Magnetic reader for bar encoded characters

A magnetic ink character recognition system for reading bar encoded characters, which comprises:

• a. magnetic sensing means for scanning a character to form bipolar sensor responses;
• b. analog processor means in electrical communication with said magnetic sensing means for forming normalized leading and trailing edge waveforms from said sensor responses;
• c. edge detecting means receiving said leading and said trailing edge waveforms for detecting a character stroke signal;
• d. deskew logic means receiving digitized leading edge and trailing edge character stroke signals from said edge detecting means for merging adjacent pulses occurring in a time period less than the time separation of two consecutive leading edges or two consecutive trailing edges of said character;
• e. horizontal location logic means in electrical communication with said deskew logic means for signaling the presence of said character;
• f. error correction means responsive to said horizontal location logic means for repairing missing character stroke edges and missing character strokes in said leading edge and said trailing edge character stroke signals;
• g. recognition means in electrical communication with said error correction means for identifying said character from corrected leading and trailing edge character stroke signals;
• h. pattern simulator means responsive to external stimuli for providing known character pattern waveforms;
• and
• i. input selector means responsive to said pattern simulator means for routing said bipolar sensor responses and said character pattern waveforms to said analog processor means.

A character recognition system for reading bar encoded characters printed in magnetic ink on a document surface, which comprises:

• a. magnetic sensing means for scanning a character and forming bipolar responses indicative of the occurrence of character stroke edges;
• b. edge detecting and digitizing means for detecting a character stroke in said leading edge and said trailing edge components of said responses and for converting the same into digitized character stroke signals;
• c. deskew logic means receiving digitized leading edge and trailing edge character stroke signals from said edge detecting means for merging duplicate edge signals caused by any oblique scanning of said character;
• d. horizontal location logic means in electrical communication with said deskew logic means for signaling the presence of said character;
• e. error correction means in electrical communication with said horizontal location logic means for detecting and repairing missing character stroke edges and missing character strokes in said leading edge and said trailing edge character stroke signals;
• and
• f. character recognition means receiving corrected leading and trailing edge character stroke signals from said error correction means for identifying said character.

A character recognition system for reading bar-spaced encoded characters printed in magnetic ink on a document surface as it passes a reading station which comprises:

• a. magnetic sensing means for scanning a character and forming bipolar responses indicative of the passage of leading and trailing edges of magnetic material on said surface;
• b. edge detecting and digitizing means for detecting a character stroke from leading edge and said trailing edge components of said responses and converting the same into digitized signals;
• c. deskew logic means receiving leading edge and trailing edge digital signals from said edge detecting means for merging duplicate edge signals caused by any oblique scanning of said character;
• d. horizontal location logic means in electrical communication with said deskew logic means for signaling the presence of said character;
• and
• e. character recognition means responsive to said horizontal location logic means and receiving said leading edge and said trailing edge digital signals for identifying said character passing said reading station.

In automatic reading of CMC7 characters as coded by variations in spacing between vertical bars of magnetic material, the method which comprises:

• a. separately sensing all magnetic materials in each of a multiplicity of side-by-side paths spanning the height of said characters and extending the length of the field on which said characters may appear to produce a like multiplicity of analog signals;
• b. summing as a time amplitude function the positive excursions of said signals above a first predetermined amplitude level;
• c. summing as a time amplitude function the negative excursions of said signals above a second predetermined amplitude level;
• d. generating a first train of pulses, one for each peak in the sum of said positive excursions;
• e. generating a second train of pulses, one for each peak in the sum of said negative excursions;
• and
• f. producing signals from said first and second trains representative of leading and trailing edges of bars forming said character for identification of each character in dependence upon said spacing.

A method of identifying magnetic ink bar-space encoded characters, which comprises:

• a. scanning said character to sense changes in magnetic flux as said characters pass a reading station;
• b. rectifying magnetic sensor responses generated during the scanning of said character to form a leading edge waveform and a trailing edge waveform;
• c. normalizing said leading edge waveform and said trailing edge waveform;
• d. signaling the occurrence of a waveform peak in said leading edge and said trailing edge waveforms;
• e. detecting the amplitude of said leading edge and said trailing edge waveforms to select a first pulse width or a second pulse width;
• f. digitizing said leading edge waveform and said trailing edge waveform to form a leading edge digital signal and a trailing edge digital signal;
• g. eliminating pulses in said leading edge digital signal occurring at the time of occurence of a leading edge waveform peak wherever a pulse width is less than said first pulse width;
• h. eliminating pulses in said trailing edge digital signal occurring at the time of occurrence of a trailing edge waveform peak wherever a pulse width is less than said second pulse width;
• i. merging adjacent pulses in said leading edge digital signal occurring within a time period equivalent to the time separation of two consecutive leading edges of said character;
• j. merging adjacent pulses in said trailing edge digital signal occurring within a time period equivalent to the time separation of two consecutive trailing edges of said character;
• k. generating leading edge and trailing edge binary interval data code streams indicative of the time separation between character stroke edges passing said reading station;
• and
• l. forming a first character decision from said leading edge stream and a second character decision from said trailing edge stream.

A character recognition system for reading magnetic ink characters printed in a CMC7 font as they pass a reading station which comprises:

• a. magnetic sensor means for scanning an information field printed on a document surface and forming bipolar analog signals in response to character stroke edges passing through registration with said sensor means;
• b. analog processing means in electrical communication with said sensor means for conditioning and normalizing said analog signals, and forming therefrom leading edge and trailing edge waveforms;
• c. edge detection means in electrical communication with said analog processing means for forming leading edge and trailing edge digital signals accurately indicating the occurrence of a character stroke edge;
• d. skew control means receiving said leading edge and said trailing edge digital signals for eliminating duplicate pulses caused by scanning said information field obliquely;
• e. logic means in electrical communication with said skew control means for generating a character window waveform and synchronizing the occurrence of said leading edge and said trailing edge digital signals with said character window waveform;
• f. edge correction means in electrical communication with said logic means for detecting and correcting for missing character stroke edge signals, and forming leading edge and trailing edge binary coded interval data streams indicative of the time periods between character strokes in said information field;
• g. character stroke correction means in electrical communication with said edge correction means for detecting and repairing missing interval data codes in said data streams and forming therefrom leading edge and trailing edge binary signals;
• and
• h. character decision means receiving said leading edge and said trailing edge binary signals for identifying said characters.