This function calculates a similarity measure between two images, after resampling one into the space of the other. The only supported measure is currently normalised mutual information, which is also used as a cost function by the registration algorithms.
similarity(source, target, targetMask = NULL, interpolation = 3L,
threads = getOption("RNiftyReg.threads"))| source | The source image, in any acceptable form. |
|---|---|
| target | The target image. Must have the same dimensionality as the source image. |
| targetMask | An optional mask image in target space, whose nonzero region will be the area over which the measure is calculated. |
| interpolation | A single integer specifying the type of interpolation to be applied to the source image when resampling it into the space of the target image. May be 0 (nearest neighbour), 1 (trilinear) or 3 (cubic spline). No other values are valid. |
| threads | For OpenMP-capable builds of the package, the maximum number of threads to use. |
A single numeric value representing the similarity between the images.
Jon Clayden <code@clayden.org>