A computational method for recording and analysis of mandibular movements

This study proposed the development of a new clinical tool capable of quantifying the movements of opening-closing, protrusion and laterotrusion of the mandible. These movements are important for the clinical evaluation of the temporomandibular function and muscles involved in mastication. Unlike current commercial systems, the proposed system employs a low-cost video camera and a computer program that is used for reconstructing the trajectory of a reflective marker that is fixed on the mandible. In order to illustrate the clinical application of this tool, a clinical experiment consisting on the evaluation of the mandibular movements of 12 subjects was conducted. The results of this study were compatible with those found in the literature with the advantage of using a low cost, simple, non-invasive, and flexible tool customized for the needs of the practical clinic

Extraction and evaluation of vocal folds dynamics using high-speed laryngeal imaging

No contexto da fonação, as pregas vocais são responsáveis pela produção primária do sinal de voz na laringe. Tão importantes quanto complexas, elas exibem uma dinâmica rica e uma série de comportamentos que determinam as características fundamentais do sinal emitido pela boca. Com o intuito de avaliar suas propriedades sob a luz dos métodos da dinâmica não-linear de sistemas, este trabalho tem por objetivo principal desenvolver uma técnica de extração e simulação de sua dinâmica. Para isto são empregados modelos determinísticos das pregas vocais e imagens de videolaringoscopia de alta velocidade. Estes elementos são usados para reproduzir a dinâmica e cinemática das pregas de indivíduos saudáveis através de um procedimento de otimização dos parâmetros mecânicos destes modelos de pregas. Feito isto, os modelos são usados para avaliar o comportamento não-linear das pregas vocais através de uma análise modal não-linear cujo propósito foi descrever como as não-linearidades estruturais das pregas podem influenciar na voz. Os resultados mostram a eficiência de um método capaz de reproduzir a maior parte dos padrões de vibração das pregas e uma relação de dependência entre sua energia mecânica e sua frequência fundamental de vibração, que é fruto das não-linearidades estruturais das pregas vocais.As far as phonation is concern, the vocal folds produce the primary voice signal within larynx. As important as complex, they exhibit a rich dynamics capable to influence the fundamental voice features. In light of nonlinear dynamical methods, this work has as purpose to develop a method to extract and simulate the vocal folds dynamics. Deterministic vocal folds models and high-speed videolaryngoscopy are used to reproduce the dynamics of healthy subjects and evaluate their nonlinear behavior and some phenomena raised by the nonlinearities. Nonlinear normal modes are employed to understanding how the nonlinearities may influence the primary phonation. The results show that the method could reflect the most important vibratory patterns. Additionally, the nonlinear analysis has shown energy-frequency dependence and a complex dynamics with structural nonlinearities

Extraction and evaluation of vocal folds dynamics using high-speed laryngeal imaging

No contexto da fonação, as pregas vocais são responsáveis pela produção primária do sinal de voz na laringe. Tão importantes quanto complexas, elas exibem uma dinâmica rica e uma série de comportamentos que determinam as características fundamentais do sinal emitido pela boca. Com o intuito de avaliar suas propriedades sob a luz dos métodos da dinâmica não-linear de sistemas, este trabalho tem por objetivo principal desenvolver uma técnica de extração e simulação de sua dinâmica. Para isto são empregados modelos determinísticos das pregas vocais e imagens de videolaringoscopia de alta velocidade. Estes elementos são usados para reproduzir a dinâmica e cinemática das pregas de indivíduos saudáveis através de um procedimento de otimização dos parâmetros mecânicos destes modelos de pregas. Feito isto, os modelos são usados para avaliar o comportamento não-linear das pregas vocais através de uma análise modal não-linear cujo propósito foi descrever como as não-linearidades estruturais das pregas podem influenciar na voz. Os resultados mostram a eficiência de um método capaz de reproduzir a maior parte dos padrões de vibração das pregas e uma relação de dependência entre sua energia mecânica e sua frequência fundamental de vibração, que é fruto das não-linearidades estruturais das pregas vocais.As far as phonation is concern, the vocal folds produce the primary voice signal within larynx. As important as complex, they exhibit a rich dynamics capable to influence the fundamental voice features. In light of nonlinear dynamical methods, this work has as purpose to develop a method to extract and simulate the vocal folds dynamics. Deterministic vocal folds models and high-speed videolaryngoscopy are used to reproduce the dynamics of healthy subjects and evaluate their nonlinear behavior and some phenomena raised by the nonlinearities. Nonlinear normal modes are employed to understanding how the nonlinearities may influence the primary phonation. The results show that the method could reflect the most important vibratory patterns. Additionally, the nonlinear analysis has shown energy-frequency dependence and a complex dynamics with structural nonlinearities

Developing of a motion capture system based on computer vision techniques

The purpose of this study was investigate the measurement techniques of human movement and to develop a system capable of capturing and reconstructing the movement trajectory on real world. The devised system uses video cameras to record the movement and a computer program to process video footage assessing the movement trajectory and calculating its kinematical variables. Those data are showed by the program as graphics or animation which simulates the reconstructed movement. To reach these objectives, the system used techniques from image processing, computer vision and anthropometric models. In the end of this work, it is exhibited an experimental evaluation of the precision and accuracy of the system and some case studies to show its potential.Mestre em CiênciasO propósito deste estudo foi pesquisar as técnicas de medição do movimento humano e desenvolver um sistema capaz de capturar e reconstruir a trajetória do movimento no espaço. O sistema desenvolvido utiliza câmeras de vídeo para registrar o movimento e um programa de computador capaz de processar as imagens extraídas dos vídeos de forma a estimar a trajetória do movimento e calcular as suas variáveis cinemáticas. Estes dados são exibidos pelo programa na forma de gráficos ou animações que reconstroem o movimento capturado. Para alcançar estes objetivos, o sistema utilizou técnicas de processamento de imagens, visão computacional, cálculos numéricos e modelos antropométricos do corpo humano. Ao final desta dissertação é feita uma avaliação experimental da precisão e exatidão do sistema proposto e alguns estudos de casos que tiveram como objetivo demonstrar o potencial deste sistema

A Real-Time Method to Estimate the Operational Condition of Distribution Transformers

In this article, an unsupervised learning method is presented with the objective of modeling, in real-time, the main operating modes (OM) of distribution transformers. This model is then used to assess the operational condition through use of two tools: the operation map and the health index. This approach allows, mainly, for a reduction in the need for the interpretation of results by specialists. The method used the concepts of k-nearest neighbors (k-NN) and Gaussian mixture model (GMM) clustering to identify and update the main OMs and characterize these through operating mode clusters (OMC). The evaluation of the method was performed using data from a case study of almost one year in duration, along with five in-service distribution transformers. The model was able to synthesize 11 magnitudes measured directly in the transformer into two latent variables using the principal component analysis technique, while preserving on average more than 86% of the information present. The operation map was able to categorize the transformer operation into previously parameterized levels (appropriate, precarious, critical) with errors below 0.26 of standard deviation. In addition, the health index opened the possibility of identifying and quantifying the main abnormal variations in the operating pattern of the transformers

A Real-Time Method to Estimate the Operational Condition of Distribution Transformers

In this article, an unsupervised learning method is presented with the objective of modeling, in real-time, the main operating modes (OM) of distribution transformers. This model is then used to assess the operational condition through use of two tools: the operation map and the health index. This approach allows, mainly, for a reduction in the need for the interpretation of results by specialists. The method used the concepts of k-nearest neighbors (k-NN) and Gaussian mixture model (GMM) clustering to identify and update the main OMs and characterize these through operating mode clusters (OMC). The evaluation of the method was performed using data from a case study of almost one year in duration, along with five in-service distribution transformers. The model was able to synthesize 11 magnitudes measured directly in the transformer into two latent variables using the principal component analysis technique, while preserving on average more than 86% of the information present. The operation map was able to categorize the transformer operation into previously parameterized levels (appropriate, precarious, critical) with errors below 0.26 of standard deviation. In addition, the health index opened the possibility of identifying and quantifying the main abnormal variations in the operating pattern of the transformers