Image Number 3 for United States Patent #4793812.
A high resolution hand held scanner is disclosed for use with a character recognizing and voice synthesizing reading machine for the blind or print handicapped people. The components for scanning swaths of printed text from single sheets or bound pages of bound volumes are housed in an elongated, dust-tight carriage. A broad roller is rotatably mounted on one edge of the carriage and a split roller is rotatably mounted on an opposite edge. The roller axes are coplanar and parallel with each other, so that when the carriage is manually moved across a page to be scanned, a window in the carriage floor is maintained a predetermined distance therefrom and the rollers guide the carriage in a substantially straight line without need of guide rails. A strobed LED array provides the illumination for a 1728 element per inch CCD array via a Selfoc.RTM. lens. Each four CCD elements are summed to synthesize over 400 pixels per inch resolution scanning, with each synthesized pixel having increased light gathering ability. A rotary encoder is belt coupled to the split roller to provide speed and scanning direction signals. Circuitry is provided for processing the CCD array output signals in accordance with the rotary encoder signals.