Fountain fringe field switching (FFFS) for wide viewing angle LCDs

To reduce or completely remove the viewing angle dependence of liquid crystal (LC) displays and devices, we have recently introduced a new electrode structure for LC displays. This electrode structure has openings (holes) in the pixel electrode (PixE) for generating fringe electric field with azimuthal degenerated distribution of the field lines around each hole, resembling a fountain. Such a field is promoting azimuthally degenerated switching of the LC molecules and thus generation of images with 360◦ viewing angle constant contrast when a pair of crossed circular polarisers are used. A theoretical model of the fountain fringe field, generated around a single circular hole and plurality of such holes in the PixE, is presented

On the Use of Wavelets and Cepstrum Excitation for Pitch Determination in Real-Time

International audienceIn the current paper, we propose a new pitch tracking technique based on a wavelet transform in the temporal domain. Our algorithm is designed to determine the pitch frequency of the speech signal using a simple voicing decision algorithm. The pitch period is extracted from the cepstrum excitation signal processed by a wavelet transform; then the pitch contour is refined by thresholding and correction algorithms without any post-processing. The results obtained show that the proposed algorithm provides very good pitch contours compared to those furnished by the Bagshaw database

Méthode région-récursive d'estimation de mouvement des séquences d'images bruitées

- L'objectif de ce travail est d'estimer le mouvement apparent 2D dans le cas des séquences d'images bruitées. Nous proposons une technique utilisant conjointement les statistiques d'ordre supérieur et une segmentation basée régions avec découpage adaptatif. Les résultats de simulation, aussi bien sur des séquences à mouvement synthétique ou réel, révèlent sa consistance en terme d'analyse de mouvement de scènes bruitées

Real-Time Signal Reconstruction from Short-Time Fourier Transform Magnitude Spectra Using FPGAs

International audienceReal Time implementation of new frequential domain synthesizer algorithm based on the Nawab approach for signal reconstruction from short-time Fourier transform magnitude spectra is proposed in this paper. A register-transferlevel (RTL) synthesizer based on our algorithm was designed and simulated using VHDL as the hardware description language in respecting real time delay. The implemented RTL model was verified by comparing its performances with those obtained from a Python language implementation of the same synthesizer. We prove in particular that the proposed algorithm can be implemented in real time with a sampling frequency up to 60 kHz. Finally a real time implementation using an Altera DE2 development kit, generating good quality audio signals, was implemented

Prediction of Cepstral Excitation Pulses for Voice Conversion

International audienceVoice conversion is one of useful techniques to enhance pathological speech to be perceived as normal speech, although it concerns also the modifications of normal source speaker's speech to be perceived as if a target speaker had uttered it. The parameters to be converted are obtained by matching the spectral envelope of the vocal tract for the source and the target speech. Gaussian Mixture Models (GMMs) parameters are determined for providing conversion functions. The main contribution of our study consists in the prediction of Fourier cepstrum coefficients related to the excitation signal. Such a prediction leads to a satisfactory voice conversion system. Subjective perceptual results indicate that the proposed approach yields significant improvements in quality of the converted voice

Real Time Context-Independent Phone Recognition Using a Simplified Statistical Training Algorithm

International audienceIn this paper we present our own real time speaker-independent continuous phone recognition (Spirit) using Context-Independent Continuous Density HMMs (CI-CDHMMs) modeled by Gaussian Mixtures Models (GMMs). All the parameters of our system are estimated directly from data by using an improved Viterbi alignment process instead of the classical Baum-Welch estimation procedure. Generally, in the literature the Viterbi training algorithm is used as a pretreatment to initialize HMMs models that will be most often re-estimated by using complex re-estimation formula. In order to evaluate and compare the performance of our system with other previous works, we use the TIMIT database. The duration test of our recognition system for each sentence is between 2 seconds (for short sentences) to 12 seconds (for long sentences). We get, by combining the 64 possible phones into 39 phonetic classes, a phone recognition correct rate of 71.06% and an accuracy rate of 65.25%. These results compare favorably with previously published works

Rehaussement de la parole œsophagienne par une technique de conversion de voix fondée sur l'estimation de multiples réseaux de neurones profonds et de fonctions de conversion spectrale

La situation sanitaire ne permettant pas d’organiser les 9èmes Journées de Phonétique Clinique dans les meilleures conditions (à savoir en présentiel), le comité de programme a décidé d’annuler cette édition 2021 et d’organiser une journée dédiée à la présentation des contributions acceptées le 27 mai 2021.National audienc