We present autofocusing in optical scanning holography (OSH) with experimental results. We first record the complex hologram of an object using OSH and then create the Fresnel zone plate (FZP) that codes the object constant within the depth range of the object using Gaussian low-pass filtering. We subsequently synthesize a real-only spectrum hologram in which its phase term contains information about a distance parameter. Finally, we extract the distance parameter from the real-only spectrum hologram using fringe-adjusted filtering and the Wigner distribution. Using the extracted distance parameter, we reconstruct a three-dimensional image of the object from the complex hologram using digital convolution, which bypasses the conventional blind convolution to reconstruct a hologram. To the best of our knowledge, this is the first report with experimental results that autofocusing in OSH is possible without any searching algorithm or tracking process.
© 2009 Optical Society of America
Original Manuscript: July 13, 2009
Revised Manuscript: October 12, 2009
Manuscript Accepted: October 12, 2009
Published: November 3, 2009
Taegeun Kim and Ting-Chung Poon, "Autofocusing in optical scanning holography," Appl. Opt. 48, H153-H159 (2009)