Get circularity measures

Calculate circularity (isoperimetric quotient) and related shape descriptors.

Usage

get_circularity(x, ..., .cols = NULL)

get_circularity_norm(x, ..., .cols = NULL)

get_circularity_haralick(x, ..., .cols = NULL)

Arguments

x

A matrix (nx2), list of matrices, or tibble with coo columns.

...

Additional arguments (reserved for future use).

.cols

Column name(s) to process when x is a tibble. If NULL, automatically detects columns containing coo objects.

Value

• If x is a single matrix: returns a numeric scalar

• If x is a list: returns a numeric vector

• If x is a tibble: returns a numeric vector extracted from coo column

Details

Circularity measures:

• get_circularity(): Isoperimetric quotient = 4π × Area / Perimeter². Value of 1 for a perfect circle, < 1 for other shapes.

• get_circularity_norm(): Normalized version = Area / (Perimeter²/(4π)). Alternative formulation, same interpretation.

• get_circularity_haralick(): Mean(radii) / SD(radii) from centroid. Higher values = more circular. Sensitive to irregularities.

All measures equal 1 for perfect circles and decrease for other shapes.

See also

measure() for adding measurement columns

Examples

get_circularity(shapes$cat)
#> [1] 0.3149543
get_circularity_norm(shapes$cat)
#> [1] 0.3149543
get_circularity_haralick(shapes$cat)
#> [1] 2.835053

# Use in measure()
bot %>% measure("circularity")
#> # A tibble: 40 × 4
#>    coo       type   dummy coo_circularity
#>    <out>     <fct>  <fct>           <dbl>
#>  1 (138 x 2) whisky a               0.466
#>  2 (168 x 2) whisky a               0.482
#>  3 (189 x 2) whisky a               0.592
#>  4 (129 x 2) whisky a               0.445
#>  5 (152 x 2) whisky a               0.478
#>  6 (161 x 2) whisky a               0.629
#>  7 (124 x 2) whisky a               0.477
#>  8 (126 x 2) whisky a               0.544
#>  9 (183 x 2) whisky a               0.524
#> 10 (193 x 2) whisky a               0.470
#> # ℹ 30 more rows
bot %>% measure(c("circularity", "circularity_haralick"))
#> # A tibble: 40 × 5
#>    coo       type   dummy coo_circularity coo_circularity_haralick
#>    <out>     <fct>  <fct>           <dbl>                    <dbl>
#>  1 (138 x 2) whisky a               0.466                     2.32
#>  2 (168 x 2) whisky a               0.482                     2.37
#>  3 (189 x 2) whisky a               0.592                     2.94
#>  4 (129 x 2) whisky a               0.445                     2.26
#>  5 (152 x 2) whisky a               0.478                     2.40
#>  6 (161 x 2) whisky a               0.629                     3.12
#>  7 (124 x 2) whisky a               0.477                     2.36
#>  8 (126 x 2) whisky a               0.544                     2.64
#>  9 (183 x 2) whisky a               0.524                     2.59
#> 10 (193 x 2) whisky a               0.470                     2.35
#> # ℹ 30 more rows