The Study of the Calibration of the Sensitivity Vectors for Electronic Speckle Displacement Measurement System

• Main Author: 李賓浩
• Other Authors: 李吉群
• Format: Others
• Language: zh-TW
• Published: 2002
• Online Access: http://ndltd.ncl.edu.tw/handle/30455646171942198530

碩士 === 國立中興大學 === 機械工程學系 === 90 === Electronic speckle pattern interferometry (ESPI) is a well-known technique in experimental mechanics for measuring the displacement field of a deformable body. In this project, theories and techniques for calibrating the ESPI system sensitivity vectors are proposed. The system calibration is based on the general setup of ESPI. There are two main purposes to estimate in this project, the position of the point light source and the target of the testing object. The system calibration is based on the original setup of the ESPI without any modifications. Using the spatial filtered laser light as the point light sources, an orthogonal sine patterns are projected onto the standard plate that has special designed patterns. The CCD camera grabs the images of these projected sine patterns and the special designed patterns on the standard plate. The images of these patterns are used to compute the lens distortion, the principal points, and the exterior orientation of the CCD camera and the position of the pinholes of these spatial filters. Method of structural light triangulation is adopted to reconstruct the profile of the object. The sine patterns are projected onto the surface of the object by the spatial filtered point light source. The CCD camera grabs the image and a technique of triangulation is used to compute the profile of the object. Combining the profile of the object and the position of the pinhole of the spatial filters, the sensitivity vectors of any interested point on the surface of the object can be computed. The sensitivity vectors are confirmed by measuring the position of the pinholes of the spatial filters and the interested object points using the coordinate measurement machine