Cumulative Spectral Change — hsa_spectral

Sums the absolute change between consecutive bands at every pixel, giving a field of total spectral variability. Flat spectra appear dark; pixels whose reflectance swings across the spectrum appear bright.

Usage

hsa_spectral_flux(
  cube,
  palette = "inferno",
  normalise = TRUE,
  stretch = c("percentile", "range", "none"),
  probs = c(0.02, 0.98)
)

Arguments

cube: An hsi_cube (from hyperspectR) or a 3-D array with dimensions (rows, cols, bands).
palette: Palette name passed to hsa_palette().
normalise: Logical. Divide by the number of band steps, so the value is a mean absolute step rather than a total. Default TRUE, which makes cubes with different band counts comparable.
stretch: Contrast stretch: "percentile" (default), "range" or "none".
probs: Percentiles for stretch = "percentile". Default c(0.02, 0.98).

Value

A ggplot2 object.

Details

Unlike a single-band image this cannot be produced from any one wavelength, and unlike a variance map it is sensitive to the ordering of the bands, so it responds to spectral shape rather than spread alone.

Examples

cube <- hsa_demo_cube()
hsa_spectral_flux(cube)