tofsims (version 1.0.2)

poissonScaling: generic method for "poissonScaling"

Description

generic method for "poissonScaling"

Possion scaling for data matrices.

Usage

poissonScaling(object, offset = 1, ...)
## S3 method for class 'MassSpectra':
poissonScaling(object, offset = 1, ...)

Arguments

object

object of class MassSpectra

offset

numeric value for poisson scaling

...

further args

Value

• object of class MassSpectra with poission scaled mass spectra in slot nz

  object of class MassSpectra

Details

Possion scaling is proposed as the method of choice for ToF-SIMS data see Keenan and Kotula 2004. This implementation was done according to a description in Multivariate Analysis of SIMS spectra in ToF-SIMS: Materials Analysis by Mass Spectrometry, Vickerman and Briggs 2013 and the eigenvector wiki. The offset is described in the eigenvector wiki.

Examples

## poisson scaling of MassSpectra objects
testImage <- MassImage('dummy')
testImage <- poissonScaling(testImage)
# poission scaling on real data
library(tofsimsData)
data(tofsimsData)
par(mfcol=c(2,2))
plot(testImage,type='l')
image(testImage)
testImage <- poissonScaling(testImage)
plot(testImage,type='l')
image(testImage)