Show all measurements that can be computed with measure().
Details
Returns names of all scalar-returning get_* functions that can be
used with measure().
Examples
available_measures()
#> [1] "area" "perim" "centroid_size"
#> [4] "centroid_size_norm" "circularity" "circularity_norm"
#> [7] "circularity_haralick" "length" "width"
#> [10] "elongation" "rectangularity" "convexity"
#> [13] "solidity" "rugosity" "compactness"
#> [16] "rectilinearity" "calliper"
