View source: R/continuum_features.R

bdri | R Documentation |

Calculate band depth ratio indices for objects of class `Specfeat`

.

bdri(x, fnumber, index = "ndbi")

`x` |
Object of class |

`fnumber` |
Integer. Index of feature to modify. |

`index` |
Method to be applied. Currently, |

Method `"bdr"`

calculates the normalised band depth ratio as

*bdr=\frac{BD}{Dc},*

with *BD* is the band depth calculated by `transformSpeclib`

and Dc is the maximum band depth called band centre.
Method `"ndbi"`

calculates the the normalised band depth index as

*ndbi= \frac{BD-Dc}{BD+Dc}.*

Method `"bna"`

calculates the band depth normalised to band area as

*bna=\frac{BD}{Da},*

where *Da* is the area of the absorption feature (see
`feature_properties`

). For further information see Mutanga and Skidmore (2004).

Object of class `specfeat`

containing the updated version of x.

Lukas Lehnert and Hanna Meyer

Mutanga, O. and Skidmore, A. (2004): Hyperspectral band depth analysis for a better estimation of grass biomass (`Cenchrus ciliaris`) measured under controlled laboratory conditions. International Journal of applied Earth Observation and Geoinformation, 5, 87-96

`transformSpeclib`

, `specfeat`

data(spectral_data) ## Transform speclib bd <- transformSpeclib(subset(spectral_data, season == "summer"), method = "sh", out = "bd") ## Isolate the features around 450nm, 700nm, 1200nm and 1500nm and ## convert to specfeat. featureSelection <- specfeat(bd, c(450,700,1200,1500)) ## Plot features plot(featureSelection,1:4) ## Calculate normalized band depth index for first feature featureSelection_bdri <- bdri(featureSelection, 1, index = "ndbi") ## Plot result plot(featureSelection_bdri)

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