GB949355A - Automatic character-, character-recognition method - Google Patents

Abstract

949, 355. Automatic character reading. STANDARD TELEPHONES & CABLES Ltd. April 6, 1962 [April 12, 1961], No. 13359/62. Heading G4R. In a system for automatically reading characters the characters are printed as a pattern of striations (Fig, 1) each distinguished by the width, spacing or angle of the lines and they are compared optically with a number of striated screens as 5, Fig. 2 in order to obtain a recognition signal. The movement of the character past its matching screen causes a maximum amplitude signal to be developed in photo-diode 6,the signal having a frequency unique to the character depending on the slope and width of the lines. A frequency responsive circuit is connected between the amplifiers 7 and 8 and only one circuit gives an output. In the form of Fig. 3 the image number "23" on a moving envelope 9 is swept over a series of screens 12 by a rotating polygonal mirror 11. The output of photo-diodes 14 are applied to frequency selective amplifiers 15 and the output signals are applied to threshold circuits there being means in circuit (1) for determining the highest of the serially arriving signals to derive a threshold level. In Fig. 4 the character images are applied to masks 19 mounted on a rotating disc 18 which in effect scan the characters vertically, the record 9 moving horizontally. A single photo-diode 20 receives the light passing through the masks successively. The width and angle of the line forming the characters are adjusted so that only three characteristic frequencies are generated. Marks 27 on the disc are detected by a photo-cell 24 to step a counter 28 and open ten gates 26 in succession. The three selective amplifiers 22 are connected to all the gates and the highest signal produces an output from one of the threshold circuits 23.