References of "Van Droogenbroeck, Marc"
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See detailAnchors of morphological operators and algebraic openings
Van Droogenbroeck, Marc ULg

in Hawkes, Peter (Ed.) Advances in Imaging and Electron Physics (2009)

Opening and closing operators play an important role in the field of mathematical morphology, mainly because of their useful property of idempotence, which is similar to the notion of ideal filter in ... [more ▼]

Opening and closing operators play an important role in the field of mathematical morphology, mainly because of their useful property of idempotence, which is similar to the notion of ideal filter in linear filtering. From a theoretical point of view, the study of openings has focused on the algebraic characterization of the operators themselves. Morphological filters have been studied for more than 30 years; the effects of the first filters (erosions, openings, and so on) are known in depth. In discussing the effects of a filter, it is not only the operator that is studied but also its relationship with the processed function or image and, in the particular case of mathematical morphology, the structuring element. In addition, there are several approaches to this analysis. For example, the analysis can consider the whole function or some subparts of the function, as in Van Droogenbroeck and Buckley (2005), who introduced the notion of morphological anchors. Anchors were defined in the context of morphological openings, as defined by the cascade of an erosion followed by a dilation. The extension to other kinds of openings is not straightforward. Despite the fact that all morphological openings induce the appearance of anchors, some opening operators (like the quantization opening defined in this chapter) might have no anchors. This chapter presents the theory of anchors related to morphological erosions and openings, and establishes some properties for the extended scope of algebraic openings. It is shown under which circumstances anchors exist for algebraic openings and how to locate some anchors; for example, it suffices for an opening to be spatial or shift-invariant to guarantee the existence of anchors. As for morphological openings, the existence of anchors may help clarify some algorithms or lead to new algorithms to compute algebraic openings. [less ▲]

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See detailDesign of a morphological moving object signature and application to human identification
Barnich, Olivier ULg; Van Droogenbroeck, Marc ULg

in International Conference on Acoustics, Speech, and Signal Processing (ICASSP 2009) (2009, April)

Many computer vision systems try to infer semantic information about a video scene content by looking at the time series of the silhouettes of the moving objects. This paper proposes a new inter-frame ... [more ▼]

Many computer vision systems try to infer semantic information about a video scene content by looking at the time series of the silhouettes of the moving objects. This paper proposes a new inter-frame feature set (signature) based on piecewise surfacic descriptions of binary silhouettes. It captures the dynamics of moving objects and compacts it into a robust set of features suitable for classification. To assess its ability to represent motion information, we use it to build a complete gait recognition algorithm that we test on a database of 21 different subjects. To highlight the efficiency of our signature, we use frontal views instead of side views of persons, which is less discussed in literature and is considered to be harder as the movement of legs is not visible. In that context, the high recognition rates obtained (over 95% of correct identifications) proves that our signature is appropriate to describe moving objects. [less ▲]

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See detailViBe: a powerful random technique to estimate the background in video sequences
Barnich, Olivier ULg; Van Droogenbroeck, Marc ULg

in International Conference on Acoustics, Speech, and Signal Processing (ICASSP 2009) (2009, April)

Background subtraction is a crucial step in many automatic video content analysis applications. While numerous acceptable techniques have been proposed so far for background extraction, there is still a ... [more ▼]

Background subtraction is a crucial step in many automatic video content analysis applications. While numerous acceptable techniques have been proposed so far for background extraction, there is still a need to produce more efficient algorithms in terms of adaptability to multiple environments, noise resilience, and computation efficiency. In this paper, we present a powerful method for background extraction that improves in accuracy and reduces the computational load. The main innovation concerns the use of a random policy to select values to build a samples-based estimation of the background. To our knowledge, it is the first time that a random aggregation is used in the field of background extraction. In addition, we propose a novel policy that propagates information between neighboring pixels of an image. Experiment detailed in this paper show how our method improves on other widely used techniques, and how it outperforms these techniques for noisy images. [less ▲]

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See detailVisual Backgound Extractor
Van Droogenbroeck, Marc ULg; Barnich, Olivier ULg

Patent (2009)

ViBe is a powerful pixel-based technique that detects the background in video sequences. Many experiments have shown that it performs better than the state-of-the-art techniques known in the scientific ... [more ▼]

ViBe is a powerful pixel-based technique that detects the background in video sequences. Many experiments have shown that it performs better than the state-of-the-art techniques known in the scientific literature. In addition the computational load is lower than simple background techniques implemented in commercial products. ViBe is the perfect solution for both softwares and hardware implementations. [less ▲]

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See detailFrontal-view gait recognition by intra- and inter-frame rectangle size distribution
Barnich, Olivier ULg; Van Droogenbroeck, Marc ULg

in Pattern Recognition Letters (2009), 30

Current trends seem to accredit gait as a sensible biometric feature for human identification, at least in a multimodal system. In addition to being a robust feature, gait is hard to fake and requires no ... [more ▼]

Current trends seem to accredit gait as a sensible biometric feature for human identification, at least in a multimodal system. In addition to being a robust feature, gait is hard to fake and requires no cooperation from the user. As in many video systems, the recognition confidence relies on the angle of view of the camera and on the illumination conditions, inducing a sensitivity to operational conditions that one may wish to lower. In this paper we present an efficient approach capable of recognizing people in frontal-view video sequences. The approach uses an intra-frame description of silhouettes which consists of a set of rectangles that will fit into any closed silhouette. A dynamic, inter-frame, dimension is then added by aggregating the size distributions of these rectangles over multiple successive frames. For each new frame, the inter-frame gait signature is updated and used to estimate the identity of the person detected in the scene. Finally, in order to smooth the decision on the identity, a majority vote is applied to previous results. In the final part of this article, we provide experimental results and discuss the accuracy of the classification for our own database of 21 known persons, and for a public database of 25 persons. [less ▲]

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See detailAnalyse et conception des systèmes de télécommunications
Van Droogenbroeck, Marc ULg

Learning material (2008)

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See detailPrincipes des télécommunications analogiques et numériques
Van Droogenbroeck, Marc ULg

Learning material (2008)

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See detailPrincipes des télécommunications analogiques et numériques
Van Droogenbroeck, Marc ULg

Learning material (2008)

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See detailTraitement numérique des images
Van Droogenbroeck, Marc ULg

Learning material (2007)

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See detailTraitement numérique des images (transparents)
Van Droogenbroeck, Marc ULg

Learning material (2007)

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See detailPrincipes de base du réseau GSM et des transmissions GPRS
Van Droogenbroeck, Marc ULg

Conference given outside the academic context (2006)

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See detailA video-based human-computer interaction system for audio-visual immersion
Dardenne, Renaud; Embrechts, Jean-Jacques ULg; Van Droogenbroeck, Marc ULg et al

in Proceedings of SPS-DARTS (2006, March)

This paper describes the video and audio tools that have been implemented in a real-type system to immerse a user into a virtual scene. The video tools include motion detection, skin detection by ... [more ▼]

This paper describes the video and audio tools that have been implemented in a real-type system to immerse a user into a virtual scene. The video tools include motion detection, skin detection by thresholding, shadow detection and extraction, and finally the user’s head and hands detection. Once this is done, the user (who is surrounded by a matrix of loudspeakers) is able to move a sound source in the horizontal plane around him. Moreover, the sound is auralized by convolution with (directional) room impulse responses, which have been pre-computed by a ray tracing method. The different sound contributions are distributed to the individual loudspeakers by applying the VBAP technique. [less ▲]

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See detailResearch Unit in Signal and Image Exploitation (INTELSIG)
Verly, Jacques ULg; Piater, Justus ULg; Van Droogenbroeck, Marc ULg et al

Scientific conference (2006)

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See detaillibmorpho: a library for mathematical morphology
Dardenne, Renaud; Van Droogenbroeck, Marc ULg

Software (2006)

libmorpho is a free software library written in ANSI C that implements several basic operations of mathematical morphology: erosions, dilations, openings, and closings by lines, rectangles, or arbitrary ... [more ▼]

libmorpho is a free software library written in ANSI C that implements several basic operations of mathematical morphology: erosions, dilations, openings, and closings by lines, rectangles, or arbitrary shaped structuring elements or by structuring functions. The software is released under the GNU General Public license. [less ▲]

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See detailRobust analysis of silhouettes by morphological size distributions
Barnich, Olivier ULg; JODOGNE, Sébastien ULg; Van Droogenbroeck, Marc ULg

in Lecture Notes in Computer Science (2006), 4179

We address the topic of real-time analysis and recognition of silhouettes. The method that we propose first produces object features obtained by a new type of morphological operators, which can be seen as ... [more ▼]

We address the topic of real-time analysis and recognition of silhouettes. The method that we propose first produces object features obtained by a new type of morphological operators, which can be seen as an extension of existing granulometric filters, and then insert them into a tailored classification scheme. Intuitively, given a binary segmented image, our operator produces the set of all the largest rectangles that can be wedged inside any connected component of the image. The latter are obtained by a standard background subtraction technique and morphological filtering. To classify connected components into one of the known object categories, the rectangles of a connected component are submitted to a machine learning algorithm called EXtremely RAndomized trees (Extra-trees). The machine learning algorithm is fed with a static database of silhouettes that contains both positive and negative instances. The whole process, including image processing and rectangle classification, is carried out in real-time. Finally we evaluate our approach on one of today's hot topics: the detection of human silhouettes. We discuss experimental results and show that our method is stable and computationally effective. Therefore, we assess that algorithms like ours introduce new ways for the detection of humans in video sequences. [less ▲]

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See detailA method based on multiple adaptive windows to improve the determination of disparity maps
Demoulin, Cédric; Van Droogenbroeck, Marc ULg

in ProRISC/IEEE Workshop on Circuit, Systems and Signal Processing (2005, November)

The correspondence problem is one of main topics in stereo vision that, despites being studied for many years, is still in progress. In this paper, we present a new method that computes the disparity map ... [more ▼]

The correspondence problem is one of main topics in stereo vision that, despites being studied for many years, is still in progress. In this paper, we present a new method that computes the disparity map. Our method is local (i.e. only information gathered in the close neighborhood is used) and is based on image statistics. More specifically it combines multiple adaptive windows and local statistical measures in order to optimize the quality of the computation of disparity maps. As the size of windows is critical for local methods, we propose an algorithm that modifies the size of windows surrounding the pixel of interest to capture enough information in regions with low texture energy. This process is based on statistical measures (mean and horizontal/vertical average deviation) taken in the windows of the original stereo images. In the last section we show that our method performs very well compared to other existing local methods. [less ▲]

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