searchlight: Create an exhaustive searchlight iterator

In neuroim2: Data Structures for Brain Imaging Data

Create an exhaustive searchlight iterator

Description

This function generates an exhaustive searchlight iterator that returns either voxel coordinates or ROIVolWindow objects for each searchlight sphere within the provided mask. The iterator visits every non-zero voxel in the mask as a potential center voxel.

Usage

searchlight(mask, radius, eager = FALSE, nonzero = FALSE, cores = 0)

Arguments

mask	A NeuroVol object representing the brain mask.
radius	A numeric value specifying the radius (in mm) of the spherical searchlight.
eager	A logical value specifying whether to eagerly compute the searchlight ROIs. Default is FALSE, which uses lazy evaluation.
nonzero	A logical value indicating whether to include only coordinates with nonzero values in the supplied mask. Default is FALSE.
cores	An integer specifying the number of cores to use for parallel computation. Default is 0, which uses a single core.

Value

A deferred_list object containing either matrices of integer-valued voxel coordinates or ROIVolWindow objects, each representing a searchlight region.

Examples

# Load an example brain mask
mask <- read_vol(system.file("extdata", "global_mask_v4.nii", package="neuroim2"))

# Generate an exhaustive searchlight iterator with a radius of 6 mm

searchlights <- searchlight(mask, radius = 6, eager = FALSE)

neuroim2 documentation built on April 11, 2025, 5:46 p.m.