Determining the resolution of scanned document images
Dan S. Bloomberg · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 1999
Given the existence of digital scanners, printers and fax machines, documents can undergo a history of sequential reproductions. One of the most important determiners of the quality of the resulting image is the set of underlying resolutions at which the images were scanned and binarized. In particular, a low resolution scan produces a noticeable degradation of image quality, and produces a set of printed fonts that cause omnifront OCR systems to operate with a relatively high error rate. This error rate can be reduced if the OCR system is trained on text having fax scanner degradations, but this also requires that the OCR system can determine in advance if such degraded fonts are present.