R/imageSimilarity.R

In stnava/ANTsR: ANTs in R: Quantification Tools for Biomedical Images

#' @title imageSimilarity
#' @description measure similarity between two images
#' @param fixed the fixed antsImage
#' @param moving the moving antsImage
#' @param type image metric to calculate
#' \itemize{
#'   \item{MeanSquares}{}
#'   \item{Correlation}{}
#'   \item{ANTSNeighborhoodCorrelation}{}
#'   \item{MattesMutualInformation}{}
#'   \item{JointHistogramMutualInformation}{}
#'   \item{Demons}{}
#' }
#' @param fixed.mask mask for the fixed image
#' @param moving.mask mask for the moving image
#' @param sampling.strategy sampling strategy, default if full sampling
#' \itemize{
#'   \item{none}{Full sampling}
#'   \item{random}{}
#'   \item{regular}{}
#' }
#' @param  nBins the number of bins for histogram metrics
#' @param radius neighborhood radius of ANTSNeighborhoodCorrelation
#' @param sampling.percentage percentage of data to sample when calculating metric
#' @return value of image to image metric
#' @examples
#' x <- antsImageRead(getANTsRData("r16"))
#' y <- antsImageRead(getANTsRData("r30"))
#' metric <- imageSimilarity(x, y, type = "MeanSquares")
#' @export
imageSimilarity <- function(
    fixed, moving,
    type = c(
      "MeanSquares", "MattesMutualInformation",
      "ANTSNeighborhoodCorrelation", "Correlation",
      "Demons", "JointHistogramMutualInformation"
    ),
    fixed.mask = NULL, moving.mask = NULL,
    sampling.strategy = "none",
    sampling.percentage = 1, nBins = 32, radius = 3) {
  type <- match.arg(type)
  metric <- antsrMetricCreate(
    fixed,
    moving,
    type = type,
    fixed.mask = fixed.mask,
    moving.mask = moving.mask,
    sampling.strategy = sampling.strategy,
    sampling.percentage = sampling.percentage,
    nBins = nBins,
    radius = radius
  )

  return(antsrMetricGetValue(metric))
}