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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

PROJECTED FRINGE PROFILOMETRY USING A HOLOGRAPHIC TECHNIQUE: A COMPACT DESIGN FOR ENDOSCOPES

Hsiao, Chih-Hung 08 August 2008 (has links)
This paper proposes a miniature gauging system for objects inside a body cavity using the projected fringe profilometry (PSPFP) combined with the endoscope. The fringe pattern is formed by launching a reading bean into a diffraction element . The diffraction element can avoid the influence of projected aberrations by lens and largely reduce the size of projected system. This system has the following properrties: 1. It is a noon-contact, and full field measurement. Only one-shot measurement is needed. It is able to carry on the immediate gauging to the dynamic object. 2. Arrangement of the projected fringe is unique due to the procedure of specific coding. It is easy to revise the errors when undergo phase unwrapping. 3. The double projection scheme compensates the defects of one-shot measurements.
2

REAL TIME PROFILOMETRY USING SIMULTANEOUS DOUBLE FRINGE PROJECTION TECHNIQUES : A COMPACT DESIGN FOR ENDOSCOPES

Hong, Jian-Fong 19 November 2010 (has links)
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3

Characteristics and analysis of calibration-based phase-shifting projected fringe profilometry

Guo, Je-You 11 July 2005 (has links)
Phase-shifting projected fringe profilometry (PSPFP) is powerful for 3D profile measurements. Test and analysis for accuracy of PSPFP is presented. A novel scheme to identify the accuracy of evaluated phases is propsed as well. This test scheme can be applied to any kind of measurements which use fringe projection techniques.
4

Application of two frequency fringe pattern for phase-shifting projected fringe profilometry

Chen, Hong-Ming 08 July 2005 (has links)
A novel accurate calibration-based phase-shifting projected fringe profilometry (Calibration-based PSPFP) for finding the absolute shape of objects is proposed. In addition to a tremendous savings in time, the benefits of using Calibration-based PSPFP also include greatly reduced environmental vulnerability. Since Calibration-based PSPFP employs a sinusoidal fringe pattern to perform the phase-shifting algorithm, the quality and accuracy of the sinusoidal fringe pattern becomes critical. To evaluate the performance of this measurement scheme and reduce the phase error caused by projected fringes, fabrication of various digital sinusoidal fringe patterns is necessary. Thus, we propose a method to fabricate various digital patterns. Application of a 2-D fringe pattern for Calibration-based PSPFP is proposed as well.
5

3D SHAPE RECONSTRUCTION USING PROJECTED FRINGE PROFILOMETRY FOR AN IMAGE BLURRED BY LINEAR MOTION

Liu, Qiao-Yuan 11 August 2008 (has links)
A projected fringe profilometry (PFP) is an optical measurements technology which is widely used at present in gauging the object's three dimensional appearance. PFP is frequently used in detecting the quality of products in the industry due to the specialty of non-contact type, the short retrieve time and low environmental effect. As a result of the development for many years, PFP treats in the gauging static state of the object's three dimensional appearance has had the extremely fine gauging efficiency and the precision in , however in the dynamic inspected object in the gauging , not yet was still mature. If could to develop a set of gauging way in the dynamic inspected object , the application would be more widespread. Taking PFP as the gauging principle, analyzing the changes between the dynamic treat measured object and the fringe. Using the simple mathematics to describe the interaction relations between the fringe and the inspected the object. Finally, reconstructed the inspected object' three dimensional appearance. May know biggest superiority by the experimental process, in the situation of without losing the information of fringe, PFP can reconstruct the inspected object' three dimensional appearance and do not need the motion condition information.
6

Projected Fringe Profilometry using Diffractive Elements

Chen, Wei-jen 26 June 2006 (has links)
A technique using diffractive elements for finding the absolute shape of a large-scale object is proposed. An accurate projected fringe profilometry can be built by applying the holographic technique in this system. The advantages of using the presented technique for projected fringe profilemetry are : (1) a large depth of field ; (2) very low fringe distortion ; (3) a compact design for the measurement system ; (4) high accuracy ; (5) fast measurement speed.
7

PROJECTED FRINGE PROFILOMETRY USING A SUPERCONTINUUM LIGHT ILLUMINATION FOR MICRO-SCALE MEASUREMENT

Huang, chia-jeng 26 June 2006 (has links)
Abstract A projected fringe profilomertry ¡]PFP¡^ using a supercontinuum light illumination for micro-scale measurement is proposed. The supercontinuum light is generated by launching ultra short laser into a highly nonlinear photonic crystal fibers. The supercontinuum light with the following advantage¡G ¡]1¡^ Depth of the field is very large in the projected system. ¡]2¡^No speckle noise in the illumination system. Experiment results has shown that using supercontinuum light is superior to other illumination system This study indicates that the proposed measurement scheme could be applied to 3D shape measurements with large depth variation, especially for semi-conductor devices¡Bmicro electro-mechanical devices and biomedical species.
8

Inspection to 3-D deformation of a dynamic object using fringe projection techniques

Ko, Wei-Ting 18 July 2012 (has links)
A projected fringe profilometry (PFP) is a wide optical measurement technology to gauge the three dimensional appearance of object.Because of non-contact type , the short retrieve time and low environmental effect,PFP was usually used in many fields.PFP has become rather efficient and precise on gauging the three dimensional appearance of the static obiect because of its persistent development in recent years.However,it is still not mature yet to gauge the dynamic object. If we could develop a gauging way in the dynamic object , the application would be more widespread. First of all,using PFP as the gauging principle and utilzing the math algorithm for analyzing the changes between the dynamic measured object and the blurred fringes.Secondly,reconstructed the inspected object's three dimensional appearance and the velocity. Finally,found out the deformation of the measured object. The technology of this thesis broke through the typical measurement of velocity.We could analyze the velocities of three dimentional dirtions by only single optic imformation.

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