Rank filter

Include <mln/morpho/rank_filter.hpp>

template<class Ratio> void rank_filter(Image image, StructuringElement se, BorderManager bm, OutputImage out)

template<class Ratio, Image I> image_concrete_t<I> rank_filter(I image, StructuringElement se, BorderManager bm)

The rank filter is non-linear filter that assigns the 𝑟-th value in a given structuring element 𝐵.

\[g(x) = r(\{ f(y) \in \mathcal{B}_x) \})\]

where r returns the 𝑟-th value of the set of pixels of the structuring element 𝑩 centered in 𝑥.

A border management may be used to manage border side-effects.
If the optional output image is provided, it must be wide enough to store the result (the function does not perform any resizing).

Parameters:

ima – Input image 𝑓
se – Structuring element 𝐵
bm – Border manager policy
output (optional) – Output image

Returns:

1. Nothing (the output image is passed as an argument)
1. An image whose type is deduced from the input image

Exception:

N/A

Notes

Complexity

Example 1 : Rank-filter by a square on a gray-level image

#include <mln/morpho/rank_filter.hpp>
#include <mln/core/se/rect2d.hpp>

// Define a square SE of size 21x21
auto input = ...;
auto rect = mln::se::rect2d(21,21);

using R = std::ratio<1, 2>; // Get the median value
auto output = mln::morpho::rank_filter<R>(input, rect, mln::extension::mirror);