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Figure 9
The spectral signal-to-noise ratio (SSNR) for the PtIr specimen. (a) The SSNR for one micrograph from the series calculated from a movie taken with a total dose of 3.7 e Å−2. The noise spectrum is almost constant because of counting detection, resulting in a close correspondence between the signal and SSNR. The low-frequency spectrum (<0.4 Å−1) reflects scattering from the carbon film and the oscillations in the CTF. (b) The SSNR from the parabolic reconstruction show the same features but enhanced by n1/2 = (20)1/2 = 4.47. The prominent peaks are associated with the reflections from the PtIr nanocrystals.

IUCrJ
Volume 13| Part 1| January 2026| Pages 77-93
ISSN: 2052-2525
https://doi.org/10.1107/S2052252525010796