1. A character presence detector for detecting the center of a character within a binary data stream, which is divided into scans, of data bits representing background and character information and passing through a memory capable of storing a plurality of said scans, comprising: a first logic means connected to said memory for producing first signals when data bits occupying the same position within adjacent scans of said stream contain character information; a first pattern network responsive to said first signals from said first logic means for signalling when said first signals meet preselected criterion detecting the center of said character across said scans; a second logic means connected to said memory for producing second signals when adjacent data bits within said data stream contain character information; and a second pattern network responsive to said second signals from said second logic means for signalling when said second signals meet preselected criterion detecting the center of said character along said scans.