R: Compile dark object DN for given sensor band

calcDODN {satellite} | R Documentation

## Compile dark object DN for given sensor band

### Description

The function estimates the DN value of a "dark object" which is used for atmospheric correction using the DOS2 and DOS4 model. Therefore, the frequency distribution of the smallest 1% of the data values is analyzed and the value for which the first derivate has the absolute maximum is taken as the DN for a dark object.

### Usage

    ## S4 method for signature 'Satellite'
    calcDODN(x, bcde)

    ## S4 method for signature 'RasterLayer'
    calcDODN(x)

### Arguments

`x` | Satellite object or RasterLayer with sensor band data, e.g. returned by `getSatDataLayer`.
`bcde` | If 'x' is a Satellite object, a band code as character.

### Details

The DN for a dark object is extracted from a histogram similar to Chavez (1988).

### Value

Numeric value of the DN for the dark object.

### References

Chavez Jr PS (1988) An improved dark-object subtraction technique for atmospheric scattering correction of multispectral data. Remote Sensing of Environment 24/3, doi:10.1016/0034-4257(88)90019-3, available online at http://www.sciencedirect.com/science/article/pii/0034425788900193

### See Also

The DN is used by `calcPathRadDOS` for computing the path radiance based on the dark object method.

### Examples

    path <- system.file("extdata", package = "satellite")
    files <- list.files(path, pattern = glob2rx("LC08*.TIF"), full.names = TRUE)
    sat <- satellite(files)

    calcDODN(sat, bcde = "B002n")
    calcDODN(getSatDataLayer(sat, bcde = "B002n"))

[Package satellite version 1.0.1 Index]