oce (version 1.7-10)

matrixSmooth: Smooth a Matrix

Description

The values on the edge of the matrix are unaltered. For interior points, the result is defined in terms in terms of the original as follows. \(r_{i,j} = (2 m_{i,j} + m_{i-1,j} + m_{i+1,j} + m_{i,j-1} + m_{i,j+1})/6\). Note that missing values propagate to neighbours.

Usage

matrixSmooth(m, passes = 1)

Value

A smoothed matrix.

Arguments

m

a matrix to be smoothed.

passes

an integer specifying the number of times the smoothing is to be applied.

Author

Dan Kelley

Examples

library(oce)
opar <- par(no.readonly = TRUE)
m <- matrix(rep(seq(0, 1, length.out=5), 5), nrow=5, byrow=TRUE)
m[3, 3] <- 2
m1 <- matrixSmooth(m)
m2 <- matrixSmooth(m1)
m3 <- matrixSmooth(m2)
par(mfrow=c(2, 2))
image(m,  col=rainbow(100), zlim=c(0, 4), main="original image")
image(m1, col=rainbow(100), zlim=c(0, 4), main="smoothed 1 time")
image(m2, col=rainbow(100), zlim=c(0, 4), main="smoothed 2 times")
image(m3, col=rainbow(100), zlim=c(0, 4), main="smoothed 3 times")
par(opar)