Aníbal J. S. Ferreira

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This paper addresses the extraction of parametric information in an audio coder that uses the MDCT filter bank. The computation of the filter bank is reformulated as a function of the Odd-DFT, in order to allow the estimation of the frequency, the phase and the magnitude of stationary sinusoids. Closed expression delivering accurate estimates are derived(More)
Recent research in high-quality audio coding seeks not only improved coding gains but also new functionalities such as easy semantic access to compressed audio material and audio modification in the compressed domain. These objectives imply the decomposition of the audio signal into several components of specific semantic value, such as sinusoidal(More)
A new DSP laboratory course has been included in the Electrical and Computer Engineering curriculum at the Facul-dade de Engenharia da Universidade do Porto, in Portugal, since the school year of 1999/2000. This paper addresses the context and motivation underlying this new course, outlines its structure and methodology, highlights the design and goals of(More)
This paper addresses the problem of automatic identification of vowels uttered in isolation by female and child speakers. In this case, the magnitude spectrum of voiced vowels is sparsely sampled since only frequencies at integer multiples of F0 are significant. This impacts negatively on the performance of vowel identification techniques that either ignore(More)
OBJECTIVES/HYPOTHESIS The aim of this article was to describe the results of an audio-perceptual evaluation carried out by 10 judges, on a database comprising 90 voice recordings plus 10 samples repetition, with the purpose of characterizing the intra- and interrater reliability. STUDY DESIGN Exploratory, transversal. METHODS The classification of the(More)
The goal of this study was to analyse perceptually and acoustically the voices of patients with Unilateral Vocal Fold Paralysis (UVFP) and compare them to the voices of normal subjects. These voices were analysed perceptually with the GRBAS scale and acoustically using the following parameters: mean fundamental frequency (F0), standard-deviation of F0,(More)
OBJECTIVES/HYPOTHESIS This article aims to establish correlations between acoustic and audio-perceptual measures using the GRBAS scale with respect to four different voice analysis software programs. STUDY DESIGN Exploratory, transversal. METHODS A total of 90 voice records were collected and analyzed with the Dr. Speech (Tiger Electronics, Seattle,(More)
We present a new algorithm for timescale expansion of audio signals that comprises: time interpolation, frequency-scale expansion and modiication of a spectral representation of the signal. The algorithm relies on an accurate model of signal analysis and synthesis, and was constrained to a non-iterative modiication of the magnitudes and the wrapped phases(More)