MODELAÇÃO DA FORMA E DO MOVIMENTO DE OBJECTOS EM SEQUÊNCIAS DE IMAGEM: APLICAÇÕES EM BIOMECÂNICA DO CORPO HUMANO

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Publications

Inter-speaker speech variability assessment using statistical deformable models from 3.0 Tesla magnetic resonance images

Publication . Vasconcelos, Maria J. M.; Ventura, Sandra Moreira Rua; Freitas, Diamantino R. S.; Tavares, João Manuel R. S.

The morphological and dynamic characterisation of the vocal tract during speech production has been gaining greater attention due to the motivation of the latest improvements in magnetic resonance (MR) imaging; namely, with the use of higher magnetic fields, such as 3.0 Tesla. In this work, the automatic study of the vocal tract from 3.0 Tesla MR images was assessed through the application of statistical deformable models. Therefore, the primary goal focused on the analysis of the shape of the vocal tract during the articulation of European Portuguese sounds, followed by the evaluation of the results concerning the automatic segmentation, i.e. identification of the vocal tract in new MR images. In what concerns speech production, this is the first attempt to automatically characterise and reconstruct the vocal tract shape of 3.0 Tesla MR images by using deformable models; particularly, by using active and appearance shape models. The achieved results clearly evidence the adequacy and advantage of the automatic analysis of the 3.0 Tesla MR images of these deformable models in order to extract the vocal tract shape and assess the involved articulatory movements. These achievements are mostly required, for example, for a better knowledge of speech production, mainly of patients suffering from articulatory disorders, and to build enhanced speech synthesizer models.

2011Journal article

Open access

Speaker-specific articulatory assessment and measurements during Portuguese speech production based on Magnetic Resonance Images

Publication . Ventura, Sandra Moreira Rua; Vasconcelos, Maria João; Freitas, Diamantino Rui; Ramos, Isabel Maria; Tavares, João Manuel R. S.

The development of two and three-dimensional magnetic resonance imaging (MRI) opened new options for a better understanding of speech production; in particular, for the articulation process, comparing with other imaging techniques, such as x-rays. Several MRI studies have been carried out considering different languages, but concerning European Portuguese the available information is far from being completely achieved. Recently, the knowledge gained with the application of deformable models in magnetic resonance images towards the automatic study of the vocal tract, has allowed an enhanced identification and description of the articulatory mechanism and its organs. Our aim is to extract and evaluate the main characteristics of the movements of vocal tract during European Portuguese speech production to achieve speaker-specific articulatory assessment from MRI. For this, we used active shape and active appearance models to identify, i.e. to segment, and simulate the vocal tracts shape in MR images and concluded that both are suitable for such tasks being the later more proficient. The findings obtained are believed to be useful for speech rehabilitation and simulation purposes, namely to recognize and simulate the compensatory movements of the articulators during speech production.Therefore, this chapter gains particular interest within the communities of speech study and rehabilitation, medical imaging and bioengineering. It is organized as follows: the introduction section starts with a literature review concerning the use, application and challenges of MRI in speech production study, in particular for speech articulation. In addition, image analysis techniques based on deformable templates, more specifically by using geometrical shapes driven by parameterized functions, are introduced. In the second section, the adopted methodology of MRI acquisition and data assessment are described. Based on this image analysis approach, in the results section the key aspects of articulatory movements during the production of relevant European Portuguese speech sounds are addressed. In the final section of this chapter, conclusions are presented and further suggestions for future work are indicated.

2012Book part

Open access