Choubeila Maaoui

• PhD
• Professor (Associate) at University of Lorraine

Stress is a complex phenomenon that affects the body and mind on multiple levels, encompassing both psychological and physiological aspects. Recent studies have used multiple modalities to comprehensively describe stress by exploiting the complementarity of multimodal signals. In this paper, we investigate the feasibility of fusing facial features...

Background: The COVID-19 pandemic has resulted in increased psychological pressure on mental health since 2019. The resulting anxiety and stress have permeated every aspect of life during confinement. Objective: To provide psychologists with an unbiased measure that can aid in the preliminary diagnosis of anxiety disorders and be used as an init...

Pulse rate (PR) is one of the most important markers for assessing a person's health. With the increasing demand for long-term health monitoring, much attention is being paid to contactless PR estimation using imaging photoplethysmography (iPPG). This non-invasive technique is based on the analysis of subtle changes in skin color. Despite efforts t...

La mesure de signaux photopléthysmographiques (PPG) sans contact est une technique de mesure non invasive permettant d'estimer un ensemble de fonctions vitales par analyse vidéo délivrée par caméra. Nous proposons, dans cet article, une méthode permettant de convertir un signal PPG mesuré par caméra en un signal PPG mesuré en contact (cPPG). L'obje...

Photoplethysmography is a method to visualize the variation in blood volume within tissues with light. The signal obtained has been used for the monitoring of patients, interpretation for diagnosis or for extracting other physiological variables (e.g., pulse rate and blood oxygen saturation). However, the photoplethysmography signal can be perturbe...

Background The remote measurement of physiological signals from video has gained a particular attention over the last past years. Estimating cardiovascular parameters like oxygen saturation and arterial blood pressure (BP) is covered by a limited volume of studies and remain a very challenging issue. Recent attempts demonstrated that BP can be esti...

Stress is a complex phenomenon that affects the body and mind on multiple levels, encompassing both psychological and physiological aspects. Recent studies have used multiple modalities to comprehensively describe stress by exploiting the complementarity of multimodal signals. In this paper, we investigate the feasibility of fusing facial features...

Human's affective state recognition remains a challenging topic due to the complexity of emotions, which involves experiential, behavioral, and physiological elements. Since it is difficult to comprehensively describe emotion in terms of single modalities, recent studies have focused on fusion strategy to exploit the complementarity of multimodal s...

Les pathologies cardiovasculaires sont désignées par l'OMS comme étant la première cause de mortalité dans le monde. Elles sont responsables de près de la moitié des maladies invalidantes aujourd'hui. Un ensemble de technologies per-mettent de mesurer différents signaux physiologiques et fonctions vitales sans qu'aucun contact avec la personne ne s...

Nous présentons dans ce papier une nouvelle architecture de bout en bout basée sur un réseau de neurones spatio-temporel profond pour l'estimation de la fréquence cardiaque à partir des trames vidéo issues d'une webcam bas coût. Contrairement aux méthodes existantes, nous estimons la valeur de la fréquence cardiaque directement sans passer par l'ex...

We present in this paper the LCOMS Lab's approach to the 1st Vision For Vitals (V4V) Challenge organized within ICCV2021. The V4V challenge was focused on computer vision methods for vitals signs measurement from facial videos, including pulse rate (PR) and respiratory rate. We propose a novel end-to-end architecture based on a deep spatiotemporal...

Imaging photoplethysmography (iPPG) is an optical technique dedicated to the assessment of several vital functions using a simple camera. Significant efforts have been made to reliably estimate heart and respiratory rates. Currently, research is focusing on the remote estimation of oxygen saturation and blood pressure (BP). The limited number of pu...

Recent technological advances in the field of sensors, signal processing and image processing favor the development of new techniques for vital parameters monitoring such as imaging photoplethysmography (iPPG). iPPG is a simple and noninvasive measurement technique. It has been employed to remotely estimate heart and respiratory rates, oxygen satur...

Désignées par l'OMS comme étant la première cause de mortalité dans le monde, les pathologies respiratoires ou car-diovasculaires sont responsables de près de la moitié des maladies invalidantes. Différentes technologies permettent désormais de mesurer signaux physiologiques et fonctions vitales sans qu'aucun contact avec la personne ne soit nécess...

Remote pulse rate measurement from facial video has gained particular attention over the last few years. Research exhibits significant advancements and demonstrates that common video cameras correspond to reliable devices that can be employed to measure a large set of biomedical parameters without any contact with the subject. A new framework for m...

Les défis de l’automatisation des systèmes sociotechniques sont fortement liés à la prise en compte des atouts et des limites des ressources techniques et humaines, tels que les caractéristiques perceptives, les capacités coopératives, les modalités de partage de tâches, la modélisation de comportements humains, ou l’apport de démarches de concepti...

Près de la moitié des maladies invalidantes sont d'origine respiratoire ou cardiovasculaire. Ces dernières sont de plus désignées première cause de mortalité dans le monde par l'OMS. Différentes technologies permettent désormais de mesurer signaux physiologiques et fonctions vitales de manière déportée. Les caméras bas coût et les webcams sont, par...

Stress is universally known to be a contributing factor in developing of many diseases. This work focuses on developing a user-independent and user-dependent stress recognition system using five physiological signals that are electromyogram, galvanic skin response, skin temperature, blood volume pulse and respiratory response. Emotional data is col...

With the advancement of Human Computer interaction and affective computing, emotion estimation becomes a very interesting area of research. In literature, the majority of emotion recognition systems presents an insufficiency due to the complexity of processing a huge number of physiological data and analyzing various kind of emotions in one framewo...

We propose, in this study, an original method that was developed to remotely measure the instantaneous pulse rate using photoplethysmographic signals that were recorded from a low-cost webcam. The method is based on a prior selection of pixels of interest using a custom segmentation that used the face lightness distribution to define different sub-...

Background: Vasoconstriction and vasodilation phenomena reflect the relative changes in the vascular bed. They induce particular modifications in the pulse wave magnitude. Webcams correspond to remote sensors that can be employed to measure the pulse wave in order to compute the pulse frequency. Objective: Record and analyze pulse wave signal wi...

One of the goals of affective computing field is to provide to computers the ability to recognize automatically the affective state of the user in order to have more intuitive human-machine communication. This paper aims to detect automatically stress user when he is interacting with computer. The developed system is based on instantaneous pulse ra...

This paper propose a new framework for emotion recognition and classification using a Continuous Wavelet Transform (CWT) for features extraction from physiological signal. Data from the emotional corpus recorded at Augsburg university were used in our study. In the first phase four wavelet families were chosen to analyze EMG RESP SC and ECG signals...

In this paper we propose a new system for human emotion recognition based on multi resolution analysis of physiological signals. In our study we have used four kinds of bio signals EMG, RESP, ECG and SC recorded at the University of Augsburg. Daubechies Symlet, Haar and Morlet wavelet transform were applied to analyze the non-stationary signals. Ph...

In this paper we propose a new system for human emotion recognition based on multi resolution analysis of physiological signals. In our study we have used four kinds of bio signals EMG, RESP, ECG and SC recorded at the University of Augsburg. Daubechies Symlet, Haar and Morlet wavelet transform were applied to analyze the non-stationary signals. Ph...

In this paper we propose a new system for human emotion recognition based on multi resolution analysis of physiological signals. In our study we have used four kinds of bio signals EMG, RESP, ECG and SC recorded at the University of Augsburg. Daubechies Symlet, Haar and Morlet wavelet transform were applied to analyze the non-stationary signals. Ph...

Dans ce travail nous ciblons la reconnaissance de l'anxiete sociale qui est une peur irrationnelle ressentie lors de toute forme de relation sociale. Elle peut etre revelee par un ensemble de traits physiques et physiologiques. L'avantage de l'utilisation des mesures physiologiques est que les individus ne peuvent pas les manipuler et chaque emotio...

We present and investigate, in the first part of this paper, a set of published works that may be employed to remotely quantify mental stress based on physiological signals by non-contact means. Several techniques can be used to this purpose, thermal imaging being currently the most advanced in our knowledge. Webcams correspond to a ubiquitous and...

Human emotional recognition using physiological signals is relatively recent. The interest to this field has been motivated by the robustness of physiological traits to avoid the artifacts created by human social masking. In this paper our attention is focus on two aims: the development of an anxiety recognition system using only one physiological...

Generally, Negative emotions can lead to health problems. In order to detect negative emotions, an advanced method of the EMG signal analysis is presented. Negative emotions of interest in this work are: fear, disgust and sadness. These emotions are induced with presentation of IAPS (International Affective Picture System) images. The EMG signal is...

We introduce a new framework for detecting mental workload changes using video frames obtained from a low-cost webcam. Image processing in addition to a continuous wavelet transform filtering method were developed and applied to remove major artifacts and trends on raw webcam photoplethysmographic signals. The measurements are performed on human fa...

Nous présentons dans cette étude une méthode qui permet de quantifier l’activité mentale d’une personne en utilisant une webcam bas coût. Les mesures sont réalisées spécifiquement sur le visage et les algorithmes que nous proposons ont été développés de manière à ce que l’application soit robuste aux bruits générés par les mouvements de la tête. Un...

Several approaches have been proposed to recognize human emotions based on facial expressions or physiological signals, relatively rare work has been done to fuse these two, and other, modalities to improve the accuracy and robustness of the emotion recognition system. In this paper, we propose two methods based on feature-level and decision-level...

In this paper we focus our attention on the development of a virtual reality exposure system to induce anxiety and a strategy for recognizing it. We describe anxiety detection in short term from blood volume pulse measurement; detailing data collection, features extraction and classification. We built a model of anxiety detection using support vect...

In this study, we present a particular technique that was developed to assess and quantify mental stress states using a low-cost webcam. The input signals are recorded on human faces and image and signal processing algorithms, bases on the continuous wavelet transform, were developed to remove trends and noise generated by involuntary motion artifa...

Photoplethysmographic signals obtained from a webcam are analyzed through a continuous wavelet transform to assess the instantaneous heart rate. The measurements are performed on human faces. Robust image and signal processing are introduced to overcome drawbacks induced by light and motion artifacts. In addition, the respiration signal is recovere...

In this paper, we focus our attention on the development of a virtual reality exposure system (VRE) to induce anxiety to phobic people and on a strategy for recognizing it. We describe a short term anxiety detection from blood volume pulse (BVP) measurement, we detail data collection, feature extraction and classification. We propose a model of anx...

Dans ce papier, nous présentons un ensemble de méthodes qui permettent de détecter des états de stress mental en utilisant des trames vidéo obtenues à partir d’une webcam bas coût. Les mesures sont réalisées spécifiquement sur les visages des participants et les algorithmes que nous proposons ont été développés de manière à ce que l’application soi...

In the present paper, we introduce a new framework for detecting workload changes using video frames obtained from a low-cost webcam. The measurements are performed on human faces and the proposed algorithms were developed to be motion-tolerant. An interactive Stroop color word test is employed to induce stress on a set of twelve participants. We r...

The aging world population requires more attention to the autonomy of individuals. The impaired physical abilities need changes in the built environment for an optimal use. Due to physical limitations, aged persons frequently become users of a wheelchair which also leads to limitations in accessing their homes. This paper describes a tool for evalu...

A method for evaluating the accessibility of an environment for someone with limited mobility consists in repeatedly computing the existence of an inverse kinematic model of its biomechanical structure. In order to validate the choices in adapting the environment to the user physical capabilities, it is necessary to quickly evaluate the impact of a...

This paper presents an automatic approach for emotion recognition from a bimodal system based on facial expressions and physiological signals. The information fusion is to combine information from both modalities. We tested two approaches, one based on mutual information which allows the selection of relevant information, the second approach is bas...

This paper describes emotion recognition system based on facial expression. A fully automatic facial expression recognition system is based on three steps: face detection, facial characteristic extraction and facial expression classification. We have developed an anthropometric model to detect facial feature points combined to Shi&amp, Thomasi meth...

Emotion recognition is one of the great challenges in human-human and human-computer interaction. Accurate emotion recognition would allow computers to recognize human emotions and therefore react accordingly. In this paper, an approach for emotion recognition based on physiological signals is proposed. Six basic emotions: joy, sadness, fear, disgu...

The emotion recognition is one of the great challenges in human-human and human-computer interaction. In this paper, an approach for the emotions recognition based on physiological signals is proposed. Six basic emotions: joy, sadness, fear, disgust, neutrality and amusement are analysed using physiological signals. These emotions are induced throu...

In this paper we presented an approach to emotion recognition based on the processing of physiological signals. Physiological data was acquired in six different affective states and two pattern recognition methods have been tested: SVM method and Fisher linear discriminant. Recognition rates of about 90% were achieved for both classifiers. However,...

During the last two decades, various studies showed the efficacy of Virtual Reality in the treatment of anxiety disorders. The goal of most of these studies was to elicit emotions and reactions in order to modify human cognition and behaviour, by simulating reality in the most accurate way. This paper proposes a brief review about emotions and it c...

The ability to recognize emotion is one of the hallmarks of emotion intelligence. This paper proposed to recognize emotion using physiological signals obtained from multiple subjects. IAPS images were used to elicit target emotions. Five physiological signals: Blood volume pulse (BVP), Electromyography (EMG), Skin Conductance (SC), Skin Temperature...

In this paper, we present a detection and tracking feature points algorithm in real time camera input environment. To trace and extract a face image, we use a modified face detector based on the Haar-like features. For feature points detection, we use good features to track of Shi and Thomasi. In order to track the facial feature points, pyramidal...

This paper investigates the performance of support vector machines with linear, cubic and radial basis function (RBF) kernels in the problem of emotion recognition from physiological signals. Five physiological signals: blood volume pulse (BVP), electromyography (EMG), skin conductance (SC), skin temperature (SKT) and respiration (RESP) were select...

In this paper, we propose a novel approach for the localization of facial features from static frontal face images. Gradient Based method is used to localize the facial features. Results on the XM2VTSDB database indicate that the proposed algorithm can accurately extract facial features.

The development of an automated system for facial expression analysis or interpret is rather difficult. There are several related problems: detection of an image segment as a face, extraction of the facial expression information, and classification of the expression (e.g., in emotion categories). This paper surveys the past work in solving these pr...

Dans cet article, nous proposons une nouvelle approche pour la localisation des caractéristiques faciales d'une image contenant un visage frontal. La méthode utilisée est basée sur le suivi du gradient. Les résultats obtenus sur la base de données XM2VTSDB indiquent que l'algorithme proposé peut extraire les caractéristiques faciales d'une manière...

2D Zernike moments belong to the useful object invariant descriptors which have been successfully applied in pattern recognition tasks. The main problem of using Zernike moments invariants is that they are not able to discriminate two objects having the same shape. In this paper, an approach based on Zernike moments applied on color images is propo...

Even if lots of object invariant descriptors have been pro- posed in the literature, putting them into practice in order to obtain a robust system face to several perturbations is still a studied problem. Comparative studies between the most commonly used descriptors put into obviousness the invariance of Zernike moments for simple geomet- ric tran...

In this paper, we propose a new approach for some augmented reality applications by exploiting minimal geometric knowledge and using Desargues theorem. The idea underlying our approach is to use a generalization of Desargues theorem in uncalibrated images context. This approach allows the realization of three applications that includes: points matc...

In this paper, we propose a new method for the detection and the recognition of objects in color images. The developed method processes in two steps. The first one concerns the object detection by a color segmentation method and a labeling algorithm. The second step deals with the recognition of extracted objects. Each object is described by color...

In this paper, we propose a new approach for matching image points by exploiting minimal geometric knowledge and in a correspondenceless way. The idea underlying our approach is to use a generalization of the Desargues theorem in images sequence context. This approach allows the matching image points over a sequence without using correlation techni...

This paper describes a new method for building a three-dimensional geometrical model of objects from a single image. This method is based on a new concept, namely, the cylindrical projective geometry, which allows us to automatically compute the shape of objects with axial symmetry from one image and without any knowledge about the camera used. Mat...

This work presents the necessary developments to set up an interface for piloting of the teleoperated systems. This interface, transparent, makes it possible to the operator to control the system in a natural way by the natural gestures and without contact, no sensor being used. To achieve this goal, we need to determine the "configuration" of the...

Dans cet article, nous présentons une nouvelle approche de reconnaissance, d'objets basée sur l'utilisation des moments Zernike appliqués sur des images couleur. La détection d'objets repose sur une approche utilisant une segmentation couleur et l'étiquetage des composantes connexes. Une méthode basée sur les séparateurs à vaste marge est utilisée...