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Figure 1
Image formation and CTF. A common wavefield (phase shift 0.5 rad, β/δ = 0.05) is propagated with fresnelPropagate(wavefield, F) to different Fresnel numbers F. A shot noise of 50 photons pixel−1 is introduced (lower-right half) to the holograms with addPoisson Noise(hologram, 50). (a) Hologram in the direct-contrast regime (F = 0.1). (b) Hologram in the holographic regime (F = 0.005). (c, d) Radially averaged power spectral density, obtained by angular Average(powerSpectralDensity(hologram)), of the noisy and clean holograms in both regimes. The CTF (weak object approximation) is also drawn. Similar graphs can be quickly produced with checkFresnelNumber(hologram, F) to verify the Fresnel numbers of experimental data. The wavefield was obtained by exponentiating the phantom [{\tt{getPhantom('irp')}}].

Journal logoJOURNAL OF
SYNCHROTRON
RADIATION
ISSN: 1600-5775
Volume 27| Part 3| May 2020| Pages 852-859
https://doi.org/10.1107/S1600577520002398
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