The determination of numerical reconstruction distance is key to recover the wavefront at focal plane in digital holography. In this paper, we propose a new autofocus method based on angular spectrum method (ASM). The proposed method takes successive Fourier transform after 1^st order spectrum selection, and then calculates the summation. It saves operations compared to classic autofocus functions. When an exhaustive z-axis search is performed, the proposed method obtains unimodality coincided with the results from four classic autofocus functions. Moreover, the proposed method is more time-effective, which is the optimal one for ASM.

Date Published: 19 February 2015
PDF: 7 pages
Proc. SPIE 9449, The International Conference on Photonics and Optical Engineering (icPOE 2014), 94492H (19 February 2015); doi: 10.1117/12.2076853

Published in SPIE Proceedings Vol. 9449:
The International Conference on Photonics and Optical Engineering (icPOE 2014)
Ailing Tian; Anand Asundi; Weiguo Liu; Chunmin Zhang, Editor(s)