Job: Select Volume

Select a volume and corresponding particle stack based on resolution.

At a Glance

Automatically select the highest resolution volume out of a number of input volumes, and output the best volume with its corresponding particle stack. This job can be useful for automated selection between multiple refinements with different parameters, for example CTF refinement parameters, masking parameters, etc.

Description

This job type inputs multiple volume-particle stack pairs. The job also takes in a single mask. The resolution of each volume is computed using the mask, and the volume with the highest resolution (measured using area-under-FSC-curve) is selected. The selected volume and its corresponding particle stack is output.

When to use Select Volume

You can use Select Volume to automate scenarios where you would run multiple refinements in parallel, and select the best result for downstream processing. For example:

• Run multiple refinement jobs with various CTF refinement parameters enabled. Connect the outputs of all these refinements to a Select Volume job, and then connect the output of Select Volume to a downstream step such as Reference-based Motion Correction. By doing so, the refinement that produces the best resolution will be selected, and the particles that are passed on to the downstream job will have the corresponding higher-order CTF aberrations corrected.

• Run multiple refinements with different input particle stacks, and use Select Volume to automatically carry forward the best input stack for downstream processing. For example, run two refinements, one with a full set of particles, and one with a subset chosed by Subset Particles by Statistic. Select Volume will select the refinement with the best resolution, and pass those particles on for downstream steps.

Inputs

Before connecting inputs, set the Number of inputs to compare parameter based on how many volumes you wish to compare.

Mask

A single mask that will be used to compute FSC curves for all input volumes.

Input volume X

Multiple of these inputs will be created when you set the Number of inputs to compare parameter. Each one takes in a volume, requiring the full map and two half-maps.

Particle stack X

The input particles corresponding to input volume X. The selected volume and corresponding particle stack are output unchanged by the job.

Commonly Adjusted Parameters

Number of inputs to compare

Sets the number of volume+particle stack inputs to compare.

Outputs

Volume

This is an unchanged copy of the selected input volume.

Particles

This is an unchanged copy of the input particle stack corresponding to the selected volume.