High Precision Contouring with Moiré and Related Methods: A Review |
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Authors: | C A Sciammarella L Lamberti A Boccaccio F M Sciammarella |
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Affiliation: | 1. Northern Illinois University, Department of Mechanical Engineering, 590 Garden Road, 60115 Dekalb, IL, USA;2. Dipartimento di Ingegneria Meccanica e Gestionale, Politecnico di Bari, Viale Japigia 182, 71026 Bari, Italy |
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Abstract: | Abstract: Optical methods of contouring that utilise image recordings by cameras are based on a fundamental discipline, projective geometry. The 3‐D world is projected in 2‐D utilising a camera modelled in the technical literature by the pinhole camera. To get back 3‐D information, the fundamental property measured is parallax. Parallax is a vector resulting from the difference of the projective coordinates of a point in space when projected onto a plane from two different points. The oldest method used for measuring parallax is photogrammetry. It is assumed to be the most precise technique, with the capability of obtaining 10?5 of the largest dimension of the measured object. This study summarises the state‐of‐the‐art methods based on projecting a spatial carrier. Starting with the concept of moiré as a form of photogrammetry, the different optical techniques for parallax determination are discussed. Although the moiré method has reached 1 μm accuracy in laboratory work, a question remains: can moiré become a standardised contouring technique yielding 10?6 m accuracy? This study is devoted to the analysis of high accuracy contour measurements, through both theoretical derivations and experimental verifications. |
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Keywords: | contouring of surfaces determination of parallax geometrical primitives merging of different views optical measurement devices projection moiré |
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