erode_mask_vol {fMRItools}

Erode 3D mask

Description

Erode a volumetric mask by a certain number of voxel layers. For each layer, any in-mask voxel adjacent to at least one out-of-mask voxel is removed from the mask.

Usage

erode_mask_vol(vol, n_erosion = 1, out_of_mask_val = NA)

Arguments

vol

The 3D array to erode. The mask to erode is defined by all values not in out_of_mask_val.

n_erosion

The number of layers to erode the mask by. Default: 1.

out_of_mask_val

A voxel is not included in the mask if and only if its value is in this vector. The first value of this vector will be used to replace eroded voxels. Default: NA. If vol is simply a logical array with TRUE values for in-mask voxels, use out_of_mask_val=FALSE.

Details

Diagonal voxels are not considered adjacent, i.e. the voxel at (0,0,0) is not adjacent to the voxels at (1,1,0) or (1,1,1), although it is adjacent to (1,0,0).

Value

The eroded vol. It is the same as vol, but eroded voxels are replaced with out_of_mask_val[1].