Dictionary: averaging

These commands average data in space or time.

average [new stack name] <volume list>

Average a series of volumes and put the result into a single-volume stack with the specified name.

average-stacks [new stack name] <stack list>

Average a series of stacks, each containing the same number of volumes, and put the result into the new stack that contains the same number of volumes as all other stacks in the list. The 1st time point of the new stack is the average of all 1st time points, and so on.

smooth-3d [resolution in mm] <volume list>

smooth-2d [resolution in mm] <volume list>

Perform isotropic 3-dimensional or 2-dimensional spatial smoothing on all volumes in the list (done is Fourier space using Gaussian multiplication).

flatten [fraction of FOV] <volume list>

Remove long-range variations in volumes by dividing each volume by a spatially smoothed version of itself, where the spatial smoothing is equal to the field of view divided by the argument entered into the command. This command mimics the RF-bias reduction used in jip-align.

average-by [# volumes in bin] [new stack name] <volume list>

Bin volumes in time by averaging across the number of selected volumes and assigning the resulting binned volume list to the new name.

average-epochs [# volumes in epoch] [new stack name] <volume list>

Create a average epoch from periodic data (e.g., block stimuli for fMRI).

average-space [integer width] [new stack name] <volume list>

standard-deviation-space [integer width] [new stack name] <volume list>

Create a new stack containing the same number of time points as the the volume list, where the result at each pixel is the either the average or standard deviation across a spatial mask of 3-dimensional width equal to ± the specified width.

Joseph B. Mandeville, Athinoula A. Martinos Center for Biomedical Imaging at MGH/MIT/Harvard