R: Similarity measures between images

similarity {RNiftyReg} | R Documentation

## Similarity measures between images

### Description

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.

### Usage

    similarity(source, target, targetMask = NULL, interpolation = 3L,
      threads = getOption("RNiftyReg.threads"))

### Arguments

`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.

### Value

A single numeric value representing the similarity between the images.

### Author(s)

Jon Clayden <code@clayden.org>

### See Also

`niftyreg`

[Package RNiftyReg version 2.6.5 Index]