D59: Unsupervised Perception-based Image Restoration of Semi-transparent Degradation using Lie Group Transformations

Bruni,V., Rossi,E., Vitulano,D.

This paper presents a generalized model for the removal of semi-transparent defects from images of historical or
artistic value. Its main feature is the combination of Lie group transformations with human perception rules that
makes restoration more flexible and adaptive to defects having different physical or mechanical causes. Specifically,
Lie groups allow to define a redundant set of transformations from which it is possible to automatically select the
ones that better invert the physical formation of the defect. Hence, the restoration process consists of an iterative
procedure whose main goal is to reduce defect visual perception. The proposed restoration method has been
successfully tested on original movies and photographs, affected by line-scratches and semi-transparent blotches.