Agreement between two masks

Per-class Dice and Jaccard (IoU) plus an overall accuracy and Cohen's kappa, comparing a reference mask a against a second mask b (e.g. an annotatR mask against a .npy ground truth, or two annotators). Classes are matched by integer value, so both masks must use the same class codebook.

Usage

at_mask_agreement(
  a,
  b,
  background = 0L,
  labels = NULL,
  call = rlang::caller_env()
)

Arguments

a

Reference annot_mask or integer matrix.

b

Comparison annot_mask or integer matrix, same dimensions as a.

background

Integer value treated as unlabeled/background and excluded from the per-class rows (still counted for overall accuracy/kappa). Default 0.

labels

Optional named vector or legend tibble (value, label) overriding the reference legend for class labels.

call

The calling environment, for error reporting.

Value

A tibble::tibble with one row per class: value, label, n_true, n_pred, tp, fp, fn, dice, iou. The overall attribute is a list of accuracy, kappa, mean_dice, mean_iou, and n_px.

See also

at_mask(), at_read_npy()

Other masks: at_mask(), at_mask_boundary(), at_mask_derive(), at_mask_legend(), at_mask_preview(), at_mask_stack(), at_mask_stats(), at_read_mask(), at_read_npy(), at_write_mask(), at_write_masks(), at_write_npy()

Examples

m <- at_mask(at_example_project(), "multiclass")
ag <- at_mask_agreement(m, m)
attr(ag, "overall")$kappa
#> [1] 1