Paper
8 October 2007 Precision displacement measurement using a modulating ESPI
Seong Jong Kim, Young June Kang, Dong Pyo Hong, Kyung Suk Kim, Nak Kyu Park, Weon Jae Ryu, Man Young Choi
Author Affiliations +
Proceedings Volume 6719, Optomechatronic Systems Control III; 671908 (2007) https://doi.org/10.1117/12.754586
Event: International Symposium on Optomechatronic Technologies, 2007, Lausanne, Switzerland
Abstract
Laser interferometry is widely used as a measuring system in many fields because of its high resolution and ability to measure a broad area in real-time all at once. In conventional LASER interferometry, for example Out-of-plane ESPI(Electronic Speckle Pattern Interferometry), In plane ESPI, Shearography and Holography, it uses PZT or other components as a phase shift instrumentation to extract 3D deformation data, vibration mode and others. However, in most cases PZT has some disadvantages, which include non-linear errors and limited time of use. In the present study, a new type of LASER interferometry using a laser diode is proposed. Using LASER Diode Sinusoidal Phase Modulating (LD-SPM) interferometry, the phase modulation can directly modulated by controlling the LASER Diode injection current thereby eliminating the need for PZT and its components. This makes the interferometry more compact. This paper reports on a new approach to the LD Modulating interferometry that involves four-bucket phase shift method. This study proposes a four-bucket phase mapping algorithm, which developed to have a guaranteed application, to stabilize the system in the field and to be a user-friendly GUI. In this paper, LD modulating interferometry had shown the theory for LD wavelength modulation and sinusoidal phase modulation. Four-bucket phase mapping algorithm then introduced.
© (2007) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Seong Jong Kim, Young June Kang, Dong Pyo Hong, Kyung Suk Kim, Nak Kyu Park, Weon Jae Ryu, and Man Young Choi "Precision displacement measurement using a modulating ESPI", Proc. SPIE 6719, Optomechatronic Systems Control III, 671908 (8 October 2007); https://doi.org/10.1117/12.754586
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KEYWORDS
Semiconductor lasers

Modulation

Ferroelectric materials

Phase shifts

Phase shift keying

Interferometry

Image processing

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