DigitalHolography
Documentation for DigitalHolography.
DigitalHolography.GeneralizedPSDH
DigitalHolography.PSDH2
DigitalHolography.PSDH3
DigitalHolography.PSDH4
DigitalHolography.ParallelPSDH
When the object wave is denoted as $u_{o} = ae^{i\phi}$ and the reference wave as $u_{r} = be^{i\delta}$, the interference fringe $I$ can be represented as $I = |u_{o} + u_{r}|^{2} = a^{2} + b^{2} + 2ab\cos(\phi - \delta)$.
DigitalHolography.GeneralizedPSDH
— MethodGeneralizedPSDH(I)
return object wave extracted by the generalized phase-shifting method. See (Creath, 1988), (Schreiber and Bruning, 2006). Store N interferograms in a three-dimensional array as I[:,:,1]
, I[:,:,2]
, ..., I[:,:,N]
. Phase difference $\delta_{n}$ corresponding to the n-th interferogram is assumed to be $\delta_{n} = \dfrac{2\pi}{N}n$.
DigitalHolography.PSDH2
— MethodPSDH2(I₁, I₂, Iᵣ, δ)
return object wave extracted by the two-step phase-shifting method (see Ref. 1).
Arguments
I₁
,I₂
: Interferograms corresponding to phases $\phi$ and $\phi - \delta$, respectively.Iᵣ
: intensity of reference wave.δ
: phase difference $\delta$.
DigitalHolography.PSDH3
— MethodPSDH3(I₁, I₂, I₃, δ)
return object wave extracted by the three-step phase-shifting method (see Ref. 1, 2). Phases of I₁
, I₂
, and I₃
correspond to $\phi - \delta$, $\phi$, and $\phi + \delta$, respectively.
DigitalHolography.PSDH4
— MethodPSDH4(I₁, I₂, I₃, I₄)
return object wave extracted by the four-step phase-shifting method. See (Creath, 1988), (Schreiber and Bruning, 2006). Phase difference δ
corresponding to I₁
, I₂
, I₃
, and I₄
are assumed to be $\delta = 0, \dfrac{\pi}{2}, \pi$, and $\dfrac{3\pi}{2}$, respectively.
DigitalHolography.ParallelPSDH
— MethodParallelPSDH(I)
return object wave extracted by the parallel four-step phase-shifting method (see Ref. 1, 2). Using 2x2 pixels with phase differences of $\dfrac{\pi}{2}$ each as units, the object wave is extracted through the four-step phase-shifting method.
- Y. Awatsuji, M. Sasada, and T. Kubota, "Parallel quasi-phase-shifting digital holography," Appl. Phys. Lett., 85, 1069-1071 (2004).
- Yasuhiro Awatsuji, "Parallel Phase-Shifting Digital Holography," in Bahram Javidi, Enrique Tajahuerce, Pedro Andrés (eds.), Multi-Dimensional Imaging, John Wiley & Sons, Ltd, pp. 1-23