Smoothing

From Nikonians Wiki - FAQs, Photo Glossary, Good Photo Locations, Help

Smoothing, as distinct from noise reduction, refers to the evening out of contrasts which are inherent in the original scene, but which are considered to be displeasing in the final image. Smoothing is almost always applied selectively, or through an adaptive process, because global smoothing simply makes the image blurry or indistinct.

There are three basic approaches to adaptive smoothing

• Some processes select tones such as highlights and apply a gaussian or other blur to them
• Some processes select lines in the image and mask them, applying blur to the rest of the image
• Advanced algorithms identify flesh tones in the image and adaptively smooth them

Additionally, some highly advanced algorithms such as Imagenomic's Portraiture identify flesh tones and then replace uneven areas with textures created from other parts of the image. This is no longer, technically speaking, smoothing, but the implementation of a range of bespoke retouching techniques.