Original Publication Date: 1986-Nov-01
Included in the Prior Art Database: 2005-Mar-09
This article describes a processing technique for categorizing scanned gray scale information from a mixed format document as either line copy (LC) or nonline copy (NLC) information. This information can then be passed to an appropriate discriminator (thresholder) for processing. Scanning divides the document into picture elements (pels) to which a video (brightness) value (V) is assigned. For each pel resulting from the scan, a pair of simulated defocused pels are generated. The defocused pels are, respectively, horizontally and vertically weighted averages of the original pel value with its neighboring pels. A gradient is computed for each pel in the two sets of simulated data. An overall gradient for each pel is formed by taking the difference of the two gradients.