Non-linear joint transform correlator for micro-displacement measurement using speckle patterns
This work presents a procedure for measuring displacements of tens micrometer, in one and two dimensions, based on the correlation between two speckle patterns. For this purpose, two objective speckle patterns arerecorded by a digital camera -one before and one after the object has been moved- and...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
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Universidad de Antioquia
2013-10-01
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| Series: | Revista Facultad de Ingeniería Universidad de Antioquia |
| Subjects: | |
| Online Access: | https://revistas.udea.edu.co/index.php/ingenieria/article/view/17037 |
| Summary: | This work presents a procedure for measuring displacements of tens micrometer, in one and two dimensions, based on the correlation between two speckle patterns. For this purpose, two objective speckle patterns arerecorded by a digital camera -one before and one after the object has been moved- and placed in the input plane of nonlinear joint transform correlator.
Nonlinear transformation of the joint power spectrum allows a sharper correlation peak and a high signal to noise ratio. The autocorrelation peak coordinates of the first pattern are set as a reference for measuring shifts of the successive cross-correlation peak. One criterion for reliable measure is proposed. Results related with different distances sample-sensor and illuminating wavelengths at 632.8 nm and 543.5 nm are presented.
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| ISSN: | 0120-6230 2422-2844 |