RESUMO Objetivo Este trabalho apresenta as margens de tolerâncias mínimas e máximas para as frequências dos três primeiros formantes (F1, F2 e F3) na pronúncia das vogais orais do português brasileiro para utilização em terapias de voz para surdos. Método As frequências foram obtidas a partir da colaboração voluntária de 53 indivíduos adultos que tiveram as vozes gravadas e convertidas em sinais digitais durante a emissão de cada uma das sete vogais (/a/, /e/, /Ɛ/, /i/, /o/, /ᴐ/, /u/), de maneira sustentada por cerca de um segundo. As amostras foram distribuídas em dois grupos, um masculino e outro feminino. A gravação e a extração dos formantes foram efetuadas através de software próprio desenvolvido para este fim na plataforma MATLAB, utilizando o algoritmo LPC (Linear Predictive Coding) de oito coeficientes. Resultados Os resultados mostraram que uma referência consistente para os valores médios das frequências de F1, F2 e F3 pôde ser obtida através da análise gráfica e estatística das amostras de sinais de voz coletada. Conclusão Os valores de referência encontrados foram analisados e podem ser usados para calibração de dispositivos e podem servir de base para o treinamento de oralização para surdos.
This paper presents a new optimization approach for estimating vocal tract configurations from the speech signal. The scheme concatenates a gradient search and linear successive approximation that provides fast convergence and small errors. The objective function is generated by the least-absolute-value (11 -norm) error between the model-derived and the speechderived first three formants. The gradient search is accelerated by using an algorithm inspired by the Fletcher -Reeves method. Linear successive approximation assures convergence in the region near the optimum articulatory vector. Constraints are imposed on the articulatory parameters to avoid physiologically impossible configurations.
The objective of this work is to provide an automatic system to count white blood cells in a blood smear. To do so an experiment was assembled, composed by a standard microscope with two step motors coupled to its knobs in order to move the microscope in x and y directions and a web cam which was mounted in the top of the microscope responsible for to acquire images from the smear. The step motors and the web cam are controlled by a microcomputer PC standard via software developed inDelphi. The motors use the parallel port to communicate with the PC and the camera use the USB port. The main idea is to set an initial point into the smear and the automated system will carry over the smear acquiring images (frames with 640 × 480 pixels) and counting the white blood cells encountered. The double histogram threshold technique is implemented to initially exclude the red cells from the image leaving only the white ones. Preliminaries results are obtained and show that the system is quite fast and has a good capacity of selection, even when different kinds of smear are used.
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