Validate Color Look-Up Table completeness

This function validates that a Color Look-Up Table (CLUT) provides complete and non-overlapping coverage of the HSV color space by testing every HSV coordinate against the CLUT definitions. Validation ensures each color maps to exactly one color class.

Usage

validate(clut = charisma::clut, simple = TRUE)

Arguments

clut

Data frame containing the Color Look-Up Table with HSV boundaries for each color class. Default is charisma::clut.

simple

Logical. If TRUE (default), tests a reduced HSV space with 1-degree increments (361 x 101 x 101 = 3,682,561 coordinates). If FALSE, uses finer 0.5-degree increments, which is more thorough but significantly slower and best suited for cluster computing.

Value

If validation passes, returns 0 and prints a success message. If validation fails, returns a data frame containing all HSV coordinates that either: (1) were not classified to any color, or (2) were classified to multiple colors (indicating overlap).

Details

The validation process:

1. Generates a complete grid of HSV color space coordinates

2. Uses parallel processing (all available cores - 1) to classify each coordinate using the CLUT definitions

3. Checks that each coordinate maps to exactly one color class

4. Reports any missing or duplicate classifications

Validation is essential when modifying the CLUT or creating custom CLUTs for different image datasets. The process can take several minutes even with simple = TRUE.

References

Schwartz, S.T., Tsai, W.L.E., Karan, E.A., Juhn, M.S., Shultz, A.J., McCormack, J.E., Smith, T.B., and Alfaro, M.E. (2025). charisma: An R package to perform reproducible color characterization of digital images for biological studies. (In Review).

See also

charisma for using validated CLUTs, color2label for color classification

Examples

if (FALSE) { # \dontrun{
# Validate the default CLUT (takes several minutes with parallel processing)

# Note: These examples are not run during R CMD check due to CRAN build
# limitations. With only 2 cores available during CRAN checks, validation
# can exceed 20 minutes.

result <- validate()

# Validate a custom CLUT
my_clut <- charisma::clut  # Start with default
# ... modify my_clut ...
result <- validate(clut = my_clut)

# More thorough validation (much slower, recommended for cluster computing)
result <- validate(simple = FALSE)
} # }