Patent GB-893319-A (GB)
Title: Improvements in automatic character recognition devices
Inventor: MYATT EDWARD RONALD
IPC: G06V10/88
Filed: 1960-12-08
Abstract: 893,319. Automatic character reading. STANDARD TELEPHONES & CABLES Ltd. Dec. 8, 1960, No. 42289/60. Class 106 (1). In apparatus for recognising characters on a photographic record of the kind where each character is optically compared with a series of standard character shapes presented in turn at a predetermined position, means are provided for bringing an image of each character in turn into coincidence with the predetermined position so that upon a matching comparison transmission of light is prevented, thereby producing a signal indicating correspondence between the character and one of the standard shapes. For the purpose of centering each character in turn at the predetermined position, the record 5, Fig. 1, and its feeding means are mounted on a rotatable carriage 4. A platform 6 coaxial with carriage 4 and connected to it by a spring 8 is driven slowly and would normally carry the carriage and record with it. A T-shaped arm attached to the carriage cooperates with a magnetic brake so that when coil 10 is energized the carriage is stopped. Light from a lamp 1 passes through the record and is focused through a window 37 in a lighttight box 14 on to the drum 19 which carries the series of standard character shapes 33, 34. As shown in Fig. 2, light passing through the window 37 is transmitted by prisms 15 and 16 to photomultipliers 17, 18. The characters on the record are transparent on a black background. When, by virtue of the rotation of the carriage 4, a character image appears in the window 37 the light is first received by prism 15 past the edge of the drum 19. Further movement brings it on to the drum 19 and the photomultiplier 17 again goes black. It then causes the magnet 10 to energize and lock the carriage 4 with the character approximately in the correct registration position. Each character shape is repeated on the drum a number of times in slightly staggered positions so that one will coincide exactly with the position in which the record character has stopped. At this instant the photomultiplier 18 goes black and the coincidence pulse is obtained which is used to gate out the values of four photocells 22-25 sensing a coded representation of the character at the other end of the drum. The photocell 26 produces a resetting pulse once in each revolution. This releases magnet 10 allowing the carriage to catch up the platform 6 and bring the next character to the comparing position. In another form, instead of interrupting the movement of the record, a mirror 49, Fig. 5, may be caused to rotate as soon as the character image is in the correct position so as to keep it in this position in spite of the continued movement of the record. For this purpose the mirror is pivoted and carries an arm which, when a magnet is energized, is drawn into frictional contact with a rotating disc. The characters on the drum 19 may be arranged in a particular order to avoid false correspondence indications. E.g. the image of a " 7 " falling on a standard " 3 " gives less light and therefore more response than an image of " 3 " falling on a standard " 7." The standard " 7 " is therefore put before the standard " 3 " because a false correspondence signal occurring after a true correspondence signal would be ignored.