Removing Back-to-Front Interference in Documents with Mirror Filtering

Very often documents are written on both sides on translucent paper making visible the ink from one side on the other. This artifact was called “back-to-front interference”. The direct binarization of documents with such interference yields unreadable documents. A mirror transformation to remove such noise was suggested over a decade ago, but there is no record in the literature either on how to implement it or of its effectiveness. This paper proves viable the mirror transformation method for generating high-quality monochromatic images of documents with back-to-front interference.