imagefx (version 0.4.1)

build.gaus: Build 2D Gaussian Image (Matrix)

Description

Build a 2-dimensional Gaussian matrix for filtering, correlations, data testing, or other various uses.

Usage

build.gaus(xdim, ydim, sig.x, sig.y, x.mid, y.mid)

Arguments

xdim

size in the x dimension

ydim

size in the y dimension

sig.x

Gaussian sqrt(variance) in x direction

sig.y

Gaussian sqrt(variance) in y direction. Defaults to sig.x if undefined

x.mid

peak location in x direction

y.mid

peak location in the y direction

Value

matrix with values corresponding to values in the 2D Gaussian.

Details

Note that if xdim or ydim are even and x.mid and y.mid are left undefined, the Gaussian peak will be off center. This can be a problem when using a Gaussian matrix for multiple filtering operations.

Examples

# NOT RUN {
############
### EG 1 ###
############

## define the dimensions of the gaussian image (matrix)
xdim=101
ydim=101

## sigma in the x direction.  The y sigma defaults to the sig.x if not supplied
sig.x=5

## build the first example
gaus1 <- build.gaus(xdim,ydim,sig.x)


###################
## PLOTTING EG 1 ##
###################
image(1:nrow(gaus1),1:ncol(gaus1),useRaster=TRUE,gaus1)


############
### EG 2 ###
############

## define the dimensions of the gaussian image (matrix)
xdim=101
ydim=201

## define a sigma in the both the x and y direction
sig.y=5
sig.y=20

## define the center (peak) location of the guassian
x.mid = 30
y.mid = 120

## now build the gaussian
gaus2 <- build.gaus(xdim,ydim,sig.x,sig.y,x.mid,y.mid)

##################
## PLOTTING EG2 ##
##################
image(1:nrow(gaus2),1:ncol(gaus2),useRaster=TRUE,gaus2)

# }