Aníbal Ferreira

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Standard conception probabilities models assume that different acts of intercourse make independent contributions to the probability of conception in viable cycles. We propose an alternative, approximate model based on the assumption that the act of intercourse closest to the time of maximum fertility is the one most likely to have caused conception. We(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)
This paper presents a new method for multiple fundamental frequency (F0) estimation on piano recordings. We propose a framework based on a genetic algorithm in order to analyze the overlapping overtones and search for the most likely F0 combination. The search process is aided by adaptive spectral envelope modeling and dynamic noise level estimation: while(More)
This paper describes our method, submitted to MIREX 2008 task “Multiple Fundamental Frequency Estimation & Tracking”. This task restricted the problem of Multiple F0 Estimation and Tracking to three cases: i) Estimate active fundamental frequencies on a frame-by-frame basis; ii) Track note contours on a continuous time basis (as in audio-tomidi); iii) Track(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)
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 accurate estimation of the frequency of sinusoids is a frequent problem in many signal processing problems including the real-time analysis of the singing voice. In this paper we rely on a single DFT magnitude spectrum in order to perform frequency estimation in a non-iterative way. Two new frequency estimation methods are derived that are matched to(More)
This paper presents an algorithm, in the context of speech analysis and pathologic/dysphonic voices evaluation, which splits the signal of the glottal excitation into harmonic and noise components. The algorithm uses a harmonic and noise splitter and a glottal inverse filtering. The combination of these two functionalities leads to an improved estimation of(More)
The concept of capturing the sound of “something” for later replication is not new, and it is used in many synthesizers. But capturing sounds and use them as an audio effect, is less common. This paper presents an approach for the resynthesis of a singing voice, based on concatenative techniques, that uses pre-recorded audio material as an(More)