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Master's Dissertation
DOI
https://doi.org/10.11606/D.3.1997.tde-01072024-142812
Document
Author
Full name
Yusuke Takahashi
Institute/School/College
Knowledge Area
Date of Defense
Published
São Paulo, 1997
Supervisor
Committee
Horikawa, Oswaldo (President)
Costa, Anna Helena Reali
Miyagi, Paulo Eigi
Title in Portuguese
Método para recuperação de formas de objetos.
Keywords in Portuguese
Engenharia mecânica
Abstract in Portuguese
O presente trabalho propoe um novo método para, valendo-se da capacidade de uma câmara de vídeo e um computador, identificar com grande precisão as variações de intensidade luminosa, identificar a trajetória através de um modelo matemático de previsão de variação de intensidade conforme a rotação e a forma do objeto. Diferente dos métodos já propostos, este método requer somente a difusão perfeita da luz na superficie do objeto e a utilização de iluminação com raios paralelos, permitindo em tese a medição de objetos com reentrância e objetos sem pontos de fácil identificação. O método foi avaliado através de simulação e através de experimento. Em ambos os casos são utilizadas desde situações mais simples, como um cilindro girando em tôrno de seu eixo, a diversas outras situações mais complexas. Os resultados da simulação e dos experimentos se mostraram satisfatórios, validando o método. No caso mais simples de recuperação de forma de uma porção cilíndrica de um objeto, chegou-se a um erro máximo de 1,1mm para um raio próximo de 35mm. Nos casos mais complexos não se chegou a avaliar a precisão devido aos erros. Contudo, em todos os casos a forma básica dos objetos foram bem identificados e os principais problemas que prejudicam a precisão da recuperação são discutidos.
Title in English
Untitled in english
Keywords in English
Mechanical engineering
Abstract in English
Recovering shape of objects through image processing presentes great advantage in providing small and versatile system. Among some methods in this category, exists a group known as Roating Object Method which allows more simple recovering and demands only one câmera ando ne light source. This method consists basically of analysis of traces of points of object on successive imagens taken from the rotating object. Previous studies have been done as to this method but all of them were based on trace obtainment through easy identification even through human vision. The present research proposes new method. It makes use of a vídeo câmera and a computerscapacity for identify variation of intensity with good precision and identifys trace through estimation of intensity variation by mathematical model according to rotation and shape of the object. Different from the methods already proposted, this method requires only perfect diffuse of ligh on surface of objects and use of parallel light source. It allows recovering of objects with dents and objects without easy-to-found points in theory. The method is verified through simulations and experiments. In both cases, from a case of a cylinder rotating around its axis to more complex case are used. The simulational and experimental results show satisfactory verification of the method. In the most simple case of shape recoveryng of a portion of cylindrical object, max error reached up to 1.1mm for a radius close to 35mm. In case of more complex shape. Verification didnt come up to precision due to erros. However in all casesthe basic shape of objects were well identified and the principal which damages the precision of recovering are discussed.T
 
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Publishing Date
2024-07-02
 
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