Abstract

Two objective speckle patterns are obtained—one before and one after the object has been moved—and are placed in the input plane of an optoelectronic nonlinear joint transform correlator.

Nonlinear transformation of the joint power spectrum permits 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 displacements of the cross-correlation peak, and also, the calibration of the measurement system is performed.

It is well known that speckle can be regarded as a random spatial carrier in which information on the shape and position of the diffusing surface is encoded. The correlation of speckle patterns is highly appropriate for measuring displacements of tens of micrometers.1,2 In this work, an alternative technique based on the correlation between two speckle patterns by means of a digital bipolar joint transform correlator3 is presented. Initially the technique is described and then experimental results are shown.

© 1998 Optical Society of America

Full Article  |  PDF Article

References

  • View by:
  • |
  • |
  • |

  1. C. Gorecki, G. Tribillon, “Speckle displacement analysis by phase correlation using a SLM-based processor,” Journal of Modern Optics 40(6). 973–978 (1993).
    [CrossRef]
  2. A. Oulamara et al., “Subpixel speckle displacement measurement using a digital processing technique.” Journal of Modern Optics 35(7), 1201–1211 (1988).
    [CrossRef]
  3. B. Javidi, Nonlinear Joint Transform Correlators in Real Time Optical Information Processing (Academic Press Inc., San Diego, CA, 1994), pp. 115–183.
  4. B. Javidi, D. Painchaud. “Distortion–invariant pattern recognition with Fourier-plane nonlinear filters,” Appl. Opt. 35(2), 318–331 (1996).
    [CrossRef] [PubMed]

1996

1993

C. Gorecki, G. Tribillon, “Speckle displacement analysis by phase correlation using a SLM-based processor,” Journal of Modern Optics 40(6). 973–978 (1993).
[CrossRef]

1988

A. Oulamara et al., “Subpixel speckle displacement measurement using a digital processing technique.” Journal of Modern Optics 35(7), 1201–1211 (1988).
[CrossRef]

Gorecki, C.

C. Gorecki, G. Tribillon, “Speckle displacement analysis by phase correlation using a SLM-based processor,” Journal of Modern Optics 40(6). 973–978 (1993).
[CrossRef]

Javidi, B.

B. Javidi, D. Painchaud. “Distortion–invariant pattern recognition with Fourier-plane nonlinear filters,” Appl. Opt. 35(2), 318–331 (1996).
[CrossRef] [PubMed]

B. Javidi, Nonlinear Joint Transform Correlators in Real Time Optical Information Processing (Academic Press Inc., San Diego, CA, 1994), pp. 115–183.

Oulamara, A.

A. Oulamara et al., “Subpixel speckle displacement measurement using a digital processing technique.” Journal of Modern Optics 35(7), 1201–1211 (1988).
[CrossRef]

Painchaud, D.

Tribillon, G.

C. Gorecki, G. Tribillon, “Speckle displacement analysis by phase correlation using a SLM-based processor,” Journal of Modern Optics 40(6). 973–978 (1993).
[CrossRef]

Appl. Opt.

Journal of Modern Optics

C. Gorecki, G. Tribillon, “Speckle displacement analysis by phase correlation using a SLM-based processor,” Journal of Modern Optics 40(6). 973–978 (1993).
[CrossRef]

A. Oulamara et al., “Subpixel speckle displacement measurement using a digital processing technique.” Journal of Modern Optics 35(7), 1201–1211 (1988).
[CrossRef]

Other

B. Javidi, Nonlinear Joint Transform Correlators in Real Time Optical Information Processing (Academic Press Inc., San Diego, CA, 1994), pp. 115–183.

Cited By

OSA participates in CrossRef's Cited-By Linking service. Citing articles from OSA journals and other participating publishers are listed here.

Alert me when this article is cited.


Figures (3)

Figure 1
Figure 1

Output plane of digital BJTC.

Figure 2
Figure 2

experimental arrangement.

Figure 3
Figure 3

Experimental measurements.

Equations (4)

Equations on this page are rendered with MathJax. Learn more.

E ( α ,   β ) = S 2 ( α ,   β ) + R 2 ( α ,   β ) + 2 R ( α ,   β )   S ( α ,   β )   cos   ( 2 x 0 α + ϕ R ϕ s )
g ( α ,   β ) = { 1 1 E ( α ,   β )     V T o t h e r w i s e .
V T = S 2 ( α ,   β ) + R 2 ( α ,   β ) .
g ( α ,   β ) = R ( α ,   β )   S ( α ,   β )   cos [ 2 x 0 α + ϕ S ( α ,   β ) ϕ R ( α ,   β ) ] .

Metrics