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Pseudo-Stokes Vector Correlation From Complex Signal Representation of a Speckle Pattern and Its Applications to Micro-Displacement Measurement |
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| Authors: | W. Wang R. Ishijima A. Matsuda S. G. Hanson M. Takeda |
| Affiliation: | Department of Mechanical Engineering, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh, EH14 4AS, UK; Laboratory for Information Photonics and Wave Signal Processing, Department of Information and Communication Engineering, The University of Electro-Communications, 1-5-1, Chofugaoka, Chofu, Tokyo, 182-8585, Japan; Department of Photonics Engineering, DTU Fotonik, P. O. Box 49, DK- 4000 Roskilde, Denmark |
| Abstract: | Abstract: As an improvement of the intensity correlation used widely in conventional electronic speckle photography, we propose a new technique for displacement measurement based on correlating Stokes-like parameters derivatives for transformed speckle patterns. The method is based on a Riesz transform of the intensity speckle pattern, which converts the original real-valued signal into a complex signal. In closest analogy to the polarisation of a vector wave, the Stokes-like vector constructed from the spatial derivative of the generated complex signal has been applied for correlation. Experimental results are presented that demonstrate the validity and advantage of the proposed pseudo-Stokes vector correlation technique over conventional intensity correlation technique. |
| Keywords: | complex signal representation displacement and strain measurement pseudo-Stokes vector correlation Riesz transform speckle photography |