Models and analysis of vocal emissions for biomedical applications

This book of Proceedings collects the papers presented at the 3rd International Workshop on Models and Analysis of Vocal Emissions for Biomedical Applications, MAVEBA 2003, held 10-12 December 2003, Firenze, Italy. The workshop is organised every two years, and aims to stimulate contacts between specialists active in research and industrial developments, in the area of voice analysis for biomedical applications. The scope of the Workshop includes all aspects of voice modelling and analysis, ranging from fundamental research to all kinds of biomedical applications and related established and advanced technologies

Reconstruction of intelligible audio speech from visual speech information

The aim of the work conducted in this thesis is to reconstruct audio speech signals using information which can be extracted solely from a visual stream of a speaker's face, with application for surveillance scenarios and silent speech interfaces. Visual speech is limited to that which can be seen of the mouth, lips, teeth, and tongue, where the visual articulators convey considerably less information than in the audio domain, leading to the task being difficult. Accordingly, the emphasis is on the reconstruction of intelligible speech, with less regard given to quality. A speech production model is used to reconstruct audio speech, where methods are presented in this work for generating or estimating the necessary parameters for the model. Three approaches are explored for producing spectral-envelope estimates from visual features as this parameter provides the greatest contribution to speech intelligibility. The first approach uses regression to perform the visual-to-audio mapping, and then two further approaches are explored using vector quantisation techniques and classification models, with long-range temporal information incorporated at the feature and model-level. Excitation information, namely fundamental frequency and aperiodicity, is generated using artificial methods and joint-feature clustering approaches. Evaluations are first performed using mean squared error analyses and objective measures of speech intelligibility to refine the various system configurations, and then subjective listening tests are conducted to determine word-level accuracy, giving real intelligibility scores, of reconstructed speech. The best performing visual-to-audio domain mapping approach, using a clustering-and-classification framework with feature-level temporal encoding, is able to achieve audio-only intelligibility scores of 77 %, and audiovisual intelligibility scores of 84 %, on the GRID dataset. Furthermore, the methods are applied to a larger and more continuous dataset, with less favourable results, but with the belief that extensions to the work presented will yield a further increase in intelligibility

Perkeptuaalinen spektrisovitus glottisherätevokoodatussa tilastollisessa parametrisessa puhesynteesissä käyttäen mel-suodinpankkia

This thesis presents a novel perceptual spectral matching technique for parametric statistical speech synthesis with glottal vocoding. The proposed method utilizes a perceptual matching criterion based on mel-scale filterbanks. The background section discusses the physiology and modelling of human speech production and perception, necessary for speech synthesis and perceptual spectral matching. Additionally, the working principles of statistical parametric speech synthesis and the baseline glottal source excited vocoder are described. The proposed method is evaluated by comparing it to the baseline method first by an objective measure based on the mel-cepstral distance, and second by a subjective listening test. The novel method was found to give comparable performance to the baseline spectral matching method of the glottal vocoder.Tämä työ esittää uuden perkeptuaalisen spektrisovitustekniikan glottisvokoodattua tilastollista parametristä puhesynteesiä varten. Ehdotettu menetelmä käyttää mel-suodinpankkeihin perustuvaa perkeptuaalista sovituskriteeriä. Työn taustaosuus käsittelee ihmisen puheentuoton ja havaitsemisen fysiologiaa ja mallintamista tilastollisen parametrisen puhesynteesin ja perkeptuaalisen spektrisovituksen näkökulmasta. Lisäksi kuvataan tilastollisen parametrisen puhesynteesin ja perusmuotoisen glottisherätevokooderin toimintaperiaatteet. Uutta menetelmää arvioidaan vertaamalla sitä alkuperäiseen metodiin ensin käyttämällä mel-kepstrikertoimia käyttävää objektiivista etäisyysmittaa ja toiseksi käyttäen subjektiivisia kuuntelukokeita. Uuden metodin havaittiin olevan laadullisesti samalla tasolla alkuperäisen spektrisovitusmenetelmän kanssa