getsdofsb-methods.RdEstimate the noise standard deviation. Uses an assumption that the standard deviation
is a linear function of the expected mean for image intensities. qA0 and qA1 define quantiles of observed image intensities that define the range of values where this assumption is made.
# S4 method for dtiData
getsdofsb(object,qA0=.1,qA1=.98,nsb=NULL,level=NULL)| object | Object of class |
|---|---|
| qA0 | level for lower quantile of image intensities |
| qA1 | level for upper quantile of image intensities |
| nsb | number of diffusion weighted image to use |
| level | level for mask |
An object of class "dtiData" with results in slot sdcoef in components
5: intercept parameter, 6: slope parameter for linear model,
7: lower bound (depending on qA0) and 8: upper bound (depending on qA1).
signature(object) = "ANY"Returns a warning.
signature(object) = "dtiData"Returns a dtiData object with estimated standard deviation parameters in
slot sdcoef.
Karsten Tabelow tabelow@wias-berlin.de
J\"org Polzehl polzehl@wias-berlin.de