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Plot a face mask for visual verification

Source: R/face_mask.R
plot_face_mask.Rd

Renders a face mask so you can confirm it covers the region you intended before passing it to diagnose_infoval() or infoval(). Accepts the same input forms the diagnostics accept: a logical or numeric vector (column-major, with img_dims supplied), a logical/numeric matrix, or a path to a PNG/JPEG mask file.

Usage

plot_face_mask(
  mask,
  img_dims = NULL,
  base_image = NULL,
  alpha = 0.5,
  col = "red",
  threshold = 0.5,
  main = NULL,
  ...
)

Arguments

mask

One of: a logical or numeric vector of length prod(img_dims) (column-major, as returned by face_mask() or load_face_mask()); a logical or numeric matrix; or a path to a PNG/JPEG mask file.

img_dims

Integer c(nrow, ncol), or a single integer for a square image. Required when mask is a vector; ignored otherwise.

base_image

Optional path to a PNG or JPEG base face. When supplied, the mask is rendered as a translucent overlay on top.

alpha

Numeric in [0, 1]. Overlay opacity. Default 0.5.

col

Highlight colour for the masked region. Default "red".

threshold

When mask is a numeric matrix or image path, pixels strictly above this value are treated as inside the mask. Default 0.5. Ignored for logical input.

main

Optional plot title.

...

Reserved for future use.

Value

Invisibly returns the resolved logical matrix (nrow x ncol, top-left origin).

Details

If base_image is supplied, the mask is drawn as a translucent overlay on top of the base face — the most useful view for verifying that the mask aligns with eyes, nose, mouth, etc. The base image must have the same dimensions as the mask; otherwise the base is dropped with a warning.

See also

face_mask(), load_face_mask(), diagnose_infoval().

Examples

m <- face_mask(c(128L, 128L), region = "eyes")
plot_face_mask(m, img_dims = c(128L, 128L), main = "eyes region")