R/convolveImage.R

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

#' convolve one image with another
#'
#' convolves images together
#'
#' @param image antsImage to convolve
#' @param kernelImage antsImage acting as kernel
#' @param crop boolean automatically crops kernelImage
#' @return convimage
#' @author Brian B. Avants
#' @keywords convolve, convolution
#' @examples
#'
#' fi <- antsImageRead(getANTsRData("r16"), 2)
#' convimg <- makeImage(c(3, 3), c(1, 0, 1, 0, -4, 0, 1, 0, 1))
#' convout <- convolveImage(fi, convimg)
#' convimg2 <- makeImage(c(3, 3), c(0, 1, 0, 1, 0, -1, 0, -1, 0))
#' convout2 <- convolveImage(fi, convimg2)
#'
#' @export convolveImage
convolveImage <- function(image, kernelImage, crop = TRUE) {
  if (image@pixeltype != "float" | kernelImage@pixeltype != "float") {
    print(args(convolveImage))
    print("input images must have float pixeltype")
    return(NA)
  }
  if (crop) {
    kernelImageMask <- getMask(kernelImage)
    kernelImage <- cropImage(kernelImage, kernelImageMask)
    kernelImageMask <- cropImage(kernelImageMask, kernelImageMask)
    kernelImage[kernelImageMask == 0] <-
      mean(kernelImage[kernelImageMask == 1])
  }
  outimg <- ANTsRCore::itkConvolveImage(image, kernelImage)
  outimg@components <- as.integer(image@components)
  return(outimg)
}