Phase Estimation in Optical Interferometry

260 ◾ Abhijit Patil, Rajesh Langoju, and Pramod Rastogi

e formulation for the intensity data recorded at a pixel (x, y) for n = 0, 1,

2, … , N − 1 data frames in the presence of a nonlinear phase step is given by

∑

=+γϕ+α

















+η

=

κ

′

II kk

ndck

k

nn

1cos

()

,

1

(7.32)

where, for the nth data frame, I

dc

is the local background intensity, κ is

the number of harmonics, and γ

k

represents the fringe visibility of the kth

harmonic; φ and

′

α

n

represent the phase dierence and the phase shi,

respectively; and η

n

is the additive white Gaussian noise with mean zero

and variance σ

2

. For N data frames, the true phase shi

′

α

n

caused by non-

linear characterist ...