Modelling and segmentation of the vocal track during speech production by using deformable models in magnetic resonance images

The first and second authors would like to thank the support of the PhD grants with references SFRH/BD/28817/2006 and SFRH/PROTEC/49517/2009, respectively, from Fundação para a Ciência e Tecnol ogia (FCT). This work was partially done in the scope of the project “Methodologies to Analyze Organs from Complex Medical Images – Applications to Fema le Pelvic Cavity”, wi th reference PTDC/EEA- CRO/103320/2008, financially supported by FCT.Since ancient times, speech production has attracted particularly interest aiming at reaching a deeper understanding of the mechanisms involved by considering both morphological and speech acoustic aspects. The central anatomical aspects and the physiology of the human vocal tract are common to all individuals. However, speech production is an exceptionally complex and individualistic process. Therefore, the modelling of the mechanisms involved in speech production implies the enclosing of adequate flexibility in order to consider individual variations accurately. In this work, the shape of vocal tract in the articulation of some European Portuguese (EP) sounds is evaluated by using deformable models applied in Magnetic Resonance (MR) images. Additionally, the deformable models built are afterwards used to automatically segment the modelled vocal tract in MR images. From the imaging modalities that have been take n into consideration in order to study the vocal tract shape and articulators, Magnetic Resonance Imaging (MRI) has been the most commonly accepted. Actually, the use of MRI allows the study of the entire human vocal tract and, in addition, the quality and resolution of soft-tissues and the use of non-ionizing radiation are key advantages presented by MRI. The deformable model used, commonly known as Point Distribution Model (PDM), was built from a set of training images acquired du ring artificially sustained articulations of 21 EP sounds. In a brief review, one can assert that PDM’s are obtained by a statistical analysis done on the co-ordinates of landmark points that represent the shape to be modelled: after aligning the training shapes, a Principal Component Analysis is performed in order to obtain the model mean shape and the modes of variation relatively to this mean shap e. Combining the geometrical information of the PDM with the grey levels of the landmark points us ed in its building one can build the Active Shape Models (ASM) and the Active Appearance Models (AAM). With these enhanced models is possible to segment the modelled shape in new images in a fully automated way. From the experimental results obtained in this work, one may conclude that the PDM built could efficiently characterize the behaviour of the voca l tract shape during the production of the EP sounds studied with MRI. Furthermore, one can ve rify that the ASM and the AAM built could be used to segment the modelled vocal tract in MR images in a successful manner. Therefore, the deformable models built should be considered towards the efficient and automatic study of the vocal tract during speech production with MRI, in particular for enhanced speech production simulation and speech rehabilitation therapies.Fundação para a Ciência e Tecnologia (FCT

Comando de um Servomecanismo usando Visão Computacional

Neste artigo é apresentada uma metodologia para controlar um servomecanismo usando visão computacional. As imagens de controlo,baseadas na linguagem gestual, são obtidas por intermédio de uma webcam genérica e processadas praticamente em tempo real. Aordem de comando em causa é reconhecida por diferença dos histogramas de orientação da imagem associada e das imagens deordens preestabelecidas. Estas imagens de ordens são guardadas durante o processo de aprendizagem do sistema de controlo.In this paper a methodology to control a servomechanism using computational vision is presented. The control images, based in hand language, are acquired by a generic webcam and processed in quasi real time. The command order in cause is recognized by the difference of the orientation histograms for the associated and preset orders images. These preset orders images are acquired in the learning process of the control system

Magnetic resonance imaging of the vocal tract: techniques and applications

Magnetic resonance (MR) imaging has been used to analyse and evaluate the vocal tract shape through different techniques and with promising results in several fields. Our purpose is to demonstrate the relevance of MR and image processing for the vocal tract study. The extraction of contours of the air cavities allowed the set-up of a number of 3D reconstruction image stacks by means of the combination of orthogonally oriented sets of slices for each articulatory gesture, as a new approach to solve the expected spatial under sampling of the imaging process. In result these models give improved information for the visualization of morphologic and anatomical aspects and are useful for partial measurements of the vocal tract shape in different situations. Potential use can be found in Medical and therapeutic applications as well as in acoustic articulatory speech modelling

New control algorithm for single-phase series active power filter

This paper presents a single-phase Series Active Power Filter (Series APF) for mitigation of the load voltage harmonic content, while maintaining the voltage on the DC side regulated without the support of a voltage source. The proposed series active power filter control algorithm eliminates the additional voltage source to regulate the DC voltage, and with the adopted topology it is not used a coupling transformer to interface the series active power filter with the electrical power grid. The paper describes the control strategy which encapsulates the grid synchronization scheme, the compensation voltage calculation, the damping algorithm and the dead-time compensation. The topology and control strategy of the series active power filter have been evaluated in simulation software and simulations results are presented. Experimental results, obtained with a developed laboratorial prototype, validate the theoretical assumptions, and are within the harmonic spectrum limits imposed by the international recommendations of the IEEE-519 Standard

Towards e-Cities: an Atlas to enhance the public realm through interactive urban cyber-physical devices

Cyber-physical devices are the backbone of a postdigital society in which the virtual and real spaces are seamlessly integrated by ubiquitous computing and networking. The incorporation of such devices in public space is a central subject of a strategic Research Project that gathers a multidisciplinary team from architecture, product design, polymer science and ICT R&D units. This paper frames the key roles of public space and ICTs for UN Sustainable Development Goals and sustainable smart cities. It also reports the architecture R&D unit review on the relations between public space, community, environment and digital interfaces. This review was materialized in an Atlas that collects, classifies and relates a corpus of heterogeneous urban cyber-physical projects case studies. We expand on three main framing concepts (Digital Twin, Interface, Awareness) and identify trends on the devices’ design and deployment strategies to counteract digitally hostile environments and early obsolescence. We also suggest the rising of new types of urban devices aiming at expanding the liveliness of urban places, the knowledge of urban life and the users’ environmental consciousness. The lessons learned from the Atlas fed the design guidelines for a developing demonstrator of a new breed of environmentally sensible interactive urban devices.Work co-funded by European Regional Development Fund (ERDF) thru Norte 2020: Project “Lab4U&Spaces - Living Lab of Interactive Urban Space Solution” (NORTE-01-0145-FEDER-000072); and Project Lab2PT - Landscapes, Heritage and Territory laboratory - UIDB/04509/2020 thru FCT - Fundação para a Ciência e a Tecnologia

Segmentation and 3D reconstruction of the vocal tract from MR images - a comparative study

Speech production is an important human function involving a set of organs with specific morphological and dynamic aspects. The inter-speaker variability, the coarticulation or the nasality are some interesting aspects to improve a realistic 3D modeling of the vocal tract. For this, the understanding of the mechanism of speech production is crucial, as the current image data is not sufficient to reproduce truthfully the speakers anatomy and articulation. Hence, the goal of 3D modeling is to generate the complete geometrical and dynamical information concerning the vocal tract from medical images, such as from magnetic reso-nance imaging (MRI). This work aims to describe and compare two different segmentation techniques to at-tain the 3D shape of the vocal tract during speech production from MR images: the former based on manual tracing of the vocal tract contours and the latter based on image thresholding. Thus, the segmented cross-sectional areas were measured, and 3D models were built from the sagittal data by blending the contours ob-tained from the two segmentation techniques. The mean error of the measures computed were low for both segmentation techniques, which let us conclude that the techniques are useful to evaluate the vocal tract ge-ometry accurately. Additionally, the 3D models built using both segmentation techniques were also very similar and truthful. However, when the coronal data was used, various difficulties occurred

OCORRÊNCIA DE CIANOBACTÉRIAS PRODUTORAS DE TOXINAS NO RIO DOS SINOS (RS) ENTRE OS ANOS DE 2005 E 2008

revista vol 13 nº 2.indd Cyanobacteria are widely distributed autotrophic prokaryotic microorganisms, whose blooms depend on ideal amounts of nitrogen and phosphorous as well optimal temperature and pH conditions. Cyanobacterial blooms in the Sinos River, Rio Grande do Sul state, Brazil, are triggered by the influx of household and industrial wastes. The present study aimed at monitoring the occurrence of cyanobacteria in the Sinos River and tracking the water quality for human consumption. Water samples were taken from February 2005 to March 2008 at the Alberto Pasqualine Oil Refinery in the municipality of Esteio, Rio Grande do Sul state, totaling 64 samples. The different genera of cyanobacteria found were identified and counted in the laboratory in Sedgewick-Rafter chambers. The genera Planktothrix and Cylindrospermopsis, as well as an unidentified unicelular cyanobacterium were the most frequently found in the samples. Planktothrix sp. achieved 87,009 cells.mL-1 in March 2005, Cylindrospermopsis sp. achieved 65,100 cells.ml-1 in August 2006, and the unidentified unicellular cyanobacterium achieved 20,000 cells.mL-1 in January 2006. Only six samples contained no cyanobacteria. Planktothrix and Cylindrospermopsis are potentially toxic, but cyanotoxins could not be detected in the samples containing more than 20,000 cells.mL-1. Cylindrospermopsis sp, were most numerous during seasonal floods of the Sinos River (over March, June and August) whereas Planktothrix sp. were most numerous during the drought periods (January, February and March). The presence of each predominant cyanobacterium may be correlated with direction of the water flow in Lake Guaíba--Sinos River system.revista vol 13 nº 2.indd Las cianobacterias son microorganismos procariotes y autotróficos que viven en distintos hábitats. El nitrógeno y el fósforo, así como condiciones adecuadas de temperatura y pH en el agua, pueden dar lugar a la formación de floraciones. En el río dos Sinos (RS), la contaminación por efluentes domésticos e industriales estimula la ocurrencia de floraciones. Este trabajo tiene como objetivo monitorear la ocurrencia de cianobacterias en el río dos Sinos, siguiendo las normas de potabilidad de agua para consumo humano. Las colectas fueron realizadas desde febrero del 2005 hasta marzo del 2008, en la zona de captación de la refinería Alberto Pasqualine S/A en Esteio (RS), haciendo un total de 64 muestreos. En laboratorio, los géneros de cianobacterias fueron identificados y luego cuantificados en una cámara Sedgewick-Rafter. Los géneros Planktothrix, Cylindrospermopsis y una cianobacteria unicelular fueron los de mayor ocurrencia. Planktothrix sp. presentó el valor más alto de 87.009 células mL-1 en marzo del 2005; Cylindrospermopsis sp. llegó a 65.100 células mL-1 en agosto del 2006 y una cianobacteria unicelular 20.000 células mL-1 en enero del 2006. Sólo en 6 muestreos no se hallaron células de cianobacterias en el agua del río dos Sinos. Los dos géneros predominantes Planktothrix y Cylindrospermopsis son potencialmente tóxicos, pero no se encontraron cianotoxinas en el agua tratada cuando los conteos de células sobrepasaron las 20.000 células mL-1 en el agua sin potabilizar. Se constató una mayor concentración de células de Cylindrospermopsis sp. durante las crecidas del río dos Sinos (mayo, junio y agosto) y de Planktothrix sp durante el estiaje (enero, febrero y marzo). Habría la posibilidad de que este relacionada la presencia predominante de una u otra cianobacteria con el sentido de flujo en el sistema que forman el lago Guaiba y el río dos Sinos.Cianobactérias são microorganismos procariontes e autotróficos encontrados em diversos habitats. A disponibilidade de nitrogênio e fósforo e de condições ideais de temperatura e de pH nas águas favorecem as florações. No rio dos Sinos (RS), a contaminação por efluentes domésticos e industriais estimulam as florações. Este trabalho teve como objetivo o monitoramento da ocorrência de cianobactérias no rio dos Sinos, seguindo normas de potabilidade de água para consumo humano. As coletas foram realizadas de fevereiro de 2005 a março de 2008, na captação da Refinaria Alberto Pasqualine S/A em Esteio (RS), totalizando 64 amostragens. Em laboratório, foram identificados os gêneros de cianobactérias e quantificados em câmara de Sedgewick-Rafter. Os gêneros Planktothrix, Cylindrospermopsis e uma cianobactéria unicelular foram os de maior ocorrência. Planktothrix sp. apresentou o valor mais alto de 87.009 células mL-1 em março de 2005, enquanto Cylindrospermopsis sp. alcançou 65.100 células mL-1 em agosto de 2006 e uma cianobactéria unicelular, 20.000 células mL-1 em janeiro de 2006. Somente em seis amostragens não foram encontradas células de cianobactérias nas águas do rio dos Sinos. Os dois gêneros predominantes Planktothrix e Cylindrospermopsis, são potencialmente tóxicos, mas não foram encontradas cianotoxinas na água tratada quando as contagens ultrapassaram a 20.000 células mL-1 na água bruta. Constatou-se uma maior concentração de células de Cylindrospermopsis sp. durante a cheia do rio dos Sinos (maio, junho e agosto) e de Planktothrix sp. durante a estiagem (janeiro, fevereiro e março). Há possibilidade de relacionar-se a presença de uma ou outra cianobactéria predominante com o sentido do fluxo no sistema lago Guaíba -- rio dos Sinos

Utilização da Imagem por Ressonância Magnética nos Estudos sobre a Produção da Fala

A fala é uma ferramenta única de comunicação, que envolve um conjunto de órgãos que trabalham sincronamente na produção de sons. Os mecanismos envolvidos são complexos, sendo várias as técnicas de estudo da fala, quer do ponto de vista acústico, quer do ponto de vista morfológico. A ressonância magnética tem revelado potencialidades únicas no estudo do tracto vocal, e que são aqui destacadas. O principal objectivo deste estudo é dar a conhecer esta técnica de imagem e demonstrar a sua utilização no estudo da produção da fala, nomeadamente do Português Europeu. Através da recolha e análise de imagens foi possível a obtenção e construção de modelos tridimensionais do tracto vocal nas mais variadas posições articulatórias. Recorrendo a uma técnica de sincronização através de monitorização cardíaca e a aquisições de imagem ultra-rápidas foi possível também a captação dinâmica por sub-amostragem e a observação dos movimentos articulatórios envolvidos durante a produção de três sílabas. A caracterização morfológica e dinâmica do tracto vocal com base nas imagens de ressonância magnética é, face aos resultados obtidos, fiável e deveras importante para o conhecimento deste mecanismo. Para além disso, a informação obtida desperta um interesse multidisciplinar e aplicações diversas com potencialidades marcantes face aos esperados avanços tecnológicos desta técnica de imagem