R/threeStage.r

In DRIP: Discontinuous Regression and Image Processing

# This is R source code for function 'threeStage', in the
# R package "image".
# Date: May 7, 2013
# Creator: Yicheng Kang

threeStage = function(image, bandwidth, edge1, edge2, 
  blur = FALSE, plot = FALSE){
  if (!is.matrix(image))
    stop("image data must be a matrix")
  else n1 = dim(image)[1]
       n2 = dim(image)[2]
  if (n1 != n2)
    stop("image data must be a square matrix")
  if (!is.numeric(bandwidth))
    stop("bandwidth must be numeric")
  if (length(bandwidth) > 1) {
    stop('bandwidth must be a positive integer')
  }
  if (n1 + 2 * bandwidth + 2 > 600)
    stop("some choice of bandwidth or the resolution of the
image is too large")
  n1 = dim(image)[1]
  z = matrix(as.double(image), ncol = n1)
  k = as.integer(bandwidth)
  edge1 = matrix(as.integer(edge1), ncol = n1)
  edge2 = matrix(as.integer(edge2), ncol = n1)
  if (blur == TRUE) {
    out = .Fortran('deblur_3stage', n = as.integer(n1 - 1),
      obsImg = z, bandwidth = k, edge1 = edge1, edge2 = edge2,
      estImg = z)
  }
  else {
    out = .Fortran('denoise_3stage', n = as.integer(n1 - 1),
      obsImg = z, bandwidth = k, edge1 = edge1, edge2 = edge2,
      estImg = z)
  }

  if (plot == FALSE) {
    return(out$estImg)
  }
  else { x = seq(0, 1, length = n1); y = x
         image(x, y, out$estImg, zlim = c(0, 255),
               col = gray((0:255)/255))
         return(out$estImg)
       }
}