This function does the opposite to decomposeAffine, building
up an affine matrix from its components. It can be useful for testing, or
for rescaling images.
buildAffine(translation = c(0, 0, 0), scales = c(1, 1, 1), skews = c(0,
0, 0), angles = c(0, 0, 0), source = NULL, target = NULL,
anchor = c("none", "origin", "centre", "center"))A 4x4 affine matrix representing the composite transformation. Note that NiftyReg affines logically transform backwards, from target to source space, so the matrix may be the inverse of what is expected.
Translations along each axis, in pixunits
units. May also be a list, such as that produced by
decomposeAffine, with elements for translation, scales,
skews and angles.
Scale factors along each axis.
Skews in the XY, XZ and YZ planes.
Roll, pitch and yaw rotation angles, in radians. If
source is two-dimensional, a single angle will be interpreted as
being in the plane as expected.
The source image for the transformation (required).
The target image for the transformation. If NULL (the
default), it will be equal to source, or a rescaled version of it
if any of the scales are not 1. In the latter case the scales will
be reset back to 1 to produce the right effect.
The fixed point for the transformation. Setting this parameter
to a value other than "none" will override the translation
parameter, with the final translation set to ensure that the requested
point remains in the same place after transformation.
Jon Clayden <code@clayden.org>
decomposeAffine, isAffine