Object wave retrieval using normalized holograms in three-step generalized phase-shifting digital holography.

Phase-shifting methods using interferogram normalization are often applied to smooth objects, for which the requirements for the normalization approach, including zero-order term elimination and the norm approximation condition, are easily achieved. Here we propose a three-step generalized phase-shifting method using the normalization approach for diffuse objects. In the proposed method, the zero-order terms are sufficiently suppressed by mutual subtraction of the phase-shifted holograms.

Color-image reconstruction for two-wavelength digital holography using a generalized phase-shifting approach.

We propose a color-image reconstruction method for two-wavelength digital holography using generalized phase-shifting digital holography (GPSDH). In this method, color interference fringes are captured by a digital camera with a Bayer array color filter, and phase shifting is simultaneously performed for all wavelengths. Color interference fringes are separated into three monochromatic interference fringes using a color-separation method that suppresses the color-filter crosstalk.

Statistical generalized phase-shifting digital holography with a continuous fringe-scanning scheme.

We propose a novel statistical generalized phase-shifting digital holography using a continuous fringe-scanning scheme. In this method, the continuous fringe-scanning scheme is implemented using a PC-based measurement system without any synchronous circuit between the digital camera and the phase shifter. Thus, nonuniformly phase-shifted interference fringes are captured sequentially because of the fluctuation of the image-capturing interval.

Robust phase-shift estimation method for statistical generalized phase-shifting digital holography.

We propose a robust phase-shift estimation method for statistical generalized phase-shifting digital holography using a slightly off-axis optical configuration. The phase randomness condition in the Fresnel diffraction field of an object can be sufficiently established by the linear phase factor of the oblique incident reference wave. Signed phase-shift values can be estimated with a statistical approach regardless of the statistical properties of the Fresnel diffraction field of the object.

Phase determination method in statistical generalized phase-shifting digital holography.

A simple estimation method of the relative phase shift for generalized phase-shifting digital holography based on a statistical method is proposed. This method consists of a selection procedure of an optimum cost function and a simple root-finding procedure. The value and sign of the relative phase shift are determined using the coefficient and the solution of the optimum cost function.

Indirect synthesis of interference terms in digital holography.

We propose a numerical wavefront manipulation method for synthesizing a new interference term from two digital holograms recorded using the same reference wavefront. The interference term of interest is synthesized indirectly, and its reconstructed image is unaffected by the reference wavefront used during hologram recording. We present experimental results of the indirect synthesis of the interference term corresponding to the lensless Fourier hologram using the Fresnel hologram.