Patent GB-1062627-A (GB)
Title: Improvements relating to pattern recognition devices
Inventor: LEMAY CHRISTOPHER ARCHIBOLD GO
IPC: G06V10/75
Filed: 1962-11-29
Abstract: 1,062,627. Automatic character reading. ELECTRIC & MUSICAL INDUSTRIES Ltd. Nov. 29, 1963. [Nov. 29, 1962], No. 45106/62. Heading G4R. In a pattern recognition device there are means for recording a plurality of groups of input signals each relating to a particular pattern together with corresponding output signals, a group of input signals relating to an unknown pattern being sequentially compared with the recorded groups, the corresponding output signals being applied to a store when the recorded group of signals matches the unknown group more closely than any previous recorded group, so that the output signal stored at the end of a sequence corresponds to the best match. Recording.-The input signals are applied to terminals (1) (Fig. 1, not shown), and pass through amplifiers (2) and gates (8) to a unit (3) which comprises modulators and demodulators. Signals emerging from this unit (3) are square waves phase modulated so as to be in phase with clock track pulses (T) for a " 1 " and out of phase for " 0." These signals are recorded on magnetic drum (4). Signals recorded on the drum in tracks (A-C) are read, demodulated in unit (3) and applied via amplifier (6) to equality gates (7). Gates (7) compare the signals from amplifiers (6) and from terminals (1) producing an output for coincidence. The outputs from gates (7) are added in a chain of units (9) and the sum applied to a maximum score store (10) which stores the highest number received. When a higher number is received an output passes to unit (11) which in turn resets flip-flops (12) which are then set by the corresponding output signals applied through gates (14) opened by the signal from unit (11) delayed at (40). These output signals are recorded (at M and N) on drum (4) and are applied to gates (14) through delays (15). During the learning operation the corresponding output signals are applied to terminals (16) at the same time as the input group is applied to terminals (1). Also a " learn " signal is applied to terminal (41) which passes to gate (33) and amplifier (22). The output of gate (33) passes to gate (20), the output of which inhibits gate (34) and is also applied directly and delayed to gate (36) and to gate (23) which allows the " learn " signal to be recorded on track (Y). At the same time gate (24) is cut off, preventing the signal from track (Y) being recorded on track (X). The desired output signals on terminals (16) pass through gates (18) to be recorded on tracks (M and N) and are also applied to equality gates (19). Signals from tracks (M and N) pass via delays (15) and gates (14) to flip-flops (12), when rise detector (11) gives a signal. As the input group is recorded it is re-read and compared in gates (7) with the same signals on terminals (1) so that a maximum output is given by adders (9), and unit (11) gives an output causing the signals from tracks (M and N) to be entered in flip-flops (12). The outputs from these flip-flops is fed back to gates (19) and compared with the same signals on terminals (16). Full equality enables all gates (21) thereby inhibiting gate (20). Gate (23) now closes and gate (24) opens so that recording in track (Y) ceases and the signals read from this track can then be recorded in track (X). Also after delay in unit (35) the signals are removed from gates (8 and 18), preventing further recording. The recording in track (X) prevents recording on a part of the drum that is already recorded. The signals from this track inhibit gate (28), thus blocking the enabling signal for gates (8 and 18). The drum makes a full rotation to determine whether the output signals have already been recorded. If they have not, the input and output signals are recorded in the first available part of the drum. Recognition.-A signal group derived from an unknown character is applied to terminals (1) and compared in gates (7) with each stored group. Each successive maximum score is kept in store (10) and produces a signal from rise detector (11) to gate the corresponding output from tracks (M and N) into flip-flop store (12). After a full revolution the outputs on terminals (39) are accepted under the control of a signal on terminal (40) signifying that the second revolution has begun. Instead of being of binary form the signals to be compared could be of analogue form.