Chris Poppe, Gaëtan Martens, Sarah De Bruyne, Peter Lambert, Rik Van de Walle

OE, Vol. 47, Issue 10, 107203, (October 2008) https://doi.org/10.1117/12.10.1117/1.3002325

KEYWORDS: Image segmentation, Video surveillance, Edge detection, Light sources and illumination, Optical engineering, Environmental monitoring, Systems modeling, Surveillance, Expectation maximization algorithms, Environmental sensing

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Proceedings Article | 15 September 2008 Paper

Rate-controlled requantization transcoding for H.264/AVC video streams

Stijn Notebaert, Jan De Cock, Peter Lambert, Rik Van de Walle

Proceedings Volume 7073, 70730T (2008) https://doi.org/10.1117/12.796405

KEYWORDS: Video, Computer programming, Visualization, Detection and tracking algorithms, Video coding, Quantization, Video compression, Image processing, Video processing, Computer architecture

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Proceedings Article | 25 April 2008 Paper

Heuristic dynamic complexity coding

Jozef Škorupa, Jürgen Slowack, Stefaan Mys, Peter Lambert, Rik Van de Walle

Proceedings Volume 7000, 70000G (2008) https://doi.org/10.1117/12.779948

KEYWORDS: Motion estimation, Computer programming, Video coding, Video, Computing systems, Video surveillance, Quantization, Video compression, Switches, Linear filtering

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Proceedings Article | 25 March 2008 Paper

Intelligent pre-processing for fast moving object detection

Chris Poppe, Sarah De Bruyne, Gaëtan Martens, Peter Lambert, Rik Van de Walle

Proceedings Volume 6978, 69780S (2008) https://doi.org/10.1117/12.777034

KEYWORDS: Systems modeling, Video surveillance, Surveillance, Image analysis, Cameras, Environmental monitoring, Image segmentation, Image resolution, Analytical research, Expectation maximization algorithms

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Proceedings Article | 24 September 2007 Paper

Low-complexity MPEG-2 to H.264 transcoding

Jan Lievens, Dieter Van de Walle, Jan De Cock, Joeri Barbarien, Rik Van de Walle, Peter Schelkens

Proceedings Volume 6696, 669604 (2007) https://doi.org/10.1117/12.731786

KEYWORDS: Computer programming, Information technology, Quantization, Motion estimation, Computing systems, Video, Visualization, Detection and tracking algorithms, Electronics, Standards development

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Proceedings Article | 24 September 2007 Paper

Compressed-domain motion detection for efficient and error-resilient MPEG-2 to H.264 transcoding

Jan Lievens, Peter Lambert, Dieter Van de Walle, Freya Dawoud, Joeri Barbarien, Rik Van de Walle, Peter Schelkens

Proceedings Volume 6696, 669609 (2007) https://doi.org/10.1117/12.732081

KEYWORDS: Motion detection, Computer programming, Detection and tracking algorithms, Video surveillance, Video compression, Video, Surveillance, Cameras, Motion estimation, Visualization

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Proceedings Article | 24 September 2007 Paper

Performance evaluation of H.264/AVC decoding and visualization using the GPU

Bart Pieters, Dieter Van Rijsselbergen, Wesley De Neve, Rik Van de Walle

Proceedings Volume 6696, 669606 (2007) https://doi.org/10.1117/12.733151

KEYWORDS: Visualization, Video acceleration, Video, Computer programming, Video coding, Video processing, Computer architecture, Motion models, Standards development, 3D modeling

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Proceedings Article | 2 October 2006 Paper

An evaluation of flexible macroblock ordering in error-prone environments

Yves Dhondt, Stefaan Mys, Peter Lambert, Rik Van de Walle

Proceedings Volume 6391, 639101 (2006) https://doi.org/10.1117/12.685823

KEYWORDS: Video, Computer programming, Error analysis, Multimedia, Video compression, Raster graphics, Video coding, Internet, Data modeling, Electronics

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Proceedings Article | 2 October 2006 Paper

A performance evaluation of the data partitioning tool in H.264/AVC

Stefaan Mys, Yves Dhondt, Dieter Van de Walle, Davy De Schrijver, Rik Van de Walle

Proceedings Volume 6391, 639102 (2006) https://doi.org/10.1117/12.685829

KEYWORDS: Video, Video coding, Visualization, Error analysis, Quantization, Cameras, Computer programming, Signal attenuation, Multimedia, Network architectures

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Proceedings Article | 24 August 2006 Paper

Quality analysis of requantization transcoding architectures for H.264/AVC

Stijn Notebaert, Jan De Cock, Davy De Schrijver, Koen De Wolf, Rik Van de Walle

Proceedings Volume 6312, 63120X (2006) https://doi.org/10.1117/12.680769

KEYWORDS: Video, Quantization, Computer programming, Visualization, Computer architecture, Multimedia, Video coding, Video compression, Matrices, Electronics

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Proceedings Article | 10 February 2006 Paper

Performance analysis of MPEG-21 technologies on mobile devices

Saar De Zutter, Frederik De Keukelaere, Chris Poppe, Rik Van de Walle

Proceedings Volume 6074, 60740L (2006) https://doi.org/10.1117/12.652750

KEYWORDS: Mobile devices, Video, Prototyping, Multimedia, Time metrology, Environmental sensing, Cell phones, Neodymium, Java, Computer programming

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Proceedings Article | 25 October 2005 Paper

Flexible macroblock ordering as a content adaptation tool in H.264/AVC

Yves Dhondt, Peter Lambert, Stijn Notebaert, Rik Van de Walle

Proceedings Volume 6015, 601506 (2005) https://doi.org/10.1117/12.630759

KEYWORDS: Video, Quantization, Video surveillance, Video coding, Computer programming, Multimedia, Cameras, Signal to noise ratio, Raster graphics, Video compression

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Proceedings Article | 24 June 2005 Paper

Comparison of prediction schemes with motion information reuse for low complexity spatial scalability

Koen De Wolf, Robbie De Sutter, Wesley De Neve, Rik Van de Walle

Proceedings Volume 5960, 59605L (2005) https://doi.org/10.1117/12.633358

KEYWORDS: Quantization, Cameras, Spatial resolution, Video coding, Motion estimation, Computer programming, Scalable video coding, Video, Standards development, Optical filters

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Proceedings Article | 2 November 2004 Paper

A performance evaluation of MPEG-21 BSDL in the context of H.264/AVC

Wesley De Neve, Sam Lerouge, Peter Lambert, Rik Van de Walle

Proceedings Volume 5558, (2004) https://doi.org/10.1117/12.564822

KEYWORDS: Video, Computer programming, Video coding, Video compression, Multimedia, Surface plasmons, Java, Profiling, Pollution control, Internet

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Proceedings Article | 4 May 2004 Paper

Simulation study comparing the imaging performance of a solid state detector with a rotating slat collimator versus parallel beam collimator setups

Steven Staelens, Stefaan Vandenberghe, Jan De Beenhouwer, Stijn De Clercq, Yves D'Asseler, Ignace Lemahieu, Rik Van de Walle

Proceedings Volume 5372, (2004) https://doi.org/10.1117/12.535611

KEYWORDS: Collimators, Sensors, Solid state electronics, Cameras, Monte Carlo methods, Spatial resolution, Computer simulations, Device simulation, Scintillation, Single photon emission computed tomography

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Proceedings Article | 18 January 2004 Paper

Assessment of the compression efficiency of the MPEG-4 AVC specification

Wesley De Neve, Peter Lambert, Sam Lerouge, Rik Van de Walle

Proceedings Volume 5308, (2004) https://doi.org/10.1117/12.526346

KEYWORDS: Video, Computer programming, Video coding, Video compression, Visualization, Video surveillance, Motion estimation, Multimedia, Standards development, Data storage

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Proceedings Article | 18 January 2004 Paper

Fully scalable video coding in multicast applications

Sam Lerouge, Robbie De Sutter, Peter Lambert, Rik Van de Walle

Proceedings Volume 5308, (2004) https://doi.org/10.1117/12.525642

KEYWORDS: Scalable video coding, Receivers, Multimedia, Video, Signal to noise ratio, Internet, Video coding, Mathematical modeling, Data modeling, Surface plasmons

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Proceedings Article | 18 January 2004 Paper

Low-level behavioral analysis of the JVT/AVC decoder

Peter Lambert, Lieven Eeckhout, Robbie De Sutter, Koen De Bosschere, Rik Van de Walle

Proceedings Volume 5308, (2004) https://doi.org/10.1117/12.526340

KEYWORDS: Principal component analysis, Video, Video coding, Computer programming, Binary data, Statistical analysis, Data analysis, Chemical species, Profiling, Quantization

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Proceedings Article | 26 November 2003 Paper

An analysis of packaging formats for complex digtal objects: review of principles

Jeroen Bekaert, Patrick Hochstenbach, Emiel De Kooning, Rik Van de Walle

Proceedings Volume 5242, (2003) https://doi.org/10.1117/12.509114

KEYWORDS: Packaging, Data modeling, Digital libraries, Computer programming, Standards development, Systems modeling, Photography, Multimedia, Integrated modeling, Image segmentation

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Proceedings Article | 19 November 2003 Paper

Advanced mobile multimedia applications: using MPEG-21 and time-dependent metadata

Robbie De Sutter, Sam Lerouge, Wesley De Neve, Peter Lambert, Rik Van de Walle

Proceedings Volume 5241, (2003) https://doi.org/10.1117/12.508638

KEYWORDS: Video, Multimedia, Standards development, Mobile devices, Software development, Video coding, Web services, Network architectures, Local area networks

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Proceedings Article | 5 June 2003 Paper

Theoretical LOR model incorporating spatial uncertainty in continuous detector PET

Steven Staelens, Yves D'Asseler, Michel Koole, Stefaan Vandenberghe, Ignace Lemahieu, Rik Van de Walle

Proceedings Volume 5030, (2003) https://doi.org/10.1117/12.480220

KEYWORDS: Sensors, Head, Positron emission tomography, Crystals, Reconstruction algorithms, 3D modeling, Convolution, Numerical integration, Photons, Cameras

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Proceedings Article | 15 May 2003 Paper

Correction for partial volume effects in brain perfusion ECT imaging

Michel Koole, Steven Staelens, Rik Van de Walle, Ignace Lemahieu

Proceedings Volume 5032, (2003) https://doi.org/10.1117/12.481885

KEYWORDS: Tissues, Brain, Neuroimaging, Single photon emission computed tomography, Image segmentation, Image resolution, Brain mapping, Positron emission tomography, Error analysis, Image processing

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Proceedings Article | 1 July 2002 Paper

Dynamic adaptation of multimedia data for mobile applications

Robbie De Sutter, Sam Lerouge, Jeroen Bekaert, Boris Rogge, Dimitri Van De Ville, Rik Van de Walle

Proceedings Volume 4862, (2002) https://doi.org/10.1117/12.473039

KEYWORDS: Multimedia, Mobile devices, Data storage, Telecommunications, Cell phones, Video, Computer programming, Electronics, Explosives, Mobile communications

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Proceedings Article | 1 July 2002 Paper

Analysis of multimedia formats for content description

Boris Rogge, Robbie De Sutter, Jeroen Bekaert, Rik Van de Walle

Proceedings Volume 4862, (2002) https://doi.org/10.1117/12.473025

KEYWORDS: Multimedia, Chemical species, Video, Standards development, Internet, Systems modeling, Visualization, Computer simulations, Data storage, Computer programming

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Proceedings Article | 1 July 2002 Paper

Generic mapping mechanism between content description metadata and user environments

Sam Lerouge, Boris Rogge, Robbie De Sutter, Jeroen Bekaert, Dimitri Van De Ville, Rik Van de Walle

Proceedings Volume 4862, (2002) https://doi.org/10.1117/12.473034

KEYWORDS: Multimedia, Video, Internet, Standards development, JPEG2000, Decision support systems, Image quality, Darmstadtium, Image resolution, Lithium

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Proceedings Article | 1 July 2002 Paper

Metadata-based access to multimedia architectural and historical archive collections

Jeroen Bekaert, Dimitri Van De Ville, Boris Rogge, Sam Lerouge, Robbie De Sutter, Emiel De Kooning, Rik Van de Walle

Proceedings Volume 4862, (2002) https://doi.org/10.1117/12.473043

KEYWORDS: Multimedia, Image segmentation, Data storage, Standards development, Video, Digital libraries, Document management, Computer programming, Electronics, Internet

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Proceedings Article | 20 July 2001 Paper

Functional metadata

Boris Rogge, Rik Van de Walle, Ignace Lemahieu

Proceedings Volume 4519, (2001) https://doi.org/10.1117/12.434284

KEYWORDS: Multimedia, Computer programming, Data storage, Video, Darmstadtium, Decision support systems, Scientific research, Internet, Chemical elements, Document management

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Proceedings Article | 3 July 2001 Paper

Evaluation of reconstruction algorithms for triple-head coincidence imaging by hot sphere detectability

Stefaan Vandenberghe, Yves D'Asseler, Chris Matthews, Michel Koole, Rik Van de Walle, Ignace Lemahieu, Rudi Dierckx

Proceedings Volume 4322, (2001) https://doi.org/10.1117/12.431162

KEYWORDS: Optical spheres, Reconstruction algorithms, Cameras, Head, Sensors, Imaging systems, Computer simulations, Positron emission tomography, Device simulation, Tumors

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Proceedings Article | 3 July 2001 Paper

Resolution recovery for list-mode reconstruction in SPECT

Luc Bouwens, Howard Gifford, Rik Van de Walle, Michael King, Ignace Lemahieu, Rudi Dierckx

Proceedings Volume 4322, (2001) https://doi.org/10.1117/12.431118

KEYWORDS: Neon, Picosecond phenomena, Ferroelectric materials, Single photon emission computed tomography, Collimators, Neodymium, Medical imaging, Image processing, Cerium, Information technology

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Proceedings Article | 3 July 2001 Paper

Template-based scatter correction in clinical brain perfusion SPECT

Michel Koole, Rik Van de Walle, Koen Van Laere, Luc Bouwens, Yves D'Asseler, Stefaan Vandenberghe, Ignace Lemahieu, Rudi Dierckx

Proceedings Volume 4322, (2001) https://doi.org/10.1117/12.431167

KEYWORDS: Brain, Photons, Data acquisition, Single photon emission computed tomography, Cameras, Imaging systems, Neuroimaging, Monte Carlo methods, Data corrections, Signal attenuation

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Proceedings Article | 28 June 2001 Paper

Separability of three-dimensional geometric sensitivity correction in triple-headed gamma camera systems

Yves D'Asseler, Stefaan Vandenberghe, Michel Koole, Luc Bouwens, Rik Van de Walle, Ignace Lemahieu, Rudi Dierckx

Proceedings Volume 4320, (2001) https://doi.org/10.1117/12.430930

KEYWORDS: Cameras, Sensors, Positron emission tomography, Head, Imaging systems, Photons, Optical filters, 3D image processing, Scanners, 3D acquisition

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Gamma camera PET (Positron Emission Tomography) offers a low-cost alternative for dedicated PET scanners. However, sensitivity and count rate capabilities of dual-headed gamma cameras with PET capabilities are still limited compared to full-ring dedicated PET scanners. To improve the geometric sensitivity of these systems, triple-headed gamma camera PET has been proposed. As is the case for dual-headed PET, the sensitivity of these devices varies with the position within the field of view (FOV) of the camera. This variation should be corrected for when reconstructing the images. In earlier work, we calculated the two-dimensional sensitivity variation for any triple-headed configuration. This can be used to correct the data if the acquisition is done using axial filters, which effectively limit the axial angle of incidence of the photons, comparable to 2D dedicated PET. More recently, these results were extended to a fully 3D calculation of the geometric sensitivity variation. In this work, the results of these calculations are compared to the standard approach to correct for 3D geometric sensitivity variation. Current implementations of triple-headed gamma camera PET use two independent corrections to account for three-dimensional sensitivity variations: one in the transaxial direction and one in the axial direction. This approach implicitly assumes that the actual variation is separable in two independent components. We recently derived a theoretical expression for the 3D sensitivity variation, and in this work we investigate the separability of our result. To investigate the separability of the sensitivity variations, an axial and transaxial profile through the calculated variation was taken, and these two were multiplied, thus creating a separable function. If the variation were perfectly separable, this function would be identical to the calculated variation. As a measure of separability, we calculated the percentual deviation of the separable function to the original variation. We investigated the separability for several camera configurations and rotation radii. We found that, for all configurations, the variation is not separable , and becomes less separable as the rotation radius tends to smaller values. This indicates that in this case, our sensitivity correction will give better results than the separable correction now applied.

Proceedings Article | 11 October 2000 Paper

Introducing streaming XML (SXML)

Boris Rogge, Rik Van de Walle, Ignace Lemahieu, Wilfried Philips

Proceedings Volume 4210, (2000) https://doi.org/10.1117/12.403829

KEYWORDS: Broadband telecommunications

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Proceedings Article | 11 October 2000 Paper

XML-based description and presentation of multimedia radiological data

Rik Van de Walle, Boris Rogge, Koen Dreelinck, Ignace Lemahieu

Proceedings Volume 4210, (2000) https://doi.org/10.1117/12.403815

KEYWORDS: Multimedia, Visualization, Standards development, Databases

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Proceedings Article | 6 June 2000 Paper

Iterative list mode reconstruction for coincidence data of gamma camera

Stefaan Vandenberghe, Yves D'Asseler, Michel Koole, Luc Bouwens, Rik Van de Walle, Ignace Lemahieu, Rudi Dierckx

Proceedings Volume 3979, (2000) https://doi.org/10.1117/12.387667

KEYWORDS: Reconstruction algorithms, Cameras, Data acquisition, 3D acquisition, Expectation maximization algorithms, Sensors, Head, Photons, Positron emission tomography, Collimation

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Proceedings Article | 25 April 2000 Paper

Geometric sensitivity calculation of three-headed gamma-camera-based coincidence detection

Yves D'Asseler, Stefaan Vandenberghe, Michel Koole, Luc Bouwens, Rik Van de Walle, Rudi Dierckx, Ignace Lemahieu

Proceedings Volume 3977, (2000) https://doi.org/10.1117/12.384530

KEYWORDS: Sensors, Head, Cameras, Positron emission tomography, Imaging systems, Single photon emission computed tomography, Chlorine, Photons, 3D image reconstruction, Oncology

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Proceedings Article | 25 April 2000 Paper

Resampling MR signals in projection reconstruction MRI

Guy Lateur, Rik Van de Walle, Ignace Lemahieu

Proceedings Volume 3977, (2000) https://doi.org/10.1117/12.384502

KEYWORDS: Magnetic resonance imaging, Signal processing, In vivo imaging, Magnetism, Image processing, Image restoration, Spatial frequencies, Demodulation, Head, Time metrology

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Showing 5 of 38 publications

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