How is the photoshop cutout filter implemented?

Question

Photoshop has a lot of cool artistic filters, and I\'d love to understand the underlying algorithms.

One algorithm that\'s particularly interesting is the Cutout filter

Answer 1

I'm not sure it could be some kind of cell shading, but it also looks like a median filter with a very big kernel size or which was applied several times.

The edge simplicity/fidelity might be options which help decide whether or not to take in account an adjacent pixel (or one which falls inside the kernel) based on difference of color with the current pixel.