dtiTensor {dti} | R Documentation |
generic function that estimates, in each voxel, the diffusion tensor from
the DWI data contained in an object of class dtiData
.
dtiTensor(object, ...)
object |
object of class dtiData |
... |
Additional arguments specifying the model
model=="linear" estimates are obtained using a linearization of the tensor model. This was the estimate used in Tabelow et.al. (2008). model=="nonlinear" uses a
nonlinear regression model with reparametrization that ensures the tensor to be positive semidefinite, see Koay et.al. (2006).varmethod=="replicates" the error variance is estimated from replicated
gradient directions if possible. Otherwise an estimate is obtained from the residual sum of squares.varmodel=="global" a homogeneous variance estimate is assumed and estimated as the median of the local variance estimates. |
an object of class dtiTensor
.
Karsten Tabelow tabelow@wias-berlin.de, Joerg Polzehl polzehl@wias-berlin.de
K. Tabelow, J. Polzehl, H.U. Voss, and V. Spokoiny. Diffusion Tensor Imaging: Structural adaptive smoothing, NeuroImage 39(4), 1763-1773 (2008).
C.G. Koay, J.D. Carew, A.L. Alexander, P.J. Basser and M.E. Meyerand. Investigation of Anomalous Estimates of Tensor-Derived Quantities in Diffusion Tensor Imaging, Magnetic Resonance in medicine, 2006, 55, 930-936.
http://www.wias-berlin.de/projects/matheon_a3/
dtiData
, dtiIndices
, medinria2tensor
, tensor2medinria
, dtiData
, dtiIndices
## Not run: demo(dti_art)