Medidas de deslocamento e vibrações através de imagens de câmeras digitais

• Ano de defesa: 2013
• Autor(a) principal: Sabino, Danilo Damasceno [UNESP]
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Estadual Paulista (Unesp)
• Palavras-chave em Português: Medição; Vibração; Imagens digitais; Processamento de imagens; Analise modal; Digital images
• Link de acesso: http://hdl.handle.net/11449/111084

In this work is discussed the development and implementation of a technique for measuring of displacements using a single digital camera, whose main focus is the measurement of structural motion and vibrations. The proposal is a non-contact measurement technique, which is based on the variation of the position of the pixels of the target measuring points in the sequence of images of a video used to capture the movement of the target points in the scene. The concepts and theoretical background are presented, involving a discussion concerning to the formation and obtaining of digital images, definition and obtaining of intrinsic parameters of the camera, as well as the image processing techniques used to identify the measuring target points in the scene. The identification of the targets is made from the use of different analysis and image processing tools such as, color separation, edge detection, thresholdding, erosion and dilation used in a complementary way. The movement of the target points in the sequence of image is tracked in terms of pixels and then they are converted in measurement unit using the ratio measurement unit/pixel obtained by a calibration process. The evaluation and validation of the proposal were made through experimental tests, involving both static and dynamic measurements. At a final stage, the technique was used to vibration analyze of a reduced scale building structure, more specifically, the output-only modal analysis of the structure. The results and analyzes showed that the methodology implemented based on the use of a unique camera provided to be a proposal with high application potential as a non-contact measurement tool, relatively simple and effective