Abstract

The evaluation of double-exposure records in optical metrology (speckle photography or particle image velocimetry) is simplified by using two-step optical processing that is performed on many interrogation areas simultaneously by a 2-D array of narrow focused light beams. A first application of this procedure to the original record, if dimensioned properly, produces an array of small nonoverlapping Young’s fringe systems. The photographic record of these patterns is subjected to the same operation once more, each beam illuminating precisely one pattern. The resulting output is an array of autocorrelation functions that are a direct representation of the displacement field since the spacing of respective side peaks gives the displacement. A single whole-field interrogation of the array of fringe systems produces an optical representation of accumulated displacement values thus rendering the statistics of the displacement field. The required matrix of light beams is generated by holographic optical elements.

© 1989 Optical Society of America

Fringe positions in double-exposure speckle photography

K. Hinsch
Appl. Opt. 28(24) 5298-5304 (1989)

Range and accuracy of speckle displacement measurement in double-exposure speckle photography

Jin Seung Kim
J. Opt. Soc. Am. A 6(5) 675-681 (1989)

Analysis and design of an anamorphic optical processor for speckle metrology and velocimetry

Steven H. Collicott and Lambertus Hesselink
Appl. Opt. 31(10) 1646-1659 (1992)

Measurement of time-varying displacement fields by multiple-exposure speckle photography

J. M. Huntley and J. E. Field
Appl. Opt. 25(10) 1665-1669 (1986)

Double exposure speckle technique for imaging system analysis and use in rod lens arrays

Shinichi Komatsu, Katsuto Sumi, and Hitoshi Ohzu
Appl. Opt. 28(10) 1869-1873 (1989)