The V-Ray Scanned material applies material information gathered by the Chaos Scans system (https://www.chaos.com/scans) to an object.
The VRscans system captures the appearance of an actual physical material sample, going beyond single-point BRDF capture to faithfully represent the textured appearance of a real-world surface using bidirectional texture function (BTF) approximation. The information is saved in a .vrscan file, which the V-Ray Scanned material then reads to reproduce the material in the rendering.
The VRscans system and V-Ray Scanned material are intended as a solution for users who need to exactly match a given real-world sample.
The Scanned material library would also be available in the Chaos Cosmos asset library after implementation of this material in V-Ray for Blender.
Video of Chaos scans in action
https://www.youtube.com/watch?v=mWk2grehBh0
Submitted on AHA Ideas (VBLENDER-I-34).