Table 1.

Glossary of terms and symbols.

(u, v)	Detector column and row coordinates
(fv, fv)	Frequency coordinates corresponding to (u, v)
(x, y, z)	Spatial coordinates of the reconstructed image
(fx, fy, fz)	Frequency coordinates corresponding to (x, y, z)
f	Radial spatial frequency in the xy-plane;
	$f^2=f_x^2+f_y^2$
fN	Nyquist frequency
m	Total number of phase steps
mθ	Total number of projections of a CT acquisition
M	Geometric magnification factor
Nk	Measured photon density at phase step k
$N_{bk}^k$	Measured photon density at phase step k in the
	background scan
${\overline{N}}_0$	Mean photon density (per phase step) incident
	on the detector
μ	X-ray linear attenuation coefficient
δ	Decrement of the real part of refractive index
ε	Talbot-Lau interferometer efficiency factor
	(visibility of the modulation pattern)
ϕ	Phase shift of the modulation pattern
λ	X-ray wavelength
p2	Period of the modulation pattern
	and analyzer grating
zT	Fractional Talbot distance
do	G0-object distance
d1	G0-G1 distance
ai	Projection sampling interval along domain i
bi	Reconstr. sampling interval along domain i
T0	Transfer function due to finite focal spot
T3	Transfer function due to spread of optical
	photons
T5	Transfer function due to photodiode aperture
T10	Reconstruction kernel
T11	Apodization filter
T12	Interpolation filter
T13	Backprojection transfer function
Θ13	Backprojection transfer function of the noise
Sa	3D NPS of ACT
Sdpc	3D NPS of DPC-CT
Ta	3D MTF of ACT
Tdpc	3D MTF of DPC-CT
NEQa	3D NEQ of ACT
NEQdpc	3D NEQ of DPC-CT
Cg	Absorption-to-DPC geometric scaling factor