
Uncertainty in Phase Measurements ◾ 323
Replacing the covariance terms by Equation (9.19), we can formally
write these sums using the convolutions
∑
∑
φ= ∗+ ∗
∂
∂
−∗
∂
∂
=⋅−φ =ℑ
Γ
−φ
()
1
()
() (,)sin()[()]
2
222
22
2
2
2
2
u
SM N
huSh
S
g
h
S
g
ug
hH eh
l
l
i
pfpp
(9.67)
9.7.3 Uncertainty from Uncorrelated Influences
When contributions that are uncorrelated among pixels but have identical
variance such as electron noise are inserted into Equation (9.67), this leads to
()
φ= ∗=
(, )
1()
{1}
1
{[](0)}
2
2
2
22
2
2
uuncorr
S
uS
MN
h
S
uSFT h
(9.68)
where we have used the fact that convolution of a function with the unit func-
tion is proportional to ...