Frédéric Bousefsaf

• 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...

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...

The segmentation of cardiac boundaries, specifically Left Ventricle (LV) segmentation in 2D echocardiographic images, is a critical step in LV segmentation and cardiac function assessment. These images are generally of poor quality and present low contrast, making daily clinical delineation difficult, time-consuming, and often inaccurate. Thus, it...

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...

Echocardiography is the most widely used medical imaging technique for diagnosing cardiovascular diseases. Further, delineation of left ventricle (LV) in 2D echocardiographic images by cardiologists is required for systolic function assessment. However, this daily task is tough to do, takes a lot of time and is not precise due to the mediocre quali...

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...

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...

Here, the authors explore the potential of multispectral imaging applied to image completion. Snapshot multispectral cameras correspond to breakthrough technologies that are suitable for everyday use. Therefore, they correspond to an interesting alternative to digital cameras. In their experiments, multispectral images are acquired using an ultraco...

In this paper, we propose an automatic selection and natural feature tracking method that uses a monocular camera for path capturing and guides the user showing him the path to be followed. The application targets Alzheimer patients for helping them in their indoor moves. By offering an automatic selection of features, the user intervention and pri...

Nous proposons d'explorer le potentiel de l'imagerie multispectrale appliquée à la complétion d'image, une thématique classique de vision par ordinateur qui consiste à automatiquement remplacer une zone de l'image de manière plausible. Pour ce faire, nous avons utilisé une caméra multispectrale de type snapshot mosaic permettant d'acquérir en temps...

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...

Cet article présente une courte synthèse des travaux de recherche que j’ai pu développer le long des quatre dernières années. Les thématiques scientifiques de ce travail transitent autour de l’e-santé, de la télémédecine et de l’informatique affective, avec pour application particulière la reconnaissance du niveau de stress de la personne basée sur...

Photoplethysmographic (PPG) signals obtained from a webcam are analyzed through a continuous wavelet transform to assess the instantaneous pulse rate. The measurements are performed on human faces. Robust image and signal processing are introduced to collect only pixels that contain photoplethysmographic information and to remove major artifacts an...

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...

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...

Monitoring physiological signals via noncontact means presents a greater challenge in personal health care, telemedicine and affective computing. Recently, digital cameras and webcams were employed to detect and compute the instantaneous heart rate of a participant by specifically recording ant track skin pixels of the face. The principle, based on...

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...

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...

Les personnes âgées utilisent de plus en plus les nouvelles technologies et plus particulièrement les ordinateurs. Des périphériques comme la Wiimote de Nintendo ou encore la Kinect de Microsoft permettent d’interagir avec l’ordinateur via les gestes de la main. Cet article décrit une étude qui permet d’examiner l’intérêt du geste de la main comme...

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...

Les personnes âgées utilisent de plus en plus les nouvelles technologies de nos jours, l’ordinateur en particulier. A l’aide de périphériques comme la Wiimote de Nintendo, ou encore la Kinect de Microsoft, interagir avec l’ordinateur devient maintenant possible via les gestes, et plus particulièrement ceux de la main. Nous proposons une étude qui p...