The filter is used to reduce noise while preserving edges. It can be used to create a cartoon effect from photorealistic images.
It offers two variations:
1) Classic aka isotropic kuwahara filter: simple and faster computation. Algorithm splits an area around a single pixel in four parts and computes the mean of the region with the lowest standard deviation.
2) Anisotropic Kuwahara filter: improves the classical approach by considering the direction of structures of regions
This patch implements both approaches above as multi-threaded operations for the full-frame and tiled compositor.
Co-authored-by: Sergey Sharybin <sergey@blender.org>
Pull Request: https://projects.blender.org/blender/blender/pulls/107015