Publication Date:
2022-05-25
Description:
Author Posting. © Optical Society of America, 2007. This is the author's version of the work. It is posted here by permission of Optical Society of America for personal use, not for redistribution. The definitive version was published in Journal of the Optical Society of America A, 24 (2007): 3054-3062, doi:10.1364/JOSAA.24.003054.
Description:
In this paper a rapid focus detection technique is developed for objects imaged
using digital in-line holograms. It differs from previous approaches in that it is
based directly on the spectral content of the object images and does not need
a full reconstruction of the actual images. It is based on new focus metrics
defined as the l1 norms of the object spectral components associated with
the real and imaginary parts of the reconstruction kernel. Furthermore, these
l1 norms can be computed efficiently in the frequency domain using a polar
coordinate system, yielding a drastic speedup of about two orders of magnitude
compared with image-based focus detection. The subsequent reconstruction,
when done selectively over these detected focus distances, leads to significant
computational savings. Focus detection results from holograms of plankton are
demonstrated showing that the technique is both accurate and robust.
Repository Name:
Woods Hole Open Access Server
Type:
Preprint
Format:
application/pdf
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