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Journal of the Optical Society of America A

Journal of the Optical Society of America A


  • Vol. 21, Iss. 4 — Apr. 1, 2004
  • pp: 632–639

Direct demodulation of Hartmann–Shack patterns

Amos Talmi and Erez N. Ribak  »View Author Affiliations

JOSA A, Vol. 21, Issue 4, pp. 632-639 (2004)

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Hartmann–Shack wave-front sensors produce a distorted grid of spots whose deviation from perfection is linear with the wave-front gradient. Usually, the centroid of each spot is calculated to provide that deviation, but it is also possible to perform the calculation by Fourier demodulation of the spot pattern [Opt. Commun. 215, 285, 2003]. We show that this demodulation can be performed directly on the grid, without reverting to Fourier transforms. Tracking the motion of each centroid individually is limited to well-defined spots with motions smaller than their pitch. In contrast, our method treats the image as a whole, is not limited to nonoverlapping or sharp spots, and allows large spot motions. By replicating the array of spots slightly beyond the edge of the aperture, we reduce the chance for boundary phase dislocations in the reconstruction of the wave front. The method is especially suited to very large arrays.

© 2004 Optical Society of America

OCIS Codes
(010.1080) Atmospheric and oceanic optics : Active or adaptive optics
(010.7350) Atmospheric and oceanic optics : Wave-front sensing
(100.2650) Image processing : Fringe analysis
(100.5070) Image processing : Phase retrieval
(150.0150) Machine vision : Machine vision
(220.4840) Optical design and fabrication : Testing

Original Manuscript: July 17, 2003
Revised Manuscript: October 27, 2003
Manuscript Accepted: December 3, 2003
Published: April 1, 2004

Amos Talmi and Erez N. Ribak, "Direct demodulation of Hartmann–Shack patterns," J. Opt. Soc. Am. A 21, 632-639 (2004)

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