Biomedical subjects

P Bruscaglioni

Publications and source records attributed to P Bruscaglioni.

6 recordsLinked to original sources

PubMed2005

Objective analysis of the singing voice as a training aid.

A new tool for robust tracking of fundamental frequency is proposed, along with an objective measure of main singing voice parameters, such as vibrato rate, vibrato extent, and vocal intonation. High-resolution Power Spectral Density estimation is implemented, based on AutoRegressive models of suitable order, allowing reliable formant tracking also in vocalizations characterized by highly varying values. The proposed techniques are applied to about 1000 vocalizations, coming from both professional and non-professional singers, and show better performance as compared to classical Fourier-based approaches. If properly implemented, and with a user-friendly interface, the new tool would allow real-time analysis of singing voice. Hence, it could be of help in giving non-professional singers and singing teachers reliable measures of possible improvements during and after training.

Acoustics↗

PubMed2001

A simple subspace approach for speech denoising.

For pathological voices, hoarseness is mainly due to airflow turbulence in the vocal tract and is often referred to as noise. This paper focuses on the enhancement of speech signals that are supposedly degraded by additive white noise. Speech enhancement is performed in the time-domain, by means of a fast and reliable subspace approach. A low-order singular value decomposition (SVD) allows separating the signal and the noise contribution in subsequent data frames of the analysed speech signal. The noise component is thus removed from the signal and the filtered signal is reconstructed along the directions spanned by the eigenvectors associated with the signal subspace eigenvalues only, thus giving enhanced voice quality. This approach was tested on synthetic data, showing higher performance in terms of increased SNR when compared with linear prediction (LP) filtering. It was also successfully applied to real data, from hoarse voices of patients that had undergone partial cordectomisation. The simple structure of the proposed technique allows a real-time implementation, suitable for portable device realisation, as an aid to dysphonic speakers. It could be useful for reducing the effort in speaking, which is closely related to social problems due to awkwardness of voice.

Humans↗

PubMed2000

A comparative analysis of fundamental frequency estimation methods with application to pathological voices.

One of the basic parameters characterising voiced phonation is the fundamental frequency, named pitch, which is the rate of vibration of the folds. In pathological voices. pitch variations within an utterance are indicative of the patient status. As such voices are corrupted by 'noise', robust pitch estimation methods are required in order to track its variations. This paper aims to compare some pitch estimation methods, pointing out their main advantages and drawbacks for present application. For each method, modifications are proposed in order to enhance performance. The methods are tested on simulated signals and then applied to real signals, coming both from healthy and pathological voices. The latter we obtained from patients who have undergone surgery for vocal folds via laser or traditional lancet techniques.

Biophysical Phenomena↗

PubMed1996

Parametric and non-parametric estimation of speech formants: application to infant cry.

The present paper addresses the issue of correctly estimating the peaks in the speech envelope (formants) occurring in newborn infant cry. Clinical studies have shown that the analysis of such spectral characteristics is a helpful noninvasive diagnostic tool. In fact it can be applied to explore brain function at very early stage of child development, for a timely diagnosis of neonatal disease and malformation. The paper focuses on the performance comparison between some classical parametric and non-parametric estimation techniques particularly well suited for the present application, specifically the LP, ARX and cepstrum approaches. It is shown that, if the model order is correctly chosen, parametric methods are in general more reliable and robust against noise, but exhibit a less uniform behaviour than cepstrum. The methods are compared also in terms of tracking capability, since the signals under study are nonstationary. Both simulated and real signals are used in order to outline the relevant features of the proposed approaches.

Computer Simulation↗

PubMed1994

Computerized cry analysis in infants affected by severe protein energy malnutrition.

A new method of computerized cry analysis has been utilized to evaluate the cries of infants affected by severe protein energy malnutrition. We studied 17 Kenian babies affected by severe malnutrition for more than four months (9 cases of marasmus and 8 of kwashiorkor) and a control group of 17 well-nourished babies. The cries of the malnourished children showed lower inter-utterance variability, formants' frequencies and cry score, assigned by the Infant Cry Modulation Assessment Scale. The melodic pattern was more often flat, rising or falling-rising, when compared to the cries of the well-nourished babies. We hypothesize that these differences reflect the state of brain damage associated with protein energy malnutrition. No differences were found between the cries of infants affected by marasmus and those affected by kwashiorkor, between the cries recorded before and after nutritional therapy and between the first cries of malnourished children who subsequently died during hospitalization and those of infants who survived.

Acoustics↗

PubMedDate not supplied

Developmental aspects of infant's cry melody and formants.

This paper deals with the analysis of cry melodies (time variations of the fundamental frequency) as well as vocal tract resonance frequencies (formants) from infant cry signals. The increase of complexity of cry melodies is a good indicator for neuro-muscular maturation as well as for the evaluation of pre-speech development. The variation of formant frequencies allows an estimation of articulatory activity during pre-speech vocalization. Subjects are three pairs of healthy identical twins (monocygozity determined by DNA-fingerprint). Spontaneous cries of these six children were recorded at different ages: 8th-9th week, 15th-17th week and 23rd-24th week. Analysis of 136 cry melodies and intensity contours was made using KAY-CSL 4300/MDVP. For formant estimation a spectral parametric technique was applied, which was based on autoregressive models (Digital spectral analysis with applications, 1987) whose order is adaptively estimated on subsequent signal frames by means of a new method (Med. Eng. Phys. 20 (1998) 432; Utras. Med. Biol. 21 (1995) 793). Cry melodies exhibited an increasing complexity during the observation period. Beginning with the second observation period (15th-17th week) an increasing coupling and tuning between melody and resonance frequencies was observed, which was interpreted as "intentional" articulatory activity. Possible applications are in cry diagnosis as well as in the evaluation of pre-speech development.

Crying↗