Low Level Features for Quality Assessment of Facial Images

International audienceAn automated system that provides feedback about aesthetic quality of facial pictures could be of great interest for editing or selecting photos. Although image aesthetic quality assessment is a challenging task that requires understanding of subjective notions, the proposed work shows that facial image quality can be estimated by using low-level features only. This paper provides a method that can predict aesthetic quality scores of facial images. 15 features that depict technical aspects of images such as contrast, sharpness or colorfulness are computed on different image regions (face, eyes, mouth) and a machine learning algorithm is used to perform classification and scoring. Relevant features and facial image areas are selected by a feature ranking technique, increasing both classification and regression performance. Results are compared with recent works, and it is shown that by using the proposed low-level feature set, the best state of the art results are obtained

Linear classification of chairlift images for presence analysis

Conférence Quality Control by Artificial Vision (QCAV) 2019, Mulhouse, France, 15-17 MaiInternational audienc

Fully automated facial picture evaluation using high level attributes

International audiencePeople automatically and quickly judge a facial picture from its appearance. Thus, developing tools that can reproduce human judgments may help consumers in their picture selection process. Previous work mostly studied the position of facial keypoints to make predictions about specific traits: trustworthiness, likability, competence, etc. In this work, high level attributes (e.g. gender, age, smile) are automatically extracted using 3 different tools and are used to build models adapted to each trait. Models are validated on a set of synthetic images and it is shown that using attributes increases significantly the correlation between human and algorithmic evaluations. Then, a new dataset of 140 images is presented and used to demonstrate the relevance of high level attributes for evaluating faces with respect to likability and competence. A model combining both facial keypoints and attributes is finally proposed and applied to picture selection: which picture depicts the most likable face for a given person

How to predict the global instantaneous feeling induced by a facial picture?

International audiencePicture selection is a time-consuming task for humans and a real challenge for machines, which have to retrieve complex and subjective information from image pixels. An automated system that infers human feelings from digital portraits would be of great help for profile picture selection, photo album creation or photo editing. In this work, two models of facial pictures evaluation are defined. The first one predicts the overall aesthetic quality of a facial image, and the second one answers the question " Among a set of facial pictures of a given person, on which picture does the person look like the most friendly? ". Aesthetic quality is evaluated by the computation of 15 features that encode low-level statistics in different image regions (face, eyes, mouth). Relevant features are automatically selected by a feature ranking technique, and the outputs of 4 learning algorithms are fused in order to make a robust and accurate prediction of the image quality. Results are compared with recent works and the proposed algorithm obtains the best performance. The same pipeline is considered to evaluate the likability of a facial picture, with the difference that the estimation is based on high-level attributes such as gender, age, smile. Performance of these attributes is compared with previous techniques that mostly rely on facial keypoints positions, and it is shown that it is possible to obtain likability predictions that are close to human perception. Finally, a combination of both models that selects a likable facial image of good quality for a given person is described

The influence of the visualization task on the Simulator Sickness symptoms - a comparative SSQ study on 3DTV and 3D immersive glasses

International audienceThe human factors are an essential aspect to take into consideration in order to explain the level of public acceptability of new stereo- scopic devices. A study using the Simulator Sickness Questionnaire allowed us to illustrate the differences in symptoms after the visual- ization of 3D images on a 3DTV screen and on a pair of prototype immersive 3D glasses. Also, the results of our study showed that the visualization task influenced the exploration of the scenes, and there- fore influenced the evolution of the simulator sickness symptoms

Pretensado exterior en la pasarela del Museo de la Ciencia en Valladolid

This article presents the practice, development and technology applied in the external prestressing cables of this singular footbridge placed in Valladolid over Pisuerga river, being part of Museum of Science urbanistic complex. There are two prestressing cable systems, the hexagonal tendons and the longitudinal ones.Hexagonal tendons have the property of having strong deviations in their layout, specific saddles were designed with low friction materials, and Freyssinet Cohestrand® was used. Real scale tests were carried out to develop these deviation devices. Hexagons stressing operations were carried out with two jacks simultaneously due to the section sensibility to non symmetrical efforts.In longitudinal tendons, with little deviations each 7 m, external prestressing grouted before stressing system was applied, which allows strand by strand substitution. Geometry adjustment of these tendons required auxiliar strand disposition as a support of a regulation system.Este artículo presenta la problemática, el desarrollo y la tecnología aplicada en el pretensado exterior de esta singular pasarela, que se encuentra en la ciudad de Valladolid sobre el río Pisuerga, integrada en el conjunto urbanístico del Museo de la Ciencia. El pretensado se divide en dos familias, los tendones hexagonales y los longitudinales.Los tendones hexagonales tienen la característica de sufrir fuertes desvíos en su trazado, para los cuales se diseñaron sillas específicas con materiales que facilitan el deslizamiento, y se empleó el cordón Cohestrand®de Freyssinet. Todo este desarrollo se apoyó en ensayos a escala real. La puesta en tensión de los hexágonos se realizó con dos gatos simultáneamente debido a la sensibilidad de la sección a esfuerzos no simétricos.En los tendones longitudinales, con suaves desvíos cada 7 m, se empleó la técnica del pretensado exterior inyectado antes de tesar, el cual permite sustituir los cordones del tendón uno a uno. El ajuste de la geometría de estos tendones requirió la disposición de cordones auxiliares de montaje como apoyo de un sistema de regulación.

Création de résumés de vidéos appliquée à la recherche par l'exemple

- Cet article décrit une méthode pour créer des résumés de vidéos possédant deux niveaux de résolution (intra-plan et inter-plan), à partir d'un descripteur couleur ou mouvement. Notre approche, applicable à tout autre type de descripteurs, consiste à extraire des images clés par regroupement de similarité suivant l'index considéré. Le regroupement non supervisé est réalisé par l'algorithme c-moyens flous (fuzzy c-means). Les résumés de vidéos ainsi obtenus permettent d'effectuer une recherche par l'exemple par combinaison d'index. La fusion est basée sur la théorie des ensembles flous qui définit la notion d'intersection des ensembles flous par l'utilisation d'une t-norme. Les résultats obtenus montrent que la recherche par l'exemple est améliorée par la combinaison des index

Algorithme de contour actif appliqué à la poursuite d'avalanche

Le traitement d'image est un outil de plus en plus utilisé dans l'étude des avalanches de neige, ceci dans le but de les prévenir. On présente ici un algorithme de contour actif spécifique à notre application : l'analyse du front des avalanches. Le but de cette étude consiste en l'extraction de paramètres dynamiques de l'avalanche à partir d'un simple film vidéo. La principale difficulté réside dans le manque évident de contraste de nos images, puisque nous avons à poursuivre un objet blanc sur un fond blanc. L'algorithme présenté repose sur le principe des contours actifs, où on recherche à minimiser une forme énergétique modélisant le contour de l'avalanche. Le résultat obtenu est une séquence de contour d'avalanche

Quantitative pulsatility measurements using 3D dynamic ultrasound localization microscopy

ABSTRACT: A rise in blood flow velocity variations (i.e. pulsatility) in the brain, caused by the stiffening of upstream arteries, is associated with cognitive impairment and neurodegenerative diseases. The study of this phenomenon requires brain-wide pulsatility measurements, with large penetration depth and high spatiotemporal resolution. The development of dynamic ultrasound localization microscopy (DULM), based on ULM, has enabled pulsatility measurements in the rodent brain in 2D. However, 2D imaging accesses only one slice of the brain and measures only 2D-projected and hence biased velocities . Herein, we present 3D DULM: using a single ultrasound scanner at high frame rate (1000–2000 Hz), this method can produce dynamic maps of microbubbles flowing in the bloodstream and extract quantitative pulsatility measurements in the cat brain with craniotomy and in the mouse brain through the skull, showing a wide range of flow hemodynamics in both large and small vessels. We highlighted a decrease in pulsatility along the vascular tree in the cat brain, which could be mapped with ultrasound down to a few tens of micrometers for the first time. We also performed an intra-animal validation of the method by showing consistent measurements between the two sides of the Willis circle in the mouse brain. Our study provides the first step towards a new biomarker that would allow the detection of dynamic abnormalities in microvessels in the brain, which could be linked to early signs of neurodegenerative diseases