Estimating the quality of face localization for face verification

Face localization is the process of finding the exact position of a face in a given image. This can be useful in several applications such as face tracking or person authentication. The purpose of this paper is to show that the error made during the localization process may have different impacts depending on the final application. Hence in order to evaluate the performance of a face localization algorithm, we propose to embed the final application (here face verification) into the performance measuring process. Moreover, in this paper, we estimate this embedding using either a multilayer perceptron or a K nearest neighbor algorithm in order to speedup the evaluation process. We show on the BANCA database that our proposed measure best matches the final verification results when comparing several localization algorithms, on various performance measures currently used in face localization. 1

Spirobicyclic and Tetracyclic Pyrazolidinones: Syntheses and Properties

International audienceThe stereoselective syntheses of spirobicyclic and tetracyclic pyrazolidinones are reported based on a (3+2) annu- lation between hydrazones and α-oxoketenes. Some of these conformationally constrained molecules were resolved as enantiopure materials by HPLC techniques and evaluated as amino- catalysts for iminium activation in a model Diels–Alder cyclo- addition

Synthesis and palladium-catalysed isomerisation of fused polycyclic tetrahydrofurans : efficient and stereoselective one-pot domino construction of functionalised bridged bicyclo[n.2.1] ring systems

International audienceA new one-pot domino reaction for a general entry to functionalised bridged bicyclo[n.2.1] ring systems from α,α'-diactivated cyclic ketones and trans-1,4-dihalides is described. The sequence combines a base promoted C-O cycloalkylation reaction leading to fused polycyclic enol ethers and their in situ palladium-catalysed isomerisation

Crystallization of α-glycine by anti-solvent assisted by ultrasound

International audienc

Estimating the Quality of Face Localization for Face Verification

Face localization is the process of finding the exact position of a face in a given image. This can be useful in several applications such as face tracking or person authentication. The purpose of this paper is to show that the error made during the localization process may have different impacts depending on the final application. Hence in order to evaluate the performance of a face localization algorithm, we propose to {\em embed} the final application (here face verification) into the performance measuring process. Moreover, in this paper, we estimate this embedding using either a multilayer perceptron or a K nearest neighbor algorithm in order to speedup the evaluation process. We show on the BANCA database that our proposed measure best matches the final verification results when comparing several localization algorithms, on various performance measures currently used in face localization

Measuring the Performance of Face Localization Systems

The purpose of Face localization is to determine the coordinates of a face in a given image. It is a fundamental research area in computer vision because it serves, as a necessary first step, any face processing systems, such as automatic face recognition, face tracking or expression analysis. Most of these techniques assume, in general, that the face region has been perfectly localized. Therefore, their performances depend widely on the accuracy of the face localization process. The purpose of this paper is to mainly show that the error made during the localization process may have different impacts which depend on the final application. We first show the influence of localization errors on the specific task of face verification and then empirically demonstrate the problems of current localization performance measures when applied to this task. In order to properly evaluate the performance of a face localization algorithm, we then propose to {\em embed} the final application (here face verification) into the performance measuring process. Using two benchmark databases, BANCA and XM2VTS, we proceed by showing empirically that our proposed method to evaluate localization algorithms better matches the final verification performance

Bi-Modal Face and Speech Authentication: a BioLogin Demonstration System

This paper presents a bi-modal (face and speech) authentication demonstration system that simulates the login of a user using its face and its voice. This demonstration is called BioLogin. It runs both on Linux and Windows and the Windows version is freely available for download. Bio\-Login is implemented using an open source machine learning library and its machine vision package

From liquid to solid bonding in cohesive granular media

We study the transition of a granular packing from liquid to solid bonding in the course of drying. The particles are initially wetted by a liquid brine and the cohesion of the packing is ensured by capillary forces, but the crystallization of the solute transforms the liquid bonds into partially cemented bonds. This transition is evidenced experimentally by measuring the compressive strength of the samples at regular intervals of times. Our experimental data reveal three regimes: 1) Up to a critical degree of saturation, no solid bonds are formed and the cohesion remains practically constant; 2) The onset of cementation occurs at the surface and a front spreads towards the center of the sample with a nonlinear increase of the cohesion; 3) All bonds are partially cemented when the cementation front reaches the center of the sample, but the cohesion increases rapidly due to the consolidation of cemented bonds. We introduce a model based on a parametric cohesion law at the bonds and a bond crystallization parameter. This model predicts correctly the phase transition and the relation between microscopic and macroscopic cohesion.Comment: 20

Porous coatings to control release rates of essential oils to generate an atmosphere with botanical actives

Essential oils have been used in diverse areas such as packaging, agriculture and cosmetics, for their antimicrobial and pesticide activity. The organic volatile compounds of the essential oils are involved in its activity. Controlling their release helps to prolong their functionality. In this study, a functionalized calcium carbonate porous coating was employed to control the release of thyme and rosemary oil in a confined space. The release rate was evaluated at 7 °C and 23 °C, gravimetrically. It was shown that the capillary effect of the porous coating slowed down the release of the volatiles into the headspace compared to the bulk essential oil. A linear drive force model was used to fit the obtained data from both essential oils. The model showed that rosemary reached the asymptotic mass loss equilibrium faster than thyme. This result can be explained by the diverse composition and concentration of monoterpenoids between the two essential oils. Temperature and degree of loading also played important roles in the desorption of the essential oils. It was observed that at high degrees of loading and temperatures the desorption of essential oils was higher. The above-described technology could be used for applications related to food preservation, pest control among others