R/labelStats.R

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

#' @title labelStats
#' @description Get label statistics from image.
#' @usage labelStats(image, labelImage)
#' @param image Image to calculate statistics from.
#' @param labelImage Label image.
#' @return Data frame with one row per label (including zero) and columns :
#'   LabelValues, Mean, Min, Max, Variance, Count, Volume
#' @examples
#'
#' img <- antsImageRead(getANTsRData("r16"), 2)
#' img <- resampleImage(img, c(64, 64), 1, 0)
#' mask <- getMask(img)
#' segs1 <- kmeansSegmentation(img, 3)
#' labelStats(img, segs1$segmentation)
#' testthat::expect_error(labelStats(img, as.array(segs1$segmentation)))
#' testthat::expect_error(labelStats(img, as.array(segs1$segmentation)))
#' sub_seg <- segs1$segmentation
#' sub_seg <- as.antsImage(sub_seg[1:62, 1:62], reference = sub_seg)
#' testthat::expect_error(labelStats(img, sub_seg))
#'
#' @export
labelStats <- function(image, labelImage) {
  image <- check_ants(image)
  labelImage <- check_ants(labelImage)

  if (!is.antsImage(image) | !is.antsImage(labelImage)) {
    stop("Inputs must be antsImages.")
  }
  if (!all(dim(image) == dim(labelImage))) {
    stop("Images must be the same size.")
  }
  image.float <- antsImageClone(image, "float")
  labelImage.int <- antsImageClone(labelImage, "unsigned int")
  df <- ANTsRCore::labelStats(image.float, labelImage.int)
  df <- df[order(df$LabelValue), ]
  df
}