Quantitative Evaluation of Reconstructed Images of Parallel Phase-Shifting Digital Holographies

Parallel phase-shifting digital holography is a technique capable of instantaneous three-dimensional measurement and can simultaneously obtain the holograms required for phase-shifting digital holography. The number of phase shifts of the reference wave in holography is inversely proportional to the number of pixels per each hologram in the technique. The authors quantitatively evaluated the quality of the images reconstructed by the three kinds of the technique in terms of the number of phase shifts. The techniques were numerically simulated and mean square errors between the object image and the reconstructed images were calculated. It was found that higher quality image is attained by smaller number of phase shifts of reference wave in the technique. This is because the smaller the number of phase shifts is, the shorter the sampling interval of spatial frequency per each hologram is, and the more detailed information of object can be reconstructed.