Method and apparatus for discriminating between characters in character recognition systems
AssigneeOptical Business Machines, Inc.
InventorHarrison B. Lidkea
Life of this patent
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Abstract
Recognition of characters, particularly handwritten characters, is facilitated by examining a character for holes (i.e. non-character portions enclosed by character portions), split characters (i.e. disconnected character segments), overhangs and underhangs (i.e. extensions of character segments to the left or right of other segments). In a specific embodiment a character to be recognized is quantized into a grid of vertical column and horizontal rows and then shifted in parallel by column, serially by row through a recognition mask which examines one row at a time. Results of the examination may be used either as positive character recognition or as pre-recognition exclusionary information to resolve possible ambiguities in conventional recognition processes.
Claims13
In a character recognition system of the type wherein a character fascsimile, in the form of electrical signals, is examined for purposes of identification, said character being superposed on a grid, wherein said electrical signals are binary levels representing respective grid locations in which the presence of a character portion is represented by one binary level and the absence of a character portion is represented by another binary level, said grid locations being arranged in a plurality of vertical columns and horizontal rows, a method for improving character identification reliability comprising the steps of:
- shifting a row at a time of said binary signals into an examination mask in the form of a shift register having as many storage locations as there are binary signals in a row;
- simultaneously examining the entire row of binary signals in said examination mask to determine the left-most and right-most storage locations containing a character portion;
- and
- sequentially interrogating only the grid locations in the examined row which lie between said left-most and right-most storage locations to determine the presence and absence of character portions.
In a character recognition system of the type wherein a character facsimile, in the form of electrical signals, is examined for purposes of identification, said character being superposed on a grid, wherein said electrical signals are binary levels representing respective grid locations in which the presence of a character portion is represented by one binary level and the absence of a character portion is represented by another binary level, said grid locations being arranged in a plurality of vertical columns and horizontal rows, apparatus for improving character identification reliability comprising:
- an examination mask including register means for temporarily storing a number of binary signals at least equal to the number of grid locations in a grid row;
- shift means for shifting a row at a time of said number of binary signals into said examination maskl
- means for simultaneously examining the entire row of binary signals in said examination mask to determine the left-most and right-most grid locations containing a character portion in the examined row;
- means for sequentially interrogating only the grid locations in the examined row which lie between said left-most and right-most grid locations to determine the presence and absence of character portions;
- and
- means responsive to the absence of character portions in a predetermined number of successively interrogated grid locations for storing indicia of a possible hole in the examined row.
In a character recognition system of the type wherein a character facsimile, in the form of electrical signals, is examined for purposes of identification, said character being superposed on a grid, wherein said electrical signals are binary levels representing respective grid locations in which the presence of a character portion is represented by one binary level and the absence of a character portion is represented by another binary level, said grid locations being arranged in a plurality of vertical columns and horizontal rows, apparatus for improving character identification reliability comprising:
- an examination mask including register means for temporarily storing a number of binary signals at least equal to the number of grid locations in a grid row;
- shift means for shifting a row at a time of said number of binary signals into said examination mask;
- means for simultaneously examining the entire row of binary signals in said examination mask to determine the left-most and right-most grid locations containing a character portion in the examined row;
- means for sequentially interrogating only the grid locations in the examined row which lie between said left-most and right-most grid locations to determine the presence and absence of character portions;
- means responsive to the presence of character portions in all of the interrogated grid locations for providing and storing a no-hole indication;
- means for storing position data of said left-most and right-most grid locations for each examined row;
- and
- logic means for comparing the stored position data and stored no-hole indications to provide a further indication when said left-most grid location of an examined row having no hole is further left than said left-most grid location of another examined row having no hole in the same character.
In a character recognition system of the type wherein a character facsimile, in the form of electrical signals, is examined for purposes of identification, said character being superposed on a grid, wherein said electrical signals are binary levels representing respective grid locations in which the presence of a character portion is represented by one binary level and the absence of a character portion is represented by another binary level, said grid locations being arranged in a plurality of vertical columns and horizontal rows, apparatus for improving character identication reliability comprising:
- an examination mask including register means for temporarily storing a number of binary signals at least equal to the number of grid locations in a grid row;
- shift means for shifting a row at a time of said number of binary signals into said examination mask;
- means for simultaneously examining the entire row of binary signals in said examination mask to determine the left-most and right-most grid locations containing a character portion in the examined row;
- means for sequentially interrogating only the grid locations in the examined row which lie between said left-most and right-most grid locations to determine the presence and absence of character portions;
- means responsive to the presence of character portions in all of the interrogated grid locations for providing and storing a no-hole indication;
- means for storing position data of said left-most and right-most grid locations for each examined row;
- and
- logic means for comparing the stored position data and stored no-hole indications to provide a further indication when said right-most grid location of am examined row having no hole is further right than said right-most grid location of another examined row having no hole in the same character.
Dependencies are inferred from the claim text.