Determines the denoiser that the Progressive Lightmapper applies to direct lighting. (Editor only).
Use denoising to remove visual noise from your lightmaps. Denoising can reduce the number of samples needed to achieve smooth lightmapped results. It can also avoid artifacts such as light leaking and detail loss which are associated with aggressive filtering.
This setting affects lightmaps generated by the Baked Global Illumination system. It only applies to the the Progressive Lightmapper.
When Unity serializes this LightingSettings object as a Lighting Settings Asset, this property corresponds to the Direct Denoiser property in the Lighting Settings Asset Inspector.
Additional resources: Lighting Settings Asset, DenoiserType.