Evaluating Methods for Show-through or Bleed-through Cancellation

Abstract: The theme of this paper is show-through andbleed-through cancellation of degraded images or manuscripts.Show-through and bleed-through is when the reverse side of amanuscripts shows/bleeds through to the front side. This canseverely impact readability. Four different cancellation algorithmswas chosen for evaluation. The methods considered areThresholding, ICA and two other methods, herewithin referredto as ’Dubojs’ and ’ISJ4’. ICA is a blind source separationmethod. Dubojs is a more sophisticated thresholding method,while ISJ4 uses statistical methods for estimating parameters ofa show-through model. In this paper, the different algorithms areevaluated on different types of common text degradations. Theauthors found that the most useful methods were ISJ4, Dubojsand ICA, with ISJ4 being the most flexible. Thresholding wasfound to be too simple. Dubojs needs improved segmentationto work properly, but was useful in a particular case of strongbleed-through. ICA was easy to use, but required linear mixturesto work properly.