Parallel two-step phase-shifting digital holography.
We propose a parallel two-step phase-shifting digital holography technique capable of instantaneous measurement of three-dimensional objects, with a view toward measurement of dynamically moving objects. The technique is based on phase-shifting interferometry. The proposed technique carries out the two-step phase-shifting method at one time and can be optically implemented by using a phase-shifting array device located in the reference beam. The array device has a periodic two-step phase distribution, and its configuration is simplified compared with that required for three-step and four-step parallel phase-shifting digital holographies. Therefore the optical system of the proposed technique is more suitable for the realization of a parallel phase-shifting digital holography system. We conduct both a numerical simulation and a preliminary experiment in the proposed technique. The results of the simulation and the experiment agree well with those of sequential phase-shifting digital holography, and results are superior to those obtained by conventional digital holography using the Fresnel transform alone. Thus the effectiveness of the proposed technique is verified.
Awatsuji
Yasuhiro
Y
Division of Electronics, Kyoto Institute of Technology, Matsugasaki, Kyoto, Japan. awatsuji@kit.ac.jp
Tahara
Tatsuki
T
Kaneko
Atsushi
A
Koyama
Takamasa
T
Nishio
Kenzo
K
Ura
Shogo
S
Kubota
Toshihiro
T
Matoba
Osamu
O