Einrichtung zum Ablesen von auf einem Schriftzeichenträger befindlichen Schriftzeichen unter Erzeugung von denselben entsprechenden, elektrischen Impulsen

885,710. Automatic character reading. RUFBUCHHALTUNG A.G. Aug. 15, 1960 [Aug. 17, 1959; June 23,1960], No. 28135/60. Class106 (1). In a character recognition apparatus, the image of a moving character 2, Fig. 1, on carrier 3 is caused by lens 5 and rotating four-sided prism 4 to sweep vertically over an apertured mask 6 behind which is a photo-cell 9, a magnetic drum 11 rotating with the prism having on it four groups of timing pulses, thirty-two in each group which are used to sample each vertical scan of the character image made by the photo-cell. The shaft 7 carrying the prism 4 and drum 11 is driven by motor 25 and also carries a worm 16 engaging with a gear 17 actuating rack 23. This is connected to carriage 20 on which the character carrier 3 is mounted so that the character moves past the scanning position. After all the characters have been read the motor 25 reverses to reset the carriage. As shown in Fig. 4 the signals from photo-cell 9 are amplified at 37, clipped at 38 and applied to a gate 36. Clock pulses from the head 13 are amplified at 32, clipped at 33 and differentiated at 34 to produce sampling pulses. The signals at 39 consist of a series of pulses in each scan, the number of which represents the length of the black part in that scan. These signals are passed to recognition circuitry and are also stored on drum 12 to be read off again, e.g. three scans later. The delayed signals are also passed to the recognition circuitry. Instead of delaying the signals in a magnetic drum store, there may be two apertures in the mask and two photo-cells, spaced apart the equivalent of one or more vertical scans.