prep_resample: Resampling constructor for spectral preprocessing

In proximetricsR: Spectral Preprocessing and Chemometric Calibration of NIR Sensors

Resampling constructor for spectral preprocessing

Description

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Creates a preprocessing constructor for resampling spectral data to a new wavelength grid. The constructor is intended to be passed to preprocess_recipe and executed via process.

Usage

prep_resample(grid)

Arguments

grid

Either a numeric vector of length 3 specifying the target wavelength grid as c(min_wav, max_wav, resolution), or the character string "proxiscout" to resample to the standard NeoSpectra wavenumber grid (see Details). When grid is a numeric vector: grid[1] (min_wav): minimum wavelength of the target grid. grid[2] (max_wav): maximum wavelength; must be greater than min_wav. grid[3] (resolution): spacing between wavelengths; must be positive. Extrapolation beyond the range of the input wavelengths is never allowed.

Details

User-defined grid (grid = c(min_wav, max_wav, resolution)): resamples spectra to the specified target grid using natural spline interpolation via resample. Column names of X must be coercible to numeric wavelength values. This mode is compatible with the "proximate" device.

NeoSpectra grid (grid = "proxiscout"): resamples spectra to the standard wavenumber grid of NeoSpectra NIR scanners (approx. 3921.569 to 7407.407 cm^{-1}, ~256 channels at ~13.617 cm^{-1} steps). Only wavenumbers overlapping with the input range are retained. This mode is compatible with the "proxiscout" device.

Value

An object of class preprocessing to be used in preprocess_recipe and executed by process.

Author(s)

Leonardo Ramirez-Lopez and Claudio Orellano

See Also

preprocess_recipe, process, get_proxiscout_wavenumbers

Examples

data("proximateCannabis")
X <- proximateCannabis$spc

# User-defined grid (proximate)
rs <- prep_resample(grid = c(1001, 1700, 2))
recipe <- preprocess_recipe(rs, device = "proximate")
X_rs <- process(X, recipe)

proximetricsR documentation built on Sept. 4, 2026, 5:08 p.m.