Patent US 4,124,870

A directional biasing method enhances the print quality of coarsely scanned characters. A coarse scanning device produces analog signals that are compressed by encoding common information in a run length coding and encoding at least an edge of the character information according to a grey level indication. The data information is reproduced wherein the grey scale information is decoded to represent a finer print than the picture element scanned. The biasing and placement of the dots is set according to the grey scale of the surrounding picture elements. Eight sums are obtained of various groups of three peripheral picture elements corresponding to eight patterns located symmetrically on both sides of 4 bisecting lines, vertical, horizontal and two 45.degree. lines. A particular matrix of print dot placement is selected according to the largest pattern sum among the eight possible cases. The dots in each matrix are designed to being strongly biased toward the direction of the associated pattern.