Apply a median filter to a matrix

For each element in a matix, replace it with the median of the values around it.

Usage

medianFilter(x, mrad, nrad)

Arguments

x

numeric matrix to median filter

mrad

number of rows on either side of the value to use for median calculation

nrad

number of rows on either side of the value to use for median calculation

Value

A matrix whose values have been median filtered

Author

Colin A. Smith, csmith@scripps.edu

Examples

mat <- matrix(1:25, nrow=5)
mat
#>      [,1] [,2] [,3] [,4] [,5]
#> [1,]    1    6   11   16   21
#> [2,]    2    7   12   17   22
#> [3,]    3    8   13   18   23
#> [4,]    4    9   14   19   24
#> [5,]    5   10   15   20   25
medianFilter(mat, 1, 1)
#>      [,1] [,2] [,3] [,4] [,5]
#> [1,]  4.0  6.5 11.5 16.5 19.0
#> [2,]  4.5  7.0 12.0 17.0 19.5
#> [3,]  5.5  8.0 13.0 18.0 20.5
#> [4,]  6.5  9.0 14.0 19.0 21.5
#> [5,]  7.0  9.5 14.5 19.5 22.0