imrankfilter

J = imrankfilter(I::GMTimage; width::Int=3, height::Int=0, rank=0.5)::GMTimage

Rank order filter.

This defines, for each pixel, a neighborhood of pixels given by a rectangle “centered” on the pixel. This set of width x height pixels has a distribution of values, and if they are sorted in increasing order, we choose the pixel such that rank(wfhf-1) pixels have a lower or equal value and (1-rank)(wfhf-1) pixels have an equal or greater value. In other words, rank=0 returns the minimun, rank=1 returns the maximum in box and rank=0.5 returns the median. Other values return the quantile.

Args

  • I::GMTimage: Input image. This can be a RGB, grayscale or a binary image.

Kwargs

  • width::Int=3: Width of the filter.

  • height::Int: Height of the filter (defaults to width).

  • rank=0.5: Rank.

Returns

A new GMTimage of the same type as I with the filtered image.

Example

using GMT

I = gmtread(TESTSDIR * "assets/small_squares.png");
J = imrankfilter(I, width=10);
grdimage(I, figsize=6)
grdimage!(J, figsize=6, xshift=6, show=true)

See Also

imdilate, imerode, imopen, imclose