SIGNAL SPECTRUM ANALYSIS BY WALSH FUNCTION AND HADAMARD OPERATIONS

摘要

1400374 Pattern recognition BURROUGHS CORP 6 March 1973 [21 April 1972] 10954/73 Heading G4R A signature is verified by deriving an electrical multi-word digital representation of the signature, performing a Hadamard transformation on the digital representation and comparing the transformed representation with a prerecorded representation of the signature. In Fig. 2, optical or handwriting pressure signals are periodically sampled and converted into a 10 bit parallel binary code 30 and each coded sample is added to or subtracted from the accumulated results obtained from the previous samples which are circulated from the output 40 of an add/subtract circuit 32 through shift registers 36 and a buffer store 38, each sample being operated on 64 times to build up for the complete signature a family of 64 Walsh functions. The Hadamard operators are fed to the add/subtract circuit 32 from a recirculating store 34. The final result is read out from the shift registers 36 to a comparator receiving reference signals from a permanent store or from magnetically recorded data on a credit card.