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Proceedings Paper

Using the wavelet transform for processing signals of a counter of speckle
Author(s): A. Ventura-Chavez; Rene A. Martinez-Celorio; Juan J. Rosales-Garcia; Luis Marti-Lopez; Oscar G. Ibarra-Manzano
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Paper Abstract

In this paper we describe a speckle speedometer based on the use of the wavelet transform for signal processing. The optical set-up is composed of the moving object, a He-Ne laser, a converging lens, a pinhole and a linear photodetector. The pinhole permits irradiance measurements within a single speckle. The random signal from the photodetector was digitized by a commercially available data acquisition card and saved in a personal computer, where it is processed with wavelet transform. The wavelet transform allows discomposing the signal in several coefficients that represent low-pass and high-pass filters applied to the signal at different frequencies. From processed data the base frequency of the signal can be obtained. That frequency is related to the speed of the moving object, which can be determined after calibration. To test the method we carried out a digital simulation of the system and experiments. In the experiment we measure the speed of points of a rotating disc of glass and compare it with the values obtained from simulations. A good correspondence between measurements and simulated speed values were obtained. Advantages and disadvantages of the method are discussed.

Paper Details

Date Published: 14 February 2005
PDF: 7 pages
Proc. SPIE 5776, Eighth International Symposium on Laser Metrology, (14 February 2005); doi: 10.1117/12.611630
Show Author Affiliations
A. Ventura-Chavez, FIMEE, Univ. de Guanajuato (Mexico)
Rene A. Martinez-Celorio, FIMEE, Univ. de Guanajuato (Mexico)
Juan J. Rosales-Garcia, FIMEE, Univ. de Guanajuato (Mexico)
Luis Marti-Lopez, Instituto Tecnologico de Optica, Color e Imagen (Spain)
Oscar G. Ibarra-Manzano, FIMEE, Univ. de Guanajuato (Mexico)

Published in SPIE Proceedings Vol. 5776:
Eighth International Symposium on Laser Metrology
R. Rodriguez-Vera; F. Mendoza-Santoyo, Editor(s)

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