CommonestFilter

CommonestFilter[image, r]
transforms image by replacing each pixel with the most common pixel value in its range r neighborhood.

CommonestFilter[data, r]
applies commonest filtering to an array of data.

CommonestFilter[image, r] computes the commonest value in (2r+1)×(2r+1) blocks centered on each pixel.

CommonestFilter[image, {r₁, r₂}] uses neighborhoods with vertical range r₁ and horizontal range r₂.

In CommonestFilter[data, ...], data can be an array of any rank, and can contain symbolic as well as numerical entries.

Replacing each pixel with the most common color in its neighborhood creates a posterization effect:

Apply commonest filtering to a vector of numbers: