Resolution estimation

The resolution of each micrograph is estimated by comparing it to projections of reconstructions of the tilt series according to the method of Cardone et al. (2005) and described (btomres) in Heymann (2007) and Heymann (2018).

This requires the alignment and CTF parameters, but can be done before a full tomogram is calculated. The fast option uses only a few adjacent micrographs in the tilt series to calculate projections and is recommended to save time.

The CTF correction is done for each micrograph during the analysis.

Estimating the resolution for one micrograph: NLOO-2D

If the -micrograph option is used, only the selected micrograph will be analyzed.

Options

• -micrograph: The micrograph number selected for analysis.
• -size: Size of the tomogram.
• -fast: Angular limit for micrographs included in calculating projections (°)
• -CTF: Contrast transfer function correction applied to a micrograph.
• -resolution: Maximum resolution in the tomogram (in Å).
• -cutoff: The threshold in the FSC curve to estimate the resolution.
• -Postscript: NLOO-2D plot.

Estimating the resolution for a tilt series: NLOO-3D

If the -micrograph option is not specified, all the micrographs in the tilt series will be analyzed sequentially. The output Postscript file will then contain two plots. The first shows the resolution versus the tilt angle, while the second shows the NLOO-3D curve.

Using script

The resolution for each micrograph with respect to the reconstruction can be determined using the script tomres.