Linear-quadratic blind source separating structure for removing show-through in scanned documents
Digital documents are usually degraded during the scanning process due to the contents of the backside of the scanned manuscript. This is often caused by the show-through effect, i.e. the backside image that interferes with the main front side picture due to the intrinsic transparency of the paper. This phenomenon is one of the degradations that one would like to remove especially in the field of Optical Character Recognition (OCR) or document digitalization which require denoised texts as inputs. In this paper, we first propose a novel and general nonlinear model for canceling the show-through phenomenon. A nonlinear blind source separation algorithm is used for this purpose based on a new recursive and extendible structure. However, the results are restricted due to a blurring effect that appears during the scanning process due to the light transfer function of the paper. Consequently, for improving the results, we introduce a refined separating architecture for simultaneously removing the show-through and blurring effects.
linear-quadratic blind source separation blurring effect show-through reduction