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Wavelet-based separation of nonlinear show-through and bleed-through image mixtures

Almeida, M. ; Almeida , L.

Neurocomputing Vol. 72, Nº -, pp. 50 - 72, December, 2008.

ISSN (print): 0925-2312
ISSN (online):

Scimago Journal Ranking: 0,51 (in 2008)

Digital Object Identifier: 10.1016/j.neucom.2007.12.048

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This work addresses the separation of the nonlinear real-life mixture of images that occurs when a page of a document is scanned or photographed and the back page shows through. This effect can be due to partial paper transparency (show-through) and/or to bleeding of the ink through the paper (bleed-through). These two causes usually lead to mixtures with different characteristics.

We propose a separation method based on the fact that the high-frequency components of the images are sparse and are stronger on one side of the paper than on the other one. The same properties were already used in nonlinear denoising source separation (DSS). However, we developed significant improvements that allow us to achieve a competitive separation quality by means of a one-shot processing, with no iteration. The method does not require the sources to be independent or the mixture to be invariant, and is suitable for separating mixtures such as those produced by bleed-through, for which we do not have an adequate physical model.