1998 Fiscal Year Final Research Report Summary
Spatial Frequency Multiplex Heterodyne Technique for Absolute Measurement of Instantaneous Phase Distribution, and Its Applications
| Project/Area Number |
09650043
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Applied optics/Quantum optical engineering
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| Research Institution | The University of Electro-Communications |
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Principal Investigator |
TAKEDA Mitsuo The University of Electro-Communications Faculty of Electro-Communications, Professor, 電気通信学部, 教授 (00114926)
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| Co-Investigator(Kenkyū-buntansha) |
MIYAMOTO Yoko The University of Electro-Communications Faculty of Electro-Communications, Research Associate, 電気通信学部, 助手 (50281655)
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| Project Period (FY) |
1997 – 1998
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| Keywords | Heterodyne Interferometry / Spatial Frequency Multiplexing / 3-D Shape Measurement / Optical Metrology / Phase Unwrapping / Optical Profilometry |
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| Research Abstract |
The purpose of this research project is to develop a new scheme of heterodyne profilometry that can perform the instantaneous measurement of the absolute phase distribution of an object with large height discontinuities and/or surface isolations. The main accomplishments are summarized in the following :
1. Invention of Spatial Frequency Multiplex and Scan Method for Absolute Phase Measurement
As an alternative to the conventional temporal frequency scan method using a frequency tunable light source, a spatial frequency scan method was proposed for the absolute phase measurement. By means of spatial frequency multiplexing, the proposed technique can determine the absolute phase from a single fringe pattern, which makes possible the measurement of instantaneous phase distribution.
2. Clarification of the Relation between the Temporal and Spatial Frequency Scan Methods
A unified theory was given to the basic principles of the various absolute phase measurement technique using temporal and spatial frequency scanning methods.
3. Development of New Phase Unwrapping Algorithm
A new phase unwrapping algorithm that eliminates phase singular points was developed and experimentally verified.
4. Experimental Demonstration of the Instantaneous Shape Measurement of Objects in Dynamic Motion
An experimental system was constructed and the validity of the proposed spatial frequency multiplex and scan method was demonstrated for objects in fast motion.
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