Removal of bleed-through effect via nonnegative least-correlation

Bleed-through effect is one of the most common degradations in old documents, even in today´s newspapers. This effect must be removed for hancing human and automatic readability. The two images scanned from the recto and verso pages of a document can be treated as a linear combination of clean text images from two sides. In this paper, we introduce a nonnegative least-correlation approach to demix bleed-through text images. Experiments have been conducted on both synthetic and real world images. In synthetic case, our method can recover the source text images exactly. Under real world conditions, our approach also performs well. In addition, our approach is computationally efficient and does not need any postprocessing task.