Entropy of fixation patterns
fixation_entropy.default.RdThese methods quantify how concentrated or diffuse a fixation pattern is using Shannon entropy. For density maps, entropy is computed from the normalized density surface. For fixation groups, entropy can be computed from either a derived density map or a discrete occupancy grid.
Usage
# Default S3 method
fixation_entropy(x, ...)
# S3 method for class 'eye_density'
fixation_entropy(x, normalize = TRUE, base = exp(1), ...)
# S3 method for class 'density'
fixation_entropy(x, normalize = TRUE, base = exp(1), ...)
# S3 method for class 'eye_density_multiscale'
fixation_entropy(
x,
normalize = TRUE,
base = exp(1),
aggregate = c("mean", "none"),
...
)
# S3 method for class 'fixation_group'
fixation_entropy(
x,
normalize = TRUE,
base = exp(1),
method = c("density", "grid"),
sigma = NULL,
xbounds = NULL,
ybounds = NULL,
outdim = c(50, 50),
grid = c(10, 10),
duration_weighted = FALSE,
...
)Arguments
- x
The input object.
- ...
Additional arguments passed to `eye_density()` when `method = "density"`.
- normalize
Logical; if `TRUE` (default), divide entropy by the maximum possible entropy for the number of valid bins so results lie in `[0, 1]`.
- base
Logarithm base used in the Shannon entropy. Defaults to `exp(1)`; use `2` for bits.
- aggregate
For multiscale density objects, one of `"mean"` (default) or `"none"`.
- method
For `fixation_group` objects, one of `"density"` (default) or `"grid"`.
- sigma
Optional bandwidth for density-based entropy on fixation groups. If `NULL`, `suggest_sigma()` is used.
- xbounds, ybounds
Optional display bounds for fixation groups. If not supplied, the observed fixation ranges are used with a small padding.
- outdim
Grid dimensions for density-based entropy from fixation groups.
- grid
Grid dimensions for occupancy-grid entropy from fixation groups.
- duration_weighted
Logical; if `TRUE`, duration-weighted KDE is used for density-based entropy.