derivative_speclib: Derivation In hsdar: Manage, Analyse and Simulate Hyperspectral Data

Description

Calculate derivations of spectra

Usage

 1 derivative.speclib(x, m = 1, method = "sgolay", ...) 

Arguments

 x Object of class Speclib. m Return the m-th derivative of the spectra. method Character string giving the method to be used. Valid options are "finApprox" or "sgolay". ... Further arguments passed to sgolayfilt.

Details

Two different methods are available:

• Finite approximation (finApprox):

\frac{dr}{dλ}=\frac{r(λ_i)-r(λ_{i+1})}{Δλ},

where r_i is the reflection in band i and Δλ the spectral difference between adjacent bands.

• Savitzky-Golay derivative computation (sgolay)

Value

Object of class Speclib.

Lukas Lehnert

References

Tsai, F. & Philpot, W. (1998): Derivative analysis of hyperspectral data. Remote Sensing of Environment 66/1. 41-51.

sgolayfilt, vegindex

Examples

  1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 data(spectral_data) ## Calculate 1st derivation d1 <- derivative.speclib(spectral_data) ## Calculate 2nd derivation d2 <- derivative.speclib(spectral_data, m = 2) ## Calculate 3rd derivation d3 <- derivative.speclib(spectral_data, m = 3) par(mfrow=c(2,2)) plot(spectral_data) plot(d1) plot(d2) plot(d3) 

hsdar documentation built on May 20, 2017, 4:03 a.m.

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