Prof. Ignace Lemahieu Profile

Prof. Ignace Lemahieu

Director of Research at Univ Gent

SPIE Involvement:

Author

Publications (36)

Proceedings Article | 17 March 2006 Paper

LROC assessment of nonlinear filtering methods in Ga-67 SPECT imaging

Stijn De Clercq, Steven Staelens, Jan De Beenhouwer, Yves D'Asseler, Ignace Lemahieu

Proceedings Volume 6146, 61460E (2006) https://doi.org/10.1117/12.655897

KEYWORDS: Nonlinear filtering, Linear filtering, Gaussian filters, Monte Carlo methods, Image filtering, Single photon emission computed tomography, Anisotropic filtering, Diffusion, Tumors, Image quality

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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 | 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 | 11 April 2002 Paper

New denoising technique for ultrasound images using morphological properties of speckle combined with tissue classifying parameters

Gjenna Stippel, Wilfried Philips, Ignace Lemahieu

Proceedings Volume 4687, (2002) https://doi.org/10.1117/12.462169

KEYWORDS: Speckle, Image segmentation, Ultrasonography, Tissues, Image filtering, Image processing, Brain, Neuroimaging, Denoising, Scanners

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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

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 | 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 | 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 | 29 December 2000 Paper

New fuzzy filter for Gaussian noise reduction

Dimitri Van De Ville, Mike Nachtegael, D. Van der Weken, Wilfried Philips, Ignace Lemahieu, E. Kerre

Proceedings Volume 4310, (2000) https://doi.org/10.1117/12.411782

KEYWORDS: Image filtering, Optical filters, Gaussian filters, Digital filtering, Electronic filtering, Fuzzy logic, Cameras, Denoising, Filtering (signal processing), Optical inspection

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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 | 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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SPIE Journal Paper | 1 October 2000

Nonlinear resampling for edge preserving moire suppression

Dimitri Van De Ville, Koen Denecker, Wilfried Philips, Ignace Lemahieu

JEI, Vol. 9, Issue 04, (October 2000) https://doi.org/10.1117/12.10.1117/1.1289535

KEYWORDS: Printing, Linear filtering, Image filtering, Fourier transforms, Halftones, Image processing, Digital filtering, Digital imaging, Image quality, Amplitude modulation

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

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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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 | 19 April 2000 Paper

Exploiting the third dimension in the lossless and near-lossless compression of medical volume images and video

Dirk De Rycke, Steven Van Assche, Wilfried Philips, Ignace Lemahieu

Proceedings Volume 3974, (2000) https://doi.org/10.1117/12.383003

KEYWORDS: Video compression, Video, Image compression, Medical imaging, 3D modeling, 3D image processing, Data compression, 3D video compression, Image quality standards, Magnetic resonance imaging

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SPIE Journal Paper | 1 October 1999

Evaluation of lossless compression techniques for high-resolution RGB and CMYK color images

Steven Van Assche, Koen Denecker, Peter De Neve, Wilfried Philips, Ignace Lemahieu

JEI, Vol. 8, Issue 04, (October 1999) https://doi.org/10.1117/12.10.1117/1.482709

KEYWORDS: CMYK color model, Image compression, RGB color model, Quantization, Image segmentation, Image processing, Binary data, Image resolution, Spatial resolution, Receivers

SPIE Journal Paper | 1 October 1999

Context-based lossless halftone image compression

Koen Denecker, Steven Van Assche, Peter De Neve, Ignace Lemahieu

JEI, Vol. 8, Issue 04, (October 1999) https://doi.org/10.1117/12.10.1117/1.482708

KEYWORDS: Image compression, Halftones, Stochastic processes, Printing, Image processing, Image resolution, Image quality, Computer programming, Raster graphics, Chromium

Proceedings Article | 28 May 1999 Paper

Consistent optical imaging and color measurement of the skin

Yves Vander Haeghen, J. Naeyaert, Ignace Lemahieu

Proceedings Volume 3659, (1999) https://doi.org/10.1117/12.349556

KEYWORDS: RGB color model, Cameras, Frame grabbers, Skin, Imaging systems, Light sources, CCD cameras, Target acquisition, Dermatology, Calibration

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Proceedings Article | 19 May 1999 Paper

CIELAB-driven adaptive quantization scheme for DCT-based compression of CMYK images

Peter De Neve, Koen Denecker, Ignace Lemahieu

Proceedings Volume 3644, (1999) https://doi.org/10.1117/12.348433

KEYWORDS: Image compression, CMYK color model, Quantization, Eye, Control systems, RGB color model, Distortion, Printing, Image quality standards, Ions

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Proceedings Article | 28 December 1998 Paper

Comparison of lossless compression techniques for prepress color images

Steven Van Assche, Koen Denecker, Wilfried Philips, Ignace Lemahieu

Proceedings Volume 3653, (1998) https://doi.org/10.1117/12.334646

KEYWORDS: Image compression, Binary data, Quantization, Spatial resolution, Data compression, Image resolution, Receivers, Image quality, Image processing, Matrices

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Proceedings Article | 22 December 1998 Paper

Region-of-interest-based progressive transmission of gray-scale images across the Internet

Boris Rogge, Ignace Lemahieu, Wilfried Philips, Koen Denecker, Peter De Neve, Steven Van Assche

Proceedings Volume 3648, (1998) https://doi.org/10.1117/12.334578

KEYWORDS: Internet, Computer programming, Image processing, Image compression, Medical imaging, Scientific research, Quantization, Image quality, Color imaging, Graphic arts

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Proceedings Article | 22 December 1998 Paper

CIEL*a*b*-based near-lossless compression of prepress images

Koen Denecker, Steven Van Assche, Peter De Neve, Ignace Lemahieu

Proceedings Volume 3648, (1998) https://doi.org/10.1117/12.334573

KEYWORDS: Image compression, CMYK color model, Quantization, Visualization, Visual compression, Visual system, RGB color model, Distortion, Error analysis, Image visualization

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Proceedings Article | 22 December 1998 Paper

Nonlinear resampling for both moire suppression and edge preservation

Dimitri Van De Ville, Koen Denecker, Wilfried Philips, Ignace Lemahieu

Proceedings Volume 3648, (1998) https://doi.org/10.1117/12.334586

KEYWORDS: Moire patterns, Printing, Fourier transforms, Halftones, Image processing, Scientific research, Laser engraving, Statistical analysis, Image filtering, Linear filtering

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Proceedings Article | 7 September 1998 Paper

Compressing CMYK images by removing color redundancy: a perceptual-based quality evaluation

Peter De Neve, Koen Denecker, Wilfried Philips, Ignace Lemahieu

Proceedings Volume 3409, (1998) https://doi.org/10.1117/12.324118

KEYWORDS: Image compression, CMYK color model, Quantization, Wavelets, Wavelet transforms, Image processing, Distortion, Printing, Data processing, Image quality standards

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Proceedings Article | 7 September 1998 Paper

Binary tree context modeling of halftone images using a fast adaptive template selection scheme

Koen Denecker, Peter De Neve, Ignace Lemahieu

Proceedings Volume 3409, (1998) https://doi.org/10.1117/12.324114

KEYWORDS: Halftones, Image compression, Stochastic processes, Printing, Statistical analysis, Chromium, Image resolution, CMYK color model, Statistical modeling, Computer programming

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Proceedings Article | 26 June 1998 Paper

Experimental comparison of 2D and 3D wavelet image compression methods for medical image sets

Jeroen Van Overloop, Wim Van De Sype, Koen Denecker, Peter De Neve, Erik Sundermann, Ignace Lemahieu

Proceedings Volume 3335, (1998) https://doi.org/10.1117/12.312510

KEYWORDS: Image compression, Wavelets, 3D image processing, Quantization, Medical imaging, Transform theory, Image filtering, Wavelet transforms, Picture Archiving and Communication System, Telecommunications

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Proceedings Article | 1 April 1998 Paper

Lossless compression of prepress images using a novel color decorrelation technique

Steven Van Assche, Wilfried Philips, Ignace Lemahieu

Proceedings Volume 3308, (1998) https://doi.org/10.1117/12.302430

KEYWORDS: Image segmentation, Image compression, Quantization, Spatial resolution, Data compression, Image resolution, Binary data, Receivers, Image quality, Image processing

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Proceedings Article | 2 January 1998 Paper

Fast autocorrelation-based context template selection scheme for lossless compression of halftone images

Koen Denecker, Steven Van Assche, Ignace Lemahieu

Proceedings Volume 3300, (1998) https://doi.org/10.1117/12.298288

KEYWORDS: Image compression, Halftones, Printing, Statistical analysis, Ions, Image quality standards, Statistical modeling, Image resolution, Tin, Chromium

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Proceedings Article | 7 February 1997 Paper

New segmented image coding method for color images

Jeroen Van Overloop, Dimitri Torfs, Wilfried Philips, Ignace Lemahieu

Proceedings Volume 2949, (1997) https://doi.org/10.1117/12.266361

KEYWORDS: Image compression, Image segmentation, Image quality, Distance measurement, Image quality standards, Image processing algorithms and systems, Distortion, Information visualization, Eye, Chromium

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Proceedings Article | 16 September 1996 Paper

Comparison of lossless coding techniques for screened continuous-tone images

Koen Denecker, Steven Van Assche, Wilfried Philips, Ignace Lemahieu

Proceedings Volume 2952, (1996) https://doi.org/10.1117/12.251263

KEYWORDS: Image compression, Chromium, Halftones, Image resolution, Printing, Photography, Stochastic processes, CMYK color model, Image processing, Adaptive optics

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Proceedings Article | 16 September 1996 Paper

Medical image compression using block-based transform coding techniques

Peter De Neve, Wilfried Philips, Jeroen Van Overloop, Ignace Lemahieu

Proceedings Volume 2952, (1996) https://doi.org/10.1117/12.251279

KEYWORDS: Image compression, Medical imaging, Image quality, Angiography, Distortion, Magnetic resonance imaging, X-ray imaging, X-rays, Quantization, X-ray computed tomography

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Proceedings Article | 12 May 1995 Paper

PET image reconstruction using simulated annealing

Erik Sundermann, Ignace Lemahieu

Proceedings Volume 2434, (1995) https://doi.org/10.1117/12.208709

KEYWORDS: Reconstruction algorithms, Algorithms, Positron emission tomography, Expectation maximization algorithms, Data modeling, Image quality, Image restoration, Image processing, Signal attenuation, Electronics

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Proceedings Article | 1 June 1994 Paper

Parallel implementation of the maximum likelihood-expectation maximization (ML-EM) reconstruction algorithm for positron emission tomography (PET) images in a visual language

Koen Bastiaens, Ignace Lemahieu

Proceedings Volume 2238, (1994) https://doi.org/10.1117/12.177711

KEYWORDS: Positron emission tomography, Scanners, Reconstruction algorithms, Visualization, Expectation maximization algorithms, Sensors, Computer programming, Visual programming languages, Image processing, Photons

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Showing 5 of 36 publications

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