mask_erode.R

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# This file is released under the GNU General Public License, Version 3, GPL-3 #
# Copyright (C) 2021 Yohann Demont                                             #
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# It is part of IFCip package, please cite:                                    #
# -IFCip: An R Package for Imaging Flow Cytometry Image Processing             #
# -YEAR: 2021                                                                  #
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#                     CHU Amiens                                               #
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#' @title Erode Mask
#' @description
#' The erode mask removes the selected number of pixels from all edges of the starting mask.
#' @param msk an object of class `IFC_msk`, the mask matrix.
#' @param n a positive integer corresponding to number of pixels to erode. Default is 1.
#' @return a logical matrix corresponding to the eroded area.
mask_erode <- function(msk, n = 1) {
  assert(msk, cla = "IFC_msk")
  n = as.integer(n); n = n[n>=0]; n = na.omit(n[is.finite(n)])
  assert(n, len=1)
  # TODO check / ask the kernel type used, the number of iteration
  foo = cpp_erode(mat = msk, kernel = make_kernel(size = n, type = "box"))
  ATT = list("IFC_msk", "erode", n, c(nrow(msk), ncol(msk)))
  names(ATT) = c("class", "type", "n", "dim")
  attributes(foo) <- ATT
  return(foo)
}