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 × 6
#>    id           coo       type   fake  price coo_circularity
#>    <chr>        <out>     <fct>  <fct> <dbl>           <dbl>
#>  1 brahma       (138 x 2) whisky a       3             0.466
#>  2 caney        (168 x 2) whisky a       1.2           0.482
#>  3 chimay       (189 x 2) whisky a       3.8           0.592
#>  4 corona       (129 x 2) whisky a       2.6           0.445
#>  5 deusventrue  (152 x 2) whisky a       1.1           0.478
#>  6 duvel        (161 x 2) whisky a       3.1           0.629
#>  7 franziskaner (124 x 2) whisky a       2.6           0.477
#>  8 grimbergen   (126 x 2) whisky a       2.9           0.544
#>  9 guiness      (183 x 2) whisky a       1.2           0.524
#> 10 hoegardeen   (193 x 2) whisky a       3.6           0.470
#> # ℹ 30 more rows
bot %>% measure(c("circularity", "circularity_haralick"))
#> # A tibble: 40 × 7
#>    id         coo       type  fake  price coo_circularity coo_circularity_hara…¹
#>    <chr>      <out>     <fct> <fct> <dbl>           <dbl>                  <dbl>
#>  1 brahma     (138 x 2) whis… a       3             0.466                   2.32
#>  2 caney      (168 x 2) whis… a       1.2           0.482                   2.37
#>  3 chimay     (189 x 2) whis… a       3.8           0.592                   2.94
#>  4 corona     (129 x 2) whis… a       2.6           0.445                   2.26
#>  5 deusventr… (152 x 2) whis… a       1.1           0.478                   2.40
#>  6 duvel      (161 x 2) whis… a       3.1           0.629                   3.12
#>  7 franziska… (124 x 2) whis… a       2.6           0.477                   2.36
#>  8 grimbergen (126 x 2) whis… a       2.9           0.544                   2.64
#>  9 guiness    (183 x 2) whis… a       1.2           0.524                   2.59
#> 10 hoegardeen (193 x 2) whis… a       3.6           0.470                   2.35
#> # ℹ 30 more rows
#> # ℹ abbreviated name: ¹​coo_circularity_haralick