R: Calculate a normalized index.

normalized_diff_ind {photobiology} | R Documentation

## Calculate a normalized index.

### Description

This function returns a normalized difference index value for an arbitrary pair of wavebands.

### Usage

    normalized_diff_ind(spct, plus.w.band, minus.w.band, f, ...)

### Arguments

`spct` | an R object
`plus.w.band` | waveband objects The waveband determine the region of the spectrum used in the calculations
`minus.w.band` | waveband objects The waveband determine the region of the spectrum used in the calculations
`f` | function used for integration taking spct as first argument and a list of wavebands as second argument.
`...` | additional arguments passed to f

### Value

A numeric value for the index

### Note

`f` is most frequently `reflectance`, but also `transmittance`, or even `absorbance`, `response`, `irradiance` or a user-defined function can be used if there is a good reason for it. In every case `spct` should be of the class expected by `f`. When using two wavebands of different widths do consider passing to `f` a suitable `quantity` argument. Wavebands can describe weighting functions if desired.

[Package photobiology version 0.9.21 Index]