Jacques Verly

University of Liège | ulg · Department of Electrical Engineering and Computer Science - Montefiore Institute

While inertial measurement unit (IMU)-based systems have shown their potential in quantifying medically-significant gait parameters, it remains to be demonstrated that they can provide accurate and reliable parameters both across various walking conditions and in healthcare settings. Using an IMU-based system we have previously developed, with one...

Road-vehicle accidents are mostly due to human errors, and many such accidents could be avoided by continuously monitoring the driver. Driver monitoring (DM) is a topic of growing interest in the automotive industry, and it will remain relevant for all vehicles that are not fully autonomous, and thus for decades for the average vehicle owner. The p...

Road vehicle accidents are mostly due to human errors, and many such accidents could be avoided by continuously monitoring the driver. Driver monitoring (DM) is a topic of growing interest in the automotive industry, and it will remain relevant for all vehicles that are not fully autonomous, and thus for decades for the average vehicle owner. The p...

Recent progress in virtual reality (VR) technologies make immersion more accessible to everyone, and, in particular, developments aimed at the entertainment industry are being brought into to the domain of health. The main uses of VR in health are of two forms. First, it is a new method to diagnose and to treat patients; second, it is a new method...

Various studies show that drowsiness reduces driver alertness and can significantly affect driver performance. In this paper, we investigate the effect of drowsiness on the interaction with the in-vehicle infotainment system (IVIS) while driving. The motivation was to investigate whether a specific type of user interface can provide better performa...

Drowsiness is a major cause of fatal accidents, in particular in transportation. It is therefore crucial to develop automatic, real-time drowsiness characterization systems designed to issue accurate and timely warnings of drowsiness to the driver. In practice, the least intrusive, physiology-based approach is to remotely monitor, via cameras, faci...

Validated extraction of gait sub-phase durations using an ambulatory accelerometer-based system is a current unmet need to quantify subtle changes during the walking of older adults. In this paper, we describe (1) a signal processing algorithm to automatically extract not only durations of stride, stance, swing, and double support phases, but also...

We develop a powerful probabilistic framework for the local characterization of surfaces and edges in range images, which is useful in many applications of computer vision, such as filtering, edge detection, feature extraction, and classification. We use the geometrical nature of the data to derive an analytic expression for the joint probability d...

Visual pursuit is a key marker of residual consciousness in patients with disorders of consciousness (DOC). Currently, its assessment relies on subjective clinical decisions. In this study, we explore the variability of such clinical assessments, and present an easy-to-use device composed of cameras and video processing algorithms that could help t...

We present a new signal processing algorithm that extracts five gait events: heel strike, toe strike, heel-off, toe-off, and heel clearance from only two accelerometers attached on the heels of the subjects usual shoes. This algorithm first uses a continuous wavelet-based segmentation that parses the signal of consecutive strides into motionless pe...

3D movies are calibrated to meet a certain screen brightness standard. Therefore, what would be the consequences on the quality of the 3D experience for spectators watching a 3D movie when movie theaters do not respect this standard? First, we attempted to better understand which factors were important for a spectator by conducting an experiment wh...

Drowsiness is a major cause of accidents, in particular in road transportation. It is thus crucial to develop robust drowsiness monitoring systems. There is a widespread agreement that the best way to monitor drowsiness is by closely monitoring symptoms of drowsiness that are directly linked to the physiology of an operator such as a driver. The be...

Drowsiness is the intermediate state between wakefulness and sleep. It is characterized by impairments of performance, which can be very dangerous in many activities and can lead to catastrophic accidents in transportation or in industry. There is thus an obvious need for systems that are able to continuously, objectively, and automatically estimat...

Welcome to the fifth (5th) edition of the “International Conference on 3D Imaging (IC3D)”, which is technically co-sponsored by the IEEE Signal Processing Society, and the proceedings of which are archived in the IEEE Xplore digital library.

We describe a new gait segmentation method based on the continuous wavelet transform to identify stride-by-stride gait cycles from measurements of foot-mounted three-dimensional (3D) accelerometers. The detection of such gait cycles is indeed a crucial step for an accurate extraction of relevant gait events such as heel strike, toe strike, heel-off...

Many applications require the use of multiple cameras to cover a large volume. In this paper, we evaluate several pairwise calibration techniques dedicated to multiple range cameras. We compare the precision of a self-calibration technique based on the movement in front of the cameras to object based calibration. While the self-calibration techniqu...

An original signal processing algorithm is presented to automatically extract, on a stride-by-stride basis, four consecutive fundamental events of walking, heel strike (HS), toe strike (TS), heel-off (HO), and toe-off (TO), from wireless accelerometers applied to the right and left foot. First, the signals recorded from heel and toe three-axis acce...

A new signal processing algorithm is developed for quantifying heel strike (HS) and toe-off (TO) event times solely from measured heel and toe coordinates during overground walking. It is based on a rough estimation of relevant local 3D position signals. An original piecewise linear fitting method is applied to these local signals to accurately ide...

We describe how we handled an unexpected impedance matching issue on the receiver side (at UHF) of the radiocommunication system aboard the OUFTI-1 nanosatellite of the University of Liège. Our approach relied on a combination of novel analytical developments combined with experimentation. This paper deals with an unexpected antenna impedance match...

We describe the principle and use of a new low-cost, wireless, 3-axis accelerometer-based device that records acceleration signals and automatically analyses them to characterize normal and pathological gait.

Comparison of the levels of drowsiness obtained via a new photooculography-based drowsiness scale and via a simple variation of the Karolinska Drowsiness Scale (KDS)

Somnolence is known to be a major cause of various types of accidents, and ocular parameters are recognized to be reliable physiological indicators of somnolence. We have thus developed an experimental somnolence quantification system that uses images of the eye and that produces a level of somnolence on a continuous numerical scale. The aim of thi...

Validation of a new automatic drowsiness quantification system for drivers

We consider the problem of matching interest points (IPs) extracted from the two images of a stereoscopic pair. We describe each IP via a descriptor consisting in one angular signature for a grayscale image, three signatures for a color image, and, more generally, N signatures for N coregistered images of different modalities. Each angular signatur...

EEG signals are often contaminated by ocular artifacts (OAs), in particular when they are recorded for a subject that is, in principle, awake, such as in a study of drowsiness. It is generally desirable to detect and/or correct these OAs before interpreting the EEG signals. We have identified 11 existing methods for dealing with OAs. Their study al...

Abstract While 3D cinema is becoming increasingly established, little effort has been focused on the general problem of producing a 3D sound scene spatially coherent with the visual content of a stereoscopic-3D (s-3D) movie. The perceptual relevance of such a spatial audiovisual coherence is of significant interest. In this paper, a subjective expe...

Air-traffic controllers cannot identify air vehicles flying with a defective or nonexistent transponder. Primary radar does not help, because it cannot classify air vehicles from echoes. Passive radar offers a potential solution, the main difficulty lying in the analysis of the data. We present a novel, automatic object-target recognition system ca...

While 3D cinema is becoming increasingly established, little effort has focused on the general problem of producing a 3D sound scene spatially coherent with the visual content of a stereoscopic-3D (s-3D) movie. The perceptual relevance of such spatial audiovisual coherence is of significant interest. In this paper, we explain why the combination of...

Researchers rarely provide solid performance and validation information about their acceleometer-based approaches to human gait analysis. We present here a novel signal processing and analysis algorithm that automatically extracts four consecutive fundamental events of walking: heel strike (HS), toe strike (TS), heel off (HO), and toe off (TO). In...

Development of an automatic reference system for directly quantifying drowsiness from a few polysomnographic signals

The presence of ocular artifacts (OA) due to eye movements and eye blinks is a major problem for the analysis of electroencephalographic (EEG) recordings in most applications. A large variety of methods (algorithms) exist for detecting or/and correcting OA's. We identified the most promising methods, implemented them, and compared their performance...

This work is part of a project that deals with the three-dimensional (3D) analysis of normal and pathological gaits based on a newly developed system for clinical applications, using low-cost wireless accelerometers and a signal processing algorithm. This system automatically extracts relevant gait events such as the heel strikes (HS) and the toe-o...

Welcome to the second edition of the “International Conference on 3D Imaging (IC3D)”, which is technically co-sponsored by the IEEE Signal Processing Society.

Experimental design for a study of drowsiness using a driving simulator

2nd Thales Radar PhD Day, Rungis, France

We consider the automatic classification of aircraft observed with a passive radar, thus using illuminators of opportunity. We deployed a testbed and developed classification algorithms. Preliminary tests show a correct recognition rate of 72%.

We describe the principle and use of a new low-cost, wireless, 3-axis accelerometer-based device that records acceleration signals and automatically analyses them to characterize normal and pathological gait.

In this paper, a novel method of measurement of the real RCS of various airplanes in real conditions, in bistatic mode, and at low frequency is derived. The presence of an airplane is detected by the use of an ADS-B receiver. The RCS of an airplane is derived thanks to the ratio of the power of the received echo signal to the power of the received...

Development of an automatic drowsiness monitoring system based on EEG and EOG signals, and preliminary tests in a professional driving simulator

Current neuronavigation systems cannot adapt to changing intraoperative conditions over time. To overcome this limitation, we present an experimental end-to-end system capable of updating 3D preoperative images in the presence of brain shift and successive resections. The heart of our system is a nonrigid registration technique using a biomechanica...

Current neuronavigation systems cannot adapt to changing intraoperative conditions over time. To overcome this limitation, we present an experimental end-to-end system capable of updating 3D preoperative images in the presence of brain shift and successive resections. The heart of our system is a nonrigid registration technique using a biomechanica...

Edges are a fundamental clue for analyzing, interpreting, and understanding 3D scenes: they describe objects boundaries. Available edge detection methods are not suited for 3D cameras such as the Microsoft Kinect or a time-of-flight camera: they are slow and do not take into consideration the characteristics of the cameras. In this paper, we presen...

This paper presents a novel classification technique based on targets bistatic backscattering coefficients acquired at low frequencies. Each target class is characterized by a subspace. Air targets are then classified based on geometrical classification criteria. An average recognition rate of 90% is achieved.

Outcomes for neurosurgery patients can be improved by enhancing intraoperative navigation and guidance. Current navigation systems do not accurately account for intraoperative brain deformation. So far, most studies of brain deformation have focused on brain shift, whereas this paper focuses on the brain deformation due to retraction. The heart of...

While 3D cinema is becoming more established, little effort has focused on the general problem of producing a 3D sound scene spatially coherent with the visual content of a stereoscopic-3D (s-3D) movie. The perceptual relevance of such spatial audiovisual coherence is of significant interest. In order to carry out such experiments, it is necessary...

Radar space-time adaptive processing (STAP) is a well-suited technique to detect slow-moving targets in the presence of a strong interference background. We consider STAP for a radar operating in a bistatic radar configuration and collecting returns with a conformal antenna array (CAA). The statistics of the secondary data snapshots used to estimat...

Very little research has been conducted so far into the general problem of producing a 3D soundscape consistent with the visual content of a 3D-stereoscopic movie. First, the following 3D sound reproduction techniques are reviewed: Vector Base Amplitude Panning (VBAP), binaural and transaural techniques, Wave Field Synthesis (WFS) and Ambisonics. S...

We consider the problem of improving outcomes for neurosurgery patients by enhancing intraoperative navigation and guidance. Current navigation systems do not accurately account for intraoperative brain deformation. We focus on the brain shift deformation that occurs just after the opening of the skull and dura. The heart of our system is a nonrigi...

Interactivity is one of the key challenges for immersive applications like gaming. Manufacturers have been working towards interfaces that are driven by a device (e.g. a Wiimote) or interfaces that are controlled by a camera with a subsequent computer vision module. Both approaches have unique advantages, but they do not permit to localize users in...

In this paper, we describe a new automatic target recognition algorithm for classifying SAR images based on the PiXiT image classifier. It uses randomized sub-windows extraction and extremely randomized trees (extra-trees). This approach requires very little pre-processing of the images, thereby limiting the computational load. It was successfully...

In this article, we describe a new automatic target recognition algorithm for classifying SAR images. It is based on the PiXiT image classifier, already used in several applications, which uses randomized sub-windows extraction and extremely randomized trees (extra-trees). This approach requires very little pre-processing of the images, thereby lim...

We consider space-time adaptive processing (STAP) when the radar returns are recorded by a conformal antenna array (CAA). The statistics of the secondary data snapshots used to estimate the optimum weight vector are not identically distributed with respect to range, thus preventing the customary STAP processor from achieving its optimum performance...

The authors consider space-time adaptive processing (STAP) when the radar returns are recorded by a conformal antenna array (CAA). The statistics of the secondary data snapshots used to estimate the optimum weight vector are not identically distributed with respect to range, thus preventing the customary STAP processor from achieving its optimum pe...

This paper considers an approach to improving outcomes for neurosurgery patients by enhancing intraoperative navigation and guidance. Currently, intraoperative navigation systems do not accurately account for brain shift or tissue resection. We describe how preoperative images can be incrementally updated to take into account any type of brain tiss...

The problem of detecting slow-moving targets using a space-time adaptive processing (STAP) radar is addressed. The determination of the optimum interference-rejection weights at each range is based on snapshots at neighbouring ranges. However, in virtually all bistatic configurations or/and when using conformal antenna arrays (CAA), snapshot statis...

This paper presents a novel approach to tracking ground targets in multiple cameras. A target is tracked not only in each camera but also in the ground plane by individual particle filters. These particle filters collaborate in two different ways. First, the particle filters in each camera pass messages to those in the ground plane where the multi-...

The increasing interest for arbitrary antenna arrays in radar space-time adaptive processing (STAP) creates a need for a thorough understanding of the role of, and dependencies between, spatial and Doppler frequencies and related quantities, especially in the characterization of clutter. We successively introduce ldquogeometricalrdquo and statistic...

We consider space-time adaptive processing (STAP) when the radar returns are recorded by a conformal antenna array (CAA). The statistics of the secondary data snapshots used to estimate the optimum weight vector are not identically distributed with respect to range, thus preventing the customary STAP processor from achieving its optimum performance...

We consider space-time adaptive processing (STAP) when the radar returns are recorded by a conformal antenna array (CAA). The statistics of the secondary data snapshots used to estimate the optimum weight vector are not identically distributed with respect to range, thus preventing the STAP processor from achieving its optimum performance. The comp...

We consider the problem of improving outcomes for neurosurgery patients by enhancing intra-operative navigation and guidance. Current navigation systems do not accurately account for intra-operative brain deformation. In this work, we focus on the brain shift deformation that occurs just after the opening of the skull and dura, before any cut and s...

We consider space-time adaptive processing (STAP) when the radar returns are recorded by a conformal antenna array (CAA). The statistics of the secondary data snapshots used to estimate the optimum weight vector are not identically distributed with respect to range, thus preventing the customary STAP processor from achieving its optimum performance...