Maurílio Nunes Vieira

On the influence of laryngeal pathologies on acoustic and electroglottographic jitter measures

This study compared acoustic and electroglottographic (EGG) jitter from [a] vowels of 103 dysphonic speakers. The EGG recordings were chosen according to their intensity, signal-to-noise ratio, and percentage of unvoiced intervals, while acoustic signals were selected based on voicing detection and the reliability of jitter extraction. The agreement between jitter measures was expressed numerically as a normalized difference. In 63.1% (65/103) of the cases the differences fell within +/-22.5%. Positive differences above +22.5% were associated with increased acoustic jitter and occurred in 12.6% (13/103) of the speakers. These were, typically, cases of small nodular lesions without problems in the posterior larynx. On the other hand, substantial rises in EGG jitter leading to differences below -22.5% took place in 24.3% (25/103) of the speakers and were related to hyperfunctional voices, creaky-like voices, small laryngeal asymmetries affecting the arytenoids, or small-to-moderate glottal chinks. A clinically relevant outcome of the study was the possibility of detecting gentle laryngeal asymmetries among cases of large unilateral increase in EGG jitter. These asymmetries can be linked with vocal problems that are often overlooked in endoscopic examinations.

Robust F/sub 0/ and jitter estimation in pathological voices

Dysphonic voices were used to compare electroglottographic (EGG) and acoustic measures of fundamental frequency (F/sub 0/) and jitter using a wavematching and an event based technique. Continuous speech was considered in the first part of the study, where the effects of pre filtering the acoustic signals and linearly smoothing the F/sub 0/ contours were analysed. The second part of the investigation compared jitter from sustained vowels (/i/ /a/, /u/), resulting in poor agreement for /i/ and /u/. In /a/ vowels, however, a relatively small mean normalised absolute difference (10.95%) was obtained with a method that is being proposed which combines peak picking and zero crossings, being able to detect a waveform pattern observed in such vowels and reject unreliable measures.

Analysis of the effects of electroglottographic baseline fluctuation on the F0 estimation in pathological voices

This paper reports an investigation of the influence of electroglottographic (EGG) baseline fluctuation on the precision of F0 estimation based on zero crossings. A passage read by 15 subjects suffering from various laryngeal pathologies was filtered with zero phase shift by several bandpass filters with a flat frequency response between 60 and 5000 Hz. A simple F0 extraction algorithm processed the filtered EGG signals providing good results even with data from severely affected larynxes. In general, all investigated errors, including a measure of jitter, reduced significantly when the attenuation in the rejection bands varied from 0 to 40 dB, with slight but consistent improvements thereafter. The best results, obtained with 80 dB of attenuation, indicated that unvoiced (or silent)‐to‐voiced errors and voiced‐to‐unvoiced (or silent) errors were under 1.17% and 2.26%, respectively, and at least 91.8% of the estimated F0 values had a precision better than 0.103%, considering an estimated error of 0.058% i...

Vibrato and tremor extent spectrum: Algorithm and applications

This work investigated the measurement of vibrato and tremor extent values. Related works have not explored the possibility of measuring extent in the spectra of fundamental frequency (f(0)) low-frequency undulations. It is shown here that by canceling average (DC) values and baseline drifts of f(0) contours, as well as weighting the respective spectra by the time window DC value, extent measures can be promptly obtained in the frequency domain. The method is illustrated with measurements from synthetic and human data.

Automatic loudness control in short-form content for broadcasting

During the early years of the International Telecommunication Union (ITU) loudness calculation standard for sound broadcasting [ITU-R (2006), Rec. BS Series, 1770], the need for additional loudness descriptors to evaluate short-form content, such as commercials and live inserts, was identified. This work proposes a loudness control scheme to prevent loudness jumps, which can bother audiences. It employs short-form content audio detection and dynamic range processing methods for the maximum loudness level criteria. Detection is achieved by combining principal component analysis for dimensionality reduction and support vector machines for binary classification. Subsequent processing is based on short-term loudness integrators and Hilbert transformers. The performance was assessed using quality classification metrics and demonstrated through a loudness control example.

Detecting arytenoid cartilage misplacement through acoustic and electroglottographic jitter analysis

The paper describes a comparative study of acoustic and electroglottographic (EGG) jitter extracted from simultaneous recordings of 45 dysphonic patients. The estimated jitter values agreed to within /spl plusmn/20% in 67% of the patients, the difference being above +20% and below -20% in 13% and 20% of the cases, respectively. In the group below -20%, EGG jitter increased due to an increase in EGG shimmer and videoendoscopic images revealed abnormal movements of the arytenoid cartilage caused, possibly, by minor selective paralysis of the intrinsic laryngeal muscles. This observation suggests a possible application of signal analysis techniques in support of the diagnosis of laryngeal disorders.